How Ocean Environments Could Save the Planet
You’ve probably heard of reforestation projects, or even peat bog restoration as examples of how nature can help us capture carbon, but have you ever thought about the power of marine environments?
Dr Ian Hendy is a Tropical Marine Ecologist and Course Leader for Marine Biology at the University of Portsmouth. In the latest episode of the Life Solved he shares some insights into the incredible capacity these natural ecosystems hold in the fight against climate change.
In order to reach our net zero goals, carbon capture and storage is a vital part of the equation. By removing carbon emissions from the atmosphere we can slow and hope to stop the warming, ‘greenhouse effect’ this causes. In addition to clever technical innovations, scientists are increasingly turning to natural processes to help us out. These are known as ‘nature-based solutions’ Ian says coastal and marine environments hold some of our most precious assets here. From sea grasses and kelp forests in our chilly British waters to mangroves in tropical environments.
The marine biome is by far the biggest biome on the planet. Organisms here will have a very good climate change mitigation impact so they can draw down CO2, get those greenhouse gases, they store them in the sediments, they create nice carbon sinks. And of course, they create structure, are a nursery function for fish and reduce coastal erosion, so they’re very good natural storm defences.
In the podcast Ian explains how integrating the socioeconomics of a region is fundamental to the success of projects that aim to restore flora and fauna in marine environments. Often coastal development or intensive fishing can come into conflict with local ecosystems and he shares examples of projects that are working with communities to adapt and maintain livelihoods in these all-important regions.
Have you heard of the term ‘ecosystem services?’ Ian says this reframing of an ecosystem’s value in terms of its benefits to human life can help us attribute economic capital that can make the case for conservation in commercial terms:
The structure provided by those ecosystems, such as the mangrove forests, seagrass bed, salt marsh, a kelp forest, creates significant spawning grounds for very important commercial fish species. So not only do they increase and enhance the biodiversity, but are also very important economically for the many people that depend upon them.
Ian is currently part of a consortia that’s leading the UK’s largest kelp restoration project. For the first three years they worked with local communities along the 30 mile stretch of coastline to understand how coastal livelihoods were impacting ecosystems here. Ian’s first job as a commercial fisherman came in handy when he needed to see how dredging and trawling had damaged the once verdant forest of kelp here along the South Coast. In projects such as this, fishing activity continues to take place, but with less invasive and destructive practices. By using more sustainable and low-impact methods such as static and drift nets, Mother Nature is able to have a helping hand in restoring habitats.
What’s more, there are plenty of other ideas on the horizon for how humans can intervene to promote and support natural processes, but Ian warns that research is vital to measure and understand any unexpected impacts.
As the UK pushes forwards on reducing carbon emissions, and begins to harness the power of coastal environments, the future looks exciting for carbon capture, oceans and marine ecologists like Ian!
You can listen to the full podcast from Tuesday 3 May 2022.
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Narrator: Welcome to Life Solved from the University of Portsmouth. Today’s guest shares his work in conservation. He’s doing research that’s changing our world, and providing environmental restoration solutions that support life and livelihoods. But he started out in commercial fishing.
Ian Hendy: I did it for about two years and I just couldn't face the destruction. I don't want to instil ecological grief because there is a big turning point now. People are striving and leaping towards conservation and low impact methods.
Narrator: Dr Ian Hendy is a Tropical Marine Ecologist. He’s a Senior Lecturer and Course Leader for Marine Biology here at the University of Portsmouth. And this time we’ll find out how his passion for restoration, socioeconomics and marine conservation are uniting in projects that bring a glimmer of hope to the plight of our planet.
Ian Hendy: My research spans from Indonesia, Southeast Asia, where I look at coral reefs, seagrass beds and mangrove forests. So my research, more my PhD, back in the day was centred on mangrove forests and the connectivity of the structure of mangroves, and how that ultimately affects the biodiversity within the mangroves, but also in the adjacent ecosystems of sea grasses and coral reefs. My research also spans over to the Caribbean, where I look at seagrass corals and mangroves over there. But in the UK, so in the cold water ecosystems, I look at salt marsh seagrasses and kelp forests.
Narrator: Let’s start with the big picture: Sea grasses, corals, mangroves and salt marsh environments around the world could hold some big clues to helping humanity face the critical problems that come from biodiversity loss, carbon emissions and climate change. What’s more, the innovative science and research that’s taking place around these mysterious and wonderful natural assets may end up offering our planet a second chance.
Ian Hendy: These coastal ecosystems are vital. If you think of the planet. Think of the land. Think of the oceans. And if you think of them as biomes, so mutually distinct ecosystems, the marine biome is by far the biggest biome on the planet. Those ecosystems in actual fact, will sequester a huge proportion of the amount of carbon that's drawn down from the atmosphere. So they're hugely significant in terms of mitigating climate change, but also they have what we call ecosystem services. So the structure provided by those ecosystems, such as the mangrove forests, seagrass bed, creates habitats and creates what we call a nursery function. So they are significant spawning grounds for very important commercial fish species. So not only do they provide an increase and enhance the biodiversity, but are also very important economically for the many people that depend upon them.
Narrator: The term ‘ecosystem services’ casts environments in a different light to the romantic, wildlife havens we’re prone to thinking of them as. In fact the economic benefits different biomes bring can provide a powerful argument when assessing their value in financial or even capitalist terms. And it’s this kind of argument that’s needed in order to make the most carbon-intensive and developing nations sit up and incorporate their conservation into their plans. Where these ecosystems have historically been under pressure, the tide is turning. Ian gave an example of one such project:
Ian Hendy: If we look to Southeast Asia and we look to the Caribbean, so we look at those ecosystems, the coastal area is under high demand, whether it's for coastal developments, for creating resorts, whether it's for cutting down mangroves and in place to put shrimp farms or shrimp ponds to make a quick buck. It's all about socioeconomics. I completely understand it and I'm an applied ecologist, so what I want to do is go out to these ecosystems, protect them. But you have to have the stakeholders and land owners on side to have a really good restoration and conservation project to work. And so what we have to do is implement a sustainable, low impact way to mitigate those losses. So mangroves, for example, we're seeing about two per cent losses of the surface area globally per year. Now I've mentioned ecosystem services that will have a huge monetary value. So there's a huge loss, in actual fact, that the net worth of mangroves is worth far more in having them than it is cutting them down to make a shrimp farm, for example. And so there are many projects now coming out to actually monetise the restoration of those projects where those funds will then go to the local communities to support the communities, not to cut those ecosystems down.
Narrator: Still wondering what a mangrove is? These shrubs and trees have unique root and filtration systems so that they can thrive in salty water and low-oxygen zones like mud. They’re especially adapted to live in tidal zones, like those along the coasts. They’re great for providing wildlife habitats, and mangrove forests can also provide a protective barrier against erosion from strong tidal action like tsunamis. They’re the heroes of coastlines around the world. But they’re also inconvenient for coastal development, so placing a value on their ‘services’ is essential to restoration projects. In the UK we’re more familiar with seagrasses. These underwater meadows are our very own version of the mangrove forest.
Ian Hendy: In the UK alone, we've lost over 50 percent of seagrasses in the last 100 years. And these will have a very good climate change mitigation impact, so they can draw down CO2, those greenhouse gases, they store them in the sediments, they create nice carbon sinks, and of course, they create structure with that nursery function that we talked about. They reduce coastal erosion, so they’re very good natural storm defences. There's a whole wealth of services that they provide, but we're losing seagrass habitats in the UK alone, I think in actual fact, the erosion rate of sea grasses is about 40 hectares per year, losing seagrasses. And if we count the same rate of loss for kelp forests by the end of this century, we'll have zero kelp forest left in and around the coast of the UK. So we're losing these ecosystems rapidly. This is primarily due to coastal development, changing habitat, what we call phase shifts. So where the ecosystem goes from a steady state to an unstable state, this could be through destructive activity what we call eutrophication. So nutrients going out to the water, changing the environment, which these ecosystems, particularly sea grasses, salt marsh kelp forests are very sensitive to.
Narrator: Eutrophication is an excessive growth of plants or algae, and can be caused by too much carbon dioxide, sunlight or fertilisers. Human activity can upset the natural balance of ecosystems to create this sort of destructive bloom. But “phase shifts”? What’s that when it’s at home?
Ian Hendy: A phase shift is where the ecosystem goes from a steady state ecosystem to an unstable state ecosystem. So it's where you're changing the environmental variables and the whole balance is knocked out of whack. Have you heard the term, the shifting baseline syndrome? As an ecologist, what we're trying to do is rewind time back to an era where ecology, the environment was healthy. So if we think of an epoch of time, for example, the Holocene, which was a perfect area of time where everything was thriving and surviving, all the organisms of plants and animals were within what we call the zone of tolerance. And what we're seeing now we've gone to the Anthropocene, the sixth mass extinction. And this is through human mediated, of course, climate change, changing environmental variables, organisms, animals, plants, fauna, flora, all going out of the zone of tolerance. We're seeing mass mortalities. Now, the shifting baseline syndrome will be, for example, my mom and dad, your mom and dad will say, Oh, you should have seen this forest or you should have seen this river 30 years ago, it was full of life, but then their parents would have said, Oh, that's nothing if you saw it 30 years before that, it was even better. So what we don't know as ecologists, is what really biodiversity and the ecology should really look like. We have an idea, but we just don't know, because all these ecosystems now have gone to a such a state where they're — I don't want to instil ecological grief — but that most of them are impacted. Even though, let's say we go to the most healthiest sites, they're still going to have impacts to them from a time gone by. If you were to compare and contrast from, say, 200 years ago, 300, 400 years ago. So what we're trying to do is create a resiliency, a robustness of ecosystems for future generations of people that are dependent upon them so we can feed the world, we can provide habitat, we can mitigate climate change and we can do it in a sustainable and low impact way.
Narrator: In Ian’s opinion, what’s the extent of the opportunity the oceans bring us to work with our oceans and face our global challenges? And how much more can they add to existing, land-based, nature-led solutions such as reforestation and the like?
Ian Hendy: Let's look at the planet as a whole. 30 percent of the planet is land. What's the population at the minute? About eight and a half billion people on the planet, something like that. Projected population in the year 2050 is going is going to be 10 billion people or just under. Now think about utilisation and exploitation of ecosystem services. At the minute we are at one point eight worth of planet's resources that we're exploiting. So we're almost two planets worth of resources that we have to reduce resources to feed the people now. And if we fast forward 30 years from now, there's going to be 10 billion people, so another two billion people on the planet. So we have to act fast. Now if we want to mitigate and reduce the impacts from climate change to restore ecosystem services. Looking to the land, I feel is going to be unlikely because there's going to be more exploitation on the land with an increased demand. Because of the increase in population, 70 percent of our planet is marine. Let's think about carbon drawdown, so greenhouse gas drawdown 55 percent of all CO2 emissions are drawn down by the oceans. Of that 55 percent of the CO2 that's drawn down into the oceans, about 50 percent of that is drawn down by mangroves, salt marsh, sea grass and macroalgae. OK. And yet those ecosystems only take up a marginal piece of that marine biome. The rest of the CO2 is drawn down by single celled phytoplankton, by the way. So all of them play a massive role in regulating our climate.
Narrator: A lot of numbers there and in them lies the truth: we’re using up our planet faster than land can provide for right now, but Ian says our underutilised oceans will have to step into the breach. In fact, it’s a no brainer when he puts it like this…
Ian Hendy: Looking to the oceans for restoration is highly likely because they pack a powerful punch relative to their surface area in terms of carbon drawdown, mitigating climate change and of course, not only do they mitigate climate change, they reduce CO2 emissions, all of those thing, but they provide food, they reduce storm waves. Of course, with climate change, you got increasing storms. So if you've got kelp forests, salt marsh and seagrass, for example, you can reduce waves around the UK coasts by up to 70 percent, so you can reduce that wave power and reduce coastal erosion. Mangroves are vital for natural storm defences. If you think of low lying islands where you have tsunamis, you've got those mangroves, they're very important natural sea defences. So rather than spending millions and millions of US dollars for sea defences. If you have these nature-based solutions, you can take all of those boxes and provide food provisioning for people that are dependent upon it. So super important.
Narrator: What sort of restoration projects are taking place now then? Well, bringing together different areas of expertise at scale takes collaboration. Ian’s part of a consortia of universities here along the South coast as well as organisations like the Zoological Society London, Sussex Wildlife Trust, the Blue Marine Foundation, Marine Conservation Society and even a TV production company.
Ian Hendy: We are leading on the UK's largest kelp restoration project. This spans a 30 mile coastline stretch of water encompassing 300 square kilometres. Now, any restoration project takes a long time, and they do move at glacial speeds, but it has to be done right and correctly. You have to work with the local stakeholders, otherwise you don't have restoration or conservation policy. There's a socioeconomic issue. So you have to primarily work with the end users. So we're creating workshops, working groups with fishermen, with businesses and local councils all along that coastline. Forty years ago, the kelp forests around Sussex, which was spanning from Brighton to Chichester, was extensive, actual thick, thick kelp beds, really dense kelp forests, and we had a thriving fishing community because of that, because of the structure provided by the kelp, now due to environmental conditions, due to destructive activities. We're now down to 4 percent of what we used to have, so we've lost 96 percent of kelp forests in that area. Now, with the loss of kelp comes a 90 per cent loss of associated biodiversity of those fisheries. So there's a huge what we call trophic collapse of the ecosystem. Now so what we've done is created this byelaw. So this is the first government sanctioned protected area in the UK that covers 300 square kilometres, now of that area. We want to restore the historical kelp forest that once covered the area, which covers an area of about 170 square kilometres. So we got a bit of a buffer zone, if you will, of protected areas. And so what we're doing is having passive restoration. So letting Mother Nature, who better to do the restoration of Mother Nature, so we're going to get Mother Nature to restore naturally areas where the kelp will grow back.
Narrator: The first three years of the project was focussed on stopping the harmful activities that were destroying the kelp forests along this stretch of coastline. But the group had to be mindful of the socioeconomic impacts of this change too.
Ian Hendy: We stopped trawling and dredging activity, so it's that mobile activity of dragging, of a beamtrawl what we call otter boards that drag the net across the seabed. So effectively what you're doing is you're getting a giant lawnmower and mowing down those kelp forests. What what we need to stress here is that when we don't want to stop commercial fishing, What we want to do is actually promote sustainable, low impact commercial fishing. So things like using lobster pots where they're static and not being dragged static nets, drift nets where they just stay still and the fish swim into those.
Narrator: Leaning back on more traditional processes has allowed the seabed and kelp to begin recovering. The inspiration for this was a project at the Lyme Bay fishery.
Ian Hendy: In Devon and Dorset, for example, there's a sustainable fishing. That’s called co-op of fishermen that fish sustainably with low impact methods that do a wonderful job at maintaining the local biodiversity and the seabed communities, the benthic communities of the seabed are thriving, the fisheries are thriving. So this is a win for the ecology, win for the environment and of course, a win for the economy, for the people that depended upon them. So we want to roll that model out around the UK and of course, globally as well. So we're using that model in Sussex. What we're going to be seeing is a net increase in the structure of the kelp forests, which will only improve the function of the ecosystem of that biodiversity. So effectively, what we've done is stopped all the destructive elements of commercial fishing, but maintained the low impact sustainable elements of commercial fishing.
Narrator: To Ian, the change in thinking that’s required is systemic and requires a more low-impact approach.
Ian Hendy: We need to be more sustainable in our thinking, we have to have more empathy for our environments, in how we treat our animals, because if we carry on at the same rate of loss — for the last 50 years, we've lost 50 percent of our ecosystem services. So if we carry on at the same rate of loss, we will have zero ecosystem services or benefits of our ecosystems left before the end of the end of the century.
Narrator: But Ian’s not coming to this from a narrow perspective. His understanding of commercial fishing began as a youngster, and has caused him to think about ways of sustaining livelihoods without damaging environments.
Ian Hendy: I was the world's worst commercial fisherman because, this would have been in the mid 80s. I would have been 13, 14, 15 and I loved fishing. I still love fishing, angling with a fishing rod. But I went out commercial fishing. I did it for about two years and I just couldn't face the destruction. And even then I realised the destruction and washing over the side, dead fish, maimed fish and watching the flow broke my heart. I would get paid weekly, and my boss at the time would say to me, right Ian, let's say it was the summer time and we would get the lobster pots and we'd go lobster fishing. We would catch quite a few lobsters each week, of course. And at the end of the week, if it was payday, they would say, What do you want the full week's wages or do you want to take most of the wages and take part payment in lobsters? So I would always take part payment with it lobsters. And of course, they were alive, so I would cycle straight back round to the sea front. I'd find a special place where there's lots of rocks in the water and just release them again. And so my mom used to find it hilarious that I would do that. But at the time, I didn't know that I was a conservationist. It just dawned on me later on in life.
Narrator: One particularly exciting, developing area of research lies in the power oceans hold to capture carbon and store it. This wide-reaching science is sometimes referred to as ‘blue carbon’.
Ian Hendy: When I teach about blue carbon, I introduce it in a way of two things blue carbon and green carbon. And so I talk about the analogy of terrestrial forests. People get that straight away because they can see it every day. So green carbon. All right. So it's in the mud. Yeah, absolutely. So what's happening is these trees are photosynthesising. They're drawing down that CO2 with oxygen and sunlight, creating their woody tissues. And what you can see is the physical CO2 in the woody structure. So that's carbon. That's above ground carbon like green carbon and the below ground carbon stocks are in the mud. Now, if you think of the ocean and the reason why they call it blue is because of the blue ocean. Simple as that. Now what happens is that carbon will get stored in the same way, but slightly different processes than the terrestrial environment.
Narrator: So how do marine environments lock away, or ‘sequester’ carbon, compared to rainforests, for example?
Ian Hendy: If you have one hectare of mangroves and one hectare of terrestrial forests, a mangrove per unit area can store between 1000 to 1200 tons of carbon per hectare in its sediments. A terrestrial rainforest can store about 250 tons of carbon per hectare. So these marine environments pack an incredibly powerful punch in terms of their ability to draw down greenhouse gases and lock them away.I'm lucky enough to be working on the world's largest mangrove restoration project, spanning four thousand hectares. So if you think about one hectare with 1000 tons of carbon, extrapolate that up to 4000 hectares and how many tonnes of carbon you can draw down from the atmosphere and lock away. Now that's just the carbon. Let's think about the biodiversity associated with that, with the commercial fisheries, so that will also have a value.
Narrator: And how much does it cost to restore a mangrove forest? Ian says this example of community-led natural resource management adds economic value to the areas where restoration is taking place.
Ian Hendy: We’ve sought funding, in actual fact about 20 million US dollars for funding for this restoration project, 60 percent of those funds will remain with the local communities to incentivise them to maintain those ecosystems. Because, as I said before, it's a socioeconomic issue which I fully understand. These people will cut down a mangrove to put a shrimp farm in for a quick buck to earn a quick living. I completely understand that everybody has to survive and they need to feed their families, I completely get that. But of course, the value of these ecosystems are worth way more to keep those ecosystems rather than to lose them. So that's why you can monetise them and therefore incentivise the people that depend upon those ecosystems to maintain them.
Narrator: How long does it take to restore a mangrove forest then? Will we see an impact of this project in our lifetime?
Ian Hendy: If we are to restore mangrove and let's say there's a mangrove that's been cut down, OK, and there's been a mangrove that's being cut down for shrimp farms, but it's not an easy process because mangroves are sensitive to hydrology and tidal elevation. So you have to be very careful with the restoration project to do your due diligence to bioengineer the habitat back to where it once was to get the trees to grow back again. That's the first point of concern. Once you've done that, you can then do the mangrove restoration, and plant the specific local mangrove tree species to that area. So once you plant those tree species in the right tidal heights, I guess from year zero probably to about year 25 or year 30, you could get up to about 800 tonnes of carbon per hectare. So a significant amount of carbon in it in a lifetime. Even though the mangroves being cut down and there's now just the mudflats, if you were to take sediment cause and measure the amount of carbon in those sediment pools, there will probably be somewhere around anywhere between 100 and 200 tons of carbon per hectare still locked away. So you have that residual carbon on top of the new mangroves growing and laying down extra carbon stores.
Narrator: And what about the species we have growing closer to home in the UK – seagrasses and kelp?
Ian Hendy: Basically trees, seagrasses, grasses are manifestations of mixture of oxygen, sunlight, water and greenhouse gases in the atmosphere. So you can see the structure, the aboveground biomass and the mud, below ground. That's carbon that would otherwise be in the atmosphere, but now locked away. We're working on a seagrass project here in the Solent. So this is working with the Ocean Conservation Trust and a company called Remedies, reducing and mitigating erosion and disturbance impacts affecting the seabed. In the Solent, there's an area called the Beaulieu Estuary the area, I believe, is about a hundred hectares, the area that we're restoring I think it's four hectares. So four hectares of area within that 100 hectare area, and we're planting two and a half million seagrass seeds. But what we're doing is very labour intensive, so we're putting the seeds in small hessian sacks with a little bit of sea grass food and we're planting those sacks in the mud and then we're seeing the growth. And again, the seagrasses will grow 20 to 30 times faster than terrestrial grasses, for example, they’re very rapid in their growth. And so they draw down carbon rapidly and they store the carbon within those sediments, but they don't store as much as a mangrove will do the top end the mass amount of carbon that the seagrass will store. You'll find those in the Mediterranean can store around 100 tonnes of carbon per hectare. But locally around the UK, maybe 20 to 30 tonnes of carbon per hectare. So a modest amount of carbon and so a significant amount of carbon is still well worth doing.
Narrator: So many amazing ideas, from biological to chemical and electrochemical processes are in the works to lock away carbon and create booming ecosystems in the sea, as well as economic benefits or commercial industries. It’s an exciting time, but Ian says that we need to exercise caution, so that we can learn along the way and not do more harm than good.
Ian Hendy: We're in the Anthropocene now, the sixth mass extinction. Things are changing at a rapid rate, we need to react to that. But what we don't want to do is rush in and create further problems, for example. In the Caribbean, I work on seagrass impacts all along the Caribbean coastline there. And what's happening at the minute, there's huge swathes of Sargassum seaweed, and what it's doing is washing in on those coasts and it's swamping the corals, but it's swamping the sea grasses and it's killing them because it's rotting on the coastlines and it creates this toxic leachate. And of course, because of these big mats that come in. It cuts out the available sunlight, it increases the water temperature, reduces dissolved oxygen availability, changing the environment. Now there are many companies out there that are saying, Why don't we get the Sargassum before it reaches the coastline and just sink to the bottom of the sea? Now, sounds like a great idea, and you think well, yeah, let's go and do that. Well, there's been no due diligence done to see, well, hang on a minute. Are we going to be eutrophicating the deep ocean trenches? And what impact is that going to have to those ocean processes? So there has to be some signs them before that. So with all of these projects, for example, with UK's largest kelp restoration project in Sussex that we're working on, what we want is passive restoration and natural restoration to occur. Now don't get me wrong, we're not so naive to think, hang on a minute, we do need to have what we call active restoration, where we have to sort of do some due diligence and do some active science to make kelp grow back. But what we don't want to do is commercialise it. So much so, that there's kelp farms coming in and these kelp fisheries coming in where it's all artificial. So what we want is a natural process. First to happen, then we can look to trialling perhaps trialling areas with many kelp farms. Now don't get me wrong, I'm all for kelp farms. I think they're wonderful idea. If they're done correctly, you can. You can utilise it to draw down carbon and harvest it — kelp is a really good superfood. You can use it as a biofuel. All of these things that are compost and of course, you're providing habitat so you can and you can commercialise it in terms of those carbon credits because you can harvest it every month. In the UK, kelp will grow about 20 centimetres a month, so it grows rapidly. So all of that is carbon that's being brought down from the atmosphere. So you could just harvest it each month so you're taking away that carbon. But then from that is edible, you can make it into food. So you can also have this circular economy where you're feeding people as well. So but we're still scratching the surface on that. So it's all new technology and new science. But at the minute, ideally what we want to do is natural restoration. We're working with the local stakeholders and end users so that again, they can earn money for that socioeconomic issue. So it's a win for the economy, win for the ecology and for the environment as well. Then we could start looking at other technologies. But what we don't want to do is create further issues and create further problems.
Narrator: Thanks to Ian for sharing his exciting insights into the solutions the oceans could hold to tackling some of our planet’s greatest challenges. You can find out more about research and Marine Biology at the University of Portsmouth on our website port.ac.uk/research and find out more about all the projects Ian mentioned. We’ll be back again next week. Follow this podcast on your favourite app so you don’t miss it. And if you liked this episode of Life Solved, why not share it with a friend and start a conversation. See you next time.