Bioturbation and manganese cycling in hemipelagic sediments

The activities of infaunal macrobenthos have major influences on the types, rates and distributions of diagenetic reactions involving manganese in relatively carbon-rich deep-sea and nearshore sediments. In some non-sulphidic hemipelagic deposits of the eastern equatorial Pacific (Panama Basin) biogenic reworking drives internal cycles of manganese, which can apparently account for up to ca. 100% of organic carbon oxidation and reduction of 02 supplied (diffusively) to the sea floor. Heterotrophic (carbon-based) manganese reduction is stimulated by simultaneous mixing of reactive organic matter and manganese oxide into suboxic-anoxic deposits. In sulphidic sediments, biogenic reworking must also enhance a lithotrophic pathway (sulphur-based) pathway of manganese reduction by promoting contact of manganese oxides and iron sulphides. Particle reworking dramatically alters the balance between aerobic and anaerobic decomposition pathways, promoting the utilization of 02 in the reoxidaton of reduced metabolites rather than direct oxidation of carbon. Irrigated burrows create microenvironments, which increase manganese reduction—oxidation and deplete Mn2+ from deeper pore waters. This may increase net Mn2+ production rates by removal of metabolites and potential co-precipitants with Mn2+. The occurrence and geometry of manganese oxide encrusted biogenic structures imply specific adaptations of infauna to manganese based microbial activity in hemipelagic sediments like the Panama Basin.

[1]  T. C. Moore,et al.  Biogenic Sediments of the Panama Basin , 1973, The Journal of Geology.

[2]  W. Martin,et al.  Organic carbon oxidation and benthic nitrogen and silica dynamics in San Clemente Basin, a continental borderland site , 1989 .

[3]  R. Aller,et al.  Open-incubation, diffusion methods for measuring solute reaction rates in sediments , 1989 .

[4]  R. Jahnke,et al.  Sediment-water exchange in shallow water estuarine sediments , 1984 .

[5]  J. Farrington,et al.  Deep Advective Transport of Lithogenic Particles in Panama Basin , 1982, Science.

[6]  R. Aller,et al.  The Effects of Macrobenthos on Chemical Properties of Marine Sediment and Overlying Water , 1982 .

[7]  C. Reimers,et al.  Organic carbon dynamics and preservation in deep-sea sediments , 1985 .

[8]  B. A. Skopintsev.  Chapter 6 Decomposition of Organic Matter of Plankton, Humif Ication and Hydrolysis , 1981 .

[9]  David M. Himmelblau,et al.  Diffusion coefficients of nitrogen and oxygen in water , 1967 .

[10]  S. Honjo,et al.  Seasonality and Interaction of Biogenic and Lithogenic Particulate Flux at the Panama Basin , 1982, Science.

[11]  J. Cole,et al.  Benthic decomposition of organic matter at a deep-water site in the Panama Basin , 1987, Nature.

[12]  C. Reimers.  An in situ microprofiling instrument for measuring interfacial pore water gradients: methods and oxygen profiles from the North Pacific Ocean , 1987 .

[13]  R. Aller,et al.  Effects of the marine deposit-feeders Heteromastus filiformis (Polychaeta), Macoma balthica (Bivalvia), and Tellina texana (Bivalvia) on averaged sedimentary solute transport, reaction rates, and microbial distributions , 1985 .

[14]  D. DeMaster,et al.  Estimates of particle flux and reworking at the deep-sea floor using234Th/238U disequilibrium , 1984 .

[15]  J. Mackin,et al.  Organic matter decomposition pathways and oxygen consumption in coastal marine sediments , 1989 .

[16]  G. Rowe,et al.  Nitrification and oxygen consumption in northwest Atlantic deep-sea sediments , 1984 .

[17]  F. Manheim,et al.  Cobalt in ferromanganese crusts as a monitor of hydrothermal discharge on the Pacific sea floor , 1988, Nature.