Carbon coastal fluxes

WoUast R. (1991) The coastal organic carbon cycle fluxes, sources, and sinks. In Physical, Chemical, and Earth Sciences Research Report, vol. 9, pp. 365—381. 

Wollast R (1991) The coastal organic carbon cycle Fluxes, sources and sinks. In Mantoura RFC, Martin MJ, Wollast R (eds.) Ocean Margin Processes in Global Change. Dahlem Workshop Reports. Chichester, Wiley Interscience, UK, pp.365-381. 

The magnitude and fate of coastal-zone biological production is a major unknown in the global carbon cycle. Since river nutrient flux into these regions may be altered with C02-induced climate change, it is important that generation and fate of coastal-zone production be better understood. 

In coastal sediments where organic carbon concentrations are high, the redox boundary is at or near the sediment-water interfece. Under these conditions, denitrification acts as a sink for nitrate. In some settings, the rate of sedimentary denitrification is fast enough to drive a diffusive flux of nitrate from the bottom waters into the sediments. Remineralization of organic matter imder suboxic and anoxic conditions releases... 

The rivers play a major role in the transfert of carbon and mineral nutrients from land to the sea and influence significantly the biogeochemical processes operating in coastal waters. Quantification of the material transport, both in the dissolved and particulate forms, has been attempted by several authors in the past (Clarke, 1924 Holeman, 1968 Garrels McKenzie, 1971 Martin et al., 1980 Meybeck, 1982 Milliman Meade, 1983). Depending on the type of sampling techniques and methods of calculations employed there are differences in the reported fluxes. A major problem in such calculations is the paucity of reliable data from some of the major rivers of the world especially of Asia (see e.g. Milliman Meade, 1983). Additionally the difficulty of obtaining representative samples from the rivers will adversely affect flux calculations. Most of the inferences drawn on the nature and transport of riverine materials rest on data collected randomly - at different points in time and space. Seasonal variations in the transport of materials are very common in some of the major world rivers, and in some cases more than 60 % of the material transport occurs within a very short period of time. Furthermore, available data are not always comparable since the analytical techniques used differ from river to river. 

Coastal wetlands have long been noted for their relatively high emission of volatile sulfur gases to the atmosphere indeed the typical odor of marshes often is due largely to DMS. Several studies have reported emissions of DMS, H2S, and other sulfur compounds, dimethyldisulfide, carbonyl sulfide, and carbon disulfide (10-12.40-42). DMS and H2S constitute the bulk of the flux, with DMS predominating in vegetated areas and H2S in mud flats. Fluxes of DMS... 

Flux estimates related to the modern carbon cycle require refinement, particularly those involving coastal margin and other shoal-water area inputs and outputs. 

Carbon dioxide water-to-air fluxes have been shown to be significant in estuaries. In estuaries with extensive marsh systems, the pathway of CO2 being fixed by marsh grasses and then exported to coastal waters in the form of organic and inorganic carbon can be described as a marsh CO2 pump. ... 

Cai, W.J., Wang, Y., Krest, 1, and Moore, W.S. (2003) The geochemistry of dissolved inorganic carbon in a surficial groundwater aquifer in North Inlet, South Carolina, and the carbon fluxes to the coastal ocean. Geochem. Cosmochim. Acta 67, 631-637. 

The potential underestimation of Phaeocystis spp. carbon by only including cell carbon is thus not likely to be >40%. Based on measurements of vertical flux around 100 m depth from Antarctica, the coastal North Sea, North Norwegian fjords, the Barents Sea and the Arctic Ocean (Fig. 5), the average carbon contribution from Phaeocystis spp. to the POC flux will increase from 3% to <5% by including mucus carbon. Despite the lack of appropriate species-specific carbon conversion rates for all Phaeocystis species, the evidence clearly indicates that Phaeocystis spp. mucus, sinking as intact colonies with cells, is not significantly contributing to the total POC export. 

Urban-Rich J, Nordby E, Andreassen H, Wassmann P (1999) Contribution by mesozooplankton faecal pellets to the carbon flux on Nordvestbanken, North Norwegian shelf 1994. Sarsia 84 253-264 Veldhuis MJW, Wassmann P (2005) Bloom dynamics and biological control of a high biomass HAB species in European coastal waters a Phaeocystis case study. Harmful Algae 4 805-809... 

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