TY - JOUR
T1 - Some like it hot
T2 - The protozooplankton-copepod link in a warming ocean
AU - Aberle, N.
AU - Malzahn, A. M.
AU - Lewowska, A. M.
AU - Sommer, U.
N1 - Publisher Copyright:
© Inter-Research 2015.
PY - 2015/1/20
Y1 - 2015/1/20
N2 - The combined effects of warming and densities of overwintering copepods on the spring succession of Baltic Sea plankton were investigated using indoor mesocosms. Three zooplankton densities (1.5, 4 and 10 copepods l-1) and 2 temperature levels (Δ0°C and Δ6°C; 0°C and 6°C above present-day temperatures in the Kiel Bight) were chosen. Both the timing and the duration of the protozooplankton (PZP) bloom were significantly affected by temperature, but not by copepod density. In contrast, the bloom intensity of PZP was highly affected by the factors temperature and copepod density and their interaction. This suggests that under elevated temperature conditions PZP grows faster, but, at the same time, is subject to higher top-down control by copepods. At low temperatures and low copepod densities, PZP, in turn, fully escaped from copepod predation. Further changes in copepod overwintering densities resulted in a strong suppression of ciliates, of which small-sized ciliates (<30 μm) were especially vulnerable to copepod predation, while other PZP size classes remained unaffected. In conclusion, results point at a pivotal regulating role of overwintering copepods under future warming conditions. Further, warming was shown to cause a distinct match between phytoplankton and PZP, thus strengthening trophic pathways through PZP. Our findings are discussed in the context of the 'trophic link-sink' debate by considering potential alterations in the flux of matter and energy up the food web.
AB - The combined effects of warming and densities of overwintering copepods on the spring succession of Baltic Sea plankton were investigated using indoor mesocosms. Three zooplankton densities (1.5, 4 and 10 copepods l-1) and 2 temperature levels (Δ0°C and Δ6°C; 0°C and 6°C above present-day temperatures in the Kiel Bight) were chosen. Both the timing and the duration of the protozooplankton (PZP) bloom were significantly affected by temperature, but not by copepod density. In contrast, the bloom intensity of PZP was highly affected by the factors temperature and copepod density and their interaction. This suggests that under elevated temperature conditions PZP grows faster, but, at the same time, is subject to higher top-down control by copepods. At low temperatures and low copepod densities, PZP, in turn, fully escaped from copepod predation. Further changes in copepod overwintering densities resulted in a strong suppression of ciliates, of which small-sized ciliates (<30 μm) were especially vulnerable to copepod predation, while other PZP size classes remained unaffected. In conclusion, results point at a pivotal regulating role of overwintering copepods under future warming conditions. Further, warming was shown to cause a distinct match between phytoplankton and PZP, thus strengthening trophic pathways through PZP. Our findings are discussed in the context of the 'trophic link-sink' debate by considering potential alterations in the flux of matter and energy up the food web.
KW - Climate change
KW - Global warming
KW - Lohmaniella oviformis
KW - Protoperidinium bipes
KW - Trophic intermediary
KW - Trophic link
KW - Trophic sink
KW - Zooplankton grazing
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UR - http://www.scopus.com/inward/citedby.url?scp=84921899739&partnerID=8YFLogxK
U2 - 10.3354/meps11081
DO - 10.3354/meps11081
M3 - Article
AN - SCOPUS:84921899739
SN - 0171-8630
VL - 519
SP - 103
EP - 113
JO - Marine Ecology Progress Series
JF - Marine Ecology Progress Series
ER -