Articles | Volume 15, issue 2
Biogeosciences, 15, 581–595, 2018
Biogeosciences, 15, 581–595, 2018

Research article 30 Jan 2018

Research article | 30 Jan 2018

Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore Emiliania huxleyi

Yuanyuan Feng1,2,3,4, Michael Y. Roleda2,5, Evelyn Armstrong6, Cliff S. Law6,7, Philip W. Boyd8, and Catriona L. Hurd2,8 Yuanyuan Feng et al.
  • 1College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin 300457, China
  • 2Department of Botany, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
  • 3Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin 300457, China
  • 4Tianjin Marine Environmental Protection and Restoration Technology Engineering Center, Tianjin 300457, China
  • 5Norwegian Institute of Bioeconomy Research, Bodø 8027, Norway
  • 6Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
  • 7National Institute of Water and Atmospheric Research (NIWA), Greta Point, Kilbirnie, Wellington 6023, New Zealand
  • 8Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7005, Tasmania, Australia

Abstract. A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2)) on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose–response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semi-quantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes.

Short summary
We conducted a series of incubation experiments to understand how the changes in five environmental drivers will affect the elemental composition of the calcifying phytoplankton species Emiliania huxleyi. These findings provide new diagnostic information to aid our understanding of how the physiology and the related marine biogeochemistry of the ecologically important species Emiliania huxleyi will respond to changes in different environmental drivers in the global climate change scenario.
Final-revised paper