Effects of elevated pCO2 on gene expression patterns and ion regulation processes in the Green crab Carcinus maenas

• Main Author: Fehsenfeld, Sandra
• Format: Thesis
• Language: English
• Published: 2010
• Subjects: Ocean acidification
• Online Access: https://oceanrep.geomar.de/id/eprint/8798/; https://oceanrep.geomar.de/id/eprint/8798/1/Dipl.%202010%20Fehsenfeld,S.pdf; https://oceanrep.geomar.de/id/eprint/8798/2/Dipl.%202010%20Fehsenfeld,S_Anhang.7z

Due to rising anthropogenic C02 emissions, a decrease in surface ocean pH of up to 0.8 units until the year 2300 is predicted, equivalent to a rise of pC02 concentrations from 39 Pa to 190 Pa. The resulting changes in carbonate chemistry termed 'ocean acidification' will become a general stress factor shaping future marine environments by differentially influencing the fitness of marine species. The Green crab Carcinus maenas inhabits the intertidal zone of temperate latitudes and currently invades new habitats around the world. It is known for its high acclimation potential to different stressors, e.g. changes in salinity or temperature. An efficient regulation apparatus located in its posterior gill epithelia is responsible for the crabs' high acclimation potential to environmental stressors, but it is not known at present which ion transporters play the key role in the acid-base compensation response. In addition, nothing is known about other cellular responses to CO2 stress. In order to promote our understanding of these processes, Green crabs of the Baltic Sea were exposed to control (39 Pa) and elevated (400 Pa) pCO2 in a flow-through seawater COrmanipulation system. Posterior gills #7 and #9 were isolated after three and seven days, and screened for differentially expressed gene transcripts using a 4,462-feature microarray. In 24 % (1,056 out of 4,462) of the genes, expression levels significantly changed with an up-regulation of 541 and a down-regulation of 502 gene transcripts, 13 transcripts being regulated in a mixed fashion (sign test with p < 0.05). Regulation patterns differed among gills and over time. In principle, mainly a fine scale adjustment of expression levels occurred as might have been expected considering the high ion-regulatory capacity of this species. However, 2 % of all investigated transcripts showed significant changes on a higher level (1.3-2.2 fold). The response of Carcinus maenas upon elevated pCO2 in this study revealed no characteristics of a classical stress response. ...