Effects of ocean warming and ocean acidification on two Arctic copepod species during overwintering
Effects of end-of-century ocean warming and acidification on overwintering Calanus spp. and Metridia spp. were investigated in the Arctic Kongsfjord (Spitsbergen). This study aims to identify possible differences in the response of both genera to future ocean conditions due to their different overwi...
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| Format: | Thesis |
| Language: | English |
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2013
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| Online Access: | https://oceanrep.geomar.de/id/eprint/23054/ https://oceanrep.geomar.de/id/eprint/23054/1/M.Sc.%202013%20Stange,%20P.pdf |
| Summary: | Effects of end-of-century ocean warming and acidification on overwintering Calanus spp. and Metridia spp. were investigated in the Arctic Kongsfjord (Spitsbergen). This study aims to identify possible differences in the response of both genera to future ocean conditions due to their different overwintering strategies. The herbivorous Calanus spp. rests in deeper depth of the fjord in a diapausing state, characterized by low metabolic rates and no feeding. M etridia spp. on the other hand is characterised by an omnivorous feeding behaviour and an active metabolism throughout the dark winter season. Organsisms were caught with a plankton net during January and February 2013 and transferred immediatly into dark climate rooms at the Kings Bay Marine Laboratory (Ny-Alesund), where they were given time to acclimatise at in situ temperature. Basic respiration, carbon content and C:N ratio of the overwintering population were measured. Additionally, shock and incubation experiments were conducted to identify immediate and acclimatized responses towards elevated temperature and pC02 conditions. For shock experiments, individuals were put directly into the respiration chambers, filled with temperated, C02 enriched water and oxygen consumption was measured for 10-12 hours. Afterwards, organisms were prepared for later determination of dry mass, carbon and nitrogen content. For incubation experiments, individuals were kept in incubation bottles under treatment conditions for 14 days. Consecutively, respiration rate was measured similar to the shock experiment. pH was measured on the total scale and samples for carbonate chemistry were taken from the manipulated water before and after the experiments as well as of the fjord. Additionally, nutrient samples were taken for later ammonium excretion analysis. Respiration rates of both genera were significantly higher under elevated temperature conditions after shock and 14-day incubation. An interaction of increasing levels of pC02 and temperature on respiration rates was ... |
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