Benthic flux

Diagrams of benthic sampiing equipment, (a) Pore water peepers used for collecting pore water in situ via moiecuiar diffusion across a 0.4- j,m polycarbonate membrane. These probes were 36 inches iong. Each of the six ports on the peeper held 6mL of equilibration fluid. The probes were deployed for 1 to 2.5 y to ensure equilibrium had been reached with the pore waters, (b) Benthic flux chamber. This chamber covered a bottom area of SSScm. Source From Aller, R. C., et al. (1998). Deep-Sea Research, 45, 133-165. 

Table 24.8 Benthic Fluxes of Nitrogen Species and Their Relative Contribution to Local Primary Production. ... 

McCaffrey, R.3., Myers, A.C., Davey, E., Morrison, G., Bender, M., Luedtke, N., Cullen, D., Froelich, P. and Klinkhammer, G., 1980. The relation between pore water chemistry and benthic fluxes of nutrients and manganese in Narragansett Bay, Rhode Island. Limnol. Oceanogr., 25(1) 31-44. 

Figure 8.6 Major sources of dissolved organic matter (DOM) to estuaries, primarily composed of riverine inputs, autochthonous production from algal and vascular plant sources, benthic fluxes, groundwater inputs, and exchange with adjacent coastal systems. (Modified from Hansell and Carlson, 2002.)...

Table 11.6 Dissolved silica SiC>2 (DSi) benthic fluxes in various coastal ecosystems (all data in mmol m-2 d-1).

Porewater ligands are strong complexing ligands, which only contribute significantly to the water column (via benthic fluxes) in estuaries with long residence times. 

Alperin, M.J., Martens, C.S., Albert, D.B., Suayah, I.B., Benninger, L.K., Blair, N.E., and Jahnke, R.A. (1999) Benthic fluxes and porewater concentration profiles of dissolved organic carbon in sediments from the North Carolina continental slope. Geochim. Cosmochim. Acta 63, 427 148. 

Berelson, W. M., Hammond, D.E., and Johnson, K. (1987) Benthic fluxes and the cycling of biogenic silica and carbon in two southern California borderland basins. Geochim. Cosmochim. Acta 51, 1345-1363. 

Burdige, D.J., Alperin, M.J., Homstead, J., and Martens, C.S. (1992) The role of benthic fluxes of dissolved organic carbon in oceanic and sedimentary carbon cycling. Geophys. Res. Lett. 19, 1851-1854. 

Foija, J.M., Blasco, J., and Gomez-Parra, A. (1994) Spatial and seasonal variation of in situ benthic fluxes in the Bay of Cadiz (south-west Spain). Estuar. Coastal Shelf Sci. 39, 127-141. 

Jahnke, R.A., Nelson, J.R., Marinelli, R.L., and Eckman, J.E. (2000) Benthic flux of biogenic elements on the southeastern U.S. continental shelf influence of porewater advective transport and benthic microalgae. Cont. Shelf Res. 20, 109-127. 

Landen, A., and Hall, P.O.J. (2000) Benthic fluxes and pore water distributions of dissolved free amino acids in the open Skagerrak. Mar. Chem. 71, 53-68. 

Devol, A., and Christensen,. (1993). Benthic fluxes and nitrogen cychng in sediments of the continental margin of the eastern North Pacific. Journal of Marine Research 51, 345—372. 

Doering, P., Kelly, J., Oviatt, C., and Sowers, T. (1987). Effect of the hard clam Mercenaria mercenaria on benthic fluxes of inorganic nutrients and gases. 94, 377—383. 

MEVIS/IPM, membrane inlet mass spectrometry/isotope pairing method TCD, gas chromatography-thermal conductivity detector AIT, acetylene inhibition technique IPM, isotope pairing method with isotope ratio mass spectrometry MIMS, membrane inlet mass spectrometry Stoichiometery, benthic flux DICiDIN stoichiometry MIMS + N03, membrane inlet mass with N03 amendment 15N2 production, 15N03 or 15NH4 conversion to 15N2. 

Viaroli, P., Bartoli, M., BondavaHi, C., Christian, R. R., Giordani, G., and Naldi, M. (1996). Macrophyto communities and their impact on benthic fluxes of oxygen, sulphide and nutrients in shallow eutrophic environments. Hydrobiologia 329, 105—119. 

Sedimentary denitrification, in contrast, shows very little expression of the enzymatic isotope effect. Benthic flux experiments have shown that, even with high rates of sedimentary denitrification, minimal increase of <5 Nni ate is observed (Brandes and Devol, 1997, 2002 Lehmann et al., 2004). The common explanation is that nitrate is nearly completely consumed at the locus of sedimentary denitrification. Because no nitrate escapes the denitrification zones, there is no expression of the isotope effect. This view is supported by the observation of extreme enrichment... 

Fl ur6 3 3 Iron concentrations in surface waters versus distance offshore on a transect from central California to Hawaii. Elrod et al. (2004) used benthic flux measurements and these water column data to make a case for transport of Fe from shelf sediments out into the open ocean gyre. Elrod et al. (2004), Geophysical Research Letters 31 L12307. 

Upon settling to the surface sediments, trace metals can be recycled back into the dissolved phase and act as a source to the deep ocean. Pore-water concentrations of trace metals can be significantly higher than that observed in the overlying water column. Elevated pore-water concentrations suggested a potential for benthic fluxes of dissolved metals out of the sediment, which has been verified by direct measurements (Elderfield et al., 1981 Westerlund et al., 1986). 

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