4:24 PM - 4:42 PM
[BPT01-10] The coral reef-dwelling Peneroplis spp. shows calcification resilience to ocean acidification conditions - results from culture experiments
Keywords:Ocean acidification, Large Benthic Foraminifera, Culture experiments, Calcification process
Ocean acidification is a consequence of the current climate changes, driven by anthropogenic activities. The concomitant decrease in pH and carbonate ion concentration in sea water may have severe impacts on marine life, and especially on calcifying organisms. Coral reefs were among the first ecosystems to be recognized as vulnerable to ocean acidification. Within coral reefs, large benthic foraminifera (LBF) are major calcium carbonate producers.
The aim of this work was to evaluate the impacts of varying pH on survival and calcification of the symbiont-bearing LBF species Peneroplis spp. We performed culture experiments to first study their resistance to ocean acidification conditions, and then their resilience once placed back under open ocean pH.
After three days, small signs of test decalcification were observed on specimens kept at pH 7.4, and severe test decalcification was observed on specimens kept at pH 6.9, with the inner organic lining clearly appearing. Similar strongly decalcified specimens were observed after 32 days under pH 7.4. All the specimens were alive at the end of the experiment. These results demonstrate the resistance of Peneroplis spp. to an acidified pH, at least on a short period of time.
After being partially decalcified, some of the living specimens were placed back at pH 7.9 (in situ value). After one month, the majority of the specimens showed recalcification features, mainly by addition of new chambers. The trace elements concentrations of the newly formed chambers were analysed by LA-ICPMS. Interestingly, more chambers were added when food was given, which highlights the crucial role of energy source in the recalcification process. Moreover, the newly formed chambers were most of the time abnormal, and the general structure of the tests was altered. These abnormalities have potential impacts on reproduction capacities and in situ survival of Peneroplis spp. In conclusion, if symbiont-bearing LBF show some resistance and resilience to lowered pH conditions, they will remain strongly affected by ocean acidification.
The aim of this work was to evaluate the impacts of varying pH on survival and calcification of the symbiont-bearing LBF species Peneroplis spp. We performed culture experiments to first study their resistance to ocean acidification conditions, and then their resilience once placed back under open ocean pH.
After three days, small signs of test decalcification were observed on specimens kept at pH 7.4, and severe test decalcification was observed on specimens kept at pH 6.9, with the inner organic lining clearly appearing. Similar strongly decalcified specimens were observed after 32 days under pH 7.4. All the specimens were alive at the end of the experiment. These results demonstrate the resistance of Peneroplis spp. to an acidified pH, at least on a short period of time.
After being partially decalcified, some of the living specimens were placed back at pH 7.9 (in situ value). After one month, the majority of the specimens showed recalcification features, mainly by addition of new chambers. The trace elements concentrations of the newly formed chambers were analysed by LA-ICPMS. Interestingly, more chambers were added when food was given, which highlights the crucial role of energy source in the recalcification process. Moreover, the newly formed chambers were most of the time abnormal, and the general structure of the tests was altered. These abnormalities have potential impacts on reproduction capacities and in situ survival of Peneroplis spp. In conclusion, if symbiont-bearing LBF show some resistance and resilience to lowered pH conditions, they will remain strongly affected by ocean acidification.