22. 04. 2026 Elliot Yu

The oldest things in the Ocean: Explained.

Copied

What do we mean when we say the “age of the Ocean”?

It could mean many things, from the oldest living thing in the Ocean to the time at which the Ocean first formed. Since there is no official definition, we can have some fun with stretching the definition of “age of the Ocean” by looking at some of the oldest things in the Ocean.

What are the very young things in the Ocean?

First, we stop off what I will call the “very young” section. These are on timespans of one to just above one thousand years. While these things are by no means short on a human timescale, they definitely are relative to the oldest things on this timeline. Most of this section is made up of animals, though not all.

We can interpret the “age of the Ocean” as meaning the oldest living thing in the Ocean.

What’s the oldest vertebrate in the Ocean?

One contender is the Greenland shark. The oldest measured was 272 years, but they are thought to be able to live to 500 years. For perspective, the oldest person ever lived to 122 years old. The Greenland shark can be found in the North Atlantic, being the largest fish to live in Arctic waters. The females of the species can grow to 4-5 metres, about the length of a small car!

These animals grow incredibly slowly and live for a long time. However, this age takes us nowhere near even the oldest living animal. We can still give the Greenland shark the title of “the oldest vertebrate” though.

One of the oldest living Ocean animals is a clam!

A similarly long-lived animal is Ming the clam. Ming was 507 years old, being born during the Ming Dynasty of China (hence the name), or the Tudor period of the UK (it was born in the same decade as Henry VIII). The story of Ming ended quite sadly and unexpectedly, as to measure the age of clams, they must be killed. The scientists doing this experiment hadn’t realised how old Ming was until it was too late, and so in an unfortunate turn of events, Ming had its life cut short.

Ming still gets the title of “the oldest animal with a precisely measured lifespan” though. While this may seem like a long-winded title, the next animal, in the “young” section, will give an idea as to why it’s important.

Greenland sharks and Ming the clam are among the oldest living animals in the Ocean. Posted by Ocean Generation. — *Ming the clam: Radiocarbon , Volume 50 , Issue 3 , 2008 , pp. 399 – 412*

Before we get onto the next animal, we move to the “age of seawater”.

How old is Ocean water?

The “age of water” is essentially a measure of how long water has gone since its last exposure to the atmosphere. This age depends on the speed of Ocean circulation, as faster circulation means younger overall water. The oldest water on Earth can be found in the deep Pacific, currently around 1400 years old.

Looking at our timeline:

Very young things in the Ocean. A timeline by Ocean Generation.

What are the young things in the Ocean?

We now head into the “young” section; the things that date from one thousand to one million years. While it is definitely weird to describe these as young, one million years old is less than 0.1% of the age of the oldest thing on this list.

What’s the oldest animal?

The title of oldest animal goes to the glass sponge (yes, sea sponges are animals). The oldest of these lives up to about 15 kyr (thousand years) old. That’s more than three times as old as the oldest (verified and non-clonal, it gets complicated) tree (about 4,900 years old) ever.

As a quick aside, this tree had a very similar story to Ming the clam, as the scientist who measured its age cut it down to count the rings, as other methods were not working.

The uncertainty on the age of these organisms is large (13 kyr – 40 kyr), due to the measurement method, there is a useful upper constraint on the sponge’s age. We know how sea level has changed in the past, and that the sponge lives at a certain depth below sea level. This means that the sponge cannot have been born below sea level at the time, and so must have been born after the sea level was at its current position.

This pick for oldest animal may be controversial, as some animals are functionally immortal (jellyfish). Despite this, this is a theoretical age limit, which is not what we are looking at. Either way, the oldest animal is in the Ocean.

One of the oldest and largest coral ecosystems

Making a big skip from 15 kyr to 600 kyr, we find ourselves in Australia, in the Great Barrier Reef. While the individual corals aren’t necessarily 600 kyr old, the ecosystem started growing that long ago. For perspective, the oldest human (Homo sapiens) fossil was 300 kyr old.

This means that it’s possible for the Great Barrier Reef to have been around for twice as long as modern humans have been on the planet. It’s uncertain whether this age makes the Great Barrier Reef the oldest living reef in the world, as there isn’t enough literature on reef ages. Despite this, the reef is still significant in age and has definitely been going for a long time.

Our updated timeline:

Young things in the Ocean. Posted by Ocean Generation, leaders in Ocean education.

What is middle-aged in the Ocean?

We finally break a million years, and we’re only into the “Middle-aged” territory.

How old can ice get?

We start off with the oldest ice found on Earth, which is about 5 Myr (millions of years) old. You may think that this ice should have melted, as this ice predates the start of the last glaciation event. However, the way that this ice was preserved was being insulated under sediments and rocks, which kept it cool for long enough to be found in the modern day. Imagine trying to keep a block of ice frozen for a single year, never mind five million. That’s impressive!

How old is the Ocean crust?

Next, we pass through the K-Pg mass extinction (66 Myr ago, read about what happened here), where all the dinosaurs died, into the birth of the oldest Ocean crust, 300 Myr ago. If we’re looking for the “age of the Ocean”, then surely the rocks that hold the Ocean can count in that definition.

The Ocean crust is the supporting basin underneath the Ocean but does not last forever. New crust is constantly being made, while old crust is being removed (called subduction), and so the maximum age of Ocean crust is limited. This oldest crust is thought to have been from a past Ocean that has now closed (yes, regions of the Ocean close up) and is found in the Mediterranean.

Sharks have been around before threes existed. Posted by Ocean Generation.

Ancient fish fossils

Rounding out our middle-aged section, we have the oldest fossil of cartilaginous fish, the group including sharks and rays. A fun fact is that the common ancestors of rays and sharks were around before grass and trees were on land. The fossil has been dated to be about 440 Myr old. While these may not be a part of the definition of “age of the Ocean”, they’re still fun to think about.

Our new timeline:

Middle aged things in the Ocean, a timeline by Ocean Generation.

What are the oldest things in the Ocean?

Now onto the very oldest parts of the Ocean, we look at things that are billions (with a b) of years old.

We have talked a couple of different fossils, but the very oldest of these fossils are found at the Strelley Pool Formation in Australia, dating back to 3.4 Gyr (billions of years) ago. These are fossilised bacteria, which predate even oxygen being on Earth in significant amounts (the Great Oxidation Event, 2.4 Gyr ago). They even had a hand in filling the atmosphere with oxygen! Finding the first fossil evidence of life is a challenge, as early life was made up of bacteria, which are difficult to preserve.

The Strelley Pool fossils are the oldest (largely) undisputed fossil evidence of life. As life is theorised to have started in the Ocean (around hydrothermal vents), perhaps we can say that the “age of the Ocean” is how long life has been in the Ocean for.

Strelley Pool fossils, posted by Ocean Generation. — *Image via doi: 10.7185/geochemlet.1817*

How long has water existed on Earth?

The very last definition of how old the Ocean is, is naturally how long water has existed on Earth as pools of water.

To see this, we can look at some of the oldest rocks on Earth, again from Australia. These rocks from Jack Hills contain minerals which date back 4.4 Gyr ago, which was quite early into the Earth’s lifetime (4.567 Gyr). Looking at the composition of these minerals, it’s possible that these minerals interacted with liquid water upon formation, suggesting the presence of at least liquid water at the time.

This water wouldn’t have been in the shape of the Ocean that we’re familiar with, rather taking a different shape due to plate tectonics. This fact emphasises that we have one Ocean that has been with us for billions of years.

The final timeline:

Old things in the Ocean, a timeline by Ocean Generation.

It should be noted that even though this seems like a complete list, these are only the oldest that we know of in each of their categories. The Ocean is largely unexplored in space (and time, for the cartilaginous fish), and so all ages should be taken with a pinch of salt.

How do we know the ages of things in the Ocean?

A question arises from all of these – how do we know all of these ages? Well, there are many different methods of what we call “dating”, which is measuring the age of something.

Counting growth lines

The simplest, and possibly the most familiar one to you, is counting growth lines. Trees famously grow rings for every year of their life, making counting their age relatively easy. Trees aren’t the only organism that this is useful to, with Ming the clam having a similar dating method.

Ming had annual growth lines that could be found on the inside of its shell (hence the scientists’ need to kill it to measure its age). This helped it be “precisely measured”.

Radiometric dating

With the simple method out of the way, we turn to “radiometric dating”, which uses the behaviour of radioactive atoms to see how old a specimen is. There are several atoms that are useful to us, depending on the timescale that we are working on.

Carbon-14 is an isotope (type of atom) of carbon that is radioactive. This means that the number of carbon-14 atoms decreases over time, with half of the carbon-14 in a sample decaying over 5730 years. We say that carbon-14 has a half-life of 5730 years. This means that we can use it as a clock. Carbon-14 dating is particularly useful for dating life, as all life contains carbon, therefore in some small amounts, carbon-14.

This was particularly helpful when figuring out the age of the Greenland shark, as they have a part of their eye that is formed on birth and does not change afterwards, meaning that from measuring the age of the eye, the age of the shark can be found. This method is also useful in finding the age of seawater, as seawater contains dissolved carbon within it.

A similar method can be done with uranium. The difference between uranium and carbon-14 is that uranium’s half-life is much longer, reaching billions of years. This means that it is useful in dating our very oldest samples. For the Strelley Pool fossils, we know the ages of the rocks around the fossils, and so can infer the age of the fossils, and for the Jack Hills minerals, we can directly find their age with uranium dating.

Dating methods in the Ocean. Posted by Ocean Generation.

Correlative or model-based dating

The last method of dating is “correlative” or model-based dating. For this one, we set up a model, effectively a link between an aspect of a sample and its age and figure out its age from that model.

The Greenland shark age also uses this method of dating. A link between the size and age of the sharks that have had their eye ages measured can be made. This can then be applied to other Greenland sharks. The advantage of this method is that it is much easier to measure the size of a shark than to carbon date its eye age. A model is also used for the glass sponges.

Why is the age of the Ocean important?

While stretching the definition of “age of the Ocean” may be for fun, each individual story in this article is important.

Diving deeper into the oldest members of each category can lead us to many conclusions. Understanding why some animals live longer than others can give us insights into why some creatures live as long as they do.

The age of seawater gives us an idea about Ocean circulation, while Ocean crust tells us about plate tectonics. The big story of the “age of the Ocean” lets us explore the smaller stories important to different aspects of science.

Post by

Elliot Yu

Fact file: Fun facts about orca (killer whales)

Monthly: Impact in your inbox.

17. 04. 2026 Elliot Yu

How did the End of the Dinosaurs Affect Marine Life?

How did the end of dinosaurs affect marine life? Explained by Ocean Generation.

Copied

A lot of people know about the meteorite that killed the dinosaurs, but how were marine creatures affected by this event?

66 million years ago, the age of the dinosaurs came to an end, becoming the known as the K-Pg (the geological abbreviation for Cretaceous-Palaeogene) Mass Extinction. A meteorite impact sent the world into darkness, leading to the downfall of the once dominant dinosaurs and many other creatures. Despite the fame of this event, little thought is given to the effects on the past Ocean.

How did the dinosaurs become extinct?

The famous driver for the extinction of the dinosaurs was, of course, the meteorite that struck the Chicxulub Impact Site in Mexico. But this wasn’t the only cause for extinction. The volcanoes of the Deccan Traps in India were violently erupting too, spewing massive amounts of lava. Together, these two events were the drivers for the mass extinction. However, the meteorite and eruptions themselves didn’t directly cause the extinction, instead it was their aftermath. So, what happened?

The world – 66 million years in the past

The world 66 million years ago. — *Map via Atlas of Earth History*

Due to plate tectonics, the world looked slightly different 66 million years ago (Ma) compared to now. Despite the similarities, the world, and so the shape of the Ocean, were different. Firstly, there were more connections between Oceanic bodies, for example from the Atlantic to the Pacific. Next, the Atlantic was much younger and much narrower. Lastly, as there were no ice caps and the climate was warmer, sea level was higher by about 200m.

What is plate tectonics?
The Earth is made up of multiple large sections called “plates”. Plate tectonics is the idea that these plates move around and past each other very slowly. This means that over many millions of years, they can move into completely different arrangements and positions.

What did Ocean life look like before the extinction?

The life found in this Ocean of the past was quite different to the present, but we do see some familiar faces. Sharks, crocodiles and fish still existed, while algal ecosystems (the photosynthesisers of the Ocean) supported the food chain. These weren’t the only things found in the marine world of the Cretaceous period, though.

Cephalopods, which are the group containing modern octopuses and squids, had multiple representatives. Ammonites had been abundant before the extinction, although were on a gradual decline in diversity towards the extinction. These animals had a spiralled shell shape a little like their living cousins, the nautiluses, and lived throughout the Ocean. Alongside them, the nautiluses were also present but made it through the extinction.

Of course, there were also the famous predatory marine reptiles of the time, commonly (incorrectly) included when referring to dinosaurs.

The relatives, the long-necked plesiosaur and the short-necked pliosaur, were two notable groups, the former having a nearly complete fossil discovered by Mary Anning. However, pliosaurs didn’t die in the K-Pg extinction, instead going extinct over 20 million years before (still considered the “late Cretaceous period”, the geological periods are long!).

Instead, the dominant predator at the K-Pg was the mosasaur, which were predatory marine reptiles, like the pliosaur. The difference was that the mosasaurs were better suited to live in the Ocean, as they could adapt better to changes in conditions, becoming more successful and thriving until the extinction.

Mosasaurs and plesiosaurs went extinct. Explained by Ocean Generation

What happened to Ocean life during the Extinction?

As per the name “K-Pg Mass Extinction”, a lot of species went extinct. It’s estimated that around 76% of all species died, being about the same for marine species, from the results of the meteorite and volcanism.

The meteorite and volcanoes weren’t the direct causes; the impact and the lava were nowhere near global scales. Instead, secondary factors caused by the impact and eruptions led to the extinction. The main effect of each was their effect on the food chain, with the death of algae.

The death of algae was a main cause of the marine extinction

When the meteorite hit the Earth, it sent high amounts of dust and debris into the atmosphere, leading to a sort of “curtain”. This curtain of dust blocked out the Sun for a considerable time, leading to an “impact winter” (a period of extreme cold, due to the meteorite blocking the Sun), and darkness. This period of darkness decreased both plant and algae numbers, with both requiring the Sun for energy.

Just as plants are the bottom of the food chain (what we call “primary producers”) on land, algae are the primary producers in the Ocean. The decrease in numbers means that the animals that eat algae would have less food and die, meaning the animals that eat those animals would have less food and die. This knock-on effect up the food chain is one of the main causes of the mass extinction, both on land and in the Ocean.

What happened during the K-Pg extinction? Explained by Ocean Generation.

The volcanoes of the Deccan Traps, along with releasing vast amounts of lava, released considerable amounts of volcanic gases too, notably carbon dioxide and sulfur dioxide. Carbon dioxide, along with being the infamous greenhouse gas, can lead to Ocean acidification and carbon dioxide poisoning. Sulfur dioxide is a potent ingredient in acid rain, also contributing to Ocean acidification.

The reason this is so important is that some algae are dependent on the Ocean being a certain acidity to live. This fast, significant change in acidity led to the death of these algae, having an impact on the marine food chain.

What happened to Ocean life after the extinction?

If all of this happened, why did anything survive at all? A key player in the extinction of animals was starvation. The longer an animal could survive without food, or the more accessible food that an animal had, the more likely it would be to survive.

Mammals and fish: the survivors of the extinction

This applies to both land and the Ocean. Mammals were able to outlive the dinosaurs as they could live off of insects and dead plant matter, paving the way for their domination.

In the Ocean, the major surviving group was the “ray-finned fish”, which make up the vast majority of fish species today. They were able to survive due to some algae thriving shortly after the extinction, leading to the success of these fish.

What happened with marine predators?

For the predators, replacement with fish also occurred. The mosasaurs and plesiosaurs that lived in the Cretaceous period had disappeared, with sharks surviving into the modern day.

The advantage that sharks had on the marine reptiles isn’t well researched, but it could have been to do with the reptiles being warm blooded, hence needing more food than the cold-blooded sharks.

Sharks, crocodiles and fish existed before the K-Pg extinction. Posted by Ocean Generation, leaders in Ocean education.

How did algae survive?

Some algae also had the adaptations required to survive the extinction, with some having an inactive state that they can go into when water conditions aren’t ideal. This means they could live through the cold and lack of light from the impact winter.

Also, reproduction methods likely influenced their survival, as some algae could reproduce by themselves, but others required a partner to reproduce. During times of reduced population numbers, like the extinction, it is more efficient to not require a partner.

Different survival strategies of young cephalopods

Finally, between the ammonites and the nautiluses, they have different survival methods when young. The young nautiluses are birthed in eggs with a yolk to feed from, but young ammonites were thought to have had eaten algae, rather than having a ready food source. Reduced algae decreased the young ammonites’ survival.

Ammonite fossil and nautilus. Posted by Ocean Generation.

How do we know what happened during the extinction?

There is uncertainty about details of the past, because we are 66 million years in the future of the event. This means we must take logical guesses at what happened because we can’t observe events directly. To do this, we look at the rocks and fossils from the past, called the geological and fossil records.

A useful inference we can make is that if a fossil appears in rocks of a certain age, but not in younger rocks, it is likely that the animal has gone extinct. We have applied this to many of the organisms of the K-Pg extinction, like the dinosaurs, which tells us around when they went extinct.

This method is not foolproof though, as this assumption is susceptible to misinterpretations and mistakes. For example, there was a group of fish called the coelacanths that were thought to have gone extinct during the K-Pg, as it hadn’t appeared in the geological record since. However, modern relatives were later found, leading to the realisation that they hadn’t gone extinct, but just happened to not preserve as fossils after the K-Pg extinction.

Why does this matter?

It may seem like studying the past life is just for fun, and while it’s fun, it’s also useful. Understanding the mechanisms and effects of past mass extinctions, especially for the Ocean, can help us prevent a human-made one. Lots of the present-day organisms affected by modern extinction, like whales and corals, live in the Ocean.

Many species could and have disappeared due to human activity, with the current rate of extinction being at least 50 times higher than the background rate (i.e. the rate without human influence). By studying the past, we can understand the effects of our actions and possibly prevent another mass extinction.

The other side of this is that the Ocean is largely unexplored in space, but also in time. Exploring past life can tell us what has once lived on our planet and the environments that they lived in telling us more about our Ocean and Earth.

The current rate of extinction is higher than the rate without human activity.

Post by

Elliot Yu

Fact file: Fun facts about orca (killer whales)

Monthly: Impact in your inbox.

11. 09. 2025 Elliot Yu

How do the Sounds of Kelp Forests Change?

Copied

The age-old question goes “If kelp falls in a kelp forest and no one is around to hear it, does it make a sound?” … or something like that.

The study of kelp forest soundscapes is new, but it is essential to understanding the ecosystem.

What are kelp forests?

Kelp forests are incredibly diverse and important ecosystems of organisms living within dense areas of (surprise) kelp in coastal regions.

Kelp forests, and more generally seaweed forests, act as major carbon storage for the planet and are, when compared to the woods, incredibly diverse, containing mammals, arthropods (shrimps), echinoids (sea urchins), brachiopods (a shelled animal that feeds via filter feeding) and much more.

What does the Ocean sound like?

The Ocean is surprisingly noisy. Sound is used to convey information over long distances, and to neighbours on the reef or in the grass. In water, sound travels farther than either light or chemical cues and moves almost five times as fast as it does in air.

Marine mammals like whales and dolphins are famously loud and use sound to communicate. Sperm whales can reach volumes louder than jet engines. But a shocking truth is that other marine animals contribute to the Ocean soundscape too! For example, did you know that some fish make hums and purrs?

Beyond marine animals, there are other sound sources in the Ocean. Geological sounds (earthquakes and landslides) and our own human activity (engines and drilling) have their own effects on the Ocean soundscape.

What do kelp forests sound like?

Kelp forests are an unfamiliar setting to most of us, so to assist on our adventure of the soundscape, we’ll venture through the woods at the same time.

In the woods, we hear distinctive, familiar noises. The twitter of birds, the chattering of rabbits and the chirps of insects dominate the soundscape. In kelp forests, we can hear the different calls of fishes and the frequent snapping of shrimp.

The noises of kelp forest can be separated by their pitches. Generally, lower tones contain the noises of marine mammals and fish. The higher tones we’d hear contain the clicks of snapping shrimp and the sound of echolocating dolphins (although this is higher than the human ear can hear so it’s silent to us).

These soundscape features often change in both environments over time due to natural factors, like seasonal changes, or human activity.

Daily changes in the kelp forest soundscape

As the night comes, the sounds of the daytime animals switch to the noise of nocturnal animals.

In the woods, hooting owls and squeaking bats take over the soundscape along with the occasional chirp from foxes. This daily change is seen in kelp forests too, where the activity of animals and therefore the volume of their sounds shifts over the course of the day.

For some species of fish, their noise peaks at sunset and dips at sunrise. As well as this, snapping shrimp are nocturnal, which shows in their activity, as they have peaks at sunset and sunrise but a decreased activity during the day.

Seasonal changes in the kelp forest soundscape

With the arrival of autumn and winter in the woods, some animals migrate or hibernate, removing their noises from the soundscape.

A seasonal change also occurs in the kelp forest, where the time of year can affect the presence of animals.

The Plainfin Midshipman fish makes nests near the coast and uses a humming noise to attract a mate. This humming is heard in the kelp forests during late spring and summer, consistent with their mating season. Contrasting this, the presence of snapping shrimps is maintained year-round.

Plainfin Midshipman fish humm during spring and summer. Posted by Ocean Generation. — *Photo by Sara Thiebaud*

Human influence on kelp forest soundscapes

On our walk through the woods, we come across barren spots without trees, caused because of storms or fires. Similarly in the Ocean, an abundance of sea urchins and a lack of suitable food can cause them to feast on kelp clearing the area and leaving a space overrun with small, malnourished sea urchins, with the East Fish camp in California having an urchin density of 26.8 urchins per square metre.

Although urchin barrens may seem like a natural environment, they are created by human activity, just as extreme weather can become more prominent because of global warming.

Normally, sea otters and the occasional fish prey on urchins before the situation gets out of hand. But, due to hunting and overfishing, sea urchin predation is decreased, allowing their population to spike and kelp forests to be removed.

Urchin barrens influence the kelp forest soundscape. Posted by Ocean Generation. — *Photo by Ed Bierman*

Sea urchin barrens influence the kelp forest soundscape as the region becomes less suitable for some species and more suitable for others. When hundreds of sea urchins move in, they change biodiversity.

A more direct human influence on woodland soundscapes is deforestation. The direct removal of trees by humans to clear space or for resources is easily a big issue, as it decreases habitat space, reducing biodiversity and harming ecosystems.

A similar situation happens with kelp as it can be harvested, as it has uses like in food and beauty products. As a consequence, the amount of kelp is decreased, showing little to no recovery after two years, and biodiversity can change to be unlike before harvesting.

Does human noise affect kelp forests?

Listening in our woods, we don’t only hear animal noises but also human noises. Cars on roads which cut through the woods or heavy machinery operating can create loud persistent noises which can disturb the soundscape, affecting the distribution of the animals.

The same is true for animals in the Ocean. Loud noises like drilling and seismic surveys are loud and the noise can be emitted for tens of kilometres, causing confusion and hearing damage in marine mammals and fish.

Other sounds like engine noises from low flying planes and boats can act as background noises which decrease the distance that animals can hear and communicate.

Sound disturbances can normally be mitigated in kelp forests by kelp’s ability to attenuate (absorb and decrease) sound. However, because of the removal of kelp forests, this mitigation can quickly be removed.

The building of docks and other structures may seem like they could bring back attenuation, but they can also transfer noise from cars and docking boats into the Ocean, affecting microenvironments.

What can we do?

It may seem daunting that humans can cause all of this damage, but not all change is bad. Just as forests can be replanted and wildlife protected, as can kelp forests.

The growth of kelp can be stimulated, and areas can become marine protected areas, which can allow areas to be conserved. An example of this is in New Zealand, where an urchin barren has recovered back into a kelp forest within a marine protected area over the period of 20 years.

Looking at how we live our lives, like where our fish comes from or our usage of boats can make a difference in helping this delicate ecosystem.

Post by

Elliot Yu

Fact file: Fun facts about orca (killer whales)

Monthly: Impact in your inbox.

5. 09. 2025 Elliot Yu

Is Seaweed the Secret to Ditching Plastic? Explained.

Copied

Plastics play an essential role in modern human civilisation. They are incredibly versatile, providing function in almost all aspects of our lives.

Why plastic is a problem for us and the Ocean?

Fossil-based plastics are infamous for their long-lasting impact on the environment, taking up to hundreds or thousands of years to fully break up. Along the way, they harm wildlife and people both as large plastic items and microplastics.

The impact of this is demonstrated perfectly in the Ocean, where wildlife can unknowingly eat or interact with plastics. It has been observed that every species of sea turtle has been affected by entanglement in plastic.

Plastics have another big problem. They’re sourced from oil, which contributes to their damage to the environment. 3.4% of global emissions were contributed by the plastic lifecycle in 2019, with 90% of that being emissions from production and converting fossil fuels into plastic making materials.

What's wrong with plastic - for us and the Ocean? Explained by Ocean Generation.

What are microplastics?

Microplastics are plastic particles less than 5mm in size formed from the breakup of plastic. They’re found across the planet, from deep in the Ocean to the snow high in the mountains. They’ve even been found in the human body. We don’t fully know yet what that means for our health, but we do know they harm marine life and can travel up the food chain.

Single use plastics, like plastic bags and straws, are big contributors to plastic waste, making up approximately half of all plastic waste. We only use them once and then throw them out, which means more and more plastic needs to be made to maintain supply.

What is the solution to our plastic usage problem?

Recycling is one solution to this problem, but in 2019, the OECD estimated that only 9% of plastics are recycled.The rest is disposed of in landfill sites (50%), incinerated (19%), or goes unregulated into uncontrolled landfills, fires or the environment, including our Ocean (22%). On top of this, not all plastics are recyclable. Is there another solution?

What are bioplastics?

According to European Bioplastics, “bioplastics” are either bio-based, biodegradable, or both. Bio-based plastics are plastic alternatives which, rather than using fossil fuels to source the plastic, use biological feedstock (materials) like starch or cellulose.

Bio-based plastics are not necessarily biodegradable. Biodegradability has no clear definition or criteria, but in general, a product is biodegradable if a substance can be broken down into water, biomass and gasses. As a result of this definition, biodegradable fossil-based plastics can be considered as bioplastics.

What are the different types of bioplastics?

There are 3 distinct generations of bioplastics, all defined by what they’re made of:

1^st generation bioplastics use food crops like corn or soybeans.
2^nd generation bioplastics use non-food crops like grass and wood.
3^rd generation bioplastics use seaweed and algae.

What are bioplastics made of? Posted by ocean Generation.

What’s the major difference between using seaweed and crops?

The major difference between crop-based and seaweed-based bioplastics is where they are planted.

The first two generations of bioplastics use fertile land which could be used for growing other crops.

Seaweed bioplastics are bio-based plastics and derived from seaweed. Seaweed bioplastics don’t have the same problems as the other generations as seaweed grows in the Ocean (which there is much more of than fertile land on Earth), and require only sunlight, atmospheric CO₂ and the naturally nutritious waters of the Ocean.

They are a relatively new discovery; the first seaweed bioplastics company was established in 2010. Lady Gaga’s music career began before bioplastics were commercial.

How are seaweed bioplastics made?

The first step is letting the seaweed spores grow before they are put into a seaweed farm. They are then harvested a few months later.

The seaweed contains molecules that can be extracted via chemical processes. These have gelling and film-making (like plastic wrap, not movies) properties which make them useful in bioplastic production.

The extraction process leaves behind residuals. These leftovers can be turned into seaweed pellets which can feed back into the bioplastic making process, reducing waste. They can also be converted into methane which comes with the disadvantage of being a greenhouse gas. However, if captured and stored, it can be a carbon effective source of methane, which can be used in the chemical industry, or as a cleaner fuel than fossil fuels.

Our molecules can be mixed with other substances like nanoclays or silver nanoparticles to improve strength or change properties like making them antimicrobial.

Seaweed bioplastics are already used commercially in places like food packaging – that’s pretty kelp-ful!

Seaweed is a macroalgae growing in the Ocean.

What is the environmental impact of seaweed bioplastics?

The life cycle assessment of seaweed bioplastics looks at its carbon footprint from harvesting it from farms in the Ocean to its disposal in bins. Pilot scale assessments (these represent full production at a smaller scale) show that their production released more carbon than plastic, however, models show that scaling up production to full scale makes their carbon output less than plastics.

What are the downsides of seaweed bioplastics?

Making seaweed bioplastics relies heavily on farming and harvesting seaweed. This may present a problem when scaling up seaweed farms, especially to the size of being able to match plastic production, if this is even possible. Seaweed farms take up space in the Ocean, and they affect organisms that are living in areas where farms are viable, like seagrasses and corals by blocking light or choking them.

This problem can be mitigated by moving seaweed farms into the open Ocean and optimising growth by growing two different species in the same space. This can be done by growing buoyant kelp and non-buoyant seaweed next to each other to best use space.

Seaweed can also wash onto the coast from farms and decay, releasing pollutants that were absorbed over the life of the seaweed, affecting the local environment and limiting biodiversity.

There is also the problem that not all bioplastics are biodegradable. While it may be entirely possible that seaweed bioplastics specifically are biodegradable, there isn’t yet enough literature to suggest that this is the case.

On top of this, the definition of biodegradability has no specific time frame in which a material should be broken down in, meaning this vagueness could be taken advantage of.

This reintroduces a problem that we were trying to solve, simply sourcing the plastics from elsewhere.

Which plastic or alternative is the bets to choose?

Which plastic (or alternative) is the best to choose?

There are many factors that go into considering a product: the production, the functionality (how good it is at what it’s supposed to do) and the environmental cost.

However, it can be difficult to remove bias. Take single use paper bags for example. At first glance, they seem much more environmental than single use plastic bags as they’re biodegradable, but when put into practice, they have a higher carbon footprint in production than plastic bags and aren’t as strong. So, it’s difficult to tell which of these is better.

As more research goes into seaweed bioplastics, we may find solutions to the problems associated with them and have a more accurate understanding of their impact as they are produced on a larger scale. For now, it is better to avoid single use items altogether, and to use seaweed bioplastics where available.

Post by

Elliot Yu

Fact file: Fun facts about orca (killer whales)

Monthly: Impact in your inbox.

The oldest things in the Ocean: Explained.

What do we mean when we say the “age of the Ocean”?

What are the very young things in the Ocean?

What’s the oldest vertebrate in the Ocean?

One of the oldest living Ocean animals is a clam!

How old is Ocean water?

What are the young things in the Ocean?

What’s the oldest animal?

One of the oldest and largest coral ecosystems

What is middle-aged in the Ocean?

How old can ice get?

How old is the Ocean crust?

Ancient fish fossils

What are the oldest things in the Ocean?

How long has water existed on Earth?

How do we know the ages of things in the Ocean?

Counting growth lines

Radiometric dating

Correlative or model-based dating

Why is the age of the Ocean important?

Related content

How did fish farts nearly end the world?