LOCATION MOSQUITO                AK

Established Series
Rev: DKS/JPM/DLM
05/2022

MOSQUITO SERIES

Depth class: very shallow to moderately deep over permafrost
Drainage class: very poorly drained
Parent material: silty alluvium or organic matter over alluvium in regions of groundwater discharge
Landform: alluvial plains in broad valleys and flats
Slope: 0 to 3 percent
Mean annual temperature: 21 to 28 degrees F.
Mean annual precipitation: 9 to 14 inches

TAXONOMIC CLASS:

TYPICAL PEDON: Mosquito peat - on a 0 percent slope under open forest of tamarack and black spruce at 1050 feet elevation. (All colors are for moist soil.

Oi--0 to 2 inches; dark brown (7.5YR 3/2) peat; many very fine to coarse roots; strongly acid (pH 5.2); clear smooth boundary.

Oa--2 to 10 inches; black (10YR 2/1) muck; few fine to medium roots neutral (pH 6.6); abrupt broken boundary.

Bg--10 to 18 inches; olive gray (5Y 4/2) and olive brown (2.5Y 4/4) silt loam; many large prominent strong brown (7.5YR 4/6) mottles massive; slightly sticky and slightly plastic; neutral (pH 6.6); abrupt wavy boundary.

Bgf--18 to 30 inches; dark yellowish brown (10YR 4/6) and dark grayish brown (2.5Y 4/2) perennially frozen silt loam; massive; very hard; slightly sticky and slightly plastic (when thawed); neutral (pH 6.6).

Cf--30 to 60 inches: permanently frozen material.

TYPE LOCATION: Gerstle River Area, Alaska; about 11 miles east of Delta Junction, Alaska; NW 1/4 of the NW 1/4 of section 10, T.10S., R.12E, Fairbanks Meridian.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: less than 32 degrees F.
Depth to permafrost: 5 to 31 inches below the mineral surface

O horizon:
Texture: peat, mucky peat, or muck, thickness varies above and below 20 inches based on microtopography
Reaction class: very strongly acid to neutral.

Bg or Bgf horizons (where present):
Matrix color: hue of 10YR to 5Y, or N; value of 3 to 6; chroma of 0 to 6
Redoximorphic features: hue of 7.5YR to 2.5Y; value of 3 to 5; chroma of 3 to 6 are usually present
Reaction class: moderately acid to neutral
Fragments of O or other horizon material are mixed into the Bg horizon by cryoturbation in some pedons.

C horizons:
Matrix color: hue of 10YR to 5Y, 5BG, or N; value of 3 to 6; chroma of 1 to 6
Redoximorphic features: hue of 7.5YR to 2.5Y; value of 3 to 5; chroma of 3 to 6 are usually present
Texture: silt loam, very fine sandy loam, stratified silt loam top loamy fine sand, or mat of permanently frozen material
Reaction class: moderately acid to neutral

COMPETING SERIES: There are no competing series in the same family.

GEOGRAPHIC SETTING:
Parent material: silty alluvium or organic matter over alluvium in regions of groundwater discharge
Landform: alluvial plains in broad valleys and flats
Slope: 0 to 3 percent
Climate: continental with short, warm summers and long, cold winters
Mean annual temperature: 21 to 28 degrees F.
Mean annual precipitation: 9 to 14 inches, approximately one third of which falls as snow

GEOGRAPHICALLY ASSOCIATED SOILS: These are Liscum and Tanacross soils. Liscum soils occur in complex with Mosquito soils; the former usually occur in places where the influence of groundwater is sufficient to prevent formation of permafrost. Tanacross soils occur on slightly higher positions than Mosquito soils, and are more acid because their organic acids are less completely neutralized by bases from the groundwater.

DRAINAGE AND PERMEABILITY: Very poorly drained. Very slow runoff. Saturated hydraulic conductivity is moderately high or high above the permafrost.

USE AND VEGETATION: Mosquito soils are used for wildlife habitat and watershed protection. Soil drainage is not improved sufficiently by clearing to allow agricultural use. The soils support forest of tamarack and black spruce, with shrub birch and cottonsedge in the understory.

DISTRIBUTION AND EXTENT: MLRA 229, Interior Alaska Lowlands. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Gerstle River Area, Alaska, 1999.

REMARKS: Diagnostic horizons or features recognized in this profile include:
Histic epipedon: 0 to 10 inches
Permafrost: below 18 inches
Cryoturbation: evident by abrupt broken horizon boundaries.

Groundwater discharge neutralizes organic acids in the organic horizon, and results in a higher pH of these horizons than in most other Ruptic Histoturbels in this region. Because permafrost is relatively impermeable, groundwater must be discharged through associated unfrozen soils.

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National Cooperative Soil Survey
U.S.A.