Impact of anthropogenic ocean acidification on thermal tolerance of the spider crab Hyas araneus

• Main Authors: H. O. Pörtner, C. Bock, F. J. Sartoris, K. Walther
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2009
• Subjects: Ecology; QH540-549.5; Life; QH501-531; Geology; QE1-996.5; Helgoland; Ocean acidification
• Online Access: https://doaj.org/article/2972430b8f5a4f608f4108318851b73e

Future scenarios for the oceans project combined developments of CO 2 accumulation and global warming and their impact on marine ecosystems. The synergistic impact of both factors was addressed by studying the effect of elevated CO 2 concentrations on thermal tolerance of the cold-eurythermal spider crab Hyas araneus from the population around Helgoland. Here ambient temperatures characterize the southernmost distribution limit of this species. Animals were exposed to present day normocapnia (380 ppm CO 2 ), CO 2 levels expected towards 2100 (710 ppm) and beyond (3000 ppm). Heart rate and haemolymph PO 2 (P e O 2 ) were measured during progressive short term cooling from 10 to 0°C and during warming from 10 to 25°C. An increase of P e O 2 occurred during cooling, the highest values being reached at 0°C under all three CO 2 levels. Heart rate increased during warming until a critical temperature ( T c ) was reached. The putative T c under normocapnia was presumably >25°C, from where it fell to 23.5°C under 710 ppm and then 21.1°C under 3000 ppm. At the same time, thermal sensitivity, as seen in the Q 10 values of heart rate, rose with increasing CO 2 concentration in the warmth. Our results suggest a narrowing of the thermal window of Hyas araneus under moderate increases in CO 2 levels by exacerbation of the heat or cold induced oxygen and capacity limitation of thermal tolerance.