Biogeochemical controls on the oxygen, nitrogen and sulfur distributions in the water column of Golfo Dulce: an anoxic basin on the Pacific coast of Costa Rica revisited

 

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Autores: Ferdelman, Timothy G., Thamdrup, Bo, Canfield, Donald E., Glud, Ronnie Nøhr, Kuever, Jan, Lillebæk, Rolf, Ramsing, Niels Birger, Wawer, Cathrin
Formato: artículo original
Estado:Versión publicada
Fecha de Publicación:2006
Descripción:Chemical distributions, respiration rates, and bacterial distributions were measured in 1994 in the water column and sediments of a small, tropical, anoxic basin (Golfo Dulce, Pacific coast of Costa Rica) to examine the biogeochemical controls on anoxia, sulfide, dissolved inorganic nitrogen, and organic carbon consumption. As reported previously, the deepest 100 m of the water column were anoxic, and sulfide concentrations in the bottom waters were less than 7 μM and then only transiently. Both free-swimming sulfide-oxidizing bacteria and Beggiatoa sp. (containing large vacuoles) were observed in the anoxic bottom waters or at the sediment-water interface. Aerobic respiration dominated the decomposition of organic matter in the surface waters and pycnocline, whereas sulfate reduction was principally restricted to the sediments. Bacteria were distributed in discrete zones and exhibited the highest densities where oxygen decreased below 1 μM around 100 m depth, and near the sediment-water interface. The sub-oxic, sub-pycnocline water column was characterized by a dissolved inorganic nitrogen (DIN) deficit of 2.9 mole m-2. With a water residence time of 35 – 57 d, estimated from a salt balance, this deficit corresponded to a DIN loss of 51 – 85 mmol m-2 d-1, comparable to the sub-pycnocline oxygen consumption. Sulfide in the water column was maintained at low concentrations by frequent inputs of oxygenated water from the Pacific Ocean. Sulfide production in the sediments due to bacterial sulfate reduction was scavenged by frequent deposition of iron-rich turbidites. Based on 210Pb distributions, the most recent emplacement of a turbidite in the basin sediments was determined to have occurred between 1989 and 1992. Rev. Biol. Trop. 54 (Suppl. 1): 171-191. Epub 2006 Sept. 30.
País:Portal de Revistas UCR
Institución:Universidad de Costa Rica
Repositorio:Portal de Revistas UCR
Lenguaje:Inglés
OAI Identifier:oai:portal.ucr.ac.cr:article/26825
Acceso en línea:https://revistas.ucr.ac.cr/index.php/rbt/article/view/26825
Access Level:acceso abierto
Palabra clave:Anoxic basin
marine sediment
microbial processes
denitrification
anammox
sulfate reduction
Golfo Dulce
Costa Rica
anoxia
sedimentos marinos
procesos microbiológicos
denitrificación
reducción del sulfato