Wetlands are part of the foundation of our nation's water resources and are vital to the health of waterways and communities that are downstream. Wetlands feed downstream waters, trap floodwaters, recharge groundwater supplies, remove pollution, and provide fish and wildlife habitat. Wetlands are also economic drivers because of their key role in fishing, hunting, agriculture and recreation.
Wetlands include swamps, marshes and bogs. Wetlands vary widely because of differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors. Wetlands are often found alongside waterways and in flood plains. However, some wetlands have no apparent connection to surface water like rivers, lakes or the ocean, but have critical groundwater connections.
Generally, wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface. Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance. Indeed, wetlands are found from the tundra to the tropics and on every continent except Antarctica.
Wetland hydrology is associated with the spatial and temporal dispersion, flow, and physiochemical attributes of surface and ground water in its reservoirs. Based on hydrology, wetlands can be categorized as riverine (associated with streams), lacustrine (associated with lakes and reservoirs), and palustrine (isolated). Sources of hydrological flows into wetlands are predominately precipitation, surface water, and ground water. Water flows out of wetlands by evapotranspiration, surface runoff, and sub-surface water outflow. Hydrodynamics (the movement of water through and from a wetland) affects hydroperiods (temporal fluctuations in water levels) by controlling the water balance and water storage within a wetland. Landscape characteristics control wetland hydrology and hydrochemistry. The O2 and CO2 concentrations of water depend on temperature and atmospheric pressure. Hydrochemistry within wetlands is determined by the pH, salinity, nutrients, conductivity, soil composition, hardness, and the sources of water. Water chemistry of wetlands varies across landscapes and climatic regions. Wetlands are generally minerotrophic with the exception of bogs. Bogs receive their water from the atmosphere and therefore their water has low mineral ionic composition because ground water has a higher concentration of dissolved nutrients and minerals in comparison to precipitation. The water chemistry of fens ranges from low pH and low minerals to alkaline with high accumulation of calcium and magnesium because they acquire their water from precipitation as well as ground water.
What is pH?
pH is a measurement of how acidic or how basic (alkaline) a solution is. When substances dissolve in water they produce charged molecules called ions. Acidic water contains extra hydrogen ions (H+) and basic water contains extra hydroxyl (OH-) ions.
pH is measured on a scale of 0 to 14. Water that is neutral has a pH of 7. Acidic water has pH values less than 7, with 0 being the most acidic. Likewise, basic water has values greater than 7, with 14 being the most basic. A change of 1 unit on a pH scale represents a 10 fold change in the pH, so that water with pH of 6 is 10 times more acidic than water with a pH of 7, and water with a pH of 5 is 100 times more acidic than water with a pH of 7.
You might expect rainwater to be neutral, but it is actually somewhat acidic. As rain drops fall through the atmosphere, they dissolve gaseous carbon dioxide, creating a weak acid. Pure rainfall has a pH of about 5.6.
Please answer the following questions to gain credit for this Earthcache:
- What is the third criteria for being a wetland?
- What percentage of wetlands have been lost?
- Every three years how many acreages of wetlands are lost in Minnesota?
- Describe the wetlands you see as you walk along the bike trail from stage 1 to stage 4
- Take a water sample anywhere along your route. Describe the water. What is its pH level?
- At Long Lake, take another water sample. What is its pH level?
- Based on your observations, which direction do you feel the water flows. What differences did you find in the water between Long and Rush lakes?
- Photos are optional, but appreciated.
