Diatom performance in a future ocean: Interactions between nitrogen limitation, temperature, and CO2-induced seawater acidification

Futian Li, John Beardall, Kunshan Gao

Research output: Contribution to journalArticleResearchpeer-review

13 Citations (Scopus)

Abstract

Phytoplankton cells living in the surface waters of oceans are experiencing alterations in environmental conditions associated with global change. Given their importance in global primary productivity, it is of considerable concern to know how these organisms will perform physiologically under the changing levels of pH, temperatures, and nutrients predicted for future oceanic ecosystems. Here we show that the model diatom, Thalassiosira pseudonana, when grown at different temperatures (20 or 24 °C), pCO2 (400 or 1000 matm), and nitrate concentrations (2.5 or 102.5 mmol l-1), displayed contrasting performance in its physiology. Elevated pCO2 (and hence seawater acidification) under the nitrate-limited conditions led to decreases in specific growth rate, cell size, pigment content, photochemical quantum yield of PSII, and photosynthetic carbon fixation. Furthermore, increasing the temperature exacerbated the negative effects of the seawater acidification associated with elevated pCO2 on specific growth rate and chlorophyll content under the N-limited conditions. These results imply that a reduced upward transport of nutrients due to enhanced stratification associated with ocean warming might act synergistically to reduce growth and carbon fixation by diatoms under progressive ocean acidification, with important ramifications for ocean productivity and the strength of the biological CO2 pump.

Original languageEnglish
Pages (from-to)1451-1464
Number of pages14
JournalICES Journal of Marine Science
Volume75
Issue number4
DOIs
Publication statusPublished - 1 Jul 2018

Keywords

  • CO2
  • diatom
  • growth
  • nitrogen availability
  • photosynthesis
  • phytoplankton
  • temperature
  • Thalassiosira pseudonana

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