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Research by soil scientists examining estuarine aquatic substrates has identified pedogenic processes, resulting in the reclassification of these aquatic substrates (sediments) as subaqueous soils (SASs). Pedogenic processes in SASs are similar in concept to those occurring in subaerial soils, and thus SASs can be described and mapped based on pedogenic similarities using Jenny's soil forming factors for interpreting soil genesis. The occurrence of SASs in estuarine and freshwater ecosystems places them at the centre of many ecosystem-dependent processes supporting food webs linked directly to the human population and its economy. Early research on SASs has been driven by addressing fishery habitat support questions for US subaquatic vegetation populations (SAV), and for estimating the carbon sequestration potential of soils with SAV. New land use interpretations for SASs include bottom type, presence of sulphidic materials, potential for submerged aquatic vegetation restoration, limitations for moorings and species lists for plants and algae common to tidal areas. Subaquatic soils are a viable, exciting frontier of soil science research that will surely foster multi-disciplinary collaborations. While their genesis is only beginning to be understood, it is clear that their importance in human-dependent land management issues such as soil and water quality, food supply and human survival is great. However, the fragility of such soils for providing vital functions to support life on Earth suggests that they need to be investigated and monitored.

Fine sediments in shallow water bodies such as Lake Okeechobee are prone to resuspension. Predominantly inorganic "mud" sediment that covers approximately 670 km2 of the lake has been recognized as a persistent source of turbidity. The objective of this study was to determine if mineral components of sediments in Lake Okeechobee and water conveyances of the northern Everglades also occur as suspended sediment and hence constitute a potential abiotic contributor to turbidity. Sediment samples were collected from nine stations within the lake and eight locations north of Water Conservation Area 2A in the Everglades. Water samples were also collected at selected locations. The silt and clay mineralogy of sediment and suspended particles was determined using X-ray diffraction, thermogravimetry, scanning-electron microscopy, energy-dispersive X-ray elemental microanalysis, and high-resolution transmission-electron microscopy. Clay fractions of the lake sediment contained the Mg silicate minerals sepiolite and palygorskite, along with smectite, dolomite, calcite, and kaolinite. Sediment silt fractions were dominated by carbonates and/or quartz, with smaller amounts of Ca phosphates and sepiolite. Mineralogy of the mud sediment was similar to that reported for geologic phosphate deposits. This suggests that the mud sediment might have accumulated by stream transport of minerals from these deposits. Suspended solids and mud-sediment mineralogy were similar, except that smectite was more abundant in suspended solids. Everglade samples also contained Mg-rich minerals. The small size, low density, and fibrous or platy nature of the prevalent mud sediment minerals make them an abiotic, hydrodynamically sensitive source of persistent turbidity in a shallow lake. Mitigation efforts focused exclusively on P-induced biogeochemical processes do not address the origin or effects of these minerals. Ecological management issues such as turbidity control, P retention, geologic P input, and suitability of dredging are related to mud-sediment properties and provenance.

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