Physiological Diagnosis of a Southern Ocean Diatom’s Responses to Future Complex Ocean Conditions

Philip W Boyd1, Brook L Nunn2, Emma Timmins-Schiffman3, Catriona L Hurd1, Evelyn Armstrong4, Peter Dillingham5 and Christina M McGraw5, (1)IMAS, ACE-CRC, University of Tasmania, Hobart, Australia, (2)University of Washington, Department of Genome Sciences, Seattle, United States, (3)University of Washington, Department of Genome Sciences, Seattle, WA, United States, (4)University of Otago, Chemistry, Dunedin, New Zealand, (5)University of New England, 3School of Science and Technology, Armidale, Australia
Abstract:
A changing climate is altering many ocean properties that consequently will modify marine productivity. Prior phytoplankton manipulation studies have focussed on individual or subsets of these properties. Here, we investigate the cumulative effects of multi-faceted change on a subantarctic diatom Pseudonitzschia multiseries by concurrently manipulating five stressors (light/nutrients/CO2/temperature/iron) that primarily control its physiology, and explore underlying reasons for altered physiological performance. Climate-change enhances diatom growth mainly due to warming and iron-enrichment, and both properties decrease cellular nutrient quotas partially offsetting any effects of decreased nutrient supply by 2100. Physiological diagnostics and comparative proteomics demonstrate the joint importance of individual and interactive effects of temperature and iron, and reveal biased future predictions from experimental outcomes when only a subset of multi-stressors is considered. Our findings for subantarctic waters illustrate how composite regional studies are needed to provide accurate global projections of future shifts in productivity and distinguish underlying species-specific physiological mechanisms.
Back to: Assessing the Cumulative Effects of Complex Ocean Change on Marine Biota I