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Publication
Effects of sea-water acidification on fertilization and larval development of the oyster Crassostrea gigas
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Advisor(s)
Abstract(s)
Oceans face a serious change to their natural biogeochemical cycle due to the rapid absorption of CO2 generated
by human activities. Ocean acidification is the common term used to describe the decrease of seawater pH caused
by the absorption of atmospheric CO2. To evaluate the effects of ocean acidification, we focused on the larval
stage of bivalves, which produce a fragile calcareous skeletal structure, very sensitive to changes in seawater
chemistry. In this context, we investigated sperm motility, fertilization rate and larval viability (survival, growth
and abnormalities) of the Pacific oyster, Crassostrea gigas, a commercially important bivalve, in a controlled CO2
perturbation experiment. The carbonate chemistry of seawater was manipulated by diffusing pure CO2, to attain
two reduced pH levels (ΔpH=−0.4 and ΔpH=−0.7) which were compared to unmanipulated seawater. The
results show high sensitivity of C. gigas veliger larvae to low values of pH, as reflected by a decrease in survival
and growth rates, as well as an increased frequency of prodissoconch abnormalities and protruding mantle.
Moreover, results also show that sperm motility, fertilization rate, and hatching success, were negatively
influenced by acidification. The exposure to ΔpH=−0.7 had a higher impact on the fertilization and larval
viability than ΔpH=−0.4. The results suggest that the reproductive success and the biological mechanisms
for calcification may be prematurely interrupted and disturbed when C. gigas veliger larvae are exposed to an
acidified environment which may reduce their viability and compromise settlement and future abundances of
this species.
Description
Keywords
Bivalvia Japanese oyster Carbon dioxide Ostreida Climate change Coastal ocean
Citation
Barros, P.; Sobral, P.; Range, Pedro; Chícharo, Luís; Matias, Domitília. Effects of sea-water acidification on fertilization and larval development of the oyster Crassostrea gigas, Journal of Experimental Marine Biology and Ecology, 440, n/a, 200-206, 2013.