Seawater carbonate chemistry and biomass and pteropod metabolism

• Main Authors: Thibodeau, Patricia, Steinberg, Deborah K, Maas, Amy E
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2020
• Subjects: Animalia; Antarctic; Benthic animals; Benthos; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Laboratory experiment; Mollusca; Other metabolic rates; Polar; Respiration; Single species; Type; Species; Registration number of species; Uniform resource locator/link to reference; Experiment; Station label; Treatment; Identification; Temperature, water; Chlorophyll a; Individuals; Dry mass; Individual respiration rate; Respiration rate, oxygen; Phosphate, excretion; Ammonium, excretion; Urea, excretion; Phosphate, organic, dissolved, excretion; Salinity; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; pH; pH, standard deviation; Calcite saturation state; Calcite saturation state, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Fugacity of carbon dioxide water at sea surface temperature wet air; Fugacity of carbon dioxide in seawater, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Aragonite saturation state; Aragonite saturation state, standard deviation; Calculated using seacarb after Nisumaa et al. 2010; Calculated using seacarb after Orr et al. 2018; Ocean Acidification International Coordination Centre OA-ICC; Antarctic Peninsula; Southern Ocean; Antarc*; Antarctica; Limacina helicina; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.929283; https://doi.pangaea.de/10.1594/PANGAEA.929283

Pteropods (pelagic snails) are abundant zooplankton in the Southern Ocean where they are important grazers of phytoplankton, prey for higher trophic levels, and sensitive to environmental change. The Western Antarctic Peninsula (WAP) is a highly dynamic and productive region that has undergone rapid warming, but little is known about how environmental changes there will affect pteropod physiology. In this study, the effects of warming seawater temperatures and shifting food availability on Limacina helicina antarctica metabolism (respiration and excretion) were determined by conducting shipboard experiments that exposed pteropods to a range of temperatures and phytoplankton (food) concentrations. Highest respiration (up to 69 μmol O2/gDW/h) and usually highest excretion rates occurred under higher temperature with more limited metabolic response to food concentration, indicating these factors do not always have an additive effect on pteropod metabolism. The proportion of dissolved organic matter (DOM) to total organic and inorganic dissolved constituents was high and was also significantly affected by shifts in temperature and food. Dissolved organic carbon, nitrogen, and phosphorus (DOC, DON, and DOP) were on average 27, 51, and 11.5% of the total C, N, and P metabolized, respectively. The proportion of total N excreted as DON and the proportion of total P excreted as DOP were significantly affected by a combination of shifting temperature and food concentrations. There were no effects of temperature or food on DOC excretion (mean 8.79 μmol C/gDW/h; range 0.44 to 44) as a proportion of total C metabolized. Metabolic O2:N ratio ranged from 2 to 9 and decreased significantly with increasing temperature and food, indicating a shift toward increased protein catabolism. Metabolic ratios of C, N, and P were all below the canonical Redfield ratio, which has implications for phytoplankton nutrient uptake and bacterial production. Respiration rates at ambient conditions of other WAP pteropods, and excretion rates for Clio pyramidata, were also measured, with respiration rates ranging from 24.39 (Spongiobranchaea australis) to 28.86 (L. h. antarctica) μmol O2/gDW/h. Finally, a CO2 perturbation experiment measuring L. h. antarctica metabolism under pre-industrial and elevated dissolved pCO2 conditions showed no significant change in mean L. h. antarctica respiration or excretion rates with higher pCO2. These insights into the metabolic response of pteropods to ocean variability increase our understanding of the role of zooplankton in biogeochemical cycles and help predict future responses to climate change. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2021) 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 2021-03-15.