Get access

Increasing importance of small phytoplankton in a warmer ocean

Authors

  • XOSÉ ANXELU G. MORÁN,

    1. Instituto Español de Oceanografía, Centro Oceanográfico de Xixón, Camín de L'Arbeyal, s/n, 33212 Xixón, Spain
    2. The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA
    Search for more papers by this author
  • ÁNGEL LÓPEZ-URRUTIA,

    1. Instituto Español de Oceanografía, Centro Oceanográfico de Xixón, Camín de L'Arbeyal, s/n, 33212 Xixón, Spain
    Search for more papers by this author
  • ALEJANDRA CALVO-DÍAZ,

    1. Instituto Español de Oceanografía, Centro Oceanográfico de Xixón, Camín de L'Arbeyal, s/n, 33212 Xixón, Spain
    Search for more papers by this author
  • WILLIAM K. W. LI

    1. Department of Fisheries and Oceans, Ecosystem Research Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada B2Y 4A2
    Search for more papers by this author

Xosé Anxelu G. Morán, Instituto Español de Oceanografía, Centro Oceanográfico de Xixón, Camín de L'Arbeyal, s/n, 33212 Xixón, Spain, tel. +34 985308672, fax +34 985326277, e-mail: xelu.moran@gi.ieo.es

Abstract

The macroecological relationships among marine phytoplankton total cell density, community size structure and temperature have lacked a theoretical explanation. The tiniest members of this planktonic group comprise cyanobacteria and eukaryotic algae smaller than 2 μm in diameter, collectively known as picophytoplankton. We combine here two ecological rules, the temperature–size relationship with the allometric size-scaling of population abundance to explain a remarkably consistent pattern of increasing picophytoplankton biomass with temperature over the −0.6 to 22 °C range in a merged dataset obtained in the eastern and western temperate North Atlantic Ocean across a diverse range of environmental conditions. Our results show that temperature alone was able to explain 73% of the variance in the relative contribution of small cells to total phytoplankton biomass regardless of differences in trophic status or inorganic nutrient loading. Our analysis predicts a gradual shift toward smaller primary producers in a warmer ocean. Because the fate of photosynthesized organic carbon largely depends on phytoplankton size, we anticipate future alterations in the functioning of oceanic ecosystems.

Get access to the full text of this article

Ancillary