Lab 9 Freshwater Ecosystems

A.      Water Monitoring

Procedural photographs-

Sampling site: a town's natural spring water supply

(aerator removed)

Temperature:

Turbidity:

Dissolved Oxygen:

Biochemical Oxygen Demand (BOD)-

5 day test:

Nitrate:

pH:

Phosphate:

Coliform:

Test Results Chart:

1.       Discuss “poor” results of how the ecosystem may be affected.

A poor coliform result indicates that a water source has been contaminated by sewage and will cause high or excessive levels of nitrate and phosphate.  This increase in bacteria from sewage or plant waste can cause the % saturation of the water to decrease.  This decrease in saturation may cause fluctuations in dissolved oxygen levels throughout the day.  This creates a difficult environment for plants and animals to live.  The water is also not safe for humans to drink!  Excess nitrate and phosphate from human waste, fertilizer and agriculture runoff increase plant growth and decay, support bacterial decomposition, and this leads to a decrease in the oxygen available for use by other organisms.  These changes make it difficult for other organisms to survive and thrive.  High levels of nitrates in drinking water may also have an effect on the ability of human’s blood to carry oxygen.  Warmer aquatic ecosystems have low dissolved oxygen levels and typically have less diverse aquatic species.  A change in pH levels can make it difficult for organisms to survive since most are adapted to a specific pH level.    

2.       Discuss “excellent” results in terms of how the ecosystem is supported.

An excellent coliform result indicates that the water is free of sewage waste and dead plant matter and is likely to have stable levels of nitrates and phosphates.  The dissolved oxygen % saturation will remain more stable without waste and animals and plants thrive and survive when more oxygen is present.  Stable levels of nitrates support the ability of plants and animals to build proteins. Stable levels of phosphates support growth of plant and animals and supports metabolic systems. Colder aquatic ecosystems have higher levels of dissolved oxygen which supports a healthy and stable ecosystem. And have more species diversity than warmer aquatic ecosystems.  A lack of change in pH is ideal or excellent since most organisms are adapted to a specific pH level.                  

B.  Thinking About the World's Water

In chapter 2 of “Water Brief” the article “Past and Future if the Salton Sea” discusses the environmental disaster that is occurring in the Salton Sea.  This disaster will impact diversity of micro-organisms and hundreds of resident and migratory birds.  Currently it is a gradual water reduction but will soon increase significantly due to decreased inflows.  The changes of the sea level will result exposed sea floor and cause an increase in dust storms that affect public health.  Fish and invertebrate populations will also be distressed by the poor water quality and their survival will be seriously threatened.  This Sea started as a result of the Colorado River sometimes flowing north into the Salton Basin and would then shift direction flowing to the south to the Gulf of California.  Dams, armored channels, controlled released flows, now protects the Salton Sea from experiencing filling and drought cycles.  Inflows are predicted to drop from 1.5 km3/year to .88 km3/year within 25 years.  Many factors are causing this decrease in inflow: reduction of inflows from Mexico, cropping patterns changing.  After 2017 the water transfer issues will also increase the decline in inflows.  Climate change is also impacting evaporation from the Sea’s surface and evapotranspiration from irrigated fields will affect the Sea’s size and water quality.  The possible Salton Sea solutions are: full restoration; partial restoration; shallow-habitat construction; and placing a legal minimum of air quality and desert pupfish management.  Due to most options being costly, not can completed in a timely manner as well as a lack of political interest to protect the Sea action will be deferred for many years and may continue until legislation requires the state of California to act.  There is one option that is not as costly as the other options and the federal government U.S. Geological Survey Salton Sea Science Office is currently running and monitoring a 40-ha pilot project.  This project is utilizing the shallow habitat construction.     

In my opinion this environmental situation with the Salton Sea is complicated and costly to restore and maintain.  I think the pilot project, i.e. shallow habitat construction, seems like the most logical option in terms of environmental health and stability as well as cost.

Resources    

Donnelly, Kristina. "The Red Sea-Dead Sea Project Update". worldwater.org. Pacific Institute. Jan. 2015. Web. 27 Oct. 2015.