Why can some animals live in fresh and saltwater? 

Why can some animals live in fresh and saltwater?

Fish that break all the rules by living in the Ocean and streams: 

Look into a river and you will find very different animals to the Ocean, even if they are just a few miles apart. Why are these wet worlds so different? In short – it is all about osmoregulation (explained below). 

Whether you live in the Ocean, in a river, on a mountain or in Thneedville (yes, that’s a Lorax movie reference) – everywhere has its challenges. One of the main challenges of living in saltwater (read more about why the Ocean is salty here) is maintaining the balance of water in an animal’s cells.

What is osmosis?
Water will travel from areas of high concentration to low concentration in an attempt to balance them (this is called osmosis). Salty water has lower water concentration than freshwater. 

Join us to explore the difficulties of swimming between the two worlds, some of the incredible journeys of the fish, like salmon, eels and bull sharks, that overcome them and crown the winner of the wet.  

What is osmoregulation? 

All living things need water, and they need salts. Maintaining the balance of both is tricky – too much or too little of either is fatal.  

Imagine a balloon full of water, but this balloon can let water in and out of it. This is our cell. The water in the balloon (our cell) has a little bit of salt in.  

If you put the balloon in a bucket of freshwater, water enters the balloon (by osmosis) to balance the concentration. This could end up bursting the balloon. Alternatively, putting the balloon in salty water will lead to the water leaving the balloon, shrivelling it.   

Osmoregulation explained by Ocean Generation.

Animals living in these environments have to adapt to avoid bursting or shrivelling – neither sound particularly fun.

Fish living in freshwater have to hold on to their salts and avoid water intake. Saltwater fish take in as much water as they can and excrete the extra salts.  

How do freshwater and saltwater fish stay hydrated AKA: do fish drink the water they live in? 

To maintain a good balance of water and salt, fish in different environments alter their drinking, gill function, kidneys and excretion (waste removal).  

Marine fish will constantly drink sea water, getting as much water in as possible. They actively remove salt from the water through cells in their gills. The pee of marine fish is highly concentrated urine (if you get dehydrated, your body does the same – your pee will be very yellow, with little water diluting it), minimising water loss.  

Freshwater fish, on the other hand, don’t drink water. They don’t need to. Think of the balloon example – they are saltier on the inside, so water wants to move in. Freshwater fish easily absorb water through their gills. They use energy to pump salts in, against the concentration gradient – they actively ingest salts. Their pee is very diluted, ensuring they don’t become swamped by discarding lots of water.  

How do fish stay hydrated? Explained by Ocean Generation.

Why can’t freshwater fish live in the Ocean?  

Knowing all that, let’s see what would happen now if we put a marine fish in freshwater. A marine fish wants to lose salt from its body and keep water. Think of the balloon – a marine fish invites water in, pushing salt out. This means the balloon will lose all its salts and get over filled with water. That is one unhappy fish.  

For a freshwater fish in the Ocean, the opposite happens. Used to a world with plenty of water and little salts, the balloon will shrivel as it is filled with more salts and loses water. The bottom line is the same – an unhappy fish.  

Are there fish that can live in both freshwater and salt environments? 

Amazingly, yes. There are examples of fish that can live in both marine and freshwater all over the world. There are two main types.  

  1. Anadromous fish are born in freshwater, spend most of their lives in the Ocean and then return to freshwater to spawn.  
  2. Catadromous fish live in freshwater most of their lives, returning to the Ocean to spawn. 

We will explore these groups through a couple of their most famous members, as well as a shark that makes it all look easy.  

Some fish live both in fresh and saltwater environments. Posted by Ocean Generation, leaders in Ocean education.
European eel photo by GerardM

How do salmon survive in both fresh and salt water 

Salmon are incredible fish.  

Not all salmon are anadromous: there are Atlantic salmon in North America called sebago, named after one of the lakes they are found in. More Atlantic salmon live in Norwegian, Swedish and Russian lakes; and yamame are a landlocked Japanese masu salmon.  

But some salmon travel thousands of miles between fresh and salt water over the course of their lives.

Chum salmon have been estimated to complete total migrations of over 10,000km (6,200 miles) across the North Pacific from feeding grounds to the Yukon river or streams in Japan.  

Anadromy appears to have evolved at a similar time that the Ocean cooled and became richer in food. This, coupled with the existence of landlocked variations, suggest that salmon were a freshwater fish that took to the sea, although this is not confirmed. What is certain is the incredible journeys and transformations many salmon go through to mate. 

For salmon, the movement from river to Ocean and back to river is integral to their life cycle.

The first few years of a salmon’s life are spent growing in the river, before they go to the food-rich Ocean. Here they gorge themselves, growing very quickly. After travelling many thousands of Ocean miles, they will return to the rivers they were hatched in, to spawn themselves.  

But how do they manage to conquer both environments?  

Through hormonal changes, salmon make behavioural and physiological changes to the ways they manage their osmotic balance. In freshwater, they won’t drink water – when in salt water they will drink a lot. Hormones change the fish’s physiology, increasing the number of ion transporters in the gills and kidneys to process the salt balance.  

The change is a costly one though, as salmon won’t feed during their return to freshwater, relying on fat reserves built up through years in the Ocean. They battle up their rivers, overcoming waterfalls, predators waiting on the banks and their own failing bodies to reach the same spot they hatched in. Here, they will spawn.  

For most of these fish, it is the last thing they do.  

Salmon move from river to Ocean and back.

What can salmon teach us? 

Just as rivers are the connection between us and the Ocean, salmon are among the clearest species to bridge that gap. And they feel the impact of people more keenly. Rivers are the frontlines, and salmon are in the trenches.  

Salmon rivers are best in old forests, as the tree roots hold the banks together and keep the rivers form – holding it narrow and fast flowing. Where forests are lost, the river can widen and the salmon population diminishes. And as we build dams to harness the power of the rivers, we block the salmon from getting home.  

The populations of salmon in different rivers show far more genetic variation than between people. Each salmon is genetically coded for its river home. Climate change, pollution, human development and fishing – salmon deal with a lot.  

But their adaptability is shown time and again. The genetic diversity they show allows them to overcome the challenges they face. Just as they are able to thrive in these two different worlds, they can take on the new world we are shaping.  

What do you call returning to the Ocean to reproduce? 

Catadromy is the mirror of salmon – starting life in the Ocean, living in freshwater and returning to the salt to spawn.  

European eels begin life as eggs riding Ocean currents, drifting through the Sargasso Sea near the Bahamas. They hatch into small, transparent, leaf-shaped larvae called leptocephali. Like so many (hungry, well-teethed) leaves in the wind, the Ocean carries the eels to the coasts of Europe, a journey taking 2-3 years.  

On reaching the coast, they metamorphose (change body shape) into glass eels – still small and see-through but eel-shaped. After up to a year, they change again into elvers (juvenile eels) and begin to travel up rivers. Here, they change again into yellow eels and can remain in freshwater for up to 20 years until they reach sexual maturity. 

This means an eel can be 23 years old before reproducing. When their time comes, they become silver eels, migrating down rivers towards the Ocean.  

European eels also switch between freshwater and the Ocean
Artwork by A. Cresci via nature.com

How do eels switch between living in fresh and saltwater? 

For the elvers and glass eels, they need to do the same as our salmon. They alter the salt uptake of their gills via specialised cells, increasing it in freshwater and decreasing in saltwater.

For many years, European eels were characterised by mystery. They were well known in the rivers of Europe, yet no one could find baby eels. Greek philosopher Aristotle suggested that they just appeared out of the mud, and this was the general belief for almost 2,000 years.  

It was Johannes Schmidt, a Danish biologist working in the early 20th century, who began to unveil the elusive eels. By finding progressively smaller eels across the Ocean, he followed the trail of breadcrumbs to the Sargasso Sea. He couldn’t find any spawning, but he drew the metaphorical arrow.  

It wasn’t until 2022 that we found the first direct evidence of adult European eels travelling to and reaching the Sargasso Sea. This study also shows us just how far the eels travel – up to 8,000km. If you’re ever lucky enough to see one of these eels, appreciate just how far it has come, and how far it still has to go.

The eels adapt twice, changing their whole bodies to swap salt for fresh and back. On the way back, the silver eels don’t feed. As with salmon, they rely on fat reserves for their journey, and their bodies slowly disintegrate, and once they have reached their spot, they reproduce and then die.  

But the switch doesn’t always have such dire consequences.  

European eel design on our sustainable apparel.
European eel design on our sustainable apparel – coming soon to our store. Every purchase supports our charity.

Are bull sharks the best sea-swappers? 

Yes. Bull sharks (Carcharhinus leucas) are the aquatic conquerors supreme. As we have seen, moving between fresh and salt water is tough. Most salmon only do it once, some can manage it a couple of times, their bodies failing them under the stress. Eels change their whole bodies when they make the switch. Yet bull sharks can move between fresh and saltwater with apparent ease.  

They have been found in unexpected places. In Africa, bull sharks are known as Zambezi sharks as they are found deep into the Zambezi river. They were initially described as a different species* – because no one expected a bull shark there. In Brisbane a bull shark was spotted swimming the streets after flooding in 2011, and they have been to Baghdad up the Tigris. They have even been found in Alton, Illinois, 2,800 km (1,740 miles) from the Gulf of Mexico.   

The ultimate tourist? A bull shark was reported in the upper reaches of the Amazon, in the Ucayali River, Peru. Nearly 5,080 km (3,157 miles) from the Ocean.  

How do bull sharks do it? 

Ready for some high-density science?  

They change how salty they are (in the balloon). In the Ocean, bull sharks’ blood is at least as salty as the water they are in due to the levels of urea and trimethylamine oxide (TMAO). But when in freshwater they excrete much more urea, lowering the salt concentration of their blood to minimise the gradient (the difference in saltiness).  

However, they are still more salty than freshwater, so they absorb water and lose salts through their gills. They change their salt and water processing to match their environment.  All sharks have rectal glands through which they excrete excess salt when in the Ocean. When in freshwater, bull sharks reduce the activity of their rectal gland (which normally gets rid of all the extra salt a shark absorbs when in the Ocean) to preserve salts. The kidneys of bull sharks in freshwater go into overdrive, producing large amounts of dilute urine to avoid the balloon-popping scenario. Both the kidneys and the gills are triggered to actively uptake salts, while the liver changes urea production

On top of all this, bull sharks have to deal with the different densities of salt and freshwater. As anyone who has visited the Dead Sea will tell you, more salt = floaty. So, bull sharks in freshwater reduce the densities of their livers to counter their reduced floaty-ness. Still, living in freshwater really does drag them down, which may be why they still mostly prefer the Ocean (can’t say we blame them).  

Bull sharks move between freshwater and saltwater. Explained by Ocean Generation, leaders in Ocean education.

Why do these species matter? 

These fish, as with our rivers, are great connectors. Their journeys are important to all those they encounter. By travelling between the separate biomes, they transport nutrients and link ecosystems, strengthening them.  

They are used as indicators of water quality and ecosystem health and provide food sources. Something harder to measure is their cultural importance, which resonates through many different social histories – they bring us closer together as well.

The challenges of moving between the Ocean and its fresh-water fingers are staggering. Yet these fish tackle it head on.  

Which do you find more impressive; the salmon battling bears and waterfalls to return to its river home; eel larvae drifting thousands of miles and swimming back, changing their whole body to tackle each step; or the bull shark that is just at home in the heart of the Amazon as a reef in the Indian Ocean?

From the legend of the salmon to the mystery of the eels to the euryhaline hero the bull shark, these fish are truly conquerors of the coast.  

Book recommendations from our Marine Scientist 

When I am writing my articles, I use a variety of sources. One of the most engaging are the books. Here are a few I used for this article, do let us know if you have a read, and watch out for more recommendations.  

Blowfish’s Oceanopedia 

Salmon by Mark Kurlansky

Sharks of the World  

Additional sources:
*Peters, W. C. H (1852): Hr. Peter legte einige neue Säugethiere und Flussfische aus Mossambique vor. – Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königlich Preussischen Akademie der Wissenschaften zu Berlin. Aus dem Jahre 1852. Berlin, pp. 273–276. (not available online)

Why are rivers important?

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Why are rivers important?

Why are rivers important? Posted by Ocean Generation.

From the creek whispering through a forest, to the confusion of huge currents twisting against each other in the channel. Rivers take on many forms. They are the direct connection between us and the Ocean but why are rivers important?  

Read about the wider water cycle and how rivers fit into it here

Why are rivers amazing? What is an estuary? And what are the threats to these wet wonders? 

What are rivers 

Let’s start with a quick definition. Rivers are large, natural flowing streams of water. They have banks on either side, they have a source and a mouth. They meander through every continent, from a few kilometres to thousands long.  

Which is the biggest river?  

What does ‘biggest’ mean? Let us start with length, and to answer that, let us start with another question: where do rivers start? Finding where a river begins is notoriously difficult.  

It’s tricky to work out where that first drop comes from. Some rivers begin from a lake or a melting glacier. Others, like the Danube in Europe, start from a spring (water bubbling out of the ground). 

River origin leads to debates over which the longest river is – the Nile or the Amazon 

The Guinness Book of World Records gives the award to the Nile but does concede “which is longer is more a matter of definition than simple measurement”.  

The Nile, in Africa, has been estimated as great as 7,088 km (4,404 miles) in length, and the same paper puts the Amazon, in South America, at 6,575km (4,085 miles). 

However, a quick search will reveal some debate. 6,650 km (4,132 miles) is more commonly quoted for the Nile, and 6,400 km (3,976 miles) for the Amazon. 

Explorers are always trying to prove otherwise, measuring in a different way, from a different point, to a different point. 
We are #TeamNile.

Next, there is the deepest river in the world: the river Congo.  

It reaches depths of 220m. That is about as deep as the world record for SCUBA diving. By that depth there is little light, and the pressure from the water above is equivalent to having three adult orcas lying on top of you.  

The Amazon stands alone in the amount of water it gathers.  

Once rivers start their journey, they gather in momentum on their mission back to the Ocean. More precipitation and groundwater help fuel their flow, and other streams, known as tributaries, join it along the way.   

Approximately 209,000m^3/s of water enters the Atlantic from the Amazon. This is equivalent to almost 20% of the total global river discharge, the total volume of water rivers release into the Ocean.  

The Amazon is more than the Nile, the Mississippi, in the USA, and the Chang Jiang (Yangtze), in Asia, combined. The brown waters can be seen as far as 100km (62 miles) out to sea, which provided an important navigation tool for sailors hundreds of years ago.  

The biggest rivers on Earth, posted by Ocean Generation.

Where are estuaries? 

Where the river reaches the Ocean, the interface is an estuary. They usually have a mix of fresh and salty water, known as brackish (there are some examples of freshwater estuaries in the Great Lakes of North America). 

Estuaries are highly productive, unique ecosystems. For many different animals they provide food, places to breed, nursery grounds and hosting migratory species.  

But why do rivers matter? 

Rivers are important, as fresh water is key to all life. Rivers have influenced our world historically, geologically and culturally. They support life where it would otherwise be unviable, on land and in the Ocean. They are the ultimate connector. 

Approximately 40 trillion cubic metres of water enters the Ocean from rivers every year. But it doesn’t come alone.  

As water moves over the land, it picks up hitchhikers (such as ions, making the sea salty – see more here). Material dissolves into the river, or the water pulls it along. These can lend colour to the river waters (and often their names). 

There is the Rio Negro in Brazil, named due to the humic acid from decomposing vegetation colouring the water black. The Red Rivers in Peru and North America, from the small pieces of rock containing iron oxides. The Drina in central Europe is green due to the limestone it flows over and the Hwang Ho (Yellow River) in China is named so because of the loess (a type of soil or sediment) it carries. 

They do more than just look good; these multicoloured masses are changing the world. 

Freshwater is key to all life on Earth. Posted by Ocean Generation.

How do rivers change the world? 

Flowing over rocks, mud and sand, each particle that the waters pick up change the course of the river and the shape of the land. Look around where you live, you can usually find the fingerprints of water at work.  

Rivers can cut away land and form new land, depositing the sediment it has picked up on the bank or in deltas where they meet the Ocean.  

The Colorado River, in North America, has produced the most remarkable example, carving away the landscape to produce the Grand Canyon, while the Nile Delta shows us how rivers build land too.  

The waters are full of nutrients, iron, nitrates and other essential building blocks for life. When these enter the Ocean, life flourishes.  

How are rivers and estuaries important for us? 

Rivers are incredibly important for one species in particular: us.  

The first great civilisations all rose up on rivers. The Nile, the Indus, the Tigris and Euphrates and the Huang all supported some of the earliest great cities in human history. Think of a big city – if it isn’t on the coast, we bet it is on a river. 

Rivers provide food: the last two very long uninterrupted rivers in Southeast Asia, the Irrawaddy and Salween, provide 1.2 million tonnes of catch annually and support agriculture of over 30 million people. In the US, approximately 68% of the commercial fish caught were caught in estuaries. 

The water rivers carry is crucial for drinking, domestic use and agriculture. More recently, we use it for power and industry, and transport.  

Rivers have held a central place in culture as well, connecting us and our world metaphysically.  

The Whanganui river in New Zealand has been regarded as an ancestor by the Māori people for centuries, and the Ganges is upheld as a place of healing and purity, personified by the goddess Ganga. In Japan, Shinto beliefs hold that each river has its own divine guardian, the Kawa-no-Kami.  

Across many different cultures, rivers have been celebrated and protected.  

Why do rivers matter? Posted by Ocean Generation, leaders in Ocean education.

What are the threats to the rivers? 

As much as rivers have impacted human civilisation, we have had our impact on them.  

Changes to our water cycle due to climate change have reduced the resilience of our rivers as they experience larger variations in flow. Add that to pollution, developing on their banks, extracting their flora and fauna and even stopping their flow – rivers have had it tough. 

In order to harness the power of our rivers, we have been interrupting their flow. Just 23% of rivers over 1000km long flow uninterrupted into the Ocean, broken up by an estimated 2.8 million dams. 

The water rivers carry is crucial

How does pollution affect rivers? 

It is important to realise there are lots of different types of pollution. The first and most obvious is big pollution – plastic, waste, shopping trolleys – that kind of thing. This rubbish can damage the life in the river itself, spoil the water for use and clog and disrupt the water flow.

The other kind of pollution is the small stuff – chemicals, microplastics and pharmaceuticals. These can disrupt aquatic wildlife, make the water unsafe to drink and accumulate through the food chain.  

The Ganges, in India, is now a stark example of river pollution. In Hinduism, the river is personified as the goddess Ganga, the goddess of purity.   

Just 37% of sewage is treated before entering the river. The banks are lined with tanneries, slaughterhouses, textile mills, chemical plants and hospitals. The waste that fills the river has an estimated 66% occurrence of waterborne disease and contains super-bacteria resistant to antibiotics.  

How are estuaries under threat? 

Estuaries face many of the same threats as rivers. An estimated 55% of global wetland areas has been lost since 1900, due to developing coastal areas. These wetlands provide unique habitats for their inhabitants, who often are not suited to either the freshwater or marine environments.  

We also benefit from the carbon dioxide absorption, offsetting our emissions, and the reduction in the risks of flooding and coastal erosion. 

But we are poisoning them too. Chemicals – pesticides and fertilisers – used in agriculture, are washed into rivers and accumulate in estuaries. This leads to nutrient overloading, or eutrophication, with harmful algal blooms appearing. When these die, the decomposition uses up the oxygen in the water – impacting the animals living there.

Estuaries absorb carbon dioxide. Posted by Ocean Generation

How can we look after our rivers? 

Everything is connected, which means you can make a difference from anywhere. Simply being aware of the connection you have with the Ocean is an important step. You can look after it, wherever you are.

Rivers connect us directly to the Ocean. A hot take? All life is essentially marine – everything is connected to and dependent on the Ocean. 

Along with estuaries, they provide important habitats, give us the water we need to survive and bring us closer together through transport and culture. But they are threatened in our new world. As ever, being aware is such a crucial first step to solving any issue.  

Educate others:  

  • Share information about river conservation and encourage others to take action. 
  • Engage in local initiatives that promote sustainable water management practices. 

Join community and advocacy events:

  • Participate in local river clean-up events to help maintain waterways and raise awareness 

Advocate for sustainable practices:

  • Support policies that protect rivers from pollution and over-abstraction 
  • Promote low-impact renewable energy to preserve free-flowing rivers 
  • Be aware of what you use. Harsh chemicals for cleaning and gardening will eventually enter our Ocean. Check your shampoo for harmful chemicals and microplastics. 

Next time you are by a river, take a moment. That is a direct line to the Ocean. See if you can understand the connection humans have felt with rivers throughout our history. Wonder at the power and beauty. Appreciate the importance of our rivers.  

You can make a difference from anywhere.

Why are rivers important?

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What is the water cycle?

Why there is no water cycle without the Ocean.

Our planet is known as the blue planet, over 70% of it is covered in water, most of which is the Ocean.

This water shapes our landscapes, influences where life thrives, affects the health of our Ocean and the weather in our skies. 

The Ocean is always closer than you may think (not in a sinister, about-to-jump-out-at-you way. It’s more of a realising-it-is-Thursday-and-the-weekend-is-only-round-the-corner-kind-of-way). 

Take a moment, think: what is different from the water you drank this morning (if you haven’t had any, this is your reminder to drink some) and the water lapping up a warm tropical beach? Every drop of water, from what’s come out of your tap to the water five kilometres deep in the middle of the Pacific, is connected.   

It is all just at different points in the water cycle. 

How does the water cycle work? 

There are four processes that drive the water cycle: evaporation, transpiration, condensation and precipitation.  

How does the water cycle work? Explained by Ocean Generation.

Water is warmed and evaporates, becoming water vapour. Amongst the many good things plants do, they release water into the atmosphere through transpiration. These two processes are responsible for putting water vapour in our air, our atmosphere.  

Water vapour is invisible.  

The steam we see when we boil the kettle (or the clouds in the sky) is water becoming liquid again, on contact with the cooler air. That is condensation, the transition back from gas to liquid. When enough of this cloud cools and turns to water, it will clump together and fall as precipitation (snow, hail and rain).  

How is the Ocean connected to the water cycle? 

This water then starts its journey back to the centrepiece of the cycle: the Ocean. 

The Ocean holds 97% of the Earth’s water – approximately 1.34 billion cubic kilometres. 86% of evaporation is from the Ocean, and 78% of precipitation re-enters the Ocean, directly. You can’t have the water cycle without the Ocean. 

Ice holds 2% of global water and just 0.001% is in the atmosphere – that is all the clouds in the sky.  

But if we add all that up, there’s a little still on the table – or more accurately, on land. That is the groundwater, lakes, swamps and the rivers. Rivers make up only 0.0002% of the total water on Earth.

The Ocean holds 97 percent of water. Posted by Ocean Generation, leaders of Ocean education.

What does the water cycle do? Why is it important? 

There are five main points of importance for the water cycle: 

1. Regulating Climate:  
The water cycle helps distribute heat around the globe, influencing weather patterns and climate conditions. It absorbs and releases energy during evaporation and condensation, which affects temperature and weather. 

2. Sustaining Ecosystems:
The water cycle provides the water necessary for plant growth and supports all forms of life by delivering freshwater to ecosystems through precipitation.

3. Shaping Landscapes:  
The water cycle contributes to erosion and sedimentation, reshaping geological features over time. 

4. Circulating Minerals and Nutrients:
Water transports minerals across the globe, enriching sea and soil and supporting plant life. 

5. Maintaining Freshwater Supplies:
The cycle replenishes freshwater sources, such as rivers and lakes, which are essential for human consumption and agriculture. 

Imagine a world without a water cycle – what would it look like?  

Why is the water cycle important? Explained by Ocean Generation.

How is the water cycle changing 

Human activity is interfering with the hydraulic cycle at every stage.  

Deforestation means less trees to transpire and absorb rainfall. Urbanisation interrupts drainage and can increase surface runoff. When it rains, the water that would have been absorbed by the ground now hits tarmac and runs down the road. 

The single greatest threat to the water cycle, and therefore to all life on Earth, is climate change.  

How is climate change impacting the water cycle?  

Climate change is intensifying the hydraulic cycle. Higher temperatures lead to more evaporation, more water vapour in the atmosphere, which results in more intense storms and rainfall. At the same time, droughts are becoming harder to predict and more severe.

These changes directly threaten our lives. 

Water related events from 2024
2024 Summary Report – Global Water Monitor

Water is the life blood of our planet, and the water cycle is the pulse that keeps it alive. 

The hydraulic cycle regulates our climate, fertilises and maintains our ecosystems and shapes our world. We are changing it through our actions and activities.  

Understanding this cycle is the first step, but acting to protect it is the most important. The question is: what will we do to safeguard the blue heart of our planet? 

Why are rivers important?

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Why is the Ocean salty?

Why is the Ocean salty? Explained by Ocean Generation

Everyone knows the Ocean is salty. But how did it get salty? Where did the salt come from? Is it getting more salty?  

These are all great questions to bring up as you ask for the salt over dinner. And after this explainer, you can answer them.  

Why is the Ocean salty: Explained 

Imagine a bowl. Now pour some slightly salty water into the bowl and put it into the sun on a hot day. Eventually, the water will evaporate, leaving that little bit of salt behind.  

Now, add some more slightly salty water to the bowl. The left-behind salt dissolves and mixes, making saltier water. Leave it in the sun again, the water will evaporate and leave salt behind. If you now attach a constant stream of slightly salty water into the bowl, you have a little model of our Ocean.  

Just like in the above example, rivers (the stream) bring tiny amounts of salt into the Ocean (the bowl) and the sun evaporates the water, leaving behind the salt. These amounts have built up over huge periods of time.  

Why is the Ocean salty: Explained by Ocean Generation

Where does the salt in the Ocean come from? 

Most of the salt in our Ocean comes from rocks on land. Carbon dioxide in the atmosphere dissolves into rainwater, making it slightly acidic. When it rains, this slightly acidic water can dissolve the rocks it falls on and over, in the form of ions (charged molecules).  

These ions, mostly sodium and chloride, are carried into rivers, which carry them into the Ocean.  

Some salt also comes from volcanic activity, where elements from the Earth’s core can be released into the Ocean through underwater volcanoes and hydrothermal vents.  

Why aren’t rivers salty? 

Rivers are, very slightly salty. Depending on what the water has run over on its journey (rocks, decomposing plants, your ex’s belongings etc.), the contents of each river, including salt levels, varies. 

For water to be considered freshwater, its salt content must be less than 0.05% salt (saltiness is also commonly shown as parts per thousand or ppt: 0.05% is 0.5ppt). This means freshwater can still have a little salt in. 

Between 0.05 and 3% salt content is brackish water, and saltwater is between 3 and 5% salt. Above 5% (or 50ppt) salt is brine.

Where does the salt in the Ocean come from: Explained by Ocean Generation.

What are the saltiest bodies of water in the world?  

One of the saltiest bodies of water is the Dead Sea. It was cut off from the river Jordan by damming in the 1950s, so there is no significant freshwater input. This means the water is gradually disappearing, as the water level drops close to 1.21 metres (4 feet) every year.  

Think back to our bowl of water example – the water evaporating leaves its salt behind, so the sea is getting more salty. Salinity is roughly 337ppt (33.7% salt) – ten times the average of the Ocean.  

But it isn’t the saltiest – that title goes to the Gaet’ale Pond in Ethiopia. It is a volcanic spring, with a salinity of 433ppt. You wouldn’t want to swim there – CO2 bubbling up presents the risk of suffocation and the hot, acidic water could leave painful burns.    

The saltiest bodies of water on Earth
Gaet’ale Pond photo by A.Savin

Does the Ocean vary in saltiness? 

Yes. Where there is more freshwater entering the Ocean, it’s less salty. This can be in places that rain a lot, have lots of rivers entering, or have ice melting. On average the Ocean has a salinity of 35 ppt. 

Have a look at the picture below. The red areas show high salinity, purple areas are low salinity. Try and work out why each area is the colour it is.

Snapshot of Ocean salinity
Snapshot of salinity on 2 March, 2025 as observed on SOTO.

The Baltic Sea is very enclosed, has lots of river input and rain, and little evaporation, so the Ocean surface can be around 10ppt. The Red Sea is much higher, 40ppt. This is due to very little rain or river input, and high evaporation.  

Is the Ocean getting saltier? 

The Ocean is now more in balance. If we go back to our bowl example, there is a bit we didn’t tell you about. Salt can mineralise at the bottom of the bowl – solidifying into rock, leaving the water. The amount of salt that mineralises is the same as the amount entering, so the Ocean stays the same level of salty.

So, with the next salty mouthful of Ocean water you get – thank the rocks and the rivers (and the rain and the sun).

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Galápagos Under Threat: Conservation, Climate Change and Hope

Galapagos under threat: Conservation, climate change and hope. Posted by Ocean Generation

Approximately 926 km (575 mi) off the coast of Ecuador lie the Islas Encantadas: the Enchanted Islands.

Better known as the Galápagos Islands, this collection of islands is named after the tortoises that once covered their shores.

Now, fewer in number (reduced to 15,000 from an original 250,000), these giant shelled residents reflect the degradation that the islands are experiencing. 

However, not all hope is lost. As our knowledge and appreciation of these incredible ecosystems has advanced, the Galápagos tortoise and the Galápagos Islands are becoming successful conservation stories. 

What is so special about the Galápagos Islands?

Below is a quote from the renown naturalist Charles Darwin. He is attributing the inspiration of his theory of evolution to the animals of the Galápagos Islands. Indeed, they are described as a ‘laboratory for evolution’, as they have a small number of species in distinct habitats, making them easy to study. 

Explore who Darwin was and how the Galápagos featured in his work here

“I have been now ever since my return engaged in a very presumptuous work and which I know no one individual who would not say a very foolish one. 

I was so struck with distribution of Galápagos organisms and with the character of the American fossil mammifers (AKA mammals) […] At last gleams of light have come, and I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable.”- C Darwin, 1844 to Hooker 

The Galapagos Islands are a laboratory for evolution. Posted by Ocean Generation.

Starting with Darwin’s visit in 1835, the islands have continued to be a focal point for scientific research and tourism.

Carrying his legacy are Peter and Rosemary Grant in 1973.  The two scientists lived the dream, moving to a remote island and watching birds. They studied the finches of the Galápagos and how populations responded to environmental conditions (for example, drought). Their observations were the first measurements of evolution in action.  

Made a UNESCO World Heritage Site in 1978, the Galápagos Islands are a place that showcases the wonders of the natural world.  

The unique species capture the imagination. They also act as a reminder of the stewardship humans have for our natural world.  

What threats do the Galápagos face? 

The Galápagos biosphere face human-made threats. Invasive species, direct human impacts such as building and pollution, climate change and overfishing all contribute to the decline of the species that make the islands unique.

Modern threats facing the Galapagos, posted by Ocean Generation.

How do invasive species threaten the Galápagos Islands? 

Humans have explored the world, linking remote places like never before, and  with us, we have brought some hitchhikers. According to the Charles Darwin Foundation, there have been 1,978 introduced species in the Galápagos, and of these, 1,898 have become established on the islands.  

Some were intentional: early pirates left goats and pigs on the islands as a food source they could come back to. Later, ornamental plants were brought for gardens, and cats and dogs for companionship.  

Others were stowaways. Rats and fire ants are two examples that managed to catch a ride into this haven, via ships or in delivered goods.  

This has made life harder for the residents. The Galápagos tortoises now have to compete with herds of goats for the vegetation they eat and hatchlings can be attacked by fire ants, cats and rats. Blackberry bushes out-compete native plants, killing off more food for the tortoise. Spanish cedars (a mid-sized tree) grow in thick stands making it challenging for the tortoises to gain access.  

Their world is changing faster than they can keep up with.  

What direct human impacts affect the Galápagos? 

More people live on and visit the Galápagos islands than ever before. The population has grown by 300% since 1990 and in the first half of 2024 alone the Galápagos accepted 142,473 visitors. 

As humans settle, we use land for agriculture and residence, reducing the land available for resident animals. This phenomenon is called land-use-change and is one of the biggest threats to global biodiversity today.  

The Galapagos thrives because of the Ocean

How is pollution impacting the Galápagos Islands?  

The islands waste collection grew 66% over the last decade to 28.6 tonnes per day, which needs shipping back to the mainland.  

But it is the waste that isn’t collected that causes more of an issue. According to Plastic Pollution Free Galápagos, over 8 tonnes of plastic is removed from the beaches each year, and 38 species have been entangled in or ingested plastic. Much of this plastic pollution this comes from the mainland, following the same route as the residents’ ancestors.  

How is climate change impacting the Galápagos Islands? 

The Galápagos thrives because of the Ocean surrounding it. Fed by nutrient-rich currents from the deep, the Ocean is full of life.  

However, climate change is slowing Ocean circulation, increasing the acidity and lowering oxygen levels of the water, reducing the amount of food supporting life on these islands. It also interferes with El Nino.  

What is the El Nino event?  

El Nino is a naturally occurring event, characterised by changes in Ocean upwelling and climate.  

Climate change is predicted to vary the strength and frequency of this event. Species on the Galápagos islands have adapted in incredible ways to deal with El Nino. For example, marine iguanas can shrink; reabsorbing bone mass, to deal with the scarcity of food.  

Climate change has major influence over the way our planet functions, coupled with the loss of population and resilience caused by other factors, populations will be stressed more than before.  

Marine iguanas at the Galapagos shrink to deal with food scarcity. Posted by Ocean Generation.

How does overfishing impact the Galápagos? 

The waters of the Galápagos are exceptionally rich and contain some of the highest densities of reef fish anywhere in the world.  

Largely, high densities of sharks (lots of sharks usually means a healthy Ocean). It is also a key spot for the largest fish in the Ocean, the whale shark – with 700 adult females passing through every year, most of them pregnant.  

We suspect this could be the location whale sharks come to give birth – hidden around the Galápagos could be the nursery for baby whale sharks!! 

Fishing has destroyed the majority of the coral reefs in this archipelago (an extensive group of islands), and sharks are targeted for their fins.  Hammerhead populations have seen a 50% decline since 2000. 13 of 28 species tracked over the last 20 years have declined sharply. 

In 2020, the tag of a whale shark called Hope suddenly logged fast movement above the surface of the water, indicating she had been caught by a fishing vessel. In 2017, a fishing boat containing the fins of 6,620 individual sharks was seized.  

The fish lover in us doesn’t like this. Losing sharks and habitats can disrupt the ecosystem, meaning less fish for feeding people. Most people like people, so most people also won’t like this.  

The Galapagos may be the nursery for baby whale sharks

What is being done to protect and restore the Galápagos Islands? 

But the Galápagos is proving we can make a difference.  

As a focal point for nature and evolution, it is only fitting that the Galápagos Islands are also a focal point of conservation efforts.  

Tourism is utilised to support the islands, with an entry fee of $200 per person. 40% of this goes directly to conservation efforts, ensuring the attraction of the islands is preserved by those attracted to it.  

Conservation efforts in the Galápagos: 

Conservation efforts use camera traps, satellite tags and intense gardening to give the natives a hand.  

The Galápagos Conservation Trust is spearheading an incredible citizen science project, Barcode Galápagos, aiming to describe the genetic profile of all species in the Galápagos. Employing local people, the venture will enable identification of new invasive species, tracking of the health of the Galápagos and tracking of illegal pet or shark fins. 

In light of the impacts of overfishing, Ecuador has protected 198,000 square km in the Galápagos Marine Reserve, including a 30,000km2 area where any fishing is prohibited. Research is being used to guide fishing practices. The aims are to reduce by-catch (the accidental trapping of unwanted marine creatures by commercial fishing nets) and waste. This ensures sustainable fishing practice, producing more fish with less effort. 

For our Galápagos tortoises, new conservation efforts aim to eradicate the invasive species threatening them, and even bring back species that were driven to extinction. 

Genetic analysis of surviving tortoises on the islands has found traces of Floreana tortoises, a species declared extinct in the 1850s. Through selective breeding programs, the Floreana Giant Tortoise could soon be roaming the islands again. 

Project Co-Galápagos targets a growing global issue – dependence on tourism and how to make it more environmentally friendly.  Co-Galápagos aims to be the global example of developing local communities in symbiosis (what a great word) with nature.

What does symbiosis mean? Symbiosis the interaction of different organisms living in close physical association, but in benefit to them both. 

The Galapagos thrives because of the Ocean

How does the Galápagos help us protect our world? 

Our abilities to understand the natural world have increased since Charles Darwin first sketched a marine iguana. We know and understand so much more about the Galápagos Islands, and the world, than we once did.  

This enables us to better protect it. The Galápagos are a unique environment due to their isolation, distinct habitats and rich biodiversity. They give us a microcosm of our planet. Charles Darwin realised this, and the islands gave him a chance to better understand the world by observing them.

Now, our world is changing, and again the Galapagos is the perfect place to understand the effects of those changes. 

The Galápagos Islands have provided inspiration in our understanding of the natural world, they are giving us the chance to understand how best to protect it.  

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Charles Darwin’s Galápagos Voyage and Theory of Evolution 

Charles Darwin’s Galapagos Voyage and Theory of Evolution. Posted by Ocean Generation.

A fresh breeze, the sounds of gulls calling, cold sea spray touching the cheeks, the slightest hint of rotten eggs in the air.

What was going through the mind of 26-year-old Charles Darwin on 15 September 1835, as he stood on the deck of HMS Beagle with the shapes of the Galápagos islands approaching? 

His letters home suggest two things. First, that he was homesick. Understandable after nearly four years away from England, which he had left at 22 years old – he truly was the pioneer of the gap year. He was also incredibly excited.

What Charles Darwin observed during his five week visit to the Galápagos would plant the seeds that would eventually grow into his Theory of Natural Selection 

In this article we will explore who Darwin was, how he came to be on the Galápagos, and the sparks of inspiration that he found there for his theory of evolution.  

Who was Charles Darwin? How did he end up on the Galápagos? 

Charles Darwin was nearly a little-known priest in Shropshire, in England. His father wanted Charles to get good employment, either following his footsteps to become a doctor or to become a man of the church. Aged 16, his father sent him to medical school in Edinburgh. His foray into the medical world was brief, however. After witnessing the brutality of surgery without anaesthetic (on a child), Charles knew he was not to be a doctor. He left the course after only two years.  

In those two years, Edinburgh did give him some important foundations; Darwin was taught geology, biological classification and taxidermy. He was also exposed to the radical ideas of the day. These denied the Divine design of humans and suggested that animals shared human mental abilities, like thinking, remembering or making decisions.  

Charles Darwin and the HMS Beagle, posted by Ocean Generation
HMS Beagle image from The Popular Science Monthly, Volume 57

On leaving Edinburgh he went to Christs College, Cambridge University, to complete a degree and take holy orders – ministry beckoned. He breezed through the degree and enjoyed his time at Cambridge. He would go out drinking, shooting and beetle collecting. College folklore claims the sounds of his shotgun would ring out as he fired blanks to extinguish candles in his rooms. 

It was at Christs that he met Professor John Stevens Henslow. Professor Henslow encouraged discussion around natural philosophy and introduced Darwin to some of the greatest minds of the era.  

It was Professor Henslow who got Charles Darwin on the voyage to the Galápagos. The Professor had been approached to be a naturalist and gentleman companion to accompany Captain Robert FitzRoy on a ship called HMS Beagle. His wife was… unwilling to let him go, so he instead recommended his protege, Charles Darwin.  

What was the mission of the HMS Beagle? 

The Beagle was sent on a two-year mission to map South America. It ended up being a five-year circumnavigation of the globe. Captain FitzRoy had completed a similar mission the year previous, and had thought a ‘naturalist’ would benefit the scientific productivity of the voyage. Few could argue with the scientific output of the Beagle.  

It was the Ocean that really started Darwin’s thinking about evolution.

While at Edinburgh Charles Darwin would collect sea slugs and sea pens, and was mentored by Robert Grant, an expert on sponges who encouraged him to study marine invertebrates. He began exploring classification and gave talks on his findings at the university.  

The Ocean got Darwin thinking, posted by Ocean Generation.
Sea pen image via Britannica

Onboard the Beagle, he made himself a plankton net with which he drew up trawls full of Ocean life. He wrote, “Many of these creatures, so low in the scale of nature, are exquisite in their forms and rich colours. It creates a feeling of wonder that so much beauty should be apparently created for such little purpose”.  

If the accepted worldview of the time was correct, and God made everything for humankinds’ benefit, why do these tiny organisms exist out at sea where no one sees them? The Ocean was creating Darwin’s first glimmers of insight.  

What are the Galápagos Islands? 

About 1,000km off the coast of Ecuador in the Pacific, are a group of islands called Islas Encantas, or Enchanted Isles. They are better known as the Galápagos.

The initial descriptions of the islands are at odds with the image of “enchanted islands”. The first man to discover the Galapagos, Fray Tomás de Berlanga, speaks of the inhospitality and lack of water on the islands.  

Captain Fitzroy, leader of the expedition Charles Darwin was part of, describes the first viewing of the Galapagos: “Black, dismal-looking heaps of broken lava, a shore fit for pandemonium”. Darwin himself compares them to the iron-foundries of Staffordshire, or the furnaces of Wolverhampton. Hardly flattering for either party.

So, not a tropical paradise. 

The Galpagos Islands is a volcanic archipelago off the coast of Ecuador. Posted by Ocean Generation.

The word galápagos comes from the Spanish word for saddle, the shape of some of the shells of the most famous residents of the islands – tortoises.  

Darwin reported that locals could determine the island tortoise by the shape of its shell. The implications of this did not occur to Darwin until later.

Unfortunately for science, and the tortoises, they were an excellent food source for long voyages. The Beagle collected 50, none of which made it back to England.  Tortoises became extinct on the island of Floreana in the 1840s, just ten years after Charles Darwin’s visit. However, careful genetic analysis and targeted breeding has created the possibility of de-extinction (click here for more). 

The names of the islands and the tortoises immediately hint at the special nature of the Galápagos.

Galapagos means saddle in Spanish.

From their discovery, the Galápagos were renowned for their rich biodiversity. 

Whalers came to benefit off the many sperm whales that gathered there, and tales of the lizards that lived there reached across the globe. 

It is important to clarify that Darwin was not struck with a bolt of genius immediately on seeing the islands.  

He was inquisitive, curious and observant about the natural world. He saw many things in the Galápagos, and documented and collected evidence he would later use to build and justify his arguments for evolution. 

But what was Charles Darwin’s theory of evolution? 

Darwin’s thinking was radical at the time. He was opposing the accepted position that species were ‘fixed’ – unchanging. This was tied into the strong Christian influence of the time – God had created all life, and it hadn’t changed since – with humankind superior to all. 

His work was an attack on the accepted views of his time: that man was supreme by divine making, and the order of the world was fixed. 

Observing the animals of the Galápagos and beyond, Darwin’s theory of natural selection proposed that the natural world was ever-changing, evolving.  

Within this, the idea that species change over time. Further, he suggested a world in which animals were not below humans, but simply different, surviving using different strategies.  

Darwin himself recognised that his theories opposed widely held beliefs. He likened publishing his work to confessing a murder. 

What did Charles Darwin find on the Galápagos? 

Darwin was in the archipelago (an area that contains a group of islands) for five weeks. During that time, he explored the islands, at one stage camping for nine days with only a few others, and collected specimens.  

Birds, reptiles, plants and plankton were all stashed in crates on board the Beagle. He was intrigued by what he found, writing in his journal, “the natural history of these islands is eminently curious, and well deserves attention.  

What’s the deal with Darwin and finches? 

If you have heard of Darwin, you have probably heard something about finches. He collected loads of finches from the Galápagos, and they became an iconic example of his theory of natural selection.  

The birds would even come to be named after the naturalist – Darwin’s finches. 

Darwin's finches are an iconic example of his theory of natural selection. Posted by Ocean Generation.
Drawing of the finches by John Gould, from “Voyage of the Beagle” , 1845

Far from being an example of his genius, the finches are an example of Darwin being human.  

He misidentified many of the finches he collected as blackbirds, wrens and “gross-bills”, and did not write down which bird came from which island. It was ornithologist John Gould of the Zoological Society of London who reported that this collection were all finches.  

After this realisation, Darwin looked again, and the differences in their beaks does lead him to commentone might really fancy… [that] one species had been taken and modified for different ends”. However, his poor documentation meant they could not be used as evidence in his work, and they do not appear in his book.  

Modern work has made the beaks of finches a poster child for natural selection. It was a clear visual example of the adaptions that can allow different animals to survive.  

On the Origin of Species: Darwin’s work, published 

Darwin held the Galápagos dear for the rest of his life. On The Origin of Species, his seminal work on natural selection, was not published until 1859, 23 years after returning to England.

The first sentence of the book affirms the importance of the voyage in developing his theory of evolution:  

When on board H.M.S. ‘Beagle,’ as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries, as it has been called by one of our greatest philosophers.” 

In the interim, Darwin had been gathering evidence and forming arguments, bracing for the backlash and interrogation his theory would receive.  

On the Origin of Species, written by Charles Darwin is one of the most important scientific books.
Page from the 1859 Murray edition of the Origin of species by Charles Darwin.

How was Charles Darwin’s theory of evolution received?  

Darwin’s theories certainly made a splash.  

The book sold out the first edition before being released, and divided opinion.  

Predictably, the Church took a strong stance against it, along with some prominent scientists such as Darwin’s former Cambridge peer, Adam Sedgewick. International press put out cartoons and insults, often focused on the idea that humans descended from apes.  

But many scientists, especially geologists, supported Darwin’s work. Atheists were especially enthusiastic.  

Charles Darwin kept in close correspondence with supporters and opponents alike. Debate continued for decades after, until his theory was general accepted in the 1940s. 

The book went to six editions during Darwin’s lifetime and is now seen as one of the most important scientific books ever written.  

It fundamentally changed how people viewed the natural world and the place of humans within it; a lifetime’s work, from a man that explored and observed, inspired by the Ocean and the Galápagos.  

Quotes from Charles Darwin: Even the best scientists have bad days  

We can all relate to Darwin, on a very personal level, after reading some of his journal inserts and letters. Here are a few quotes that remind us even the brightest minds have down days:  

“But I am very poorly today & very stupid & hate everybody & everything.” – C. Darwin, letter to Charles Lyell 1861 

“I am rather low today about all my experiments, – everything has been going wrong” – Letter to W. D. Fox 1855 

“I beg a million pardons. Abuse me to any degree but forgive me- it is all an illusion (but almost excusable) about the Bees. I do so hope that you have not wasted any time for my stupid blunder. – I hate myself I hate clover & I hate Bees-” Letter to John Lubbock, 1862 

“I am very tired, very stomachy & hate nearly the whole world. so good night, & take care of your digestion which means Brain” – Letter to T. H. Huxley, 1860 


Thank you to Prof David Norman of Christ’s College for his time and writing. 

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What is the UN Ocean Decade: Everything you need to know

We’re halfway through the UN’s Decade of Ocean Science

2025 is the year NASAs Artemis III mission hopes to land the first people on the moon since 1972, we’ll welcome the year of the Snake in the Chinese New Year, there will be a total eclipse visible across some of North America, Greenland and Europe – and 2025 marks the halfway point in the Ocean Decade.  

What is the Ocean Decade? 

In 2017 the UN General Assembly announced something exciting. 2021- 2030 would be the UN Decade of Ocean Science for Sustainable Development, or (much catchier) the Ocean Decade.  

Its vision is encapsulated in the phrase, ‘the science we need for the Ocean we want’. 

The science we need for the Ocean we want encapsulates the vision of the UN Ocean decade.

The aims of the Ocean Decade are;  

  • Stimulating Ocean science and knowledge generation 
  • Creating new opportunities for sustainable ecosystem development 
  • Accelerating the implementation of Sustainable Development Goal (SDG) 14: Life Below Water which is all about conservation and sustainable use of the Ocean
  • Fostering international cooperation in Ocean science. 

That is a lot of long words to say, the goal of the Ocean Decade is to put the Ocean front and centre.

How is the Ocean Decade helping the Ocean? 

The UN has identified key Ocean Decade challenges and set targets to address them. 10 Ocean Challenges, aiming for 7 Outcomes of collective impact.  

The 10 key UN Ocean Decade Challenges, posted by Ocean Generation.

Here’s a simplified breakdown of the challenges (in reverse order just to keep you on your toes).  

Challenge 10: Restore society’s relationship with the Ocean
Challenge 9: Skills, knowledge, technology and participation for all 
As the great Jacques Cousteau said, “people protect what they love”. Restoring a link between people and the Ocean, instilling stewardship through education, is key to improving its health.  

Challenge 8: Create a digital representation of the Ocean 
Challenge 7: Sustainably develop the Global Ocean Observing System  
7 and 8 offer how to deepen that knowledge of the Ocean and use technology to further it and share it. Making models, exploring further and don’t forget to tell everyone about it. 

Challenge 6: Increase coastal resilience to Ocean and coastal risks
Challenge 5: Unlock Ocean-based solutions on climate change 
We can enlist the Ocean as an ally. It already absorbs up to 89% of our excess heat and has taken up 40% of carbon dioxide emitted. However, intensification of storms and rising sea levels threaten communities closest to the sea. Challenges 5 and 6 look at the practicalities of our relationship with the Ocean. 

The goal of the UN Ocean Decade is to put the Ocean front and centre.

Challenge 4: Develop a sustainable, resilient and equitable Ocean economy
Challenge 3: Sustainably nourish the global population 
Beyond that, our Ocean can be a cornucopia, providing food and resources. To ensure it is, these two aim to tackle the management and guidance needed to avoid a harmful relationship with the Ocean and benefit everyone. 

Challenge 2: Protect and restore ecosystems and biodiversity
Challenge 1: Understand and beat marine pollution 
Finally, Ocean Decade challenges 1 and 2 aim to protect and restore. Undo the harm that has been done to our Ocean, and tackle how it is still being damaged.  

For a healthy planet, we need a healthy Ocean. 

These challenges cover the full range, from prompting a sense of responsibility in people to tackling the specific threats.  

The goal is simple – nurture an Ocean that is healthy, resilient, clean, productive and safe, but also predictable, accessible and inspiring. These are the outcomes the Ocean Decade targets. (Read: Why is the Ocean so important?

For a healthy planet, we need a healthy Ocean. Posted by Ocean Generation.

We are all part of the Ocean Decade 

Ocean Generation’s mission is to bring the Ocean to everyone, everywhere.  

We translate complex Ocean science into engaging content and run three youth engagement programmes for 3 – 25-year-olds. Our Ocean Intelligence approach is endorsed by UNESCO as an Ocean Decade Project; making us part of Ocean Decades solutions.  (Which challenge are we meeting?).

Look through the challenges, see if you can engage with any.

UN Ocean Decade: First look complete 

Over the coming year, we’ll check in with the Ocean Decade. We will explore the plans it has, discover how it ties in with the different elements of the work we do, and summarise the progress it has made in a final check up at the end of the year.  

We are all part of the UN Ocean Decade.

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COP29 outcomes: Wins and disappointments

COP29 outcomes, wins and disappointments, explained by Ocean Generation

COP29 finished on the 24th November 2024, after two weeks of tough, technical negotiations.

It was full of colouring books, expensive sandwiches and drama! Let’s break down the COP29 outcomes: the wins and disappointments – and have a look across to COP16 (the biodiversity one) too. 

What is COP16? Why are there multiple? What are all the acronyms? Read our explainer here

Money, money, money.

COP29 was held in Baku, Azerbaijan and was painted as the ‘finance COP’ with the hopes of a climate finance deal being agreed.  

Hold up – what is climate finance? Broadly speaking, climate finance refers to any money “that seeks to support mitigation or adaption actions that will address climate change” – UNFCCC (remember what it stands for? Spoiler: United Nations Framework Convention on Climate Change) 

Richer countries – often referred to as the Global North (that also includes Australia, Israel and New Zealand) – have emitted the vast majority of the CO2 that is responsible for climate change. As of 2019, the Global North have emitted 2.5 times their fair share of the emissions allowed for 1.5 degrees of warming.  

The focus of COP29 was climate finance.

Countries in the Global North industrialised much earlier than the Global South, making a lot of money at the cost of carbon dioxide emissions. It has been called for, and agreed, that the richer countries should provide money to the developing countries, to allow them to develop without emitting so much CO2.  

Furthermore, there’s a loss and damage fund to help countries most affected by climate change. Many of the countries most vulnerable to the effects of climate change (sea level rise, droughts, heatwaves, floods, intense storms etc.) are poorer countries.  

What were the themes of COP29?

So, what actually happened this year? Let’s explore a few of the themes that came from the COP29 summit this year.  

Presents and petrol stations.

Countries have their own stands – as an opportunity for cultural sharing and integration. Many gave out gifts: Georgia handed out some wine tasters, the UK provided coffee.

Go to the Russian stand and you could pick up an ecological colouring book, full of tips for environmental sustainability. Some were slightly cynical, as it was produced by a major fossil fuel company.

What were the themes of COP29? Explained by Ocean Generation.
Photos by Dharna Noor/ The Guardian

Fossil fuels have been present throughout COP29. Azerbaijan, the host country, is a country with 90% of its exports comprised of fossil fuels. The capital, Baku (save that for the pub quiz) houses the very first industrial oil well and was the world’s first oil town (dating back to the 1840s). 

For the second year running, COP was attended by more fossil fuel lobbyists than the ten most climate change vulnerable countries‘ delegations combined. The host nation Azerbaijan, next year’s host Brazil and one of the countries competing for COP31 presidency, Turkey, were the only countries with more attending. 

Although the 1,773 attendees from fossil fuel companies made up only 1.5% – there were only three countries with more.  

Should discussions around climate change happen in the house of the industry most responsible for the damage?  

Or does it represent an opportunity to engage and include those most capable of changing our world? 

Al Gore said, “It’s unfortunate that the fossil fuel industry and the petrostates have seized control of the COP process to an unhealthy degree.”  

Or, as Oil Change International member David Tong said: “It’s like tobacco lobbyists at a conference on lung cancer.”  

The president of Azerbaijan made headlines this year describing oil and gas as “a gift from God”. This was denounced by a multitude of faith groups. And the Brazilian environment minister Marina Silva said: “We should take care in moderation of the gifts we are given – if we eat too much sugar, we get diabetes.” 

A report published during COP highlighted that eight fossil fuel companies had paid at least $17.6 million to Meta (which owns Facebook and Instagram) alone for pushing their posts – 700 million impressions, all within the last year.  

Al Gore quote about fossil fuel lobbyists at COP29. Posted by Ocean Generation.

Activism has always been a big part of COP.  

It presents an opportunity to make voices heard by the decisionmakers and gives a platform to send big messages.  

Attendees of the COP29 summit were welcomed by a realistic, full-sized model of a dead sperm whale on the waterside in Baku. Created by Belgian art collective Captain Boomer, the piece hopes to highlight “the disruption of our ecological system”. 

In the run-up to COP29, the cop29.com website was acquired by Global Witness, which called for fossil fuel CEOs to pay for the damage they have done to the climate.

There was a protest outside BP headquarters in London, and a number of demonstrations in Baku, including a large snake, with the message “weed out the snakes” – aimed at the fossil fuel attendees.  

Activism at COP29 presents an opportunity to make our voices heard.

COP29: Agreements and outcomes.

After two weeks, and running over by 34 hours, COP29 closed with a number of agreements. What did all the sleepless nights in smelly conference halls produce? (at one point the plumbing failed, filling the corridors with the smell of you-know-what).

There were finally some numbers for climate finance – $1.3 trillion per year, needed by 2035. This number is based in the recommendations of the Independent Expert Group on Climate Finance (IHLEG). “At least” $300 billion of this is to come from developed countries. The rest could come from a range of sources including private finance and taxes on cryptocurrency, airplane tickets and the super-rich – known as solidarity levies.  

There was no agreement reached on how to take the Global Stocktake from COP28 forward, so it was pushed back to COP30 next year.  

Article 6 of the Paris Agreement, describing ‘carbon markets’, was finalised, marking the last element of the Paris Agreement to be completed, although it was not agreed on. This just means that the text has been written, but countries have not yet signed on the dotted line. 

The reaction to COP29 has been, optimistically, mixed 

The focus, following on from the expectations coming into COP29 (finance COP), has been on climate finance. The amount pledged by the Global North has come under fire: “A paltry sum” and “a joke” by delegates from India and Nigeria respectively.  

However, some took a more positive view. Marshall Islands climate envoy Tina Stege said, “it isn’t nearly enough, but it is a start”. An observer was quoted by the Carbon Brief as saying, “momentum was neither lost nor gained, just maintained” so overall, it achieves “a passing grade”.  

UNFCCC (remember what that stands for?) Executive Secretary Simon Steill said

“This new finance goal is an insurance policy for humanity, amid worsening climate impacts hitting every country. But like any insurance policy – it only works – if premiums are paid in full, and on time. Promises must be kept, to protect billions of lives.” 

$300 billion per year, it has been widely agreed, is not enough. But the creation of a deal is a good step and could be enough to spur on the further investment required from private finance and new sources, such as carbon markets and new taxes.  

What happened at COP29 and COP16: Explained by Ocean Generation.

Outside the negotiating rooms.

Beyond the walls of formal negotiations, there were some big developments. 

  • Indonesia, the 8th biggest emitter of CO2, unexpectedly pledged a complete phase out.  
  • Mexico was the last G20 country to not commit to net zero, but did during COP29.  
  • UK and the EU joined 30 nations in an agreement to slash emissions further, specifically targeting methane emissions.  
  • China’s influence grew in the absence of strong US leadership. It announced the opening of the largest wind farm in the world. 
  • Some NDCs (Nationally Determined Contributions) announced: UK pledged a reduction of 81% against 1990 levels by 2035. Brazil announced a 59-67% reduction against 2005 levels.
  • At COP29, over 70 events were hosted in the dedicated Ocean Pavilion over the two weeks.  

What happened at COP16 (the biodiversity summit)? 

Just 10 days before the first delegates landed in Baku, COP16 wrapped up in Cali, Columbia. This followed very similar themes. It was focused on money. Specifically, where to find the money required to tackle biodiversity loss and restoration.  

The Cali Fund was established and though limited in being entirely voluntary with debated scope, can be a positive step.  

Another main objective for COP16 was the updating National Biodiversity Strategies and Action Plans, and unfortunately only 44 countries out of 196 had done so by the end of the conference.  

119 countries submitted national biodiversity targets, building on the work of the Global Biodiversity Framework agreed on at COP15.  

COP16 formally recognised the importance of indigenous peoples and local communities (IPLCs) to conservation efforts, creating a body to amplify their voices in the CBD.  

The Ocean took centre stage at COP16.

At COP16, the Ocean was prominent in a way not previously seen.  

The Small Island Developing States (SIDS) pushed for progress. The Maldives announced14% protection of their coral reefs with more protection pencilled in. The Azores announced the largest MPA network in the North Atlantic, protecting 30% of its waters.  

Parties approved a new process to identify ecologically or biologically significant marine areas (EBSAs) (bet you thought we were done with new acronyms).  

This doesn’t guarantee protection but can guide the creation of marine protected areas (MPAs) in areas that will be most effective, including the high seas.  

Generally, the progress made for the Ocean was received very positively.   

COP29 and COP16:  the transition from negotiation to actions.  

Awareness, knowledge and respect for the natural world is growing. Frustration at pace of progress is evident throughout the process, from those in the room to those hearing the news. We need to appreciate how far we have come, while also maintaining the push onwards.  

What was top of the COPs? 

TopsNots
Agreement to triple climate finance to $300 billion Amount falls far short of that hoped by developing countries 
Carbon markets approved after a decade of trying Fears of carbon markets being misused in bad offsetting and fraud 
Cali Fund established No mandatory contributions – entirely voluntary, no guarantees 
Loss and Damage Fund should be operational in 2025, and has $730 million pledged No further progress on last year’s Global Stocktake – phasing out fossil fuels  
Mexico and Indonesia surprise with net zero and emission cutting announcements  Some countries and parties obstructing progress  
China announces more voluntary contributions to climate finance  
COP29 ment a transition from negotiations to actions. Posted by Ocean Generation.

Brazil has made it clear it intends to make COP30 a “Nature COP”. If it can maintain momentum, COP29 has given foundation for the transition into tangible action. 

These big global treaties can feel very far away, and it can seem that there is nothing you or I could do. But we are the key parts of this puzzle. Appreciate every small action you take.  

Turn down your heating by one degree this winter – barely enough to notice but saving a lot of emissions.  

Be conscious of what you eat – choosing local, seasonal food can be your difference.

Get talking. You are already doing something important – staying informed. Having conversations with other people, making people more aware, is a crucial part of the process. Engage with us! We love to hear the actions you are taking, and we will answer every question sent our way.

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Everything you need to know about COP: COP29, COP16s and the things between

Everything you need to know about COP: Explained by Ocean Generation.

Heard a lot about the COP conferences but not sure what’s going on? Acronyms got you all in a twist?

Welcome to a white-knuckle ride into climate-summit world, where we explain everything you need to know about COP.

What is COP?

COP is our first acronym (can be written as Cop or all in caps). It stands for Conference Of the Parties, the name given to the group of countries (Parties) all coming together to make big decisions.

It consists of negotiations between representatives, presided over by the host country. They’re also used as a platform for scientific developments and activism: talks are held, and papers are released aiming to maximise impact.  

Why are there multiple COPs?

COP is most used to refer to the COP of the United Nations Framework Convention on Climate Change (UNFCCC) – the big annual summit on climate change. The 2024 edition was the 29th summit, so it is known as COP29 – easy!  

But COP can be used to describe the meetings held for other conventions too.  

2024 also had the COP for the United Nations Convention on Biological Diversity (UNCBD) in October and the COP for the UN Convention to Combat Desertification (UNCCD) in December. Both of these are biennial (one every two years) and meeting for the 16th time, so both are known as COP16 – useful (not).

Three conventions of the Rio Trio aim to tackle threats to humanity. Posted by Ocean Generation

The three COPs were all created at the UN Earth summit in 1992 in Rio de Janeiro, so are known as the ‘Rio Conventions’ or more informally the Rio Trio. They aim to tackle three major threats to humanity – climate change, biodiversity loss and desertification. 

The most famous COP outcome was the Paris Agreement.

The Paris Agreement was negotiated at COP21 in 2015. You’ll never guess where. It’s a legally binding (means enforceable by law) agreement with the primary goal of keeping global average temperature well below 2 degrees above pre-industrial levels.  

The basic plan? Every country gradually ramps up their climate actions, detailed in Nationally Determined Contributions (NDCs). NDCs are refreshed every five years, and the next round are coming in 2025 – watch this space.  

The Agreement also provides a framework of support between countries. Financial, technological and capacity building support is guide lined to enable and encourage cooperation.  

Countries also established an enhanced transparency framework (ETF) for gathering relevant data, which will then feed into the Global Stocktake, the progress report for our climate. The Global Stocktake will be published every five years, with the first released last year at COP28. 

Everything you need to know about COP: The Ocean is our biggest ally against climate change.

What does COP mean for the Ocean?

This depends which COP you are talking about.  

Climate change is a global threat, against which the Ocean has acted as our shield for years. The Ocean absorbs excess heat and carbon dioxide, maintaining our biosphere’s balance. Ocean acidification, marine heat waves and intensifying weather patterns are just some symptoms of a stressed system.  

The Ocean is our biggest ally against climate change and the actions at COPs can safeguard our Ocean. While they are not specific to the Ocean, the decisions made at COP can decide the health of our Ocean ecosystems. 

The CBD COP (the biodiversity one) is more directly linked to the Ocean: at COP15 the Kunming-Montreal Global Biodiversity Framework officially set the target to protect 30% of countries land and seas by 2030, known as the 30×30 agreement.  

Read more about the agreements made at COP29 and learn more about the outcomes of COP16 here. 

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How Climate Change threatens polar species: Polar bears, Orcas and Narwhals 

How Climate Change threatens polar species: Polar bears, Orcas and Narwhals

Many polar species depend on sea ice for essential activities like resting, hunting, and avoiding predators but climate change poses a threat.

Polar species have finely tuned their behaviours, and physiological traits to the seasonal advance and retreat of sea ice.

However, as sea temperatures rise and the Arctic (in the Northern Hemisphere) warms at four times the global average rate, sea ice is shrinking and breaking up earlier each year.

This trend presents growing challenges for polar species that rely on ice, highlighting just how important it is to tackle climate change to ensure their survival. 

How polar bears are impacted by climate change 

Characterised by their large size, dense white fur, and flattened cranium, polar bears are apex predators in the Arctic ecosystem. Their primary prey are ice-dependent seals, particularly ringed and bearded seals. 

Seals use the ice as a platform for resting, breeding, and giving birth. Using an ambush technique, polar bears wait at seal breathing holes, catching seals as they come up for air. This saves them energy compared to more active hunting methods.

Ringed and bearded seals in the Arctic, posted by Ocean Generation

Polar bears’ hunting success peaks in the spring and early summer, coinciding with the weaning period of seal pups. This makes it a critical time for the bears to build fat reserves essential for survival through winter. 

Climate change delays sea ice formation in autumn, and it’s reducing the time available for hunting seals later in the year. As a result, it’s becoming increasingly difficult for polar bears to build or maintain their fat reserves. 

Increased fragmentation of sea ice also forces polar bears to swim longer distances to reach stable ice. In some regions, polar bears have been recorded swimming over 50km. This is an energy draining task for these not-so efficient swimmers, due to their paddling motion and the added drag of swimming at the water’s surface.

Polar bears wait at seal breathing holes

With summer sea ice disappearing, polar bears are becoming more dependent on food sources on land. These offer far less nutrition compared to the energy-rich blubber of seals and increases human-wildlife conflict. 

They are currently listed as Vulnerable under the IUCN Red List (last assessed in 2015), facing threats from residential and commercial development, human disturbance and climate change. 

How narwhals are impacted by climate change 

Narwhals, distinguished by their long, protruding tusks, are remarkable divers capable of reaching depths of up to 1,500 meters in pursuit of prey. Their diet primarily consists of fish (Greenland halibut in particular), cephalopods (such as squid), and crustaceans.  

Narwhals depend on breathing holes in the ice to survive

To support their slow, endurance swimming, narwhals have evolved a high proportion of specialised slow-twitch muscles, which make up about 90% of the muscle fibre in their bodies. These muscles are rich in myoglobin. This is an oxygen-binding protein that enhances their ability to store and use oxygen efficiently during extended dives.

Narwhals, like other marine mammals, depend on the stability of breathing holes in the ice to survive. However, climate change has made these ice conditions increasingly unpredictable, leading to entrapment and fatalities for narwhals when they can’t locate a breathing hole. 

Their narrow temperature range coupled with strong attachment to specific locations and migratory routes makes them particularly vulnerable in the rapidly warming Arctic.

Currently listed as Vulnerable on the IUCN Red List (last assessed in 2023), narwhals are increasingly threatened by climate change, as well as energy production and mining activities. 

How orcas are impacted by climate change 

Orcas inhabit the Oceans worldwide, ranging from polar regions to tropical waters. They are categorised into three distinct forms, A, B and C, with type B exhibiting cooperative hunting behaviour in pursuit of seals. In these strategies, family group members work together to create synchronised waves that wash seals off the ice.  

Orcas find new opportunities in the changing polar regions

When searching for potential prey, orcas adapt their travel behaviours to the surrounding ice conditions. In open water with minimal ice, they tend to stay close together, while in pack ice, they spread out and often travel as individuals or pairs.

Near ice floes (thin sheets of frozen seawater), individuals engage in spy-hopping to locate seals, taking multiple views from various angles around the edge of the floe.

After observing, they swim away briefly to vocalise and communicate with other group members before returning. 

Before attacking, the whales swim together in loose formation, often rolling at the surface. They move side-by-side away from the ice floe before charging back rapidly in a coordinated manner, generating waves as they approach.  

Depending on the size of the floe, they create two distinct wave types. One is a breaking wave for smaller floes that can wash seals directly into the water, the other is a non-breaking wave for larger floes that shatters the ice and drives seals off. 

Many Arctic marine species use frozen areas as a refuge from orcas.

Bowhead whales, which can break through the sea ice to create breathing holes, face few predators besides humans and orcas. However, as sea ice shrinks, orcas are increasingly detected in Arctic waters.  

Many polar species use frozen areas as a refuge from orcas, but climate change and shrinking sea ice threatens them. Posted by Ocean Generation

While this provides new prey opportunities for these apex predators, it could significantly stress prey species, potentially altering their behaviour and population sizes. For example, the specialised locomotor muscles of narwhals make them too slow to escape orcas. 

Moreover, the increased presence of orcas may impact indigenous communities that rely on subsistence hunting to sustain their way of life.  

Orcas are currently listed as Data Deficient under the IUCN Red List (last assessed in 2017). This highlights the need for more research to comprehensively understand population trends and conservation priorities. 

Turning climate challenges into opportunities 

The survival of polar species is increasingly threatened by climate change, which leads to shrinking sea ice and altered ecosystems.

These changes not only challenge the feeding and breeding behaviours of these animals but also affect indigenous communities that depend on these species for their livelihoods.

We can help through supporting conservation organisations, taking climate action, advocating for policy change, engaging in sustainable practices, and raising awareness about our impacts on polar ecosystems.  

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Surviving the Polar Regions: Animal strategies and adaptations 

Surviving the polar regions, animal strategies and adaptations. Explained by Ocean Generation

The polar regions are among Earth’s most unique environments 

Characterised by low temperatures, limited food availability, harsh climates and extreme seasonality, it’s challenging to live in the polar regions. Species inhabiting the Arctic and Antarctic have evolved various physiological, morphological (structural), and behavioural adaptations to survive in these challenging conditions.

Where is the Arctic? Where is the Antarctic

The Arctic is in the Northern hemisphere whereas Antarctica is in the Southern hemisphere.

Iconic Arctic species include the polar bear, Arctic fox, narwhal, walrus, and bearded seal.  

In contrast, the Antarctic is home to species such as the leopard seal, Emperor and Adélie penguins, and rock ptarmigan (a medium-sized game bird). 

Iconic Arctic and Antarctic animals, posted by Ocean Generation.

Slow and steady is key to survival. 

Temperature has a major impact on how fast species develop. A pattern of slow development rates has been observed among Antarctic marine ectotherms (species that rely on the environment to regulate their body temperature). 

For example, the development rates of marine larvae are slower at low temperatures compared to those in temperate and tropical regions. This is likely due to lower temperatures reducing protein synthesis and folding, resulting in fewer functional proteins available for growth.  

With the close link between metabolism and development, polar species tend to have slower metabolic rates and use up minimal energy. Antarctic Nototheniodei fish, for instance, have evolved with reduced quantities of red blood cells and haemoglobin , the protein responsible for transporting oxygen throughout the body.

This reduction in haemoglobin reflects their lower metabolic rates and oxygen demands compared to species in warmer, temperate climates.  Slow metabolism and development are key to surviving with the limited food available in the polar regions.  

Slow metabolism and development are key to surviving in the polar regions.

How species cope with food scarcity in the polar regions 

The polar regions experience dramatic seasonal shifts in solar radiation, with continuous daylight in the summer and nearly total darkness in the winter.  

This is accompanied by blizzards, freezing temperatures and limited food availability.  

During winter, reduced sunlight limits the growth of primary producers like phytoplankton and plants, which in turn affects the entire food chain. Additionally, the sea ice that forms over the Ocean restricts access to open water, where many marine animals feed. Snow cover makes it more challenging for land animals to access their food sources.  

For some animals, these harsh winter conditions are too extreme, and they migrate to more favourable areas. For those that remain, many build up fat reserves during the summer and early autumn to prepare for the limited food availability.  

How animals cope with food scarcity in the polar regions

In the Svalbard rock ptarmigan, for example, these fat reserves are primarily used during episodes of acute starvation rather than supplementing daily energy needs.

Some animals also exhibit surplus killing and hoarding behaviour in the summer, such as the Arctic fox. The fox has been observed storing food, with one cache containing as many as 136 seabirds.   

Many animals will limit physical activity to conserve their energy and reduce their resting metabolic rate. This refers to the amount of energy the body uses at rest to maintain basic physiological functions.

Adult King penguins can go without food for up to one month. Meanwhile, chicks can endure fasting for up to five months during the subantarctic winter, losing up to 70% of their body mass while relying mostly on stored fat reserves. 

Small invertebrates that live on the seafloor, or meiofauna, have adapted to polar environments by feeding on degraded organic matter, which remains available year-round.  

In many Arctic marine mammals, the milk produced for their young is exceptionally rich in energy and nutrients, which is vital for the pups to survive in the harsh, cold environment.  

How animals cope with freezing temperatures, explained by Ocean Generation, leaders in Ocean education

How species cope with freezing temperatures 

Air temperatures in the polar regions can occasionally drop to -60°C, while Ocean temperatures are close to freezing. To maintain a stable core temperature, organisms must employ strategies to minimise heat loss through conduction, convection, radiation, and evaporation. 

One common adaptation is the evolution of a rounded body shape to reduce exposed surface area. For instance, walruses have a large, tubular body with minimal projecting extremities, such as visible ears or a tail, reducing heat loss through conduction and convection.  

Rounded body shapes help cope with freezing temperatures of the polar regions.

Many polar species develop dense fur for insulation, such as reindeer and caribou (also a species of deer), whose hollow guard hairs provide air-filled cavities for additional warmth. In marine animals, where fur offers little insulation value, a thick layer of blubber becomes essential for protection against cold seas. It also serves as a food reserve.

Many species have evolved sophisticated blood flow regulation systems in body parts exposed to the cold. In marine mammals, a network of blood vessels in the flippers operates as a counter-current heat exchange system. This is when warm blood flows to the flipper transferring heat to cooler blood returning from it. This adaptation allows them to conserve heat in critical areas while maintaining functionality in their extremities. 

Moreover, both Arctic and Antarctic fish have independently evolved antifreeze glycoproteins, which are secreted into their blood to prevent the formation of harmful ice crystals. These compounds are produced during the cold winter months in Arctic fish and year-round in Antarctic fish. 

Behavioural adaptations also play a key role in survival 

Emperor penguins form large huddles in extreme Antarctic cold and wind, with groups consisting of hundreds of individuals. The penguins take turns occupying the warmer centre of the huddle, where ambient temperatures can reach 37.5°C, helping conserve energy and incubate eggs during the winter.  

Emperor penguins form huddles to shelter from the cold

Snow place like home 

Survival in the polar regions requires a combination of physiological, morphological and behavioural adaptations, enabling species to endure extreme cold, limited food availability and harsh climatic conditions.  

As climate change continues to alter these environments, the ability of polar species to adapt will be crucial for their ongoing survival in an increasingly warming world. 

Check out How Climate Change threatens polar species: Polar bears, Orcas and Narwhals, where we discuss the opportunities and challenges for animals in a changing world.  

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Balancing conservation and community in polar wildlife conflicts 

Balancing community and conservation in polar wildlife conflicts

Addressing human-wildlife conflict is essential for both wildlife conservation and human well-being. 

As human populations expand into natural habitats, finding solutions that promote coexistence between people and wildlife becomes increasingly important. By fostering harmony, we can support thriving species, healthy ecosystems, and positive relationships between local communities and conservation efforts.

Reducing conflicts benefits wildlife and eases financial losses for local communities. It also aligns with the UN’s Sustainable Development Goals by enhancing livelihoods, building community resilience, and creating economic opportunities for local populations. 

Mitigating human-wildlife conflict on land 

Climate change intensifies human-wildlife conflict by changing the historical range and behaviour of wild species, increasing the frequency of interactions between humans and wildlife.

Climate change intensifies human-wildlife conflict. Posted by Ocean Generation, leaders in Ocean education.

While addressing climate change is key to reducing these conflicts, communities can adopt strategies to minimise interactions with conflicting species. Some of these approaches are listed below: 

  • Fencing key resources, such as livestock, and securing protected areas. Planting buffer crops could also reduce wildlife consuming important resources.  
  • Implementing animal-safe food storage facilities and improving waste management systems can prevent wildlife from being attracted to human food sources. 
  • Integrating guarding measures, such as specialised livestock-guarding dogs or patrol officers, into resource protection could provide early warning signs to alert residents to potential conflicting wildlife. 
  • The use of non-lethal deterrents, such as visual, chemical, and acoustic repellents, can further discourage wildlife from approaching human settlements and resources.  
  • Economic costs of conflicts could also be reduced through compensation schemes, alternative income generation, or increasing wildlife-related tourism. 

A better understanding of animal movement can help predict high-risk areas and times, allowing for more targeted mitigation efforts. For example, researchers studying moose found that the risk of vehicle collisions increases in winter when snow depth is below 120 cm and nighttime traffic is higher due to longer nights.

This highlights the need for seasonally adaptive strategies to mitigate such risks.  

Mitigating human-wildlife conflict in the Ocean

Fishers have several options to minimise encounters with marine mammals.

Ocean mammals often become entangled in fishing lines

Mammals often collide with or become entangled in vertical lines attached to buoys, which mark where nets have been set. To prevent wildlife harm and gear damage, fishers could reduce the number of vertical lines in the water column or use ropes in colours more visible to mammals.

Common rope colors like yellow, green, or blue may be difficult for whales to detect. Switching to colours such as white, black, or striped patterns could make the ropes more visible to whales, potentially helping them avoid entanglement.

Another approach involves weakening lines so that entangled animals can break free more easily. However, this solution can result in financial losses due to reduced catch and replacing lost gear. 

Technological innovations, such as acoustic buoy releases that surface only when triggered, could eliminate the need for vertical lines. Another potential solution is the use of pingers, which are devices placed on lines that emit noises at specific frequencies to warn whales and other marine mammals away from boats and fishing gear.

Fisheries-have-several-options-to-minimise-encounters-with-marine-animals

While these strategies could help reduce human-wildlife conflict in fisheries, more testing is needed to see how effective they are. Supportive initiatives, like financial compensation programs to cover losses from wildlife, can ease the economic strain on fishers and encourage the use of non-lethal deterrents. 

Collaboration between scientists and communities is key to solving these challenges. For example, the Alaska Longline Fishermen’s Association partnered with biologists and bioacoustic experts in 2003 to study whale behaviour and minimise interactions with longline boats. This led to the creation of the Southeast Alaska Whale Avoidance Project (SEASWAP), a successful project improving our understanding of depredation.  

Balancing conservation and community needs 

The key to addressing human-wildlife conflict involves recognising and valuing the diverse attitudes towards conservation that influence both the conflict and resolution.

By appreciating the different perspectives of stakeholders, conservation plans can be designed to address the needs and interests of everyone involved. Engaging meaningfully with communities is key to developing policies that are not only effective but also widely supported. 

Balancing conservation and community to mitigate polar wildlife conflicts, posted by Ocean generation

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