open access publication

Article, 2023

Nitrogen-fixing sulfate reducing bacteria in shallow coastal sediments under simulated resuspension

In: Estuarine Coastal and Shelf Science, ISSN 1096-0015, 0272-7714, Volume 280, Page 108165, 10.1016/j.ecss.2022.108165

Contributors (6)

Liesirova, Tina (Corresponding author) [1] Aarenstrup-Launbjerg, Tobias [2] Hallstrøm, Søren (0000-0003-2234-8860) [2] Bittner, Meriel Jennifer (0000-0002-3798-6315) [2] Riemann, Lasse (0000-0001-9207-2543) [2] Voss, Maren (0000-0002-5827-9062) [1]


  1. [1] Leibniz Institute for Baltic Sea Research
  2. [NORA names: Germany; Europe, EU; OECD]
  3. [2] University of Copenhagen
  4. [NORA names: KU University of Copenhagen; University; Denmark; Europe, EU; Nordic; OECD]


Nitrogen (N2) fixation by heterotrophic non-cyanobacterial diazotrophs is common in marine deep-sea sediments. However, in shallow coastal areas, where resuspension of sediments is extensive, the magnitude of sediment-associated N2 fixation during resuspension is unknown. We examined nitrogen fixation in dark slurry incubations with sediments (0–5 cm and 0–10 cm depths) under simulated resuspension from five shallow stations (water depth <1 m) and an anoxic site in the Bay of Gdansk (109 m) in the Baltic Sea. Abiotic variables and the composition of nitrogen fixing organisms (diazotrophs) were measured at the study sites. To estimate the contribution of nitrogen fixing sulfate reducing bacteria to total nitrogen fixation, parallel incubations with sodium molybdate as inhibitor were performed. Our data show low but variable nitrogen fixation rates (n.d. - 23.7 nmol N g−1 d−1), promoted in small-grained sediments associated with increased organic carbon content and high nutrient concentrations in pore waters. Highest nitrogen fixation at the shallow sites was encountered in the upper 0–5 cm of the sediments while rates were negligible below. Sulfate reducing bacteria (e.g. Desulfobacterales and Desulfovibrionales) were responsible for most of the heterotrophic nitrogen fixation and appear as key players for pelagic N2 fixation during resuspension. Our study reveals an important sediment – water coupling, which may be accentuated by the increased storms and resuspension events predicted for the Baltic Sea region.


Baltic Sea, Baltic Sea region, Bay, Bay of Gdansk, Gdansk, N2 fixation, Sea, Sea region, abiotic variables, anoxic sites, area, bacteria, carbon content, coastal areas, coastal sediments, composition, composition of nitrogen, concentration, content, contribution, contribution of nitrogen, coupling, data, deep-sea sediments, diazotrophs, events, fixation, fixation rates, heterotrophic nitrogen fixation, high nitrogen fixation, high nutrient concentrations, incubation, inhibitors, key players, magnitude, molybdate, nitrogen, nitrogen fixation, nitrogen fixation rates, non-cyanobacterial diazotrophs, nutrient concentrations, organic carbon content, organisms, parallel incubations, pelagic N2 fixation, players, pore water, rate, region, resuspension, resuspension events, resuspension of sediments, sediments, shallow coastal areas, shallow coastal sediments, shallow sites, shallow stations, sites, slurry incubations, sodium molybdate, stations, storms, study, study sites, sulfate, variables, water


  • Danish Agency for Science and Higher Education
  • Deutsche Forschungsgemeinschaft