scholarly journals Composition and Dominance of Edible and Inedible Phytoplankton Predict Responses of Baltic Sea Summer Communities to Elevated Temperature and CO2

2021 ◽  
Vol 9 (11) ◽  
pp. 2294
Author(s):  
Carolin Paul ◽  
Ulrich Sommer ◽  
Birte Matthiessen
Keyword(s):  
Baltic Sea ◽  
Elevated Temperatures ◽  
Seawater Temperature ◽  
Late Summer ◽  
Combined Effects ◽  
Significant Gain ◽  
Filamentous Cyanobacteria ◽  
Size Classes ◽  
Copepod Grazing ◽  
Total Phytoplankton

Previous studies with Baltic Sea phytoplankton combining elevated seawater temperature with CO2 revealed the importance of size trait-based analyses, in particular dividing the plankton into edible (>5 and <100 µm) and inedible (<5 and >100 µm) size classes for mesozoopankton grazers. While the edible phytoplankton responded predominantly negative to warming and the inedible group stayed unaffected or increased, independent from edibility most phytoplankton groups gained from CO2. Because the ratio between edible and inedible taxa changes profoundly over seasons, we investigated if community responses can be predicted according to the prevailing composition of edible and inedible groups. We experimentally explored the combined effects of elevated temperatures and CO2 concentrations on a late-summer Baltic Sea community. Total phytoplankton significantly increased in response to elevated CO2 in particular in combination with temperature, driven by a significant gain of the inedible <5 µm fraction and large filamentous cyanobacteria. Large flagellates disappeared. The edible group was low as usual in summer and decreased with both factors due to enhanced copepod grazing and overall decline of small flagellates. Our results emphasize that the responses of summer communities are complex, but can be predicted by the composition and dominance of size classes and groups.

scholarly journals Climate-driven change in a Baltic Sea summer microplanktonic community – desalination play a more important role than ocean acidification

2016 ◽  
Author(s):  
Angela Wulff ◽  
Maria Karlberg ◽  
Malin Olofsson ◽  
Anders Torstensson ◽  
Lasse Riemann ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Food Web ◽  
Heterotrophic Bacteria ◽  
Combined Effects ◽  
Filamentous Cyanobacteria ◽  
Microcosm Experiment ◽  
Scenario Modeling ◽  
Salinity Levels ◽  
Baltic Proper ◽  
The Baltic

Abstract. Scenario modeling suggests that the Baltic Sea, one of the largest brackish-water bodies in the world, could expect increased precipitation (decreased salinity) and increased concentration of atmospheric CO2 over the next 100 years. These changes are expected to affect the microplanktonic food web, and thereby nutrient and carbon cycling, in a complex and possibly synergistic manner. In the Baltic Proper, the extensive summer blooms dominated by the filamentous cyanobacteria Aphanizomenon sp., Dolichospermum sp. and the toxic Nodularia spumigena, contribute up to 30 % of the yearly new nitrogen and carbon exported to the sediment. In a 12 days outdoor microcosm experiment, we tested the combined effects of decreased salinity (from 6 to 3) and increased CO2 concentrations (380 and 960 µatm) on a natural summer microplanktonic community, focusing on diazotrophic filamentous cyanobacteria. Based on our results, the most important factor was salinity, and pCO2 showed only minor effects on total biovolumes of phytoplankton and abundances of heterotrophic bacteria. No interaction effects of salinity and pCO2 were found on any of the measured parameters. The biovolume of the toxic N. spumigena was negatively affected by salinity 3, and the treatment with salinity 3 and 960 µatm CO2 resulted in increased biomass of the presumably non-toxic Dolichospermum sp. Biovolumes of ciliates, diatoms and dinoflagellates were lower in salinity 3. Thus, the lower salinity seemed more important than increased pCO2, and considering the Baltic Proper, we do not expect any dramatic effects of increased pCO2 in combination with decreased salinity on the microplanktonic food web. We believe that our study can add one piece to the complicated puzzle to reveal the combined effects of increased pCO2 and reduced salinity levels on the Baltic microplanktonic community.

scholarly journals Growth performance and survival of larval Atlantic herring, under the combined effects of elevated temperatures and CO2

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0191947 ◽  
Author(s):  
Michael Sswat ◽  
Martina H. Stiasny ◽  
Fredrik Jutfelt ◽  
Ulf Riebesell ◽  
Catriona Clemmesen
Keyword(s):  
Growth Performance ◽  
Elevated Temperatures ◽  
Atlantic Herring ◽  
Combined Effects

Late summer metalimnetic oxygen minimum zone in the northern Baltic Sea

2010 ◽  
Vol 80 (1-2) ◽  
pp. 1-7 ◽  
Author(s):  
M. Raateoja ◽  
H. Kuosa ◽  
J. Flinkman ◽  
J.-P. Pääkkönen ◽  
M. Perttilä
Keyword(s):  
Baltic Sea ◽  
Late Summer ◽  
Oxygen Minimum Zone ◽  
Minimum Zone ◽  
Oxygen Minimum

Combined effects of UV light and elevated temperatures on wood discolouration

2015 ◽  
Vol 49 (6) ◽  
pp. 1225-1237 ◽  
Author(s):  
Laszlo Tolvaj ◽  
Satoru Tsuchikawa ◽  
Tetsuya Inagaki ◽  
Denes Varga
Keyword(s):  
Elevated Temperatures ◽  
Uv Light ◽  
Combined Effects

Ship-of-opportunity based phycocyanin fluorescence monitoring of the filamentous cyanobacteria bloom dynamics in the Baltic Sea

2007 ◽  
Vol 73 (3-4) ◽  
pp. 489-500 ◽  
Author(s):  
J. Seppälä ◽  
P. Ylöstalo ◽  
S. Kaitala ◽  
S. Hällfors ◽  
M. Raateoja ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Filamentous Cyanobacteria ◽  
The Baltic Sea ◽  
Cyanobacteria Bloom ◽  
The Baltic

scholarly journals No observed effect of ocean acidification on nitrogen biogeochemistry in a summer Baltic Sea plankton community

2016 ◽  
Vol 13 (13) ◽  
pp. 3901-3913 ◽  
Author(s):  
Allanah J. Paul ◽  
Eric P. Achterberg ◽  
Lennart T. Bach ◽  
Tim Boxhammer ◽  
Jan Czerny ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Baltic Sea ◽  
N2 Fixation ◽  
Spring Bloom ◽  
Plankton Community ◽  
Organic N ◽  
Filamentous Cyanobacteria ◽  
The Baltic Sea ◽  
N Supply ◽  
The Baltic

Abstract. Nitrogen fixation by filamentous cyanobacteria supplies significant amounts of new nitrogen (N) to the Baltic Sea. This balances N loss processes such as denitrification and anammox, and forms an important N source supporting primary and secondary production in N-limited post-spring bloom plankton communities. Laboratory studies suggest that filamentous diazotrophic cyanobacteria growth and N2-fixation rates are sensitive to ocean acidification, with potential implications for new N supply to the Baltic Sea. In this study, our aim was to assess the effect of ocean acidification on diazotroph growth and activity as well as the contribution of diazotrophically fixed N to N supply in a natural plankton assemblage. We enclosed a natural plankton community in a summer season in the Baltic Sea near the entrance to the Gulf of Finland in six large-scale mesocosms (volume ∼ 55 m3) and manipulated fCO2 over a range relevant for projected ocean acidification by the end of this century (average treatment fCO2: 365–1231 µatm). The direct response of diazotroph growth and activity was followed in the mesocosms over a 47 day study period during N-limited growth in the summer plankton community. Diazotrophic filamentous cyanobacteria abundance throughout the study period and N2-fixation rates (determined only until day 21 due to subsequent use of contaminated commercial 15N-N2 gas stocks) remained low. Thus estimated new N inputs from diazotrophy were too low to relieve N limitation and stimulate a summer phytoplankton bloom. Instead, regeneration of organic N sources likely sustained growth in the plankton community. We could not detect significant CO2-related differences in neither inorganic nor organic N pool sizes, or particulate matter N : P stoichiometry. Additionally, no significant effect of elevated CO2 on diazotroph activity was observed. Therefore, ocean acidification had no observable impact on N cycling or biogeochemistry in this N-limited, post-spring bloom plankton assemblage in the Baltic Sea.

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