Downward fluxes of elemental carbon, metals and polycyclic aromatic hydrocarbons in settling particles from the deep Ionian Sea (NESTOR site), Eastern Mediterranean

[摘要] To assess sources and major processes controlling the vertical transport ofboth anthropogenic and natural chemical species in a deep basin of theEastern Mediterranean Sea (SE Ionian Sea, Nestor site), we performed chemicalcharacterization (elemental carbon, major and trace metals and polycyclicaromatic hydrocarbons) of marine sinking particles. Sediment traps weredeployed at five successive depths, 700, 1200, 2000, 3200 and 4300 m fromthe sea surface from May 2007 to October 2008. Fluxes of all measuredchemical species, attributed to both natural and anthropogenic sources,exhibited minimum values from January to March 2008 and maximum from April toSeptember 2008. Crustal matter flux from atmospheric inputs – either"freshly" deposited or stored in the surface layers – plays an importantrole in the temporal variability of particulate marine matter fluxes alongwith particulate organic carbon export, imposing ballast effects. Tracers(elemental carbon, retene) of the devastating forest fires that occurred inAugust 2007 in southern Greece were detected in sediment trap material fromall depths with a delay of 15 days at 4300 m, indicating a rapid andwell-coupled transport of sinking particulate material between thesea-surface and deep layers of the Eastern Mediterranean Sea. This is inaccordance with an evident covariance between certain compounds, suggestingcommon sources and/or transport mechanisms to depth. Lateral inputs ofpollutants at the deepest trap (4300 m) are probably of importance, relatedto the periodic influence of deep Adriatic water at the study site.

[学科分类] 地球化学与岩石