Week 31 - Human Activities Affect Aquatic Environments

Monitoring Water Quality

One widely used strategy, used to monitor the `health' of an ecosystem, is to monitor the health and numbers of one or more organisms that are particularly sensitive to the presence of pollutants or other environmental disturbances. Organisms that are used in this way are called `biological indicators.'
An organism that is commonly used to monitor aquatic ecosystems is an alga species called Raphidocelis subcapitata.
http://www.marietta.edu/~biol/introlab/ecosystem%20%20bioindicator%20lab.pdf .

When pesticides are used to control a target insect or weed species, beneficial insects and plants may also be adversely affected by direct contact with the pesticide. Pesticides can also harm beneficial organisms through a process called biomagnification . This refers to the increase in the concentration of a chemical in an organism over time, compared to the concentration of the chemical in the environment.

Biomagnification occurs if a pesticide does not break down quickly. As insects, birds and animals eat contaminated food, the chemical accumulates in their bodies. With every step in the food chain, larger quantities of accumulated pesticide are eaten. This may continue to the point where these animals are adversely affected, or are unsafe for consumption.

Water Quality Tests	Description
Dissolved Oxygen	Testing for dissolved oxygen (DO) of water
BOD	Testing for biochemical oxygen demand (BOD) of water
Total Solids	Testing for total solids (TS) in water
Turbidity	Testing the Turbidity of water samples
pH	Testing the pH of water
Nitrates	Testing for nitrates (NO3) in water
Total Phosphates	Testing for total phosphates in water
Total Fecal Coliform	Testing for total fecal coliform in water
Alkalinity and Acidity	Testing the alkalinity and acidity of water

Dissolved Oxygen
This test is the most important of the nine water quality tests to measure water's ability to support plants and animals. There are many different factors that affect the amount of dissolved oxygen in water, the main one being temperature. As temperature rises, less gas will dissolve.
Turbidity
Turbidity measures water clarity, which allows sunlight to penetrate to a greater depth. The main sources of turbidity are erosion, living organisms, and those from human endeavors
Total Solids
Total solids measures both dissolved and suspended solids. There are six major types of total solids; silt, clay, soil runoff, plankton, industrial waste, and sewage.
Ph Level
The PH of water is important to aquatic life. If the PH falls below 4 or above 9 everything is dead.
Temperature and Flow Rate
Temperature is a very important part of a river's ecology. There are many natural and human factors that can affect a river's temperature. Human factors include industry, development, and dams. To measure temperature and flow rate you must find two places along the river that are about 1.6 kilometers apart that have the same conditions, then two people measure the temperature at approximately the same time. If the difference is greater than 2 degrees Celsius, then there is thermal pollution. To find flow rate you use a buoyant object, we used an orange, and float it down the river.
Nitrates
Nitrogen is necessary for plant and animal life. Water is tested for nitrates to monitor and control eutrofication , which causes more plant growth and decay.
Fecal Coliform
This nasty stuff is a certain bacteria that propagate in the digestive tracts of humans and animals. They coexist with other bacteria so they are often used as indicators of possible pathogenic contamination. There are many ways fecal coliform can enter a waterway such as animal waste, untreated sewage, combined sewage overflow, and septic tanks.
Biochemical Oxygen Demand
BOD is a measure of oxygen removed from an aquatic environment by aerobic microorganisms. It measures levels of organic pollution in lakes and streams.
Phosphorous
Phosphates is a nutrient needed in growth. The phosphate ion is found in shells, bones, and in animal teeth. By removing phosphorous from sewage the amount of phosphate ions in the water will be lowered.