Present-day biosiliceous sedimentation in the northwestern Ross Sea, Antarctica
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, more Also appears in:Le Fèvre, J.; Tréguer, P. (Ed.) (1998). Carbon Fluxes and Dynamic Processes in the Southern Ocean: Present and Past. Selected papers from the International JGOFS Symposium, Brest, France, 28-31 August 1995. Journal of Marine Systems, 17(1-4). Elsevier: Amsterdam. 1-619 pp., more |  |
| Keywords | Accretion
Chemical compounds > Silicon compounds > Silica
Cycles > Chemical cycles > Geochemical cycle > Biogeochemical cycle
Cycles > Chemical cycles > Geochemical cycle > Biogeochemical cycle > Nutrient cycles
Isotopes > Lead isotopes > Lead 210
Minerals > Silicate minerals > Opal
Motion > Water motion > Circulation > Water circulation > Ocean circulation
Particulates > Suspended particulate matter > Sediments > Resuspended sediments
Physics > Mechanics > Dynamics > Sediment dynamics
Residence time
Sediment mixing > Bioturbation
Sedimentation
Topographic effects > Bottom topography effects
Tracer techniques
Bacillariophyceae [WoRMS]
PS, Ross Sea [Marine Regions]
Marine/Coastal |
| Authors | | Top | - Langone, L.
- Frignani, M.
- Labbrozzi, L.
- Ravaioli, M.
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| Abstract | Sedimentological and oceanographic inferences have been obtained for the NW Ross Sea using sedimentary Full-size image (<1 K) as a tracer together with determinations of biogenic silica and organic carbon. Full-size image (<1 K) chronologies give apparent accumulation rates ranging between 14 and 80 mg cm-2 yr-1 (0.02–0.12 cm yr-1) in the shelf basins. Even if a profile of Full-size image (<1 K) is present in sediments from the top of the banks, here sediment accumulation rate is practically null, and physical mixing is responsible for the downward transport of fine particles and associated Full-size image (<1 K). The accuracy of Full-size image (<1 K)-derived accumulation rates is discussed with respect to Full-size image (<1 K) dates. The annual rate of biogenic accumulation from Full-size image (<1 K) appears to be ca. 8 times higher than the value derived using radiocarbon. Bioturbation is probably responsible for the discrepancy but also temporal and spatial variations in opal accumulation play a key-role. Contrasting measured and expected inventories of Full-size image (<1 K), a residence time of about 50 years has been tentatively estimated for the water in the NW Ross Sea. Furthermore, the data suggest that the pattern of present-day biosiliceous sediment accumulation in the Ross Sea is mainly driven by biogenic silica production in the water column, the SW area being the most productive part of the Ross Sea, by high sediment accumulation rate which enhances the seabed preservation, and by hydrodynamics, which is so effective to resuspend fine biogenic particles from the topographic highs. Resuspended particles are then deposited onto the flanks. The material which accumulates in the central part of the basins derives basically from primary production and settling through the water column. |
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