Seawater pH predicted for the year 2100 affects the metabolic response to feeding in Copepodites of the Arctic Copepod Calanus glacialis

• Main Authors: Thor, Peter, Bailey, Allison, Halsband, Claudia, Guscelli, Ella, Gorokhova, Elena, Fransson, Agneta
• Format: Dataset
• Language: English
• Published: PANGAEA 2016
• Subjects: Alkalinity; total; standard deviation; Animalia; Aragonite saturation state; Arctic; Arthropoda; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calanus glacialis; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Coulometric titration; DNA content per individual; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Metabolic rate of carbon per carbon mass; OA-ICC; Ocean Acidification International Coordination Centre; Other; Partial pressure of carbon dioxide; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Polar; Potentiometric titration; Registration number of species; Respiration; RNA/DNA ratio; Salinity; Arctic copepod; Kongsfjord*; Ocean acidification; Copepods; Spitsbergen
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.874790; https://doi.org/10.1594/PANGAEA.874790

Widespread ocean acidification (OA) is transforming the chemistry of the global ocean, and the Arctic is recognised as a region where the earliest and strongest impacts of OA are expected. In the present study, metabolic effects of OA and its interaction with food availability was investigated in Calanus glacialis from the Kongsfjord, West Spitsbergen. We measured metabolic rates and RNA/DNA ratios (an indicator of biosynthesis) concurrently in fed and unfed individuals of copepodite stages CII-CIII and CV subjected to two different pH levels representative of present day and the "business as usual" IPCC scenario (RCP8.5) prediction for the year 2100. The copepods responded more strongly to changes in food level than to decreasing pH, both with respect to metabolic rate and RNA/DNA ratio. However, significant interactions between effects of pH and food level showed that effects of pH and food level act in synergy in copepodites of C. glacialis. While metabolic rates in copepodites stage CII-CIII increased by 78% as a response to food under present day conditions (high pH), the increase was 195% in CII-CIIIs kept at low pH-a 2.5 times greater increase. This interaction was absent for RNA/DNA, so the increase in metabolic rates were clearly not a reaction to changing biosynthesis at low pH per se but rather a reaction to increased metabolic costs per unit of biosynthesis. Interestingly, we did not observe this difference in costs of growth in stage CV. A 2.5 times increase in metabolic costs of growth will leave the copepodites with much less energy for growth. This may infer significant changes to the C. glacialis population during future OA.