User:Tivinjd/Freshwater marsh

Soil[edit]
Soils contain organic matter, air, water and mineral matter. The soil has very slow decomposition rates and is often black or brown. Soils are characterized by hue, chroma and value. The soils in wetlands are often hydric in nature, which means they are completely saturated and have no oxygen. The soils of marshes and wetlands play an important role as carbon sinks. Carbon sinks are formed in these marshes through the slow decomposition of organic matter that arose from anaerobic conditions due to flooding.

Hydrology[edit]
Freshwater marshes are dynamic ecosystems. Aspects of the water like depth, velocity, oxygen concentration, and temperature change frequently. Marshes can be classified based on their hydrology. Marshes can be flooded permanently, intermittently, temporarily, seasonally, and semi-permanently. Groundwater reserves, water moving across the surface and precipitation are the three main sources of water in marshes. Marshes are commonly found in areas of topography that have depressions. The depressions in the land aid in the ability for marshes to be able to collect and hold water. Geographic locations of marshes coincide with depressions formed by glacial movement, water movement and tectonic activities. They hydrologic processes of marshes varies based on location due to changes in precipitation, evapotranspiration, groundwater in-flow and runoff.

Precipitation
Water forms that reach marshes directly or indirectly and influence surface water or ground water flow is deemed as precipitation that plays a role in wetland hydrology. There is a positive correlation between high annual precipitation in the form of rain, snow, or mist and wetland/marsh presence. Snow has the ability to melt and recharge ground-water in temperate marshes where four annual seasons are present.

Evapotranspiration
The combination of atmospheric evaporation and plant transpiration is defined as Evapotranspiration. This is the total amount of water that leaves the surface of of a landscape and it put back into the atmosphere. Seasonal evapotranspiration can be highly variable due to changes in solar radiation, humidity, moisture in the soil and plant type/density. The position of the water table can play a role in how much moisture is evaporated. Water tables that are closer to the surface of the marsh have a higher chance of losing more water than marshes with lower water tables.

Differences Between Marshes and Swamps
Marshes and swamps are two types of forested wetlands that are primarily found near bodies of water and are comprised of mineral rich, hydric soil. One main difference between marshes and swamps are their respective types of vegetation. Swamps are characterized by the presence of woody plants, such as Tupelo and Cypress trees, and saturated soils with standing water throughout some of the year. Marsh vegetation is primarily soft-stem vegetation and herbaceous plants and experience frequent or continual flooding from near bodies of water.

Human Impacts
Freshwater wetlands are subjected to a myriad of human impacts that affect the ecosystem services. The change in flow regime of a marshes' primary water source can deplete the size of the marsh, therefore limiting habitat for organisms. Humans redirect water sources and drain marshes to provide land for development and agriculture. Excess runoff from city sewage or agriculture can overload marshes with nutrients causing harmful phytoplankton blooms. An increase in phytoplankton and other organic matter can lead to the deoxygenation of marshes which results in lower water qualities and a loss of biodiversity.