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Seagrass sediments as a global carbon sink: Isotopic constraints
Author(s) -
Kennedy Hilary,
Beggins Jeff,
Duarte Carlos M.,
Fourqurean James W.,
Holmer Marianne,
Marbà Núria,
Middelburg Jack J.
Publication year - 2010
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2010gb003848
Subject(s) - seagrass , blue carbon , environmental science , sediment , carbon sink , total organic carbon , sink (geography) , habitat , carbon fibers , carbon sequestration , ecology , oceanography , geology , ecosystem , carbon dioxide , biology , geography , paleontology , materials science , cartography , composite number , composite material
Seagrass meadows are highly productive habitats found along many of the world's coastline, providing important services that support the overall functioning of the coastal zone. The organic carbon that accumulates in seagrass meadows is derived not only from seagrass production but from the trapping of other particles, as the seagrass canopies facilitate sedimentation and reduce resuspension. Here we provide a comprehensive synthesis of the available data to obtain a better understanding of the relative contribution of seagrass and other possible sources of organic matter that accumulate in the sediments of seagrass meadows. The data set includes 219 paired analyses of the carbon isotopic composition of seagrass leaves and sediments from 207 seagrass sites at 88 locations worldwide. Using a three source mixing model and literature values for putative sources, we calculate that the average proportional contribution of seagrass to the surface sediment organic carbon pool is ∼50%. When using the best available estimates of carbon burial rates in seagrass meadows, our data indicate that between 41 and 66 gC m −2 yr −1 originates from seagrass production. Using our global average for allochthonous carbon trapped in seagrass sediments together with a recent estimate of global average net community production, we estimate that carbon burial in seagrass meadows is between 48 and 112 Tg yr −1 , showing that seagrass meadows are natural hot spots for carbon sequestration.