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RESOURCE LIMITATION OF BACTERIAL PRODUCTION DISTORTS THE TEMPERATURE DEPENDENCE OF OCEANIC CARBON CYCLING
Author(s) -
López-Urrutia Ángel,
Morán Xosé Anxelu G.
Publication year - 2007
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/06-1641
Subject(s) - trophic level , biomass (ecology) , ecosystem , ecology , carbon cycle , environmental science , abundance (ecology) , cycling , carbon fibers , plankton , global warming , chlorophyll a , primary producers , climate change , biology , phytoplankton , nutrient , botany , geography , materials science , archaeology , composite number , composite material
Our view of the effects of temperature on bacterial carbon fluxes in the ocean has been confounded by the interplay of resource availability. Using an extensive compilation of cell‐specific bacterial respiration (BR i ) and production (BP i ), we show that both physiological rates respond to changing temperature in a similar manner and follow the predictions of the metabolic theory of ecology. Their apparently different temperature dependence under warm, oligotrophic conditions is due to strong resource limitation of BP i but not of BR i . Thus, and despite previous preconception, bacterial growth efficiency (BGE = BP i /[BP i + BR i ]) is not directly regulated by temperature, but by the availability of substrates for growth. We develop simple equations that can be used for the estimation of bacterial community metabolism from temperature, chlorophyll concentration, and bacterial abundance. Since bacteria are the greatest living planktonic biomass, our results challenge current understanding of how warming and shifts in ecosystem trophic state will modify oceanic carbon cycle feedbacks to climate change.