Data for manuscript 'Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO2 tolerance in phytoplankton productivity'

Brief description

This data set was collected from a ocean acidification minicosm experiment performed at Davis Station, Antarctica during the 2014/15 summer season. It includes:
- description of methods for all data collection and analyses.
- marine microbial community data; Chlorophyll a concentration, particulate organic matter concentration (carbon and nitrogen), bacterial cell abundance.
- phytoplankton primary productivity data; 14C-sodium bicarbonate incorporation raw data (decays per minute: DPM) and modelled productivity from photosynthesis versus irradiance (PE) curves, O2-evolution derived net community productivity, respiration, and gross primary productivity.
- phytoplankton photophysiology data; community photosynthetic efficiency from PAM measurements (maximum quantum yield of PSII: Fv/Fm), PAM steady state light curve data and derived non-photochemical quenching of Chl a fluorescence (NPQ), relative electron transport rates (rETR), and effective quantum yield of PSII (delta F/Fm').
- phytoplankton carbon concentrating mechanism (CCM) data; maximum quantum yield of PSII (Fv/Fm) and effective quantum yield of PSII (∆F/Fm') from PAM measurements on size-fractionated phytoplankton samples (less than 10 microns and greater than 10 microns cells) exposed to; ethoxzolamide (EZA) which inhibits both intracellular carbonic anhydrase (iCA) and extracellular carbonic anhydrase (eCA), acetazolamide (AZA), which blocks eCA only, and a control (no inhibitor) sample.
- bacterial productivity data; 14C-Leucine incorporation raw data (decays per minute: DPM) and calculated productivity.

Lineage

Progress Code: completed

Statement: The minicosm experimental design measured the microbial community growth in six unreplicated fCO2 treatments. Therefore, sub-samples from each minicosm were within-treatment pseudoreplicates and thus, results of statistical analysis must be interpreted conservatively.

Notes

Purpose
One community-level study has been performed in Antarctic waters on a natural coastal marine microbial community at Davis Station, Antarctica during the 2008/09 summer season. This study in Prydz Bay, East Antarctica reported declines in primary and bacterial productivity when CO2 concentration exceeded 780 micro atm. A shift in community composition was also observed, with increased abundance of small picoeukaryotes and a decline in large diatoms. Based on the results of this previous study, a natural community of Antarctic marine microbes from Prydz Bay, East Antarctica were exposed to a range of CO2 concentrations in 650 l minicosms to simulate possible future ocean conditions up to the year ∼2200. Productivity was examined at CO2 concentrations between 343 to 1641 μatm to determine whether tipping points existed, above which CO2 concentration reduced rates of primary productivity, bacterial productivity, and the accumulation of particulate organic matter (POM). Photophysiological assays were also performed to assess whether possible mechanisms driving changes in the phytoplankton community could be determined.