Publicación:
Climate-driven changes in sedimentation rate influence phosphorus burial along continental margins of the northwestern Mediterranean
Climate-driven changes in sedimentation rate influence phosphorus burial along continental margins of the northwestern Mediterranean
No hay miniatura disponible
Fecha
2018-07
Autores
Cortina, Aleix
Filippelli, Gabriel
Ochoa, Diana
Sierro, Francisco Javier
Flores, José-Abel
Grimalt, Joan O.
Título de la revista
Revista ISSN
Título del volumen
Editor
Elsevier
Proyectos de investigación
Unidades organizativas
Número de la revista
Abstracto
The burial of phosphorus (P) in continental margin sediments is a critical component of the marine reactive P budget, and thus an important factor in marine biological productivity. We determined downcore records of P from a site drilled on the upper slope of the Gulf of Lions (PRGL 1), northwestern Mediterranean Sea. Changes in total P content were monitored from Marine Isotope Stage (MIS) 6 to MIS 11. In addition, in two selected intervals (248–277 ka and 306–342 ka) the total P record was expanded by adding detailed geochemical analyses of the various P fractions, including oxyhydroxide-associated P, authigenic P, detrital P and organic P. Increased sedimentation rates during glacials owing to seaward migration of the Rhone's mouth, enhanced the burial of reactive P (oxyhydroxide-associated + authigenic + organic) phases by decreasing its time at the reactive sediment/water interface, in turn resulting in increasing proportion of authigenic to detrital phosphorus. The inverse was found for interglacial stages. The effects of glacial/interglacial variation in sedimentation rate over P geochemistry resulted in changes in sediment-water interface oxygenation, as well as in the efficiency of P burial, as shown by (C:P)org and Corg:Preact proxies respectively. Two events of high P deposition associated with authigenic P formation, at 335 ka (Paut1) and 275 ka (Paut2), were associated with periods of rapid disintegration of North Atlantic ice sheets leading to Ice Rafted Debris (IRD) deposition. These high P deposition events appear to be linked to short warm periods that followed cold episodes. Enhanced continental runoff owing to more humid conditions during short warm episodes could play a critical role for enhanced biogenic productivity and posterior authigenic P accumulation.
Descripción
Palabras clave
Terminación IV,
Paleoredox,
Paleoproductividad del fósforo,
Golfo de León,
MIS 8