by Marlien Nooren, Forest Carbon Analyst

February 7, 2024

The Permian Podcast Episode six with Marlien Nooren

“Blue Carbon”

Welcome to The Permian Podcast, the show where we dive deep into conservation topics that matter. Today, we have an incredibly important subject to discuss – Blue Carbon. Joining us is Marlien Nooren, Forest Carbon analyst here at Permian Global and an expert in marine ecosystems and Blue Carbon. Welcome, Marlien! 


Marlien: Thank you, Mike! It’s a pleasure to be here and talk about the significance of Blue Carbon. 


Mike: To start things off, Marlien, could you provide our listeners with a quick overview of your background what exactly “Blue Carbonis. 


Marlien: Certainly, Mike. I have always been deeply passionate about the ocean as I partially grew up in the Caribbean. So, from an early age I was quite fond of the ocean and its marine life. Then, when I obtained a bachelors in Sustainability Sciences, my interest in relation to the carbon cycle and sustainability grew and I knew I wanted to further explore that interest. I was going back and forth between obtaining a masters in climate sciences or marine sciences. It was then actually a very cute video of a zebra shark that made me choose a master’s in marine sciences! Then through my internship at a maritime company I was introduced to Permian Global. After my internship I had the opportunity to further explore blue carbon at Permian Global, which has been an incredibly valuable learning experience as I’m surrounded by so many experts who are really passionate about what they do.  


Now, what is blue carbon? Blue Carbon refers to the carbon stored in coastal and marine ecosystems like mangroves, seagrass beds, salt marshes, and kelp forests. These ecosystems play a vital role in capturing and storing atmospheric carbon dioxide. Even though there are less of these coastal ecosystems than terrestrial forests, which are more known for sequestering carbon dioxide, the contribution of these coastal vegetations to long-term carbon sequestration is much larger than that of terrestrial forests. However, they are being lost at high rates worldwide as a result of coastal development and anthropogenic induced climate change. 


Mike: Fascinating! Now, let’s dive (applicably) into the different types of Blue Carbon systems – mangroves, seagrass, salt marshes, and kelp forests. Can you share why each of these is crucial? 


Marlien: Absolutely. These ecosystems hold many different functions but to give a few examples; Besides being incredible carbon sinks, they can act as protective buffers against storms, stabilize coastlines, and contribute significantly to marine biodiversity. These functions can also be interlinked! For instance, blue carbon ecosystems promote biodiversity enhancement and habitat provision for my favorite species, which are of course sharks, by serving as physical structures. And notably, the conservation and enhancement of carbon reserves in these ecosystems is intertwined with local food web dynamics, emphasizing the importance of preserving predator populations, such as sharks. 


Mike: That’s a diverse set of ecosystems. Let’s focus in on carbon storage. How exactly do these Blue Carbon systems capture and store carbon? 


Marlien: Blue carbon systems are vegetation. They can thus take up carbon from the atmosphere through photosynthesis and store this carbon in their underlying sediments. Additionally, they can store carbon that has been exported from adjacent waters. The magic lies in their ability to sequester not only carbon in their biomass but mainly in the soil beneath them due to a combination of high productivity and slow soil decomposition rates. For instance, mangrove forests store a lot of carbon belowground as their roots function as a more efficient nutrient conserving and cycling mechanism and dead belowground biomass helps the soils of mangroves adapt to saline waters. Additionally, larger roots help stabilize the ecosystem. Thus, it is advantageous for mangroves to proportionally store more carbon below ground! 


Mike: Beyond carbon sequestration, are there other co-benefits associated with Blue Carbon ecosystems? 


Marlien: Absolutely. These ecosystems contribute to climate change resilience by acting as natural buffers against sea-level rise. Moreover, they support local communities by providing livelihoods, protecting against natural disasters, and enhancing biodiversity. Not only can these functions be interlinked, as we saw earlier in the example of sharks and carbon storage, but these ecosystems can also be interlinked! The relationship between mangroves, seagrass and coral reefs is a classic example of nature’s interconnectedness. While mangroves are the most effective at protecting the coast both under non-storm and storm conditions, live corals and seagrasses also moderate the impact of waves and storms, thereby further reducing the vulnerability of coastal regions. Seagrasses can even compensate for the long-term degradation of the barrier reef.  


Mike: That leads us to an important point – the role of Blue Carbon in climate change resilience and its impact on local communities. Could you elaborate on this? 


Marlien: Sure. Blue Carbon ecosystems act as a natural defense against rising sea levels. Studies have shown that as a mangrove forest begins to develop, the sea bed begins to rise due to reduced sediment resuspensions, caused by the mangroves, and sediment trapping. The ability of mangrove forests to gradually create a buffer between sea and land occurs even when the area is subjected to potential sea level rises. They also provide resources like fish and timber, supporting the livelihoods of millions of people around the world. Specifically, food is important for local communities. Many fish species permanently reside in mangroves, as do shellfish, bivalves, and other organisms that represent food security for people in and near mangroves. Not only are mangroves important for local communities but also vice versa! Studies have shown that local communities with high awareness of the different ecosystem services offered by mangrove forests promote the health of the ecosystem. For example, if they are aware that fish can be sourced out from mangroves, local communities are often less likely to unsustainably extract trees and branches. This preserves the health of the ecosystem which safeguards all the benefits these ecosystems have to offer. This truly illustrates how important the exchange of knowledge is. 


Mike: Lastly, let’s touch upon biodiversity, stability of sediment, and water quality. How do Blue Carbon ecosystems contribute to these aspects? 


Marlien: These ecosystems are biodiversity hotspots, supporting a wide range of marine life from species as big as sharks to species as small as benthic microorganisms. Additionally, the stability of sediment provided by these systems prevents erosion. Mangroves for instance prevent erosion due to soil building up around their roots and reducing energy from waves and tidal currents. And seagrasses are known to reduce erosion and improve water quality by reducing water speed adjacent to the sediment surface. This allows suspended particles in the water to fall to the bottom, thus encouraging the build-up of bottom sediments and helping to improve water quality.  


However, as I mentioned earlier, these ecosystems are threatened by anthropogenic drivers. The loss of these ecosystems is not only facilitating an increase in atmospheric greenhouse gases, but also diminishing the potential of these ecosystems to support the combat against climate change and threatening the other important functions we have highlighted today. These drivers of deforestation and degradation are often linked to economic development.  

Thus, the scale of investment needed to protect and restore these ecosystems is immense. I think REDD+ is important as it provides a financial incentive to achieve blue carbon conservation and/or restoration goals. It’s good to see that methodologies in the REDD+ framework are increasingly addressing blue carbon ecosystems, like mangrove forest and seagrass. I think it’s vital we start paying as much attention to these ecosystems as to for instance terrestrial forests, specifically because of their high potential for long-term carbon sequestration. I’m excited to keep exploring blue carbon and its potential as a nature-based solution to help our society shift towards more sustainable business and to support local communities and marine biodiversity. 


Mike: Fascinating insights, Marlien. Thank you for joining us today and shedding light on the crucial role of Blue Carbon in our planet’s health. 


Marlien: Thank you, Mike. It’s been a pleasure discussing Blue Carbon with you. 

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