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CARBON SEQUESTRATION IN ECOSYSTEMS: THE ROLE OF STOICHIOMETRY
Author(s) -
Hessen Dag O.,
Ågren Göran I.,
Anderson Thomas R.,
Elser James J.,
de Ruiter Peter C.
Publication year - 2004
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/02-0251
Subject(s) - autotroph , decomposer , ecosystem , heterotroph , detritus , ecology , nutrient , biomass (ecology) , ecological stoichiometry , primary producers , environmental chemistry , organic matter , carbon sequestration , environmental science , biology , carbon dioxide , chemistry , phytoplankton , genetics , bacteria
The fate of carbon (C) in organisms, food webs, and ecosystems is to a major extent regulated by mass‐balance principles and the availability of other key nutrient elements. In relative terms, nutrient limitation implies excess C, yet the fate of this C may be quite different in autotrophs and heterotrophs. For autotrophs nutrient limitation means less fixation of inorganic C or excretion of organic C, while for heterotrophs nutrient limitation means that more of ingested C will “go to waste” in the form of egestion or respiration. There is in general a mismatch between autotrophs and decomposers that have flexible but generally high C:element ratios, and consumers that have lower C:element ratios and tighter stoichiometric regulation. Thus, C‐use efficiency in food webs may be governed by the element ratios in autotroph biomass and tend to increase when C:element ratios in food approach those of consumers. This tendency has a strong bearing on the sequestration of C in ecosystems, since more C will be diverted to detritus entering soils or sediments when C‐use efficiency is low due to stoichiometric imbalance. There will be a strong evolutionary pressure to utilize such excess C for structural and metabolic purposes. This article explores how these basic principles may regulate C sequestration on different scales in aquatic and terrestrial ecosystems.