Sensitivity of Antarctic phytoplankton species to ocean acidification: Growth, carbon acquisition, and species interaction

• DOI: 10.4319/lo.2013.58.3.0997
• Publication Date: 2013-04-19T09:24:54Z
• Authors: Scarlett Trimborn; Tina Brenneis; Elizabeth Sweet; Björn Rost
• Keywords: Chaetoceros; Total inorganic carbon; Mixotroph

Despite the fact that ocean acidification is considered to be especially pronounced in Southern Ocean, little known about CO 2 ‐dependent physiological processes and interactions of Antarctic phytoplankton key species. We therefore studied effects partial pressure (P CO2 ) (16.2, 39.5, 101.3 Pa) on growth photosynthetic carbon acquisition bloom‐forming species Chaetoceros debilis, Pseudo‐nitzschia subcurvata, Fragilariopsis kerguelensis, Phaeocystis antarctica. Using membrane‐inlet mass spectrometry, O evolution inorganic (C i fluxes were determined as a function concentration. Only C. debilis was enhanced under high P . Analysis concentrating mechanism (CCM) revealed operation very efficient CCMs (i.e., C affinities) all species, but there species‐specific differences regulation individual CCM components uptake kinetics, carbonic anhydrase activities). Gross rates appear increase with cell surface area volume ratios. Species competition experiments P. subcurvata different levels confirmed ‐stimulated observed monospecific incubations, also presence Independent , initial abundances led reduced For better understanding future changes communities, ‐sensitive need identified, must taken into account because their interplay determines success