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31.
Emmanuelle Ducassou Thierry Mulder Sbastien Migeon Eliane Gonthier Anne Murat Marie Revel Lucilla Capotondi Stefano M. Bernasconi Jean Mascle Sbastien Zaragosi 《Quaternary Research》2008,70(3):382-391
Clastic mud beds rich in continental organic matter are observed recurrently in the Nile deep-sea turbidite system. They formed during flooding periods of the river similar to those that induce sapropel formation and occurred during periods of increased density stratification of the eastern Mediterranean. The very fine-grained flood deposits are intercalated within pelagic sediments, sapropels and Bouma-type turbidites. These flood deposits form by the successive reconcentrations of surface (hypopycnal) plumes by convective sedimentation, which in turn generate a fine-grained low-energy hyperpycnal flow. Sea-level high stands seem also to favor hypopycnal plume formation and increase clastic mud bed formation. Consequently, these muddy clastic beds provide a direct link between deep-marine sedimentary records and continental climatic change through flood frequency and magnitude. 相似文献
32.
Mariana Guenther Moacyr Araújo Carlos Noriega Manuel Flores‐Montes Eliane Gonzalez‐Rodriguez Sigrid Neumann‐Leitão 《Marine Ecology》2017,38(2)
Multiple biotic and abiotic drivers regulate the balance between CO2 assimilation and release in surface waters. In the present study, we compared in situ measurements of plankton carbon metabolism (primary production and respiration) to calculated air–water CO2 fluxes (based on abiotic parameters) during 1 year (2008) in a hypereutrophic tropical estuary (Recife Harbor, NE Brazil – 08°03′S, 34°52′W) to test the hypothesis that high productivity leads to a net CO2 flux from the atmosphere. The calculated CO2 fluxes through the air–water interface (FCO2) were negative throughout the year (FCO2: –2 to –9 mmol C·m?2·day?1), indicating that Recife Harbor is an atmospheric CO2 sink. Respiration rates of the plankton community ranged from 2 to 45 mmol C·m?2·hr?1. Gross primary production ranged from 0.2 to 281 mmol C·m?2·hr?1, exceeding respiration during most of the year (net autotrophy), except for the end of the wet season, when the water column was net heterotrophic. The present results highlight the importance of including eutrophic tropical shallow estuaries in global air–water CO2 flux studies, in order to better understand their role as a sink of atmospheric CO2. 相似文献