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Competitive fitness of a predominant pelagic calcifier impaired by ocean acidification
Nature Geoscience
  • Ulf Riebesell, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Lennart T Bach, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Richard G J Bellerby, East China Normal University
  • J R Bermúdez Monsalve, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Tim Boxhammer, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Jan Czerny, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Aud Larsen, Hjort Centre for Marine Ecosystem Dynamics, Norway
  • Andrea Ludwig, GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Kai G Schulz, Southern Cross University
Document Type
Article
Publication Date
1-1-2017
Peer Reviewed
Peer-Reviewed
Abstract
Coccolithophores—single-celled calcifying phytoplankton—are an important group of marine primary producers and the dominant builders of calcium carbonate globally. Coccolithophores form extensive blooms and increase the density and sinking speed of organic matter via calcium carbonate ballasting. Thereby, they play a key role in the marine carbon cycle. Coccolithophore physiological responses to experimental ocean acidification have ranged from moderate stimulation to substantial decline in growth and calcification rates, combined with enhanced malformation of their calcite platelets. Here we report on a mesocosm experiment conducted in a Norwegian fjord in which we exposed a natural plankton community to a wide range of CO2-induced ocean acidification, to test whether these physiological responses affect the ecological success of coccolithophore populations. Under high-CO2 treatments, Emiliania huxleyi, the most abundant and productive coccolithophore species, declined in population size during the pre-bloom period and lost the ability to form blooms. As a result, particle sinking velocities declined by up to 30% and sedimented organic matter was reduced by up to 25% relative to controls. There were also strong reductions in seawater concentrations of the climate-active compound dimethylsulfide in CO2-enriched mesocosms. We conclude that ocean acidification can lower calcifying phytoplankton productivity, potentially creating a positive feedback to the climate system.
Citation Information

Riebesell, U, bach, LT, Bellerby, RGJ, Monsalve, JRB, Boxhammer, T, Czerny, J, Larsen, A, Ludwig, A & Schulz, KG 2017, 'Competitive fitness of a predominant pelagic calcifier impaired by ocean acidification', Nature Geoscience, vol. 10, no. 1, pp. 19-23.

Published version available from:

https://dx.doi.org/10.1038/ngeo2854