Seawater carbonate chemistry and Antarctic macroalgal biochemical composition and amphipod grazer feeding preferences, supplement to: Schram, Julie B; Schoenrock, Kathryn M; McClintock, James B; Amsler, Charles D; Angus, Robert A (2017): Ocean warming and acidification alter Antarctic macroalgal biochemical composition but not amphipod grazer feeding preferences. Marine Ecology Progress Series, 581, 45-56

• 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 2017
• Subjects: Animalia; Antarctic; Arthropoda; Behaviour; Benthic animals; Benthos; Biomass/Abundance/Elemental composition; Chromista; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Desmarestia anceps; Desmarestia menziesii; Gondogeneia antarctica; Laboratory experiment; Macroalgae; Ochrophyta; Polar; Single species; Species interaction; Temperature; Type; Species; Registration number of species; Uniform resource locator/link to reference; Experiment duration; Treatment; Sample ID; Tissue, dry mass; Date; Protein; Mass; Lipids; Identification; Time in hours; Feeding rate; Mass change; 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; Experiment; Spectrophotometric; Potentiometric titration; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Antarctic Peninsula; McClintock; Antarc*; Antarctica; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.892654; https://doi.pangaea.de/10.1594/PANGAEA.892654

Increased anthropogenic atmospheric CO2 concentrations have resulted in ocean warming and alterations in ocean carbonate chemistry, decreasing seawater pH (ocean acidification). The combination of ocean warming and acidification (OWA) may alter trophic interactions in marine benthic communities along the western Antarctic Peninsula (WAP). Abundant and diverse macroalgae–grazer assemblages, dominated by macroalgae (e.g. chemically defended Desmarestia anceps and D. menziesii) and gammarid amphipods (e.g. Gondogeneia antarctica), occur on the nearshore benthos along the WAP. In the present study, the amphipod G. antarctica and macroalgae D. anceps and D. menziesii were exposed for 39 and 79 d, respectively, to combinations of current and predicted near-future temperature (1.5 and 3.5°C, respectively) and pH (8.0 and 7.6, respectively). Protein and lipid levels of macroalgal tissues were quantified, and 5-way choice amphipod feeding assays were performed with lyophilized macroalgal tissues collected at time zero and following exposure to the 4 temperature-pH treatments. For D. anceps, we found a significant interactive temperature-pH effect on lipid levels and significantly lower protein levels at reduced pH. In contrast, tissues of D. menziesii exhibited significantly greater lipid levels after exposure to reduced pH, but there was no temperature effect on lipid or protein levels. Despite shifts in macroalgal biochemical composition, there were no changes in amphipod feeding preferences. Our results indicate that despite altered macroalgal nutritional quality under OWA, both macroalgae retained their ability to deter amphipod feeding. This deterrent capacity could become an important contributor to net community resistance of macroalgae-mesograzer assemblages of the WAP to predicted OWA. : 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 by seacarb is 2018-07-12.