PLS 147 Lecture Notes - Lecture 7: Histosol, Palustrine Wetland, Estuary
Eliska Rejmankova ESP 155 wetlands in the fall
What are wetlands?
systems that have standing water
main determinants:
● geomorphology: area where water can form
● climate: rain
● interplay between hydrology, soils, biota
about 90% of California wetlands are gone
● coastal marshes, freshwater marshes/lake margins, freshwater marshes/floodplains,
sloughs, bogs and fens, vernal pools, seeps, riparian forests
● can be seasonally flooded (not permanent standing water)
● floodplains drained for agriculture
Wetland classification
● systems: marine, estuarine, riverine, lacustrine, palustrine
Wetland Soils
hydric (hydromorphic) soils
● soils flooded long enough to develop and maintain anaerobic (no O2) conditions
○ dry soils are well aerated, gases move through rapidly
○ once the soil is flooded, airspaces filled w/ water, gases move 10,000 slower
○ oxygen is gone very rapidly, used by microbes and plant roots
■ slow gas diffusion through flooded soils
○ anaerobic processes start happening
■ oxidized iron compounds get reduced, soils become pale/olive gray color
● areas around plant roots that can leak oxygen iron stays in
oxidized form, soil is rusty color
■ nitrate?
■ can become so anaerobic that methane is produced
minerals or
Organic (Peat Soils, histosols)
● peat can originate from many plants
● contain more than 20-35% organic material
● peat soil is light, fluffy,
● bulk density: very little dry mass per volume
○ mineral soils: more dry mass
● high porosity (can soak in a lot of water, hold on to water)
○ mineral soils: low
● important characteristics of organic soils
Document Summary
Eliska rejmankova esp 155 wetlands in the fall. What are wetlands? systems that have standing water main determinants: Interplay between hydrology, soils, biota about 90% of california wetlands are gone. Coastal marshes, freshwater marshes/lake margins, freshwater marshes/floodplains, sloughs, bogs and fens, vernal pools, seeps, riparian forests. Can be seasonally flooded (not permanent standing water) Soils flooded long enough to develop and maintain anaerobic (no o2) conditions. Dry soils are well aerated, gases move through rapidly. Once the soil is flooded, airspaces filled w/ water, gases move 10,000 slower. Oxygen is gone very rapidly, used by microbes and plant roots. Oxidized iron compounds get reduced, soils become pale/olive gray color. Areas around plant roots that can leak oxygen iron stays in oxidized form, soil is rusty color. Can become so anaerobic that methane is produced minerals or. Bulk density: very little dry mass per volume. High porosity (can soak in a lot of water, hold on to water)
