Marine sediments, distributions

L. Ciaralli, R. Giordano, G. Lombardi, E. Beccaloni, A. Sepe, S. Costantini, Antarctic marine sediments distribution of elements and textural characters, Microchem. J., 59 (1998), 77-88. 

Joly observed elevated "Ra activities in deep-sea sediments that he attributed to water column scavenging and removal processes. This hypothesis was later challenged with the hrst seawater °Th measurements (parent of "Ra), and these new results conhrmed that radium was instead actively migrating across the marine sediment-water interface. This seabed source stimulated much activity to use radium as a tracer for ocean circulation. Unfortunately, the utility of Ra as a deep ocean circulation tracer never came to full fruition as biological cycling has been repeatedly shown to have a strong and unpredictable effect on the vertical distribution of this isotope. 

Degens, E. T. and Mopper, K. (1976). Factors controlling the distribution and early diagenesis of organic material in marine sediments. In "Chemical Oceanography" (J. P. Riley, ed.), Vol. 6, pp. 59-113. Academic Press, New York. 

Records of past environmental change are preserved in a broad range of Earth materials. Past environments are inferred from "proxy" records, meaning measurements of physical and chemical parameters of marine and terrestrial sediment, polar ice, and other materials that were in some way influenced by their environment during accumulation. Examples of proxy records are the distribution of glacial deposits, the isotopic composition of terrestrial and marine sediments and ice, the abundance and species composition of plant and animal fossils, and the width of tree rings. 

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... 

Ward, T.J., R.L. Correll, and R.B. Anderson. 1986. Distribution of cadmium, lead and zinc amongst the marine sediments, sea grasses and fauna, and the selection of sentinel accumulators, near a lead smelter in South Australia. Austral. Jour. Mar. Freshwater Res. 37 567-585. 

However, as far as we know, the distribution of LAS biodegradation intermediates according to depth in the sediment column has been determined only in marine sediments [58]. This study was performed in a saltmarsh channel (Sancti Petri Channel, Cadiz Bay, Spain), receiving untreated urban wastewater effluents. In this zone the benthic organisms are very scarce [59], and the capacity for irrigation of... 

The haptophyte microalga Emiliania huxleyi produces biomarkers in the form of long-chain (C37, C38, and C39) alkenones (Brassell, 1993). Alkenones are well preserved in marine sediments and their molecular distributions and isotopic composition have been used to infer paleo-temperatures (Brassell, 1993) and pC022 values (Jasper et ak, 1994), respectively. Unsaturation patterns in the alkenone series are related to the growth temperature of the haptophyte algae that produce these compounds (Brassell et ak, 1986 Prahl and Wakeham, 1987), and hold great promise as indicators of absolute ocean paleotemperature. 

Grain-size distribution in common marine sediments and in various sediment sources. Source From Gross, M. G. (1987). Oceanography A View of the Earth, 4th ed. Prentice Haii, inc., p. 81. 

In the preceding sections, we have discussed the marine processes that control calcium carbonate s formation, dissolution, and delivery to the seafloor. Their combined effects determine the geographic distribution of calcium carbonate in marine sediments seen in Figure 15.5. As noted earlier, the global distribution of calcareous sediments does not seem to follow that of plankton production. This points to the overriding importance of the processes that control the dissolution and sedimentation of calcium carbonate. 

Geographic distribution of giauconite in marine sediments. Source Gaiiiher, E. W. (1935). Bulletin of the American Association of Petroleum Geologists 19, 1569-1601. 

Some component of the terrestrial POM must be extremely nonreactive to enable a higher burial efficiency as compared to autochthonous POM. A possible candidate for this nonreactive terrestrial POM is black carbon. This material is a carbon-rich residue produced by biomass burning and fossil fuel combustion. Some black carbon also appears to be derived from graphite weathered from rocks. It is widely distributed in marine sediments and possibly carried to the open ocean via aeolian transport. 

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... 

Aller RC. 1980b. Quantifying solute distributions in the bioturbated zone of marine sediments by defining an average microenvironment. Geochimica et Cosmochimica Acta 44 1955-1965. 

Rice D, Seltenrich C, Spies R, et al. 1993. Seasonal and annual distribution of organic contaminants in marine sediments from elkhorn slough moss landing harbor and nearshore monterey bay California. Environmental Pollution 82(1) 79-91. 

Rouxel O, Galy A, Elderfield H (2006) Germanium isotope variations in igneous rocks and marine sediments. Geochim Cosmochim Acta 70 3387-3400 Rouxel O, Ono S, Alt J, Rumble D, Ludden J (2008) Sulfur isotope evidence for microbial sulfate reduction in altered oceanic basalts at ODP Site 801. Earth Planet Sd Lett 268 110-123 Rozanski K, Sonntag C (1982) Vertical distribution of deuterium in atmospheric water vapour. Tellus 34 135-141... 

Even though the relative distribution remains constant, the total level of PAH decreases dramatically with distance from urban centers. Figure 4 shows a plot of the total PAH abundance in five marine sediment samples taken from Massachusetts Bay as a function of distance from Boston (10). One can see that there is a three order of magnitude decrease in the total abundance of PAH within 100 kilometers of Boston. At that point, the total PAH level is about 100 ppb remarkably, this is what we see in almost all other remote samples. 

---