Interpretations of Subaqueous Soils.

In the last 10 years significant advancements have been made in the mapping, characterization, and classification of subaqueous soils. Although the development of a set of methods to map and characterize subaqueous soils is far from complete, current needs are for the develop of subaqueous-soil based interpretations. Examples of interpretations include which soils are the best for eelgrass habitat restoration, which soils have the highest shellfish productivity, or what are the effects of dredging and placement of the dredge materials on the land surface. In this study, we are investigating the effects of the placement of dredge materials on the soil surface. Soils from four representative soil-landscape units from two coastal lagoons and two embayments in Rhode Island were sampled to a depth of 25 cm. These samples were placed in mesocosms, allowed to drain, and exposed to atmospheric conditions.  Rainfall leachate was collected on a regular basis and analyzed for salinity, pH, and sulfate content.  Preliminary results suggest dredge materials from finer textured soils have a much larger drop in pH than dredge materials sampled from coarser soils. Salinity and sulfate contents follow a similar trend supporting the conclusion that more sulfides are in the finer textured dredge materials.