Estuaries importance

Tsai WT, Lai CW, Hsien KJ (2003) Effect of particle size of activated clay on the adsorption of paraquat from aqueous solution. J Coll Interface Sci 263 29-34 Turner A (1996) Trace-metal partitioning in estuaries Importance of salinity and particle concentration. Marine Chemistry 54 27-39... 

Josefson, A.B., and Rasmussen, B. (2000) Nutrient retention by benthic macrofaunal biomass of Danish estuaries importance of nutrient load and residence time. Estuar. Coastal Shelf Sci. 50, 205-216. 

Stordal, M.C., Gill, G.A., Wen, L.S., and Santschi, P.H. (1996) Mercury phase speciation in the surface waters of three Texas estuaries importance of colloidal forms. Limnol. 

Chambers, R. M., Fourqurean, J. W., Hollibaugh, J. T., and Vink, S. M. (1995). Importance of terrestrially-derived particulate phosphorus to phosphorus dynamics in a west coast estuary. Estuaries 18,518-526. 

The transport rate of mercury flowing from the land to the oceans in rivers has been increased by a factor of about three by human activity. While the increased rate is still relatively less important than the total transport of Hg through the atmosphere, it can represent a significant stress on the exposed organisms, particularly since the increased flux is unevenly distributed. That is, human activity has created local environments where the transport of mercury or its concentration in a river or estuary is many tens of times higher than background levels. 

An important issue that influences estuarine behavior is the determination of the riverine component. Variations in the riverine endmember may occur over timescales that are short compared to the residence times of water in the estuary, which result in nonlinear relationships between salinity and trace elements across the estuary as different riverine compositions progress through the estuary (Loder and Reichard 1981 Officer... 

River inputs. The riverine endmember is most often highly variable. Fluctuations of the chemical signature of river water discharging into an estuary are clearly critical to determine the effects of estuarine mixing. The characteristics of U- and Th-series nuclides in rivers are reviewed most recently by Chabaux et al. (2003). Important factors include the major element composition, the characteristics and concentrations of particular constituents that can complex or adsorb U- and Th-series nuclides, such as organic ligands, particles or colloids. River flow rates clearly will also have an effect on the rates and patterns of mixing in the estuary (Ponter et al. 1990 Shiller and Boyle 1991). 

Honeyman and Santschi 1989). Therefore, flocculation of colloids to form settling particles in estuaries is an important mechanism for trace element removal (Sholkovitz 1977). This is particularly true of Fe, which is a ubiquitous colloidal species and is removed at low salinities. Additional removal may occur by adsorption onto floes, as demonstrated by mixing of organic-rich waters with seawater in the laboratory (Sholkovitz 1977). 

In the Delaware and Chesapeake estuaries (USA), uranium shows distinctly nonconservative behavior at salinities <5 (Sarin and Church 1994 Church et al. 1996). This was suggested to be due to sedimentary redox processes in the extensive salt marshes in the Delaware and Chesapeake bays. From mass balance calculations it was concluded that almost two-thirds of the uranium in the tidal waters were retained in the sediments. It was also suggested that, extrapolated globally, uranium removal in salt marshes and marine wetlands, including mangroves, are important sinks for U that may responsible for up to 50% of the total marine removal (Church et al. 1996). Removal of U is also observed within the Baltic Sea, related to the association of U with colloids (see Section 2.5). 

Estuaries, in contrast, appear to be important sites for manganese redox reactions. Manganese maxima have been observed in several estuaries [421-423]... 

Ozoh, P.T.E. 1992c. The importance of adult Hediste (Nereis) diversicolor in managing heavy metal pollution in shores and estuaries. Environ. Monitor. Assess. 21 165-171. 

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