The effects of diel cycles and temperature on size distributions of pico- and nanophytoplankton in the subtropical and tropical Pacific Ocean

• Sato Mitsuhide

  Graduate School of Agricultural and Life Sciences, the University of Tokyo

• Kodama Taketoshi

  Graduate School of Agricultural and Life Sciences, the University of Tokyo National Research Institute of Fisheries Science

• Hashihama Fuminori

  Tokyo University of Marine Science and Technology

• Furuya Ken

  Graduate School of Agricultural and Life Sciences, the University of Tokyo

Abstract

To elucidate what determines plankton community structures in subtropical and tropical oceans, cell size distributions of pico- and nanophytoplankton were extensively measured throughout the North and South Pacific Ocean. Mean cell sizes of three different populations, Synechococcus, nano-sized cyanobacteria, and eukaryotes, showed a clear diel cycle with a peak in the late afternoon. After subtracting the effect of the diel variation by fitting sine curves, the mean cell sizes of the three populations were regressed against temperature and nutrient concentrations. The multiple regression analyses revealed that a positive correlation between the cell size of eukaryotes and temperature was the only significant parameter. Size histograms demonstrated that in the warm waters, the contribution of pico-sized eukaryotes to total phytoplankton biomass was relatively small, which in combination with the numerical dominance of Prochlorococcus caused bipolarization of the size spectrum of the entire pico- and nanophytoplankton community. These results demonstrate that commonly used biogeochemical models require amendment to account for the fact that an increase in sea surface temperature will simply lead to a prevalence of smaller phytoplankton. To reveal the effect of temperature on the entire food web, extensive surveys of zooplankton community structures will be required in future studies.

Journal

• Plankton and Benthos Research

  Plankton and Benthos Research 10 (1), 26-33, 2015

  The Plankton Society of Japan, The Japanese Association of Benthology

Keywords

• climate change
• flow cytometry
• phosphorus
• size distribution
• temperature

Details

• CRID: 1390282680242659968
• NII Article ID: 130004946448
• NII Book ID: AA12130745
• DOI: 10.3800/pbr.10.26
• ISSN: 1882627X
• ISSN: 18808247
• NDL BIB ID: 026263385
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I026263385
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed