Oceanography Episode 14: Blue Carbon in Antarctica
Antarctica’s Hidden Carbon Vault — Beneath the icy surface of the Southern Ocean lies a powerful ally in the fight against climate change: Antarctic blue carbon. In this episode of Oceanography, host Clark Marchese speaks with marine ecologist Dr. Narissa Bax about how deep-sea coral gardens, sponge fields, and seafloor ecosystems around Antarctica are quietly locking away carbon for thousands of years. Together, they unpack what makes Antarctic blue carbon different from coastal mangroves or seagrass, how climate change and global treaties shape its protection, and why these frozen carbon stores may hold a rare note of optimism for our warming world.
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Episode Transcript and more information on the Pine Forest Media website
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Hosted, produced, and edited by Clark Marchese
Find Dr. Narissa Bax website here.
Read Dr Bax’s publication: The Growing Potential of Antarctic Blue Carbon
Find all Dr. Bax’s publications on Google Scholar
Cover art by Jomiro Eming
Theme music by Nela Ruiz
Find some more Pine Forest Media podcasts below:
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Listen to Something in the Water on Spotify or Apple Podcasts
Transcript:
Clark Marchese (00:11.468)
Hello there and welcome back to another episode of Oceanography, the podcast that dives deep into the science of our oceans, the latest in marine research and the scientists working hard to better understand and protect our blue planet. And today we are learning all about blue carbon.
Clark Marchese (00:51.41)
All right, first of all, thank you so much for being here today on the Oceanography Podcast. My name is Clark Marchese. I am your host. And we have what might be for you as it was for me, a brand new scientific and oceanographic vocabulary word. If you have never heard of blue carbon before, that's what we're going to be learning about together right now. Now climate change, carbon, CO2, emissions, greenhouse gases,
A lot of these are pretty important words and those that you will hear a lot of if you follow environmental news. Despite all of us and every living thing being made out of carbon, and despite carbon being a really important molecule in a lot of our earth systems, the way that we humans are throwing off the balance of carbon in these different systems is causing quite a lot of problems.
Now, you may know that one of the reasons it's so important to preserve our Earth's rainforests is because they play a major role in pulling carbon dioxide from the atmosphere. And there are several systems within the ocean ecosystem that do the same thing. And today we're going to be focusing on one ocean in particular, the Southern Ocean, the one nearest to Antarctica, which we are beginning to understand is playing a much bigger role in global carbon storage than we ever imagined. And I will say Oceanography does have a sister podcast. It is called South Pole. And there we learn all about the science and research being done on and around Antarctica. And this interview actually was and is going to be released as part of a third season of that show. But of course, Blue Carbon has a lot of relevance for our oceans as well. So I thought it would be a good fit for a crossover. Stay tuned for more information about our next season of South Pole. And you can listen to the first two seasons in the meantime but don't be surprised if the focus of my chat with our guest is quite Antarctica-heavy. And before we get into that chat, I want to take just a minute to talk about the importance of science communication. Pride and Forrest Media is the only podcast network in the world entirely dedicated to creating environmental science content. And if you'd like to support the work that we are doing in a time where climate research is being actively defunded and undermined, we would invite you to share this episode with someone you know. And we thank everyone.
Clark Marchese (03:08.152)
who feels called to support us by just listening to the episodes we put out, subscribing, sharing them with friends, reading and reviewing, and letting us know how we're doing so far. All of these things help us reach more ears and help our entire network to grow. Alright, back to Blue Carbon. To help us unpack this concept, today I am joined by Dr. Nerissa Bax, a marine ecologist who has been at the forefront of this research. Dr. Bax has led expeditions in some of the most remote marine environments on Earth from the Southern Ocean to the sub-Antarctic, and her work has been recognized by the IPCC, COP27, and Australia's 100 Climate Conversations. She is also one of the co-authors of an article published in Frontiers and Ocean Observing titled, The Growing Potential of Antarctic Blue Carbon. And in this episode, we're going to explore what exactly Antarctic blue carbon is and how it works, why Antarctic seafloor habitats are unexpectedly becoming massive carbon sinks, the political and economic implications of recognizing Handarctica as a global carbon store, and what all of this means for the future of marine protection and climate policy. All right, I think that's all I have before we begin. So let's get started.
Clark Marchese (04:36.438)
Alright, so we are recording. Hello Dr. Bax, welcome to the show. The first question I have is if you could just introduce yourself and tell us a little bit about your research.
Dr. Narissa Bax
So my name's Nerissa Bax. I'm originally from New Zealand and I have been working mainly based from Tasmania in Australia for Antarctic research for the last decade or so, but I'm currently based in Greenland. So yeah, within working groups, working across both poles on predominantly blue carbon. But I came into this research first during my student years, looking at deep sea exploration and biodiversity.
Clark Marchese
You know, when I stumbled across your work, I don't think I had ever heard the term blue carbon before. So can you maybe start off by giving us a basic understanding of what that word means?
Dr. Narissa Bax
Yeah, so it's a term that is relatively new in the scheme of global blue carbon. So I think it was around 2009 when it was first put forward. And it's basically the idea of ocean life in marine habitats and the carbon that is stored and sequestered within those habitats.
And it's predominantly being focused on more tropical ecosystems, so mangroves, salt marshes, and seagrass. And it ends up being something I think particularly with the mangrove ecosystem that people can grasp as a way to quantify how much carbon an ecosystem is taking in.
Clark Marchese (06:09.358)
Okay, so let me just check my understanding. Blue carbon refers to the aspects within the ocean or the ocean environment that pull carbon from the atmosphere. And then I'll just assume Antarctic blue carbon is sort of a subsection of that within the Southern Ocean. Because for example, you mentioned that a lot of blue carbon could include mangroves, but I don't believe that there are any mangroves in or around Antarctica. So, if it's not mangroves, what sorts of things in Antarctica and the Southern Ocean would pull CO2 from the atmosphere.
Dr. Narissa Bax
Yeah, exactly. So you think about your surface phytoplankton and where it goes and a lot of the really beautiful biodiversity in Antarctica, particularly where my research groups have have focused, we've had more access to understanding the deeper areas, so exploring the seafloor and you can find these beautiful coral gardens, sponge fields. So it's basically like thinking about somewhere like the Great Barrier Reef, but putting it in a cold, deep, dark, Antarctic context. So people have looked at the sea floor and captured imagery over time series, the short time series that we have, and seen that there's actually a lot more colonization than you would imagine from these animals. And as a consequence, we are also seeing the ice melt, and this is changing the composition of the animals in the surface column as well. So we're seeing more blooms, for example, and this is producing an environment where more food is reaching these animals. And so in some contexts, we're seeing that they are increasing in their capacity, you know, to feed, to reproduce and to grow. And as a consequence, they have a higher capacity to take in carbon into their skeletons. And if this is buried,
Dr. Narissa Bax (08:03.042)
below the sediment, below the oxygenated layer, it actually ends up being taken out of the carbon cycle for hundreds to thousands of years. And this is really important from a climate change perspective. And this is something that is happening naturally and has been happening naturally on the seafloor, but is increasing from an Antarctic perspective.
Clark Marchese
Okay, there's a lot going on there. So I'm hearing changing conditions at the surface are resulting in increased numbers of photosynthesizing organisms, phytoplankton, that pulls CO2 to make energy. Then I'm hearing that this shift adds to an already thriving community of coral reefs in the deep sea that use carbon dioxide in the ocean to build their shells. And then once those shells and skeletons get buried deep enough, the carbon inside them that was once in the atmosphere is now stored there in place for what is essentially a very long-term sequestration within deep sea ocean sediments. One thing I'm curious about though is if Antarctic blue carbon or the processes involved are distinct in any way from processes in other oceans or other regions of the world, or how important is Antarctic blue carbon in the ocean wine context?
Dr. Narissa Bax
Yeah, so in the scheme of the world, the Southern Ocean is particularly important for these processes. More broadly, it's absorbing a large portion of our emissions and a large portion of our heat already. But the fact that it's potentially increasing through time, and it's across such a large area as well, means that it may have quite a large consequence comparatively. So you could quantify Even though it's quite a small amount, you can imagine if you have, you know, a square kilometer you can measure. But when you scale that up across such a large area on the sea floor, that ends up being quite, quite expensive and important. And it's also for the most part protected because we have a very unique.
Dr. Narissa Bax (10:04.322)
governance system for the Antarctic as well as the Antarctic Treaty system. So there's potentially pathways to protect this as an ecosystem service for society.
Clark Marchese
Okay, the protected area thing is important because listeners may be familiar with a process called bottom trawling, which is an industrial fishing method that sort of scoops up everything on the seafloor and has proven to be really destructive to coral reefs. But the conservation of Antarctic Marine Living Resources, or CAMLR, has some restrictions on bottom trawling in Antarctic waters. As just one example, among the many ecosystem services that coral reefs provide, If they are destroyed, they cannot store this carbon. But also there's one distinction I heard you make that I want to understand, which is that carbon storage and long-term sequestration are not exactly the same thing. Can you speak to that?
Dr. Narissa Bax
So it's more about we've been able to quantify carbon storage, but there's a lot of gaps in terms of how much of the storage translates into long-term sequestration. And it's also in terms of syncing up the pathway. So terms like blue carbon often get kind of politicized in the way that they are taken on board as a way for countries to meet their emissions. And so it's a framework for conservation in that regard. And so what we tend to find, which makes a lot of sense, is that if you find an area that has a higher amount of biodiversity, you will find that it has a higher capacity to store carbon and then potentially a high capacity for sequestration. But within the current framework for blue carbon as something like carbon credits,
Dr. Narissa Bax (11:57.706)
It's an economic model of looking at quantifying it in monetary terms.
Clark Marchese
Right. So when we talk about carbon credits, we're essentially talking about a market based system where companies or countries that emit carbon dioxide can purchase credits from projects that are removing or reducing carbon from the atmosphere. And these credits are meant to offset emissions. So if a company cannot or isn't interested in reducing its own carbon output, it can invest in initiatives that are capturing and storing carbon elsewhere.
And this strategy operates in the larger context of countries working to fulfill their individual commitment to reduce their climate impact under the Paris Agreement. More on this in a couple of weeks when we cover the COP 30. But this is where the distinction between carbon storage and long-term sequestration becomes crucial. In the carbon credit system, only carbon that is permanently removed from the atmosphere for centuries or more is truly considered sequestration. When applied to the ocean, Blue carbon projects like restoring mangroves, seagrass meadows, or salt marshes are increasingly being used in the system. However, the deep sea, where carbon can be stored for thousands of years, operates differently from coastal blue carbon. And because carbon markets are political as much as they are scientific, who gets to claim credit for that sequestration, how it's verified, and whether it's really offsetting emissions long term are ongoing debates.
That's why distinguishing between temporary carbon storage and permanent sequestration is key. But the topic of carbon credits is directly in the context of climate change. So while we're on that topic, let me ask you, do we know if or how climate change might impact the current process of blue carbon sequestration in Antarctica or elsewhere?
Dr. Narissa Bax (13:47.628)
Yeah, so there's been some projections. It's at the moment in terms of we kind of have this piecemeal approach of taste study locations. So around the Antarctic Peninsula, some of the Antarctic locations, there's big unknowns for areas such as East Antarctica, you kind of less studied areas. And so it would be inaccurate to extrapolate across all of those areas as if they are one. But there are large areas that there is no data for this. And it's sort of increasing through time with different research groups and different collaborations and case studies to get an overall picture.
Clark Marchese
Okay, well while we're waiting for that data, probably best not to do anything to make it worse. One thing I saw in some of your work is that we may need a further layer of policy protection to safeguard the ecosystem's ability to perform less carbon storage and sequestration. Can you speak to that?
Dr. Narissa Bax
Yeah, so it's a really interesting time because this sort of the way that we look at this in recent years has changed, I think, throughout the process of talking about it. So originally, when we got together as a multidisciplinary group, so we had the science side, but we partnered with lawyers and Antarctic policy experts to think of a way to do this. And so the government's governance structure that you already have in place is the Antarctic Treaty system. And the Antarctic Treaty system was something that was formed, you know, in a very different era. And it's a very beautiful treaty in many regards, you know, it's put forward to protect Antarctica as a place for peace and science. And we also have the Biodiversity Beyond National Jurisdiction Treaty, which is coming into
Dr. Narissa Bax (15:35.446)
into being as well, but it is coming in at a time when there is much more talk of climate change, understandably. so finding ways to make these treaties that are globally applicable and collaborative, meaningful, is to also understand that biodiversity and climate change are linked. So that was kind of more what we were putting forward as a conservation measure.
But I think now so many people are thinking about this, hopefully, that there's also, there was a paper recently by Santos and colleagues, and they were talking more about the idea of climate smart marine spatial planning. So it's something that could be incorporated within that as well. And you have the structures for Antarctica in terms of your ecosystems are largely under KEMELA, which is the Commission for the Conservation of Antarctic Marine Living Resources. I think also because of the time in which it came into being, it has a legacy of much more fisheries focus. Whereas the time in which we live, the global issue to come together on is climate change and how these ecosystems will change as a consequence. And particularly your polar areas and your deep sea and keeping these pathways and processes intact is what is going to enable the function of our planet, the whole term.
Clark Marchese
Okay, and I know that the Southern Ocean is huge and I know that there are a lot of logistical obstacles, specifically in the context of Antarctic research, and that there also must be lots of things we still have to learn about blue carbon. But I'm wondering what sorts of questions do we still have about Antarctic blue carbon and that you think would be really interesting to find out or that you think that the research community should be addressing at the moment.
Dr. Narissa Bax (17:28.492)
Yeah, I think one of the things that I am very hopeful for is just how much of a legacy of collaboration and multidisciplinary capacity that we have at this point. So I think that to have the working groups that are looking at it from multiple different levels and something that we were thinking about for the Falkland Islands, for example, which is a Southern Antarctic ecosystem is to find ways to, you know, you're not only protecting your blue carbon habitat, but you're protecting the linkages in the chain across the board. So that would mean actually also understanding your terrestrial ecosystems and how they are linked and, you know, moving into your fjords and your kelp forests, and then also looking deeper. Probably the way that conservation was viewed when I first came into science was to find those places that are, you know, beautiful, visually beautiful and have the conservation value that we expect them to have. But if you look at it in the context of the processes and maintaining those processes that keep these ecosystems intact and functioning across the board, then you're not necessarily just thinking about protecting this beautiful coral garden. You're also protecting the area where the animals from that garden go to die. So the graveyard locations that may not be so visually appealing, but they hold great importance in terms of contributions to climate change.
Clark Marchese
That makes sense. We keep learning how connected Antarctica and the Southern Ocean is to everything around it and everything around the world, but we are going to round out some of our last questions. The first one I have for you is, is there anything we didn't talk about today that you think listeners must know about Antarctic Blue Carbon, specifically that you would like to add before we finish?
Dr. Narissa Bax (19:20.94)
There is definitely a lot of doom and gloom around climate change and stories that can be, you know, they can bring you down and be a bit disengaging if it's constantly about, you know, the decline and the, yeah, the huge loss and the lack of hope. And so it's not like blue carbon is something that will be the silver bullet and will change everything for us. But it is an example of working with something that holds a bit of hope because it's based on protecting areas that are largely intact and biodiverse and functioning in their healthy natural state for the most part, as far as we know. I think it's incredibly important to protect those areas for the future, obviously, but it's also really beautiful for and hopeful as a scientist to be able to work in those locations and to hold on to that idea that you're working on something that will translate into conservation and you're not necessarily documenting the decline, you're looking from a collaborative explorative perspective as well. So it's not necessarily saying know that these are the only things that we need to focus on or anything, but this is sort of an easy win for humanity to come together on to protect these areas at the poles and in the deep sea in that regard. And it's part of the story to look at protecting the service of carbon sequestration that keeps our planet functioning.
Clark Marchese
Yeah, I think that's an optimistic way to end, in a sense, but also something that we need to balance the optimism and the realism, and I also appreciate that too. I guess that's the stage we're in in 2025, so thank you for saying that. Well, my last question is, where can people find you and follow your work?
Dr. Narissa Bax (21:21.078)
Yeah, so I thought about this one too. I mean, I have all the social media. You can find me on Twitter and Instagram. I'm not so prolific. I have a website, but I think what is more important and something that I see a little bit in science because we are so, you know, we need money to be able to do science. And so this means that our lives end up being quite focused on getting grants and sort of selling ourselves and our science and why it's important. And that can mean that as a person, you become a bit of a brand in that regard. And I don't think that that sits very well with me. It's not what is the main goal. So what I would prefer is for people to engage in these conversations because they're happening right now. But you can sort of see all of these sort of vying for the oceans will not only be conserved but how the oceans will be used and politicised. And I recognise especially for somewhere like Antarctica that can seem so remote and out of mind and not necessarily part of our everyday lives. But it is somewhere that impacts us all and is a place for all of us. So I hope that people would engage in the conversation and yeah, go beyond and you you can read my papers as well.
Clark Marchese
I'll be sure to include those links to some of those topics that you mentioned as well as the paper that we discussed today in the episode description so that anyone listening who is interested in learning more can find them and do so easily there. And this is the part where I say thank you so much for taking the time to talk to me today. Thank you for teaching us about Antarctic Blue Carbon and most importantly thank you for your really important research in this space.
Dr. Narissa Bax
Thank you very much, Clark.
Clark Marchese (23:26.606)
if you've been listening to Oceanography. More information about the podcast and this episode's guest can be found in the episode description. Just a reminder to anyone who is interested in helping us reach more people and share scientific research like this, a five-star rating or a written review on Apple Podcasts or wherever you're listening are the easiest and most effective ways you can help us out. Oceanography is a Pi and Forest Media production. You can find more information about that network in the episode description as well.
The cover art for the show was done by Jamiro Emming, and the music you're listening to was done by Nihilair Ruiz. The show was hosted and edited by me, Clark Marquesi, and you can find more information about Pine Forest Media and our other science podcasts at pineforestpost.com, or follow us on social media at Pine Forest Media. That is all I have for you today. Thank you so much for joining us, and I'll see you right back here next week.
