© P. Schubert
MEKUN: Interview with Philipp Schubert, Seagrass Researcher
CO₂ storage under water - how seagrass and algae can help protect the climate
Hi, I'm Rolf Karez, I'm a marine biologist and I work at the SH State Office for the Environment. I'm responsible for seagrasses and large algae. Everyone is talking about them because they could perhaps help to mitigate climate change. I talk about this with Philipp Schubert, a seagrass researcher from GEOMAR.
Philipp Schubert
Seagrass Researcher at GEOMAR Helmholtz Centre for Ocean Research, Kiel
Philipp Schubert: Yes, hello Rolf. Exactly, I've been researching seagrass here in the Baltic Sea for 15 years now.
And we are both delighted that the German government has launched the Natural Climate Protection Action Programme (ANK). This is a major programme that protects and promotes very different habitats, including marine habitats. On the one hand, because they are important for biodiversity, but also because they can probably store carbon dioxide (CO2). This is now to be researched. Schleswig-Holstein has submitted five projects, three of which are being supervised by the LfU.
These are the ZOBLUC, FUBLUC and LABLUC projects, which are looking at various plants in the Baltic Sea and near Helgoland. And Philipp, you are working on ZOBLUC, ZO from Zostera, which is the Latin name for seagrass.
Exactly.
ZOBLUC has now been relaunched. What is it all about?
ZOBLUC is an ANK project on the storage potential of seagrass for CO2.
To do this, we first have to take a look at where seagrass can be found along our coastline, using a completely new level of remote sensing, i.e. from satellites, from drones and also using acoustic methods from ships. It's called a multi-beam, where the seabed is really scanned, also with cameras, and it's checked to see where the seagrass is located. And then hopefully a holistic picture will emerge of where seagrass is and how the seagrass develops over the course of the year and also between the years. Mapping is the first pillar.
In addition, we also look at how CO2 is actually stored under seagrass meadows. This is because seagrass meadows are considered to be the peatlands of the sea.
They are known to store CO2 very well, but how exactly and, for example, from which source this CO2 comes - i.e. does it come from the seagrass meadows themselves or does it come from the plankton or from the surrounding water and is only sedimented in seagrass meadows - this still needs to be researched and also how exactly the storage works.
“Overall, you also have to look at the storage capacity. Is the CO2 stored in the long term? On the one hand, algae store the carbon, but what happens when the algae die off? Then the CO2 is exported, but where to?”
Philipp Schubert
Host City Local Partner
The Ocean Race Europe 2025
Now there are also two brown algae projects. How do brown algae contribute to CO2 storage?
Overall, you also have to look at the storage capacity. Is the CO2 stored in the long term? On the one hand, algae store the carbon, but what happens when the algae die off? Then the CO2 is exported, but where to? And this is what the LABLUC and FUBLUC projects are about. There are two species of large algae involved, one is Fucus (for FU in FUBLUC) and the other Laminaria (for LA in LABLUC). Fucus is the bladder wrack and laminaria are kelparts, which are only found on Heligoland in Germany. And where are these huge quantities of algae biomass exported to? They can be transported to deep basins where there is silt or something and then removed from the atmosphere. Or they can also be thrown ashore. This happens regularly after storms. And then you have to look closely at how much carbon is exported in which direction.
© C.Howe
“We absolutely want to preserve the algae forests and seagrass meadows for what they are: namely CO2 reservoirs and biodiversity hotspots.”
Philipp Schubert
© C.Howe
And all this is now to be researched. And if it then turns out that these are indeed important reservoirs: What can be done to protect and perhaps even increase these algae forests and seagrass meadows?
The most important thing is, of course, as you say, to protect them.
We absolutely want to preserve the algae forests and seagrass meadows for what they are: namely CO2 reservoirs and biodiversity hotspots. In other words, the most important thing is effective protection for these ecosystems.
But in the past we have lost seagrass meadows and also algae forests. And we have to make sure that they come back. There is also a new law at EU level that now requires ecosystems to be restored if they have been lost or impaired.
Okay, these three projects are just getting started. They will continue for three to five years, depending on the project. If you want to find out about the further progress, ...
... can of course do this online, for example about seagrass meadows at Seegraswiesen.de. And the other projects will certainly also have a website, which you can search for and find under FUBLUC or LABLUC searchresults. But they have only just been launched. So it's very topical at the moment.
All right, thank you Philipp.
Yes, pleasure.
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