Long-term acclimation to elevated pCO2 alters carbon metabolism and reduces growth in the Antarctic diatom Nitzschia lecointei

• Main Authors: Torstensson, Anders, Hedblom, Mikael, Mattsdotter Björk, M y, Chierici, Melissa, Wulff, Angela
• Format: Dataset
• Language: English
• Published: PANGAEA 2015
• Subjects: Alkalinity; total; Antarctic; Aragonite saturation state; Bacteria; Bacterial production of carbon; Bacterial production of carbon per cell; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell density; Chromista; Comment; Dry mass per cell; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Generation; Growth/Morphology; Growth rate; Identification; Laboratory experiment; Laboratory strains; Nitzschia lecointei; Number; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Other metabolic rates; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; Percentage; pH; Phytoplankton; Potentiometric titration; Primary production/Photosynthesis; Primary production of carbon; Primary production of carbon per cell; Registration number of species; Salinity; Sample ID; Single species; Species; Spectrophotometric; Temperature; Antarc*; Ocean acidification; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.869122; https://doi.org/10.1594/PANGAEA.869122

Increasing atmospheric CO2 levels are driving changes in the seawater carbonate system, resulting in higher pCO2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to increased pCO2, and few on slow-growing polar organisms with a relative low adaptation potential. In order to recognize the consequences of climate change in biological systems, acclimation and adaptation to new environments are crucial to address. In this study, physiological responses to long-term acclimation (194 days, approx. 60 asexual generations) of three pCO2 levels (280, 390 and 960 µatm) were investigated in the psychrophilic sea ice diatom Nitzschia lecointei. After 147 days, a small reduction in growth was detected at 960 µatm pCO2. Previous short-term experiments have failed to detect altered growth in N. lecointei at high pCO2, which illustrates the importance of experimental duration in studies of climate change. In addition, carbon metabolism was significantly affected by the long-term treatments, resulting in higher cellular release of dissolved organic carbon (DOC). In turn, the release of labile organic carbon stimulated bacterial productivity in this system. We conclude that long-term acclimation to ocean acidification is important for N. lecointei and that carbon overconsumption and DOC exudation may increase in a high-CO2 world.