Research article - Peer-reviewed, 2021
Nitrogen fixation estimates for the Baltic Sea indicate high rates for the previously overlooked Bothnian Sea
Olofsson, Malin; Klawonn, Isabell; Karlson, BengtAbstract
Dense blooms of diazotrophic filamentous cyanobacteria are formed every summer in the Baltic Sea. We estimated their contribution to nitrogen fixation by combining two decades of cyanobacterial biovolume monitoring data with recently measured genera-specific nitrogen fixation rates. In the Bothnian Sea, estimated nitrogen fixation rates were 80 kt N year(-1), which has doubled during recent decades and now exceeds external loading from rivers and atmospheric deposition of 69 kt year(-1). The estimated contribution to the Baltic Proper was 399 kt N year(-1), which agrees well with previous estimates using other approaches and is greater than the external input of 374 kt N year(-1). Our approach can potentially be applied to continuously estimate nitrogen loads via nitrogen fixation. Those estimates are crucial for ecosystem adaptive management since internal nitrogen loading may counteract the positive effects of decreased external nutrient loading.Keywords
Aphanizomenon; Baltic Sea; Dolichospermum; Filamentous cyanobacteria; Nitrogen fixation; Nodularia spumigenaPublished in
AMBIO: A Journal of the Human Environment2021, volume: 50, number: 1, pages: 203-214
Publisher: SPRINGER
Authors' information
Swedish Meteorological and Hydrological Institute (SMHI)
Klawonn, Isabell
IGB Leibniz Inst Freshwater Ecol and Inland Fisheri
Karlson, Bengt
Swedish Meteorol and Hydrol Inst
Sustainable Development Goals
SDG14 Life below water
UKÄ Subject classification
Environmental Sciences
Publication Identifiers
DOI: https://doi.org/10.1007/s13280-020-01331-x
URI (permanent link to this page)
https://res.slu.se/id/publ/105418