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| Titel |
Seasonal and interannual evolution of the diatom fluxes in the Northwest Mediterranean based on the study of a 12-year-long sediment trap record |
| VerfasserIn |
Andrés Rigual-Hernández, María de los Ángeles Bárcena, Francisco Javier Sierro, José Abel Flores, Serge Heussner |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039722
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| Zusammenfassung |
| We studied the seasonal and annual evolution of the diatom assemblages through the analysis
of two sediment trap records from the Gulf of Lions (Northwest Mediterranean). The general
circulation in the GoL is dominated by an along-slope current called Northern Current (NC)
that flows in a cyclonic direction along the continental slope
Particle fluxes to the sea floor were controlled by changes in sea surface circulation and
primary productivity, which underwent strong annual cycles. To investigate seasonal and
annual changes in particle fluxes over the last decade two sediment traps were deployed in the
middle part of the Planier and Lacaze-Duthiers canyons and samples were taken fortnightly
or monthly from 1993 to 2006.
Diatoms annual cycle can be divided in four stages that approximately coincide with the
four seasons. The diatom fluxes exhibited an unimodal pattern with maximum fluxes at the
beginning of the spring season that present the perfect conditions for the diatom growth with
a photic zone replenish with nutrients and optimum radiation.
More than 120 diatom species were identified in the samples. Thalassionema frauenfeldii
was the dominant taxa during the study period for both traps. Planier station was the
trap with less influence of the continental shelf and, among others, exhibited the
classical succession Skeletonema-Chaetoceros-Rhizosolenia through the spring
bloom. Lacaze-Duthiers station showed important differences with Planier, as higher
productivity caused by the fertilizing effect of the Rhône river or maximum diatom
productivity peaks in different moments. Despite the differences between the two
tramps, both showed very strong seasonal variations and repetitive from year to year. |
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