Terrigenous matter

In contrast to rivers and lakes, autochthonous processes appear to be the overwhelmingly dominant source of DOC in the oceans. In a survey of shallow and deep waters of the Atlantic and Pacific Oceans, Opsahl and Benner (1997) used concentrations of lignin in DOM to determine that terrigenous matter accounted for only 0.7-2.4% of the DOC present. Terrigenous DOC concentrations were about 2.6 times higher in the Atlantic than in the Pacific Ocean, presumably because of the 3.6 times greater riverine water discharge to the Atlantic. 

In the West and East Pontian regions, the sediment formation is strongly influenced by mountain rivers and numerous water channels that supply terrigenous matter as well as by coastal abrasion. 

In the southeast, the delta of the Kuban River with vast flooded plains and numerous channels extends over about 100 km. The Kuban River enters the top part of the open Temryuk Bay. Low seacoasts gradually descend to a flat sandy bottom. The depths smoothly increase with the distance from the coast. The largest depths are observed in the central part of the sea in Taganrog Bay, they range from 2 to 9 m. In Temryuk Bay, mud volcanoes are known. The main sources for the supply of the terrigenous matter that forms the bottom sediments of the Sea of Azov are represented by the products of coastal abrasion and the riverine alluvium. The bottom sediments are mostly represented by clayey and silty oozes and sands. 

In contrast to the fluvial transport regime the aeolian transport is highly efficient for the deposition of terrigenous matter in the deep sea. 

Terrigenous matter is silt originating from the land. 

Terrigenous material is either fluvial or aeolian. River supply in recent times has been limited, but windblown material has been indicated in several studies of the Canary area (Sarnthein et al., 1982). Studies of aerosol populations show that organic compounds may be adsorbed on windblown particles, as well as within pieces of vegetation (Gagosian et al., 1981, 1987). Terrigenous matter exposed to the atmosphere for a long time should be more prone to alteration than river transported material due to more effective oxygen exposure. 

Volkman, J. K., 1986, A Review of Sterol Markers for Marine and Terrigenous Organic Matter Organic Geochemistry, Vol. 9, pp. 83-99. 

Volkman, J.K. 1986. A review of sterol markers for marine and terrigenous organic matter. 

In some sediments, downcore variations in the bulk chemical composition are interpretable as records of temporal shifts in the elemental composition of the sinking POM. Such shifts are caused by changes in the production of sinking POM, which are in turn the result of fluctuations in the abundance and diversity of the overlying plankton community. In nearshore sediments, fluctuations in river runoff and lateral transport can lead to shifts in the supply rate of terrigenous organic matter. An example of a nearshore sediment core in which such fluctuations have been recorded is shown in Figure 23.18. 

Westerhausen L, Poynter J, Eglinton G, Erlenkeuser H, Sarntheim M (1993) Marine and terrigenous origin of organic matter in modern sediments of the equatorial East Atlantic the 6 C and molecular record. Deep Sea Res 40 1087-1121... 

Not included in total because phase is contained within other components. Diatoms + calcite + terrigenous + nondiatom organic matter. 

Opsahl, S., and R. Benner. 1997. Distribution and cycling of terrigenous dissolved organic matter in the ocean. Nature 386 480—482. 

Benner, R. H., Louchouarn, P, and Amon, R. M. W. (2005). Terrigeneous dissolved organic matter in the Arctic Ocean and its transport to surface and deep waters of the North Atlantic. Global Biochem. Cycles 19. GB2025, doi 10.1029/2004 GB002398. 

Koch, B. R, Witt, M., Engbrodt, R., Dittmar, T., and Kattner, G. (2005). Molecular formulae of marine and terrigenous dissolved organic matter detected by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Geochim. Cosmochim. Acta 69, 3299-3308. 

Hernes, R J., and Benner, R. (2006). Sources and fluxes of terrigenous organic matter in the North Atlantic Ocean and North Atlantic Deep Water. Mar. Chem. 100, 66-79. 

Gordon, E.S., and Goni, M.A. (2003) Sources and distribution of terrigenous organic matter delivered by the Atchafalaya River to sediments in the northern Gulf of Mexico. Geochim. Cosmochim. Acta 67, 2359-2375. 

Opsahl, S., Benner, R., and Amon, R.M.W. (1999) Major flux of terrigenous dissolved organic matter through the Arctic Ocean. Limnol. Oceanogr. 44, 2017-2023. 

The northwestern region is characterized by large provenance areas, from which alluvial matter is supplied via the deltas of the Danube, Dniester, and Dnieper rivers. The Danube River, which features a wide delta with numerous channels and branches provides the greatest solid runoff to the shelf zone. The delta is composed of terrigenous sediments and is advanced toward the sea by 7-10 km. 

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