PEECE II mesocosm experiment: Dynamics of extracellular enzyme activities in seawater under changed atmospheric pCO2, 2011, supplement to: Arnosti, Carol; Grossart, Hans-Peter; Mühling, M; Joint, Ian; Passow, Uta (2011): Dynamics of extracellular enzyme activities in seawater under changed atmospheric pCO2: a mesocosm investigation. Aquatic Microbial Ecology, 64(3), 285-298

• Main Authors: Arnosti, Carol, Grossart, Hans-Peter, Mühling, M, Joint, Ian, Passow, Uta
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2011
• Subjects: Biomass/Abundance/Elemental composition; Coast and continental shelf; Field experiment; Mesocosm or benthocosm; North Atlantic; Other metabolic rates; Pelagos; Temperate; Identification; Experimental treatment; Partial pressure of carbon dioxide water at sea surface temperature wet air; Experiment day; Time, incubation; Cell density; Cell density, standard deviation; Proportion of total bacteria attached to particles; Bacteria, production as carbon; Bacterial cell multiplication; Sample ID; Chondroitin sulfate hydrolysis; Laminarin hydrolysis; Xylan hydrolysis; Fucoidan hydrolysis; Salinity; Temperature, water; Carbon, inorganic, dissolved; Alkalinity, total; Carbonate system computation flag; pH; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; 14C-leucine incorporation; Thymidine incorporation; see references; Measured; Calculated using seacarb after Nisumaa et al. 2010; Biological Impacts of Ocean Acidification BIOACID; European network of excellence for Ocean Ecosystems Analysis EUR-OCEANS; European Project on Ocean Acidification EPOCA; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.778190; https://doi.pangaea.de/10.1594/PANGAEA.778190

As part of the PeECE II mesocosm project, we investigated the effects of pCO2 levels on the initial step of heterotrophic carbon cycling in the surface ocean. The activities of microbial extracellular enzymes hydrolyzing 4 polysaccharides were measured during the development of a natural phytoplankton bloom under pCO2 conditions representing glacial (190 µatm) and future (750 µatm) atmospheric pCO2. We observed that (1) chondroitin hydrolysis was variable throughout the pre-, early- and late-bloom phases, (2) fucoidanase activity was measurable only in the glacial mesocosm as the bloom developed, (3) laminarinase activity was low and constant, and (4) xylanase activity declined as the bloom progressed. Concurrent measurements of microbial community composition, using denaturing-gradient gel electrophoresis (DGGE), showed that the 2 mesocosms diverged temporally, and from one another, especially in the late-bloom phase. Enzyme activities correlated with bloom phase and pCO2, suggesting functional as well as compositional changes in microbial communities in the different pCO2 environments. These changes, however, may be a response to temporal changes in the development of phytoplankton communities that differed with the pCO2 environment. We hypothesize that the phytoplankton communities produced dissolved organic carbon (DOC) differing in composition, a hypothesis supported by changing amino acid composition of the DOC, and that enzyme activities responded to changes in substrates. Enzyme activities observed under different pCO2 conditions likely reflect both genetic and population-level responses to changes occurring among multiple components of the microbial loop. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) 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).