Carbon, nitrogen and O2 fluxes associated with the cyanobacterium <i>Nodularia spumigena</i> in the Baltic Sea

Ploug, Helle; Adam, Birgit; Musat, Niculina; Kalvelage, Tim; Lavik, Gaute; Wolf-Gladrow, Dieter; Kuypers, Marcel M. M.

doi:10.1038/ismej.2011.20

Cited by 102 publications

(128 citation statements)

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“…These respiration rates were similar to those in August 2009 and 2011, when dark respiration varied between 0.038 and 87 nmol O 2 h À 1 in Nodularia colonies with diameters from 0.3 to 5.0 mm (see also Ploug et al, 2011). Many aggregates of N. spumigena held interior anoxia because of their size, high respiration rates and their compact structure.…”

Section: Resultssupporting

confidence: 76%

Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates

et al. 2015

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Colonies of N 2 -fixing cyanobacteria are key players in supplying new nitrogen to the ocean, but the biological fate of this fixed nitrogen remains poorly constrained. Here, we report on aerobic and anaerobic microbial nitrogen transformation processes that co-occur within millimetre-sized cyanobacterial aggregates (Nodularia spumigena) collected in aerated surface waters in the Baltic Sea. Microelectrode profiles showed steep oxygen gradients inside the aggregates and the potential for nitrous oxide production in the aggregates' anoxic centres.15 N-isotope labelling experiments and nutrient analyses revealed that N 2 fixation, ammonification, nitrification, nitrate reduction to ammonium, denitrification and possibly anaerobic ammonium oxidation (anammox) can co-occur within these consortia. Thus, N. spumigena aggregates are potential sites of nitrogen gain, recycling and loss. Rates of nitrate reduction to ammonium and N 2 were limited by low internal nitrification rates and low concentrations of nitrate in the ambient water. Presumably, patterns of N-transformation processes similar to those observed in this study arise also in other phytoplankton colonies, marine snow and fecal pellets. Anoxic microniches, as a pre-condition for anaerobic nitrogen transformations, may occur within large aggregates (X1 mm) even when suspended in fully oxygenated waters, whereas anoxia in small aggregates (o1 to X0.1 mm) may only arise in lowoxygenated waters (p25 lM). We propose that the net effect of aggregates on nitrogen loss is negligible in NO 3 À -depleted, fully oxygenated (surface) waters. In NO 3 À -enriched (41.5 lM), O 2 -depleted water layers, for example, in the chemocline of the Baltic Sea or the oceanic mesopelagic zone, aggregates may promote N-recycling and -loss processes.

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Section: Resultssupporting

confidence: 76%

Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates

et al. 2015

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“…Extensive blooms of Trichodesmium occur in the tropical ocean, whereas the genera Nodularia and Aphanizomenon bloom in brackish waters, and Aphanizomenon in lakes (Capone, et al, 1997;Ibelings and Maberly, 1998;Larsson et al, 2001). These N 2 -fixing cyanobacteria form colonies and leak a substantial fraction of newly fixed N 2 to the surrounding water (Mulholland and Capone 2001;Ploug et al, 2010Ploug et al, , 2011. However, quantitatively little is known about the fate of this newly fixed nitrogen, its role for the microbial and classical food webs and for large-scale biogeochemical fluxes (Mulholland, 2007).…”

Section: Introductionmentioning

confidence: 99%

N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community

et al. 2015

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We investigated the role of N 2 -fixation by the colony-forming cyanobacterium, Aphanizomenon spp., for the plankton community and N-budget of the N-limited Baltic Sea during summer by using stable isotope tracers combined with novel secondary ion mass spectrometry, conventional mass spectrometry and nutrient analysis. + fluxes to Aphanizomenon colonies at low bulk concentrations (o250 nM) as compared with N 2 -fixation within colonies. No N 2 -fixation was detected in autotrophic microorganisms o5 μm, which relied on NH 4 + uptake from the surrounding water. Aphanizomenon released about 50% of its newly fixed N 2 as NH 4 + . However, NH 4 + did not accumulate in the water but was transferred to heterotrophic and autotrophic microorganisms as well as to diatoms (Chaetoceros sp.) and copepods with a turnover time of 5 h. We provide direct quantitative evidence that colony-forming Aphanizomenon releases about half of its recently fixed N 2 as NH 4 + , which is transferred to the prokaryotic and eukaryotic plankton forming the basis of the food web in the plankton community. Transfer of newly fixed nitrogen to diatoms and copepods furthermore implies a fast export to shallow sediments via fast-sinking fecal pellets and aggregates. Hence, N 2 -fixing colony-forming cyanobacteria can have profound impact on ecosystem productivity and biogeochemical processes at shorter time scales (hours to days) than previously thought.

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“…In the Baltic Sea, it is has been shown that ca. 40-80% of the fixed nitrogen is released as dissolved bioavailable nitrogen for redistribution in the food web (Ohlendieck et al, 2007;Wannicke et al, 2009Wannicke et al, , 2013Ploug et al, 2011). Larsson et al (2001) have estimated that N 2 -fixation in the Baltic Sea Proper is 180-430 kt N year −1 , and this amount would be sufficient to sustain 30-90% of the pelagic net community production during summer.…”

Section: Introductionmentioning

confidence: 99%

Approach for Supporting Food Web Assessments with Multi-Decadal Phytoplankton Community Analyses—Case Baltic Sea

et al. 2016

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Combining the existing knowledge on links between functional characteristics of phytoplankton taxa and food web functioning with the methods from long-term data analysis, we present an approach for using phytoplankton monitoring data to draw conclusions on potential effects of phytoplankton taxonomic composition on the next trophic level. This information can be used as a part of marine food web assessments required by the Marine Strategy Framework Directive of the European Union. In this approach, both contemporary taxonomic composition and recent trends of changes are used to assess their potential consequences for food web functioning. The approach consists of four steps: (1) long-term trend analysis of class-level and total phytoplankton biomass using generalized additive models (GAMs) and calculating average biomass share of each phytoplankton class from the total phytoplankton biomass, (2) comparing the current phytoplankton community composition and its long-term changes with non-metric ordination analysis (NMDS) of genus-level biomass, (3) describing which taxa (the most accurate taxonomic level) are primarily responsible for forming the biomass and for causing the possible changes, and (4) interpretation of the phytoplankton results to assess the potential effects on the next trophic level. Within step 4, special attention is given to the following characteristic of taxa: potential suitability or quality as food for grazers, harmfulness, size, and trophy. These characteristics are selected based on existing scientific knowledge on their relevance to the higher trophic levels. In this article, we present the concept of the suggested approach and demonstrate the phytoplankton analyses with multi-decadal monitoring data from the northern Baltic Sea. We also discuss the future development of the approach toward a food web index by combining or replacing the taxonomic analyses with functional trait-based approaches.

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Carbon, nitrogen and O2 fluxes associated with the cyanobacterium Nodularia spumigena in the Baltic Sea

Cited by 102 publications

References 47 publications

Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates

Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates

N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community

Approach for Supporting Food Web Assessments with Multi-Decadal Phytoplankton Community Analyses—Case Baltic Sea

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