However, these models have received little or no testing in the laboratory or through field observations.
Muddy sediments are geologically relevant, and some research has been conducted on the transport of low concentrations of fine-grained sediments. Dense concentrations [>10 grams per liter (i.e., fluid muds)] are also observed in the marine environment, and their transport is poorly understood.
Carbonate sediments are widespread at low latitudes, but the effects of physical processes on their dispersal have not been thoroughly studied. Differences in the particle shapes and densities of carbonate sediments from more common sources make it difficult to extrapolate existing theory of sediment transport.
Theory regarding the formation of sediment layering within the seabed and its dependence on sediment transport and biological activity has evolved rapidly. Additional laboratory and field documentation is needed to link formative mechanisms and preserved strata.
The overall importance of the coastal ocean extends far beyond its relatively small areal extent. An environment of remarkably high biological productivity, this transition zone between land and open ocean is of considerable importance for recreation, waste disposal, and mineral exploitation. Such societal issues as pollution (in its many forms), bioremediation, waste disposal, and risk assessment cannot be addressed adequately until we make substantial advances in our basic understanding of the coastal ocean. A holistic approach to the coastal ocean system, blending marine meteorology with biological, chemical, geological, and physical oceanography, should enable us to progress sufficiently so that we will be better prepared to make the technical and policy decisions facing us over the next decades. Four issues of particular importance are air-sea interactions, cross-margin transport, carbon cycles, and particle dynamics. A balanced program would include studies focused on specific processes, long-term measurements, modeling, and instrumentation development. To take best advantage of the results of these studies, strong working relationships with the applied science communities need to be forged.
Coastal measurements will be an important part of a global ocean observing system because it is at the coasts that most countries, particularly developing nations, will make most of their measurements. Therefore, it is essential that the design of a GOOS include coastal measurements as a critical element of the system.