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Subaqueous soils are soils formed in sediment found in shallow, permanently flooded environments or soils in any areas permanently covered by water too deep for the growth of rooted plants. The study of subaqueous soils is a relatively new field in Pedology or soil science. The concept that sediments in shallow water environments undergo soil-forming processes, are capable of supporting rooted plants (such as Eelgrass), and meet the definition of soil according to criteria in Soil Taxonomy has been moving soil scientists into a new frontier of soil survey – mapping subaqueous soils. The National Cooperative Soil Survey (NCSS) is a nationwide partnership of Federal, regional, State, and local agencies and institutions. This partnership works together to cooperatively investigate, inventory, document, classify, and interpret soils and to disseminate, publish, and promote the use of information about the soils of the United States and its trust territories. The activities of the NCSS are carried out on National, regional, and State levels. The USDA-Natural Resources Conservation Service (NRCS) is the lead federal agency for mapping and developing interpretations for the nation's soil resources and the extension of soil survey technology to global applications. ==Subaqueous and Submerged Soils== As the name implies, subaqueous and submerged soils are soils that occur under water (both fresh and salt water). The depth range of the water column where these soils may be found is not known, an arbitrary depth of 2.5 meters below the surface has been set for soil survey inventory but some states have extended this depth to 5 m (NAVD 88). The difference between subaqueous and submerged soils is that submerged soils formed in an upland environment then became submerged as a result of rising water tables, flooding events (such as a Beaver Dam), or sea level rise. Subaqueous soils formed under a continuous water column (such as in an estuary), although their sediments may have originated from an upland area such as a dune. Although proposals to include permanently submersed sediments as soil have been put forth since the mid-1800s, it was not until the early 1990s that the concept of subaqueous soils was developed in the U.S. The pioneer in U.S. subaqueous soils is the late George Demas, a soil scientist working for the National Cooperative Soil Survey in the Chesapeake Bay region of Maryland. Dr. Demas observed that subaqueous areas met the definition of soil by being able to support rooted plant growth (such as Eelgrass) and had formed soil horizons. Further study revealed that these submersed sediments underwent other soil forming (pedogenic) processes including additions, losses, and transformations of energy and matter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「subaqueous soil」の詳細全文を読む スポンサード リンク
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