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Coastal Zone Soil Survey of Little Narragansett Bay
Several U.S. states have begun the process of mapping and inventorying
subaqueous soils. States with these types of soils are responsible for
determining the activity in their state related to coastal zone mapping.
How Are These Soils Mapped?
Traditional soil mapping is conducted by a field soil scientist trained to
understand the interaction of soil forming processes and soil-landscape
relations. Mapping soil involves mostly field work with the soil scientist
traversing the landscape and digging many holes to observe the soil condition
and classify the soil. Subaqueous soil mapping is performed in much the same
way, except the soil is under water. Instead of topographic maps to provide
landscape position, subaqueous soil mapping uses bathymetric maps to identify
landscapes and landforms. Shovels are replaced with augers and special tools
such as peat corers and vibracores to obtain the soil samples.
Subaqueous and Submerged Soils
As the names imply, subaqueous and submerged soils are soils that occur under
water (both fresh and salt water). The difference between subaqueous and
submerged soils is that submerged soils became submerged as a result of rising
water tables, flooding events (such as a beaver dam), or sea level rise.
Submerged soils formed in an upland environment but are now underwater.
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.
Significance of Subaqueous Soils
Although proposals to include permanently submersed sediments as soil had
been put forth since the mid 1800’s, it was not until the early 1990’s that the
concept of subaqueous soils was developed in the U.S. The pioneer in U.S.
subaqueous soils was the late Dr. 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.
Soil Taxonomy defines the upper limit of soil as the boundary between soil
and air, shallow water, live plants, or plant materials that have not begun to
decompose. The lower limit of soil has been arbitrarily set at 200 cm. The
horizontal boundaries of soil are areas where the soil grades into deep water
(typically 2.5 meters deep), barren areas, rock, or ice (Soil Survey Staff
2006).
The United States Department of Agriculture - Natural Resource Conservation
Service (USDA- NRCS), a member of the National Cooperative Soil Survey, is the
lead federal agency for the mapping and interpretations of the nation’s soil
resources. The well established standards, techniques, and protocols used to map
and interpret the nation’s soil resources have been applied to this project.
Objectives of the coastal zone soil survey of Little Narragansett Bay
- To inventory, map, and develop interpretations for subaqueous soils with
particular emphasis upon existing and potential eelgrass and shellfish
habitat;
- To refine and standardize protocols required for future surveys of
subaqueous soils throughout the Long Island Sound Estuary (an Estuary of
National Importance), and the northeast coastal habitats;
- To apply established pedological soil-landscape conventions to explain
relationships of subaqueous soil to submersed geomorphic settings that pertain
to the conservation of eelgrass and shellfish habitat; use and management of
estuarine resources; and
- To develop partnerships with agencies, organizations, and institutions
involved with Long Island Sound restoration efforts.
The need for coastal–zone mapping to inform policy makers and management is
widely recognized as critical for mitigating hazards, creating resource
inventories, and tracking environmental changes (National Research Council,
2004; U.S. Commission on Ocean Policy, 2004).This study will help increase
understanding of the rare subaqueous soils in the ecosystem of Long Island
Sound. It will hopefully lead to the development of a program to inventory
additional coastal resources and develop interpretations that will assist in
making better informed natural resources decisions.
Coastal Zone
Soil Survey of Little Narragansett Bay - Maps
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