Variations in sediment accumulation rates and the flux of labile organic matter in eastern Lake Superior basins

Journal Article · Sun Jan 01 00:00:00 EST 1989 · J. Great Lakes Res.; (United States)

DOI:https://doi.org/10.1016/S0380-1330(89)71465-9· OSTI ID:6077369

Klump, J V; Paddock, R; Remsen, C C; Fitzgerald, S; Boraas, M; Anderson, P

Benthic environments in Lake Superior are variable and dynamic. The complex topography and morphology of eastern Lake Superior results in a variety of depositional environments. Direct observations of bottom types and collection of sediments across the gradient in environments reveal benthic systems that range in sediment accumulation rates from approx. 1.7 mm per year to virtually zero net long-term accumulation. Diagenetic modeling of organic carbon and nitrogen under steady state conditions indicate that 15% to 40% of the organic carbon and nitrogen deposited is recycled into the overlying water. This metabolizable fraction has a residence time in the sediment column estimated to be 30 to 60 years for organic carbon and 15 to 30 years for nitrogen. Concentration gradients of total dissolved inorganic carbon, ammonium, and oxygen in sediment pore waters yield fluxes of reminearlized carbon and nitrogen across the sediment-water interface consistent with diagenetically modeled fluxes. Spatial variability in sediment accumulation patterns, however, is great, particularly in the deep, steep relief basins in the open lake. Evidence of aperiodic bottom currents were observed in the deepest charted basin of the lake as extensive fields of sediment ripples over hard, compacted relict silt and clays. While no currents were observed in these summertime dives, it is assumed that storms during isothermal conditions generate sufficient bottom currents at depth to very effectively scour the bottom. Differences in sediment metabolism appear to be determined by the flux of labile organic matter to the bottom coupled to the physical processes of sedimentation, resuspension, and horizontal transport.

• Research Organization: Univ. of Wisconsin, Milwaukee (USA)
• OSTI ID: 6077369
• Journal Information: J. Great Lakes Res.; (United States), Vol. 15:1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
LAKE SUPERIOR
WATER POLLUTION
NITRATES
ENVIRONMENTAL TRANSPORT
ORGANIC MATTER
SEDIMENTS
CONTAMINATION
BENTHOS
DEPOSITION
DIAGENESIS
ECOLOGICAL CONCENTRATION
INTERSTITIAL WATER
MATHEMATICAL MODELS
SEDIMENT-WATER INTERFACES
SPATIAL DISTRIBUTION
VARIATIONS
AQUATIC ORGANISMS
DISTRIBUTION
GREAT LAKES
GROUND WATER
HYDROGEN COMPOUNDS
INTERFACES
LAKES
MASS TRANSFER
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
POLLUTION
SURFACE WATERS
WATER
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)