BESC 320 – Water and Bioenvironmental Science(Week 4; 29 Jan 2020)

Wetlands biological functions Do rivers flow south in the northern hemisphere and vice versa? See http://geography.about.com/od/learnabouttheearth/a/northrivers.htm

WetlandsDefined by biologists as areas that are saturated with water at the surface, permanently or seasonally (e.g. swamps, marshes and estuaries). Recent re-reversal of wetlands definition by EPA—now to this agency wetlands no longer include small or temporary water bodies (Google search).

Historically over 220 million acres existed in the lower 48 states. About 20% of land was wetlands.

Since then, extensive losses due to land use conversions.

We now have about 105.5 million acres of wetland. (US EPA)

Why kill a wetland?Drained wetlands are attractive for agricultural uses and for commercial and residential development. They make good agricultural fields because of their productive soils, high water table, and flat topography. Large, efficient farming equipment is easier to use on drained wetlands than on rolling land. Wetlands are in demand as building sites. In coastal areas, where suitable home sites are in short supply, drained wetlands are highly valued for residential development.

Why preserve?Ecosystem services—Wetlands provide habitat for a variety of plants and animals, including certain endangered species. Wetlands also help moderate floodwaters, control sediments, and improve water quality. The tranquility and beauty of wetland areas make them popular for recreation and relaxation as well. They also provide for recharge of inland groundwater.

Aesthetic side—wetlands are majestic. Moral side—wetlands harbor such biodiversity it is basically evil and arrogant to assume a right to destroy them. Rhetorically metaphorical: What will be the Provider’s first question to you after your life as a human? Did you think I laid so much water down accidentally?

Reflect… What’s with the midwest? MI, WV v. IL to KA? Cali? Maine/Montana? FL?

The Fed protects wetlands through regulations, such as the Clean Water Act, provisions of the Food Security Act, EPA regs, economic incentives (tax deductions for selling or donating wetlands to a

qualified organization), and acquisitions (i.e., establishing national wildlife refuges), and direct prohibitions of development (e.g. ANWAR). A recent strategy involves cooperative agreements between federal, state, tribal, and local governments with the goal of protecting entire watersheds. However, ~75 percent of wetlands are privately owned, so individual landowners are crucial to preservation/protection of wetland ecosystems. NGOs also provide protections (e.g. WWF, DU).

Cultural differences in this arena are huge… In Scandinavia you may be fined for destroying nature. Greta Thunberg…

Estuariesphoto source: NOAA

Estuaries are special. They are the areas of confluence of fresh and salt waters. They are extremely dynamic, generally involving tidal fluxes from the salt side, and continued input of nutrients and sediment from the freshwater side. The recipe of moving water, nutrient input and rich sediment makes for high biological productivity. These areas are highly

productive and harbor awesome arrays of biological diversity. They serve as nursery grounds for 75% of important seafood organisms.

See Vignette 28 in the Atlas of WaterRelative species richness by habitat:

Marine – 0.2Terrestrial – 2.7Freshwater – 3.0

Populations of FW species declined by 50% from 1970-2000This is a global phenomenonCase: Lake Victoria, central Africa

Habitat degradation, overfishing, and introduced species cut endemic species to nearly ½ (about 120-150 of 300 endemic ‘cichlid’ fish)

This ‘productivity’ can be overdone when combined with anthropogenic inputs. With too much enrichment and so high a biomass, the system can essentially choke itself, creating a “dead zone”.

There is a 8,543 mi² dead zone where the Mississippi River entered the Gulf of Mexico.

This can make one ashamed to be a human, no?

Image Source: NASA

Here is a map of dead zones all over the planet (source: UNEP, GEO Yearbook 2003):

I have read and endorse Wikipedia’s entry on the Estuary topic (as of 1/22/2018):http://en.wikipedia.org/wiki/Estuary

Conceptually parallel system:

Papyrus swamps.

Water flowing through is filtered but repiration of microbial films so great nearly all oxygen stripped from the water.

So I studied that.

Aquifers – underground stores of water

• Located in porous layers of sand, gravel, or porous rock lying above impermeable rock or clay.• If pressurized by geological events, or head, water flows from a puncture without pumping (i.e. artesian wells are created)• Recharge area/zone - Area where water infiltrates into an aquifer (watershed.• Recharge rate is often very low—reflect… Why is this so?• Groundwater is being removed by humans faster than it can be replenished in many areas• Groundwater flow transports materials (e.g. minerals in solution, frack fluids, radioactivity, etc.). reflect… Implications for land management?• Groundwater vocabulary : http://www.co.portage.wi.us/groundwater/undrstnd/gloss.htm

• Question: 1000 gallons of rain fall on a recharge area… 600 gallons runs over the surface to lakes and streams in the watershed. How much water percolates into the groundwater supply?

Do a mental experiment—assume the lake is the ocean coast. Now look back at the confined freshwater recharge area and standing freshwater lake. How might seawater interact or not with that area?