STORY: This seagrass field in the Baltic Sea helps store millions of tons of carbon, and plays a vital role in the fight against climate change.

But in the face of falling water quality and disease, it is shrinking fast.

Scientists in Germany are now working on ways to restore the plant, as well as adapt it to better cope with warming temperatures.

[Angela Stevenson, Postdoctoral Marine Scientitst, Geomar Helmholtz Center for Ocean Research]

"So seagrasses, forests, peatlands have for centuries to millennia captured CO2 and been storing them for us. And so a big aspect to think about here is conservation is to conserve these systems, to make sure that that CO2 does not get re-emitted and further add to this these emissions."

Source: Geomar Helmholtz Centre for Ocean Research

The Baltic region contains about 180 square miles of seagrass, storing some three to 12 megatons of carbon.

Stevenson and her colleagues have planted a test field using seeds and single-shoot transplants from the natural meadows.

With the test plants, they are able to explore different cultivation methods and see how the seagrass copes with heat.

"So right now we're doing experiments to see how the seagrass will fare under future climate scenarios. So we're really stressing them. We have plants that are at what we might expect the ambient, what we call ambient temperature, so the same temperature and conditions you might see in the fjord. And then we also have plants that are at one degrees higher temperature to three, all the way up to 5.5, to really see how they will fare under a long term warming stress in the future. So we expect to see that in the Baltic Sea in many years to come. And we want to just be ready to prepare to see how these plants will do under those circumstances."

Europe alone lost one third of its seagrass areas between the 1860s and 2016, according to one 2019 study.

However, Stevenson stresses that restoring the meadows is not a silver bullet in the effort to bring carbon emissions down to net zero: a goal the German government has pledged to reach by 2045.

"If we were to restore all of the seagrass areas in Germany that have lost seagrass, so areas that are unvegetated in the Baltic Sea, we could get only 100 up to a 100 kilo tonnes of CO2 annually, which is a very small percentage of the German budget."