Publication Date:
2024-03-15
Description:
Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2) concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C) and dinitrogen (N2) fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 μatm), mid (median 353 μatm), and high (median 548 μatm) CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2) and 40 ± 25% (mid vs. high pCO2), as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low) and 44% (high vs. mid) at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP) was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the Baltic Sea are discussed.
Keywords:
Abundance; Abundance, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Bacteria; Bacteria, abundance; Bacteria, abundance, standard deviation; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbon, organic, dissolved; Carbon, organic, dissolved, standard deviation; Carbon, organic, particulate; Carbon, organic, particulate, standard deviation; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Carbon fixation rate; Carbon fixation rate, per particulate organic carbon; Carbon fixation rate, standard deviation; Carlo Erba EA 1108 + Thermo Finnigan Delta S mass-spectrometer; Chlorophyll a; Chlorophyll a, standard deviation; Colorimetric; Counting by flow cytometer; Cyanobacteria; DATE/TIME; Fluorometry (TURNER, 10-AU-005); Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Incubation duration; Laboratory experiment; Laboratory strains; MarsXpress (CEM); Microscopy; Nitrogen, inorganic, dissolved; Nitrogen, inorganic, dissolved, standard deviation; Nitrogen, organic, dissolved; Nitrogen, organic, particulate; Nitrogen, organic, particulate, standard deviation; Nitrogen, organic, standard deviation; Nitrogen fixation rate; Nitrogen fixation rate, per particulate organic carbon; Nitrogen fixation rate, standard deviation; Nodularia spumigena; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Other metabolic rates; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate organic phosphorus, standard deviation; Pelagos; pH; pH, standard deviation; Phosphate; Phosphate, standard deviation; Phosphorus, organic, dissolved; Phosphorus, organic, particulate; Phosphorus, organic, standard deviation; Phytoplankton; Potentiometric; Primary production/Photosynthesis; Salinity; Single species; Species, unique identification; Species, unique identification (Semantic URI); Species, unique identification (URI); Spectrophotometer Hitachi U-2000; Temperature, technical; TOC analyzer (Shimadzu); Treatment; Type
Type:
Dataset
Format:
text/tab-separated-values, 636 data points
Permalink
