Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya) - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biogeosciences Discussions Année : 2004

Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya)

Résumé

The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya) by ?13C analysis of bacteria-specific PLFA (phospholipid fatty acids) and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC) and ?13CTOC data. PLFA ?13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1 cm) typically showed more enriched ?13C values than deeper (up to 10 cm) sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material.
Under the assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74%) corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71%) across different seagrass sites. Based on these results and a compilation of literature data, we suggest that allochtonous carbon trapped in seagrass beds may often represent a significant fraction of the substrate for benthic mineralization - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that community respiration data systematically overestimate the role of mineralization in the overall seagrass C budget.
Fichier principal
Vignette du fichier
bgd-1-311-2004.pdf (927.17 Ko) Télécharger le fichier
Origine : Accord explicite pour ce dépôt
Loading...

Dates et versions

hal-00297748 , version 1 (18-06-2008)

Identifiants

  • HAL Id : hal-00297748 , version 1

Citer

S. Bouillon, T. Moens, F. Dehairs. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya). Biogeosciences Discussions, 2004, 1 (1), pp.311-333. ⟨hal-00297748⟩

Collections

INSU EGU
266 Consultations
205 Téléchargements

Partager

Gmail Facebook X LinkedIn More