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| Titel |
Impact of ocean acidification and elevated temperatures on early juveniles of the sub-polar shelled pteropod \textit{Limacina helicina} (Thecosomata): mortality, shell growth and shell degradation |
| VerfasserIn |
Silke Lischka, Jan Büdenbender, Tim Boxhammer, Ulf Riebesell |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051247
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| Zusammenfassung |
| Due to their aragonitic shell thecosome pteropods may be particularly vulnerable to ocean
acidification driven by anthropogenic CO2 emissions. This applies specifically to species
inhabiting Arctic surface waters that are projected to become locally undersaturated
with respect to aragonite as early as 2020. Because of the high solubility of CO2
in cold waters, undersaturation will first occur during winter when the water is
coldest.
The thecosome pteropod Limacina helicina contributes significantly to the Arctic
zooplankton biomass at times and has a key function in the Arctic epipelagic food
web. Due to their aragonitic shell, pteropods are expected to be among the first
major group of calcifying organisms to be adversely effected by undersaturation in
CaCO3.
This study investigated the effects of rising pCO2 partial pressures and elevated
temperature on pre-winter juveniles of the polar pteropod Limacina helicina in the
Arctic Kongsfjord (Svalbard). In September/October 2009 a 29 days experiment was
carried out at three different temperatures and under pCO2 scenarios projected for
this century. Mortality, shell diameter, shell increment and shell degradation were
investigated.
Temperature and pCO2 were shown to have a significant effect on mortality, but
temperature was the overriding factor. Shell diameter, shell increment and shell degradation
were significantly impacted by pCO2 but not by temperature. Mortality was 46% higher at 8Ë
C compared to 3Ë C (in situ), and 14% higher at 1100 μatm CO2 as compared to 230 μatm
CO2. Shell diameter and increment were reduced by 10% and 12% at 1100 μatm CO2 as
compared to 230 μatm CO2, respectively, and shell degradation was 41% higher at elevated
compared to ambient pCO2 partial pressures. We conclude that pre-winter juveniles will be
negatively affected by both rising temperature and pCO2 which may result in a possible
abundance decline of the overwintering population, the basis for next year’s reproduction. |
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