Shelf break

Godfrey, L.V, White, W.M. and Salters, VJ.M. (1986) Dissolved zirconium and hafnium distributions across a shelf break in the Northeastern Atlantic Ocean. Geochim. Cosmochim. Acta, 60, 3995-4006. 

The coastal ocean is a dynamic region where the rivers, estuaries, ocean, land, and the atmosphere interact. Coastlines extend over an estimated 350,000 km worldwide, and the coastal ocean is typically defined as a region that extends from the high water mark to the shelf break. 

The resulting Bosporus plume ventilates the interior of the Black Sea at the depth represented by its density when it reaches the shelf break [12,13]. Generally the Bosporus origin waters are pushed eastward by Western Gyre waters [14] following the Rim Current (Fig. 1). The most common entrainment conditions result in ventilation of the upper 500 m, but evidence suggests there must occasionally be rare ventilation events that reach the bottom. 

Rees, A. P., Joint, I., and Donald, K. M. (1999b). Early spring bloom phytoplankton-nutrient dynamics at the Celtic Sea Shelf Break. Deep Sea Res. 146, 483—510. 

Zooplankton. Studies of the outer edge and shelf-break region of the Scotian Shelf were also extended to the vertical and horizontal distributions of zooplankton. The most intriguing feature of these vertical profiles was the consistent location of copepods above the subsurface chlorophyll... 

Frontal systems can also develop at shelf breaks, where shallowing and the associated increase in current velocity can result in upwelling and high primary productivity. Smaller frontal zones can be produced in the wake of islands, resulting in upwelling and elevated productivity (e.g. Flawaii and Isles of Scilly). 

Sea, the estimate was 0.3molNirf2y-1 (Simpson Rippeth, 1998). These estimates are in line with newer field measurements of denitrification (Lohse etal., 1996 Trimmer etal., 1999). Hydes etal. (1999) used the NERC-NSP data from January 1989 to show that the concentration of P predicted, from a concentration-salinity relationship, at the salinity of source waters at the shelf break, matched the observed concentration. However, the predicted concentration of nitrate was significantly lower than at the shelf break. The nitrate deficit in the southern North Sea was equivalent to a denitrification rate of 0.25 mol N m-2 y-1, assuming a flushing time of one year for the North Sea. 

The anomalously high PAH concentration for the Hudson Canyon sample agrees with the similarly high alkane values obtained by Farrington and Tripp (26) for this site. They relate this anomaly to the accumulation of sediment transported in the channel and across the shelf break to this location (25). Sediment movement therefore can be an important mode of transport in some areas of the transect. Whether this mode is solely responsible for PAH found in the Abyssal Plain sediments is unknown. 

Upwelling Vertical, upward movement of water at the shelf break, often tidally induced. 

The horizontal transports of DOC and POC across the shelf in the ECS can be derived from the mean DOC and POC concentrations and exchanged water volumes. The cross-shelf export of DOC (414 Gmol C/yr) is roughly four times that of POC (106 Gmol C/yr) and more than double the riverine flux of DOC (155 Gmol C/yr) to the shelf. DOC concentrations are relatively high (>1,020 pg/L) in the inner shelf and slope waters, but low (about 780 pg/L) around the shelf break, where Kuroshio upwelling occurs. Such a distribution pattern shows little temporal variation. DOC distribution in the shelf waters appears... 

Hampton, M. A., and Bouma, A.H. 1977. Slope instability near the shelf break, western Gulf of Alaska. 

Southard, J.B., and Stanley, D.J. 1976. Shelf-break processes and sedimentation. In Marine Sediment Transport and Environment Management, Stanley, D.J., and Swift, D.J.P, eds., Wiley-Interscience, New York, pp. 351-377. 

Stanley, D.J., Addy, S.K., and Behrens, E.W. 1983. The mudline Variability of its position relative to shelf break. In The Shelf Break Critical Interjace on Continental Margins, Stanley, D.J., and Moore, D.G., eds.. Society of Economic Paleontologists and Mineralogists, Special Publication 33, Tulsa, OK, pp. 279-298. 

Watkins, D.J., and L.M.Kraft 1976. Stability of the continental shelf and slope off Louisiana and Texas Geotechnical aspects. In Beyond the shelf break, AAPG Memoir. Also, Research and Development Report AD76-916, McClelland Engineers, Houston, TX. 

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