Effect of ocean acidification and elevated temperature on growth of calcifying tubeworm shells (Spirorbis spirorbis): An in-situ benthocosm approach

Abstract. The calcareous tubeworm Spirorbis spirorbis is a wide-spread serpulid species in the Baltic Sea, where it commonly grows as an epibiont on brown macroalgae (genus Fucus). It lives within a Mg-calcite shell and could be affected by ocean acidification and temperature rise induced by the predicted future atmospheric CO2 increase. However, Spirorbis tubes grow in a chemically modified boundary layer around the algae, which may mitigate acidification. In order to investigate how increasing temperature and rising pCO2 may influence S. spirorbis shell growth we carried out four seasonal experiments in the 'Kiel Outdoor Benthocosms' at elevated pCO2 and temperature conditions. Compared to laboratory batch culture experiments the benthocosm approach provides a better representation of natural conditions for physical and biological ecosystem parameters, including seasonal variations. We find that growth rates of S. spirorbis are significantly controlled by ontogenetic and seasonal effects. The length of the newly grown tube is inversely related to the initial diameter of the shell. Our study showed no significant difference of the growth rates between ambient atmospheric and elevated (1100 ppm) pCO2 conditions. No influence of daily average CaCO3 saturation state on the growth rates of S. spirorbiswas observed. We found, however, net growth of the shells even in temporarily undersaturated bulk solutions, under conditions that concurrently favored selective shell surface dissolution. The results suggest an overall resistance of S. spirorbis growth to acidification levels predicted for the year 2100 in the Baltic Sea. In contrast, S. spirorbis did not survive at mean seasonal temperatures exceeding 24 °C during the summer experiments. In the autumn experiments at ambient pCO2, the growth rates of juvenile S. spirorbis were higher under elevated temperature conditions. The results reveal that S. spirorbis may prefer moderately warmer conditions during their early life stages but will suffer from an excessive temperature increase and from increasing shell corrosion as a consequence of progressing ocean acidification.

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Effect of temperature rise and ocean acidification on growth of calcifying tubeworm shells (Spirorbis spirorbis): an in situ benthocosm approach

Biogeosciences ◽

10.5194/bg-15-1425-2018 ◽

2018 ◽

Vol 15 (5) ◽

pp. 1425-1445 ◽

Cited By ~ 3

Author(s):

Sha Ni ◽

Isabelle Taubner ◽

Florian Böhm ◽

Vera Winde ◽

Michael E. Böttcher

Keyword(s):

Ocean Acidification ◽

Baltic Sea ◽

Temperature Rise ◽

Growth Rates ◽

Shell Growth ◽

The Baltic Sea ◽

Saturation State ◽

Temperature Conditions ◽

Significant Difference ◽

The Baltic

Abstract. The calcareous tubeworm Spirorbis spirorbis is a widespread serpulid species in the Baltic Sea, where it commonly grows as an epibiont on brown macroalgae (genus Fucus). It lives within a Mg-calcite shell and could be affected by ocean acidification and temperature rise induced by the predicted future atmospheric CO2 increase. However, Spirorbis tubes grow in a chemically modified boundary layer around the algae, which may mitigate acidification. In order to investigate how increasing temperature and rising pCO2 may influence S. spirorbis shell growth we carried out four seasonal experiments in the Kiel Outdoor Benthocosms at elevated pCO2 and temperature conditions. Compared to laboratory batch culture experiments the benthocosm approach provides a better representation of natural conditions for physical and biological ecosystem parameters, including seasonal variations. We find that growth rates of S. spirorbis are significantly controlled by ontogenetic and seasonal effects. The length of the newly grown tube is inversely related to the initial diameter of the shell. Our study showed no significant difference of the growth rates between ambient atmospheric and elevated (1100 ppm) pCO2 conditions. No influence of daily average CaCO3 saturation state on the growth rates of S. spirorbis was observed. We found, however, net growth of the shells even in temporarily undersaturated bulk solutions, under conditions that concurrently favoured selective shell surface dissolution. The results suggest an overall resistance of S. spirorbis growth to acidification levels predicted for the year 2100 in the Baltic Sea. In contrast, S. spirorbis did not survive at mean seasonal temperatures exceeding 24 °C during the summer experiments. In the autumn experiments at ambient pCO2, the growth rates of juvenile S. spirorbis were higher under elevated temperature conditions. The results reveal that S. spirorbis may prefer moderately warmer conditions during their early life stages but will suffer from an excessive temperature increase and from increasing shell corrosion as a consequence of progressing ocean acidification.

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Review comments for: “Effect of ocean acidification on the structure and fatty acid composition of a natural plankton community in the Baltic Sea” by J. R Bermúdez et al.

10.5194/bg-2015-669-rc3 ◽

2016 ◽

Author(s):

Anonymous

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Ocean Acidification ◽

Baltic Sea ◽

Acid Composition ◽

Plankton Community ◽

The Baltic Sea ◽

The Baltic

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Shifts in the microbial community in the Baltic Sea with increasing CO2

10.5194/bg-2015-606 ◽

2016 ◽

Cited By ~ 7

Author(s):

K .J. Crawfurd ◽

C .P. D. Brussaard ◽

U. Riebesell

Keyword(s):

Carbon Dioxide ◽

Microbial Community ◽

Ocean Acidification ◽

Baltic Sea ◽

Community Dynamics ◽

The Other ◽

The Baltic Sea ◽

Viral Lysis ◽

Large Shift ◽

The Baltic

Abstract. Ocean acidification, due to dissolution of anthropogenically produced carbon dioxide is considered a major threat to marine ecosystems. The Baltic Sea, with extremely low salinity and thus low pH buffering capacity, is likely to experience stronger variation in pH than the open ocean with increasing atmospheric carbon dioxide. We examined the effects of ocean acidification on the microbial community during summer using large volume in situ mesocosms to simulate present to future and far future scenarios. We saw distinct trends with increasing CO2 in each of the 6 groups of phytoplankton with diameters below 20 μm that we enumerated by flow cytometry. Of these groups two picoeukaryotic groups increased in abundance whilst the other groups, including prokaryotic Synechococcus spp., decreased with increasing CO2. Gross growth rates increased with increasing CO2 in the dominant picoeukaryote group sufficient to double their abundances whilst reduced grazing allowed the other picoeukaryotes to flourish at higher CO2. Significant increases in lysis rates were seen at higher CO2 in these two picoeukaryote groups. Converting abundances to particulate organic carbon we saw a large shift in the partitioning of carbon between the size fractions which lasted throughout the experiment. The heterotrophic prokaryotes largely followed the algal biomass with responses to increasing CO2 reflecting the altered phytoplankton community dynamics. Similarly, higher viral abundances at higher CO2 seemed related to increased prokaryote biomass. Viral lysis and grazing were equally important controlling prokaryotic abundances. Overall our results point to a shift towards a more regenerative system with potentially increased productivity but reduced carbon export.

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

Biogeosciences ◽

10.5194/bg-13-3901-2016 ◽

2016 ◽

Vol 13 (13) ◽

pp. 3901-3913 ◽

Cited By ~ 9

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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Towards modeling growth rates of cyanobacteria in the Baltic Sea

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2020.106853 ◽

2020 ◽

Vol 242 ◽

pp. 106853

Author(s):

Malgorzata Stramska ◽

Joanna Stoń-Egiert ◽

Miroslawa Ostrowska

Keyword(s):

Baltic Sea ◽

Growth Rates ◽

The Baltic Sea ◽

The Baltic ◽

Modeling Growth

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Coccolithophores and calcite saturation state in the Baltic and Black Seas

Biogeosciences ◽

10.5194/bg-5-485-2008 ◽

2008 ◽

Vol 5 (2) ◽

pp. 485-494 ◽

Cited By ~ 72

Author(s):

T. Tyrrell ◽

B. Schneider ◽

A. Charalampopoulou ◽

U. Riebesell

Keyword(s):

Calcium Carbonate ◽

Baltic Sea ◽

Black Sea ◽

The Other ◽

The Black Sea ◽

Potential Importance ◽

The Baltic Sea ◽

Saturation State ◽

Calcite Saturation ◽

The Baltic

Abstract. The Baltic and Black Seas are both brackish, that is to say both have salinities intermediate between freshwater and seawater. The coccolithophore Emiliania huxleyi is abundant in one, the Black Sea, but absent from the other, the Baltic Sea. Here we present summertime coccolithophore measurements confirming this difference, as well as data on the calcium carbonate saturation state of the Baltic Sea. We find that the Baltic Sea becomes undersaturated (or nearly so) in winter, with respect to both the aragonite and calcite mineral forms of CaCO3. Data for the Black Sea are more limited, but it appears to remain strongly supersaturated year-round. The absence of E. huxleyi from the Baltic Sea could therefore potentially be explained by dissolution of their coccoliths in winter, suggesting that minimum annual (wintertime) saturation states could be most important in determining future ocean acidification impacts. In addition to this potential importance of winter saturation state, alternative explanations are also possible, either related to differences in salinity or else to differences in silicate concentrations.

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