Abstract
11 pages, 4 figures, 1 table, 1 appendix
This study was aimed at identifying macroecological patterns in the relationship between phytoplankton cell size, abundance and metabolism in 2 marine ecosystems characterised by marked differences in resource availability and water-column stability. Several patterns emerged: (1) nearly isometric size-scaling of phytoplankton carbon fixation rate was described for both open-ocean and coastal ecosystems (mean slope: 1.17 and 0.90, respectively), supporting the idea that biomass-specific photosynthesis rates are largely independent of cell size; (2) less steep values for the size-scaling of abundance (mean slope: -0.73) were found in the coastal ecosystem compared to the open ocean (mean slope: -1.15); (3) large phytoplankton used more photosynthetic energy than smaller cells in the coastal ecosystem, but a constant flow of energy along the size spectrum was found in the open ocean; and (4) phytoplankton biomass turnover rates were 1 order of magnitude higher in the coastal ecosystem than in the open ocean, implying physiological limitation of phytoplankton growth in the oligotrophic ocean. Bottom-up and top-down mechanisms and their interaction with nutrient supply dynamics were suggested as major factors determining the contrasting phytoplankton size abundance distributions observed in coastal and open-ocean waters. © Inter-Research 2014
D.C.L.S. and T.R.R were supported by postgraduate fellowships from the Spanish Ministry of Education, the Mexican Council of Science and Technology (CONACyt) and the Xunta de Galicia (Spain). M.H.O. was supported by the postdoctoral fellowship Fundación Juana de Vega and P.C. by the postdoctoral research program Ramon y Cajal. We acknowledge the funding received from the Spanish Ministry of Science and Innovation through projects ‘Trichodesmium and nitrogen fixation in the Atlantic Ocean’ (CTM2004-05174-C02), ‘Macro ecological patterns in marine phytoplankton’ (CTM2008-03699), and ‘MALASPINA 2010’ (CSD2008-00077)
Peer Reviewed