Autors de l'ICTA

Projectes relationats

Últims articles publicats

2014 Is coccolithophore distribution in the Mediterranean Sea related to seawater carbonate chemistry?[disponible en anglès]

2014 Decline in coccolithophore diversity and impact on coccolith morphogenesis along a natural CO2 gradient.[disponible en anglès]

2014 Effects of mid-latitude westerlies on the paleoproductivity at the Atlantic margin of South Africa during the penultimate glacial cycle: evidence from coccolith Sr/Ca ratios[disponible en anglès]

2014 The role of ocean acidification in Emiliania huxleyi coccolith thinning in the Mediterranean Sea[disponible en anglès]

Abrupt shoaling of the nutricline in response to massive freshwater flooding at the onset of the last interglacial sapropel event

2012, PALEOCEANOGRAPHY - ISSN: 0883-8305 - DOI 10.1029/2012PA002288

Autors de l'ICTA:
Gianluca Marino, Patrizia Ziveri

Tots els autors:
Michaël Grelaud, Gianluca Marino, Patrizia Ziveri, Eelco J Rohling

A detailed assessment of the respective roles of production, export, and subsequent preservation of organic carbon (Corg) in the eastern Mediterranean (EMED) sediments during the formation of sapropels remains elusive. Here we present new micropaleontological results for both surface samples taken at several locations in the EMED and last interglacial sapropel S5 from core LC21 in the southeastern Aegean Sea. A strong exponential anticorrelation between relative abundances of the lower photic zone coccolithophore Florisphaera profunda in the surface sediments and modern concentrations of chlorophyll a (Chl-a) at the sea surface suggests that F. profunda percentages can be used to track past productivity changes in the EMED. Prior to S5 deposition, an abrupt and large increase of F. profunda percentages in LC21 coincided (within the multi-decadal resolution of the records) with the marked freshening of EMED surface waters. This suggests a strong coupling between freshwater-bound surface to intermediate water (density) stratification and enhanced upward advection of nutrients to the base of the photic zone, fuelling a productive deep chlorophyll maximum (DCM) underneath a nutrient-starved surface layer. Our findings imply that (at least) at the onset of sapropel formation physical and biogeochemical processes likely operated in tandem, enabling high Corg accumulation at the seafloor.

© 2008 ICTA - Universitat Autònoma de Barcelona - Tots els drets reservats