| Summary: | 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. Longterm dataData from laboratory experiment on the sea ice diatom Nitzschia lecointei. Data columns in all data files are explained in more detail in the separate Readme file.Longterm.csvCumulative generations cleanClean version of longterm data, i.e. without NAcumgen.csvSpecific BCP cleanClean version of longterm data, i.e. without NASpec_BCP.csvSpecific PP DOC cleanClean version of longterm data, i.e. without NASpec_PP_DOC.csvSpecific PP POC cleanClean version of longterm data, i.e. without NASpec_PP_POC.csvSpecific PP TOT cleanClean version of longterm data, i.e. without NASpec_PP_TOT.csvR ScriptsR Scripts (written in R ...
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