Near-shoring

Andesite volcanism and subsidence from near-shore to shallow-sea environments (30( )-ca. 17 m.y. ago). 

Bugna GC, Chanton JP, Cable JE, Burnett WC, Cable PH (1996) The importance of ground water discharge to the methane budgets of near shore and continental shelf waters of the northeastern Gulf of Mexico. Geochim Cosmochim Acta 60 4735-4746... 

Where Ao is the activity at the sediment surface, w is the sedimentation rate (cm yr ), D is the mixing rate (cm yr ), is the decay constant for the nuclide of interest (yr ) and z is the depth in the sediment (cm). In some near-shore environments both sedimentation and bioturbation must be considered. But in most open marine environments the sedimentation rate is sufficiently slow that it can be ignored and the equation simplifies to ... 

This equation is particularly useful to derive apparent estuarine water mass ages (Fig. 6) because the term /em is removed. Using ( Ra/ " Ra) isotope ratios in this manner is based on the assumption that the initial ( Ra/ " Ra) activity ratio must remain constant. This conclusion is reasonable as the long-lived parent isotopes ( Pa and Th) have relatively constant activity ratios in sediments, and the intermediate Th isotopes ( Th and Th) are scavenged efficiently in the near-shore water column. The utility of Ra as... 

Scotland mainland and some island coasts (near shore) ... 

An estimate of the accuracy of both analytical methods was performed on bis(tri-n-butyltin) oxide and tri-n-butyltin chloride solutions (8.9-35.6 ig/l) prepared in filtered (0.45 im) near-shore seawater free of detectable organ-otins. Average mean recoveries of 92.8% by both methods were determined for tributyltin standard solutions. Low ng/1 levels of mono-, di-, and tributyltin were found in samples taken from San Diego Bay. 

Hammerschmidt CR, Fitzgerald WF (2004) Geochemical controls on the production and distribution of methylmercury in near-shore marine sediments. Environ Sci Technol 38 1487-1495... 

In marine ecosystems, the high copper levels measured in heavily contaminated coastal areas sometimes approach the incipient lethal concentrations for some organisms (Neff and Anderson 1977). Elevated copper concentrations in marine and estuarine environments may result from atmospheric deposition, industrial and municipal wastes, urban runoff, rivers, and shoreline erosion. Chesapeake Bay, for example, receives more than 1800 kg of copper daily from these sources (Hall et al. 1988). Copper concentrations in abiotic marine materials are generally higher near shore than... 

Howarth, R. W., Jensen, H. S., Marino, R., Postma, H. (1995). Transport to and processing off P in near-shore and oceanic waters. In H. Hessen (Ed.) Phosphorus in the Global Environment, SCOPE, John Wiley Sons, pp. 323-356. 

Near-shore facilities are typically characterized by shallow groundwater conditions. The occurrence of LNAPL product on the water table presents the need for immediate containment and continued recovery of the product to abate degradation of ground-water quality, hydrocarbon vapor migration, and discharge of hydrocarbon product to surface waters. A pneumatically operated, double-diaphragm, suction-lift pump has been frequently used in such circumstances to contain and recover LNAPL. 

The continuous availability of trillions of independent microreactors greatly multiplied the initial mixture of extraterrestrial organics and hydrothermal vent-produced chemicals into a rich variety of adsorbed and transformed materials, including lipids, amphiphiles, chiral metal complexes, amino add polymers, and nudeo-tide bases. Production and chiral amplification of polypeptides and other polymeric molecules would be induced by exposure of absorbed amino adds and organics to dehydration/rehydration cydes promoted by heat-flows beneath a sea-level hydro-thermal field or by sporadic subaerial exposure of near-shore vents and surfaces. In this environment the e.e. of chiral amino adds could have provided the ligands required for any metal centers capable of catalyzing enantiomeric dominance. The auto-amplification of a small e.e. of i-amino adds, whether extraterrestrially delivered or fluctuationally induced, thus becomes conceptually reasonable. 

Measurements of radionuclides and metals in marine sediments and particulate matter are conducted for a variety of purposes, including the determination of sedimentation rates, trace metal and radionuclide fluxes through the water column, enrichment of metals in specific phases of the sediments, and examination of new sedimentary phases produced after sediment deposition. Such studies address fundamental questions concerning the chronology of deep-sea and near-shore sedimentary deposits, removal mechanisms and cycling of metals in the ocean, and diagenesis within deep-sea sediments. 

A third approach was developed by Aller (1980a, b) who studied solute fluxes in near-shore marine sediments showing seasonal variation. In this approach, the geometry of the burrow-sediment system is allowed for explicitly and transport in the sediment between the burrows is described with appropriate diffusion equations. It is assumed that the burrows are oriented normal to the sediment surface and distributed uniformly or randomly in the horizontal plane (Figure 2.11). Thereby a cylindrical zone of influence is ascribed to each burrow with a radius... 

The Athabasca sedimentary Basin consists of Helikian polycyclic, mature fluvial to marine quartz-rich sandstone deposited in a near-shore shallow shelf environment (Ramaekers 1990) with an estimated filling beginning at about 1700 to 1750 Ma (Armstrong Ramaekers 1985). The estimate maximum thickness of the basin was 5 to 6 km from fluid inclusion studies (Pagel 1975). 

Pacific herring Clupeus harenguspallast) spawn synchronously by the millions near shore, their suspended milt discoloring the water. Small clusters of males start, then activity spreads to an entire school. Spawning lasts several hours in... 

Sweeney RE, Kaplan IR (1980) Natural abundance of as a source indicator for near-shore marine sedimentary and dissolved nitrogen. Mar Chem 9 81-94 Sweeney RE, Liu KK, Kaplan IR (1978) Oceanic nitrogen isotopes and their use in determining the source of sedimentary nitrogen. In Robinson BW (ed.) DSIR Bull 220 9-26 Swihart GH (1996) Instrumental techniques for boron isotope analysis. Rev Miner 33 845-862 Swihart GH, Moore PB (1989) A reconnaissance of the boron isotopic composition of tourmaline. Geochim Cosmochim Acta 53 911-916... 

Tables I to III provide a summary of some representative data for total arsenic concentrations in sediments, marine algae, and marine animals. There can be considerable variation in the arsenic levels in these samples, in contrast to the levels in seawater, which are reasonably uniform in the world s oceans at about 0.5-2 /ug/liter (9,10). For sediments, there is perhaps a tendency for arsenic concentrations to be lower in samples from coastal regions and estuaries compared with deep-sea sediments. Industrial discharges of arsenic-enriched effluents can, however, result in arsenic contamination of near-shore sediments...

Concentrations of PBBs in sediments upstream from the Michigan Chemical Corporation plant were below the detection limit (100 g/kg) with the exception of one sample (Hesse and Powers 1978). The concentration of PBBs in sediment from one upstream sample was 350 g/kg. Hesse and Powers (1978) explained that this higher value was due to contamination by upstream currents during periods of water level regulation at the St. Louis dam. The concentrations of PBBs in near shore sediment near the Michigan Chemical Corporation plant sewer outfall were 77.0 mg/kg. PBB concentrations in Pine River sediments downstream from the plant showed a gradual decrease from a maximum value of... 

In the North Sea the pipeline surroundings will be at sea bottom temperature, so we are Interested in minimum temperatures at that location. Surprisingly, in the deeper water (250 ) of the northern North Sea areas which are affected by the Gulf Stream, the minimum sea bottom temperatures may be as high as 46 to 48°F. In southern North Sea areas which are less affected by the Gulf Stream and also may be shallower, with bottom temperatures more influenced by wave action, we can expect minimums of 40°F or less. Only in very shallow waters near shore can we expect minimum temperatures approaching 32 F. 

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