Kiel University develops a new method for largescale mapping of seagrass in the Baltic Sea
Seagrass meadows belong to the most important ecosystems in the ocean. They are nursery grounds for many sea creatures and serve as coastal protection by weakening strong waves. However, these shallow water habitats are currently retreating worldwide. Also in the Baltic Sea they are considered critically endangered e.g. due to the increased input of nutrients in coastal areas. But, seagrass role as carbon storage is becoming ever more important. Seagrass meadows take up significantly more CO2 than a comparable area of forest on land and can therefore play an important role in buffering the effects of climate change. While modern satellites can be used to document wide swathes of habitats and their changes, like forest degradation, on land, this technology is not yet available in the ocean. The European project ECOMAP, which is coordinated at Kiel University, is testing new methods of efficient and precise mapping of seagrass meadows that were developed in cooperation with partners in Poland and Germany. These show that the area coverage of seagrass meadows can be mapped with previously unreached efficiency and accuracy in the decimeter range.
“Our aim is to ensure a high precision in our methods which allows us to draw baselines of the current stocks and document larger areas. Because of this we are mainly using a sound-based sensing of the ocean floor and vegetation,” states ECOMAP project leader Dr. Jens Schneider von Deimling, a geophysicist at the Institute of Geosciences at Kiel University. “The first results show that we have been able to assess the stock dynamics confidently with our approach and multiple measurements over the past few years.”
Apart from the advanced sound-based other methods such as dive, drone, airplane and satellite observations are regularly used for classification of selected seagrass meadows in Schleswig Holstein. Recently, the ECOMAP team returned from a research cruise on the Littorina with a new dataset for the coastal areas of Gelting Bay, Kalkgrund, Boknis Eck and Heidkate. For all these locations a new fan echosounder prototype was used to gather the data at a depth of 5 to 8 meters. Through the regular mapping of this baseline the scientists hope to assess whether stocks of seagrass, particularly Zostera marina, are moving into deeper or moving to shallower waters. The datasets collected from the research vessel using the fan echosounder prototype will be analysed at Kiel University using artificial intelligence and compared to measurements taken from airplanes using the modern laser measurement devices (LIDAR), drone flight data (areal images) or from samples taken during dives. With these new methods and the complex processing of the data from various measurements with the use intelligent algorithms the scientists are entering unknown territory. The long-term aim is to fully integrate methods to enable measurements of shallow water with its high plant biodiversity, lively upper layers of sediment to depths of about 2 meters and collect real-time data on the state of environmental health.
ECOMAP has received a total of 2.5 million euros in funding from the transnational research-and development programme in the Baltic area (BONUS) which has been funded by the EU for 3 years. Apart from partners in Germany like the GEOMAR Helmholtz Centre for Ocean Research in Kiel and the Leibniz Institute for Ocean Research in Warnemünde (IOW), international institutions from Poland and Denmark, as well as maritime agencies and stakeholders like the BSH, LKN and LLUR are involved. The results of the project are meant to contribute to the EU ocean strategy guidelines and support future ocean planning, coastal protection and the sustainable use of the Baltic sea. The research methods developed in the during the project are suitable for the entire Baltic sea and can also be adapted to all coastal areas world-wide. The results of these new methods, including the fan echosounder and others, have been published in a special edition on ocean floor mapping in the scientific journal MDPI Geosciences.
www.kms.uni-kiel.de/en?set_language=en (Research priority area Kiel Marine Science/KMS)
Held, P.; Schneider von Deimling, J. - New Feature Classes for Acoustic Habitat Mapping—A Multibeam Echosounder Point Cloud Analysis for Mapping Submerged Aquatic Vegetation (SAV). Geosciences2019, 9, 235. https://doi.org/10.3390/geosciences9050235