Porewater redox species and processes in the Black Sea sediments

摘要: During the 2003 KNORR and 2005 ENDEAVOR cruises to Black Sea, voltammetric solid-state microelectrode data were collected for vertical distribution of redox species in porewaters from upper 200 300 mm layer sediments with resolution. We discuss distributions dissolved sulfide, manganese iron oxic, suboxic, anoxic/sulfidic parts Sea. Results profiling demonstrate many processes governing porewater chemistry oxic shelf sediments, suboxic slope deep anoxic (Unit I), turbidites sediments. Sediments areas appear be spatially similar their revealing same sequence species, as elsewhere Ocean, except lack manganese. This is explained by its diagenetic remobilization accumulation waters part reveal high concentrations (II) porewaters. Still, flux Mn(II) these comprises only a Mn(IV) that precipitates water column can diagenetically recycled These major net sink it not accumulated either or The cores showed spatial variations magnitude even direction sulfide. eastern central Sea show an expected Unit 1 source sulfide overlying have content, up 1600 μM. In western near coastal cores, cause significant loss down nondetectable (b0.2 μM). latter origin oxidized Mn Fe content turbidites. © 2007 Elsevier B.V. All rights reserved.