Juvenile sea stars exposed to acidification decrease feeding and growth with no acclimation potential

TitleJuvenile sea stars exposed to acidification decrease feeding and growth with no acclimation potential
Publication TypeJournal Article
Year of Publication2014
AuthorsAppelhans, Y, Thomsen, J, Opitz, ST, Pansch, C, Melzner, F, Wahl, M
JournalMarine Ecology Progress Series
Volume509
Pagination227-239
Date Published08/2014
KeywordsAsterias rubens, Calcification, CO2 · Predation, Juvenile, metabolism, Ocean acidification, Sea star, Selection
Abstractmarine invertebrates, particularly during their early life history. We exposed field-collected juveniles of Asterias rubens from Kiel Fjord (western Baltic Sea) to 3 seawater CO2 partial pressure (pCO2) levels (ranging from around 650 to 3500 μatm) in a long-term (39 wk) and a short-term (6 wk) experiment. In both experiments, survival and calcification were not affected by elevated pCO2. However, feeding rates decreased strongly with increasing pCO2, while aerobic metabolism and NH4 + excretion were not significantly affected by CO2 exposure. Consequently, high pCO2 reduced the scope for growth in A. rubens. Growth rates decreased substantially with increasing pCO2 and were reduced even at pCO2 levels occurring in the habitat today (e.g. during upwelling events). Sea stars were not able to acclimate to higher pCO2, and growth performance did not recover during the long-term experiment. Therefore, the top-down control exerted by this keystone species may be diminished during periods of high environmental pCO2 that already occur occasionally and will be even higher in the future. However, some individuals were able to grow at high rates even at high pCO2, indicating potential for rapid adaption. The selection of adapted specimens of A. rubens in this seasonally acidified habitat may lead to higher CO2 tolerance in adult sea stars of this population compared to the juvenile stage. Future studies need to address the synergistic effects of multiple stressors such as acidification, warming and reduced salinity, which will simultaneously impact the performance of sea stars in this habitat.