LOCATION WEQUETEQUOCK CT+RI

Established Series
Rev. DAS-MKP-JTI
01/2021

WEQUETEQUOCK SERIES

The Wequetequock series consists of very deep, subaqueous soils permanently submerged beneath 20 through 200 cm of tidal estuarine water in submerged stream valleys and mainland coves in bays. The Wequetequock soils are formed in loamy marine deposits over deep buried organic materials. Slope ranges from 0 through 2 percent, mean annual air temperature is about 10 degrees C., and mean annual precipitation is about 1295 mm.

TAXONOMIC CLASS: Coarse-loamy, mixed, active, nonacid, mesic Fluventic Sulfiwassents

TYPICAL PEDON: Wequetequock silt loam on a south facing, concave slope in a submerged stream valley under 1.3 m of estuarine water. Tidal range is 80 cm. (Colors are for moist soil).

Ase -- 0 to 15 cm; black (N 2.5/) silt loam; gray (5Y 6/1) dry; 2 percent unrubbed and 0 percent rubbed herbaceous fibers; massive; very fluid; 10 percent organic matter; sulfurous odor; strongly saline; slightly alkaline (pH 7.8), very strongly acid (pH 4.7) after 8 weeks; clear boundary. (0 to 15 cm thick)

ACse -- 15 to 40 cm; black (N 2.5/) silt loam; 1 percent unrubbed and 0 percent rubbed herbaceous fibers; massive; very fluid; 9 percent organic matter; sulfurous odor; strongly saline; slightly alkaline (pH 7.7), very strongly acid (pH 4.9) after 8 weeks; clear boundary.

Cse1 -- 40 to 60 cm; very dark gray (2.5Y 3/1) silt loam; 1 percent unrubbed and 0 percent rubbed herbaceous fibers; massive; moderately fluid; 7 percent organic matter; sulfurous odor; strongly saline; moderately alkaline (pH 7.9), extremely acid (pH 4.0) after 8 weeks; clear boundary.

Cse2 -- 60 to 105 cm; very dark gray (2.5Y 3/1) sandy loam; 1 percent unrubbed and 0 percent rubbed herbaceous fibers; massive; moderately fluid; 6 percent gravel; 5 percent organic matter; sulfurous odor; strongly saline; moderately alkaline (pH 8.0), ultra acid (pH 2.6) after 8 weeks; abrupt boundary. (Combined thickness of C horizons is 20 to 120 cm thick.)

2Oaseb -- 105 to 150 cm; dark brown (7.5YR 3/3) muck, broken face sapric material, very dark gray (10YR 3/1) rubbed; 16 percent unrubbed and 2 percent rubbed herbaceous fibers; massive; very fluid; about 48 percent mineral content; sulfurous odor; strongly saline; slightly alkaline (pH 7.8), neutral (pH 6.6) after 8 weeks.

TYPE LOCATION: New London County, Connecticut; located about 600 feet south of the Providence and Worcester Rail Road Bridge and 1000 feet northeast of Goat Island in Wequetequock Cove. USGS Mystic, CT topographic quadrangle, Latitude 41 degrees, 20 minutes, 61 seconds N. and Longitude 71 degrees, 53 minutes, 3.8 seconds W., NAD 1983.

RANGE IN CHARACTERISTICS: The soils are permanently submerged. One or more horizons with a combined thickness of at least 15 cm within 50 cm of the mineral soil surface contain sulfidic materials. Soil has a 5:1 salinity greater than 0.6 dS/m throughout the profile. Buried organic soil materials occur below 100 cm from the mineral soil surface. Reaction is neutral through moderately alkaline and oxidized pH is ultra acid through slightly acid throughout.

The A horizon, where present, has hue of 10YR through 5Y, or is neutral, value of 2 through 3, and chroma of 0 or 1. Texture is mucky silt loam through loam. It is massive. Organic matter is 5 through 15 percent. Consistence is very fluid.

Some pedons have an AC horizon with similar characteristics to the A horizon. It is 0 through 25 cm thick.

The C horizon has hue of 2.5Y or 5Y, value of 2 through 3, and chroma of 1 or 2. Texture ranges from silt loam through sandy loam. It is massive. Gravel content is 0 through 10 percent. Consistence is nonfluid through very fluid.

The 2Ob horizon has hue of 7.5YR through 5Y, value of 2 through 3, and chroma of 1 through 3. It is muck or mucky peat. It is massive. Consistence is very fluid.

Some pedons have a 2C or 3C horizon with hue of 2.5Y or 5Y or is neutral, value of 4, and chroma of 0 through 3. Texture is sandy loam through loamy coarse sand. It is massive or single grain. Gravel content is 0 through 25 percent. Consistence is nonfluid.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Wequetequock soils are permanently submerged with salt or brackish water in submerged stream valleys and mainland coves within bays where they are subject to minimal currents and wave action. Slope ranges from 0 through 2 percent.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anguilla, Napatree, Pishagqua, Fort Neck, and Billington soils. Anguilla soils are on submerged mainland beaches and have a sandy particle-size class. Napatree soils are on submerged headlands and submerged mainland beaches, are sandy in the upper part, and lack sulfidic materials. Pishagqua soils are in low energy lagoon bottom landscapes, do not have organic horizons, and are fine-silty particle-size class. The Fort Neck soils have an n-value of 0.7 or less in some horizon at a depth between 20 and 50 cm below the mineral soil surface. Billington soils have an organic horizon, 20 cm or more thick, within 100 cm of the soil surface.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Subaqueous, peraquic moisture regime, moderately high or high saturated hydraulic conductivity due to low bulk density. Soil is permanently submerged with salt or brackish water.

USE AND VEGETATION: This soil supports submerged aquatic vegetation and aquatic habitats. The area is used for the harvest of crabs. In addition fishing is commonplace and the species found in the area are smelt, small cod, flounder, scup, menhaden, and white perch. Some areas are vegetated with native rooted vegetation such as eelgrass (Zostera marina) and floating algae. Vegetative cover ranges from 0 through 15 percent.

DISTRIBUTION AND EXTENT: New London County, Connecticut, and in Rhode Island. MLRA 144A. The soils of this series are not extensive (approximately 257 acres).

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Amherst, Massachusetts.

SERIES ESTABLISHED: New London County, Connecticut, 2010.

REMARKS: Diagnostic horizons and features in this pedon include:
1. Peraquic feature - positive soil water potential (permanently submerged) at the soil surface (under 1.3 m of water at the time of coring).
2. Sulfidic materials - the zone from 40 to 105 cm (Cse1 and Cse2 horizons).
3. Fluventic feature - irregular decrease in the content of organic carbon from a depth of 25 cm to a depth of 125 cm (ACse, Cse1, Cse2 and 2Oaseb horizons).
4. High n-value - the zone from 0 to 150 cm has an n-value greater than 0.7, as surmised by the very fluid and moderately fluid manner of failure (Ase, ACse, Cse1, Cse2 and 2Oabse horizons).
5. Buried soil feature - the zone from 105 to 150 cm (the 2Oaseb horizon). Radiocarbon dating measurements for the underlying marsh deposits are 2650 +/- 40 years BP measured and 2600 +/- 40 years BP conventional radiocarbon age.
6. Particle-size control section - the zone from 25 to 100 cm (ACse, Cse1, and Cse2 horizons).

ADDITIONAL DATA: Type location taken from pedon S2005CT011006 in New London County, Connecticut by KSSL, Lincoln, NE. Additional support pedons include S2005CT011005, S2006CT011002, and S2006RI009002.

National Cooperative Soil Survey
U.S.A.