Data/hora: 08/06/2024 13:56:53

Provedor de dados: | 5
País: | France
Título: | Dynamique du carbone et des nutriments dans la zone côtière Baie de l’Aiguillon-Pertuis Breton et influence des apports terrestres du bassin versant du Marais poitevin
Autores: | Lannuzel, Reva.
Data: | 2018-06
Ano: | 2018
Palavras-chave: | Zone côtière; Biogéochimie; Carbone; Nutriments; Chlorophylle a; Limitation potentielle et réelle; Dynamique.; Coastal zone; Biogeochemistry; Carbon; Nutrients; Chlorophyll a; Real and potential limitation; Spatio-temporal dynamic.
Resumo: | Coastal zones represent key systems in biogeochemical cycle couplings between continents, oceans and the atmosphere transporting considerable amounts of matter, energy and nutrients (C, N, P et Si) from land to sea. Despite its relatively modest surface area (7 % of the global ocean surface), this zone accounts for 14–30 % of all oceanic primary production. The present study deals with nutrients and carbon dynamics during a full hydrologic cycle in 2017 over the terrestrial-aquatic continuum formed by the Poitevin Marsh-Aiguillon Bay- Breton Sound to better understand terrestrial export influence on the coastal zone. Carbon and nutrient concentrations were sampled twice a month over heterogeneous sites (estuaries, channels and coastal sites) to integrate spatio-temporal variations and controlling factors. Hydrodynamic systems such as estuaries showed very high SPM concentrations (6067,0±3817,0 mg L-1 in average in the Sèvre Niortaise) and pCO2 partial pressures (1338,0±583,6 and 2393,0±1021,0 ppmv) due to intense organic matter mineralization. To the contrary, channels waters looked clearer and less turbid (SPM: 114,2±120,6 mg L-1, Chenal Vieux) and so more productive (chl a :42,7±25,8 μg L-1, Canal de Luçon) with in turn lower water pCO2 (1365,0±911,7 ppmv into Curé water) over the year. Terrestrial inputs significantly influenced coastal waters (Lay and Sevre stations) in terms of nutrients' dynamics especially in winter under stronger discharges and hydraulic locks management in the watershed too. Globally nutrients appeared to limit to a small extent primary production with however lower concentrations of phosphorous noticed during winter (Si:N (0,14) et N :P (1486,7) Curé water) and nitrogen during summer (Si :P (23,19) et N :P (7,19) Lay water). Carbon and nutrient exports from the Poitevin Marsh were estimated in 2017 at 39535 and 4984 t an-1 (8.92 et 1.12 t km-2 an-1) respectively with DIC&gt;POC&gt;DIN&gt;DSI and DIP. Estuarine systems ensured the majority of exports to coastal waters compared to channels; however climate and anthropogenic pressures (soil occupation,...) can strongly modify terrestrial processes and fluxes and in turn the biogeochemical functioning of the costal zone.
Tipo: | Text
Idioma: | Francês

Identificador:

http://archimer.ifremer.fr/doc/00445/55647/57299.pdf

http://archimer.ifremer.fr/doc/00445/55647/

Formato: | application/pdf

Fonte:

2018 Ifremer, Univesité de La Rochelle

info:eu-repo/semantics/openAccess

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