Increasing importance of small phytoplankton in a warmer ocean

• Published in: Global Change Biology
• Main Authors: MORÁN, XOSÉ ANXELU G., LÓPEZ‐URRUTIA, ÁNGEL, CALVO‐DÍAZ, ALEJANDRA, LI, WILLIAM K. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2010
• Subjects: North Atlantic
• Online Access: http://dx.doi.org/10.1111/j.1365-2486.2009.01960.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2486.2009.01960.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2486.2009.01960.x

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.