Seawater acidification more than warming presents a challenge for two Antarctic macroalgal-associated amphipods

• Main Authors: Schram, Julie B, Schoenrock, Kathryn M, McClintock, James B, Amsler, Charles D, Angus, Robert A
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2016
• Subjects: Animalia; Antarctic; Arthropoda; Behaviour; Benthic animals; Benthos; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Gondogeneia antarctica; Growth/Morphology; Laboratory experiment; Mortality/Survival; Paradexamine fissicauda; Polar; Single species; Temperature; Type; Species; Registration number of species; Uniform resource locator/link to reference; Date; Consumption rate per individual; Treatment; Incubation duration; Individuals; Sample ID; Wet mass; Dry mass; Protein; Lipids; pH; pH, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Temperature, water; Temperature, water, standard deviation; Salinity; Salinity, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Aragonite saturation state; Aragonite saturation state, standard deviation; Calcite saturation state; Calcite saturation state, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Monitoring station; Spectrophotometric; Potentiometric titration; Calculated using CO2calc; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Antarctic Peninsula; Antarc*; Antarctica; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.870407; https://doi.pangaea.de/10.1594/PANGAEA.870407

Elevated atmospheric pCO2 concentrations are triggering seawater pH reductions and seawater temperature increases along the western Antarctic Peninsula (WAP). These factors in combination have the potential to influence organisms in an antagonistic, additive, or synergistic manner. The amphipods Gondogeneia antarctica and Paradexamine fissicauda represent prominent members of macroalgal-associated mesograzer assemblages of the WAP. Our primary objective was to investigate amphipod behavioral and physiological responses to reduced seawater pH and elevated temperature to evaluate potential cascading ecological impacts. For 90 d, amphipods were exposed to combinations of seawater conditions based on present ambient (pH 8.0, 1.5°C) and predicted end-of-century conditions (pH 7.6, 3.5°C). We recorded survival, molt frequency, and macroalgal consumption rates as well as change in wet mass and proximate body composition (protein and lipid). Survival for both species declined significantly at reduced pH and co-varied with molt frequency. Consumption rates in G. antarctica were significantly higher at reduced pH and there was an additive pH-temperature effect on consumption rates in P. fissicauda. Body mass was reduced for G. antarctica at elevated temperature, but there was no significant effect of pH or temperature on body mass in P. fissicauda. Exposure to the pH or temperature levels tested did not induce significant changes in whole body biochemical composition of G. antarctica, but exposure to elevated temperature resulted in a significant increase in whole body protein content of P. fissicauda. Our study indicates that while elevated temperature causes sub-lethal impacts on both species of amphipods, reduced pH causes significant mortality. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2016) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation is 2016-12-29.