Solute Reservoirs Reflect Variability of Early Diagenetic Processes in Temperate Brackish Surface Sediments

摘要: Coastal marine sediments are a hotspot of organic matter degradation. Mineralization products early diagenetic processes accumulate in the pore waters sediment, subject biological uptake and secondary biogeochemical released back into water column via advective diffusive fluxes across sediment-water interface. Seven representative sites shallow coastal area southern Baltic Sea (15–45 m depth), ranging from permeable sands to fine grained muds, were investigated on seasonal basis for their key mineralization as well solid phase composition identify drivers variability different sediment types. The sandy showed about one order magnitude lower carbon contents compared while oxygen rates similar both Significantly higher determined two near-shore muddy than deeper basin, which is due nutrient loads corresponding addition fresh algal sites. Pore concentration profiles studied usually characterized by typical zonation with oxic, suboxic, sulfidic zones. An up 15 cm thick suboxic zone was sustained downward transport oxidized material dissolved iron phosphate indicate an intensive reduction reactive Fe release adsorbed phosphorus. While geochemical stable over time muds high observed near-coastal bay probably mainly controlled mixing activities. can be essentially factors based near-surface benthic solute reservoirs: (1) accumulation efficiency (2) redox-state. Benthic reservoirs top decimeter generally more prone exchange between bottom water. three great dissimilarities respect predominating redox-sensitive metabolites (dissolved iron, manganese, sulfide). Surface-near like irrigation rearrangement cohesive had particularly strong influence most important cause spatiotemporal reservoirs.