Seawater chemistry, nutrients, chlorophyll a, and growth rate of Phaeocystis globosa during experiments

• Main Authors: Hoogstraten, Astrid, Peters, M, Timmermans, Klaas R, de Baar, Hein J W
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2012
• Subjects: Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Chromista; EPOCA; European Project on Ocean Acidification; Growth/Morphology; Haptophyta; International Polar Year (2007-2008); IPY; Laboratory experiment; Laboratory strains; Light; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Pelagos; Phaeocystis globosa; Phytoplankton; Primary production/Photosynthesis; Single species; International Polar Year; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.810898; https://doi.org/10.1594/PANGAEA.810898

Phaeocystis globosa (Prymnesiophyceae) is an ecologically dominating phytoplankton species in many areas around the world. It plays an important role in both the global sulfur and carbon cycles, by the production of dimethylsulfide (DMS) and the drawdown of inorganic carbon. Phaeocystis globosa has a polymorphic life cycle and is considered to be a harmful algal bloom (HAB) forming species. All these aspects make this an interesting species to study the effects of increasing carbon dioxide (CO2) concentrations, due to anthropogenic carbon emissions. Here, the combined effects of three different dissolved carbon dioxide concentrations (CO2(aq)) (low: 4 µmol/kg, intermediate: 6-10 µmol/kg and high CO2(aq): 21-24 µmol/kg) and two different light intensities (low light, suboptimal: 80 µmol photons/m**2/s and high light, light saturated: 240 µmol photons/m**2/s) are reported. The experiments demonstrated that the specific growth rate of P. globosa in the high light cultures decreased with increasing CO2(aq) from 1.4 to 1.1 /d in the low and high CO2 cultures, respectively. Concurrently, the photosynthetic efficiency (Fv/Fm) increased with increasing CO2(aq) from 0.56 to 0.66. The different light conditions affected photosynthetic efficiency and cellular chlorophyll a concentrations, both of which were lower in the high light cultures as compared to the low light cultures. These results suggest that in future inorganic carbon enriched oceans, P. globosa will become less competitive and feedback mechanisms to global change may decrease in strength.