Abiotic Water Testing

Dissolved Oxygen Rapidly moving water, such as in a mountain stream or large river, tends to contain a lot of dissolved oxygen, whereas stagnant water contains less. Bacteria in water can consume oxygen as organic matter decays. Thus, excess organic material in lakes and rivers can cause eutrophic conditions, which is an oxygen-deficient situation that can cause a water body "to die." Aquatic life can have a hard time in stagnant water that has a lot of rotting, organic material in it, especially in summer (the concentration of dissolved oxygen is inversely related to water temperature), when dissolved-oxygen levels are at a seasonal low https://water.usgs.gov/edu/dissolvedoxygen.html

Dissolved Oxygen Probe http://www.vernier.com/products/sensors/dissolved- oxygen-probes/do-bta/ We will be using a dissolved oxygen probe to determine the level of DO in River’s Edge’s lake. Please use extreme care when using this equipment out in the lake!

Nitrate and Nitrite Ions Nitrate (NO3) and Nitrite (NO2) Naturally-occurring compounds that are a metabolic product of microbial digestion of wastes containing nitrogen, for example, animal feces or nitrogen-based fertilizers Exposure to higher levels of nitrates or nitrites has been associated with increased incidence of cancer in adults, and possible increased incidence of brain tumors, leukemia, and nasopharyngeal (nose and throat) tumors in children in some studies (8, 9, 11, 13-19) but not others (20-29). The U.S. EPA concluded that there was conflicting evidence in the literature as to whether exposures to nitrate or nitrites are associated with cancer in adults and in children (1, 2). Acceptable levels of Nitrates would be less than 1ppm http://www.epa.gov/teach/chem_summ/Nitrates_summary.pdf

Ammonia Ammonia (NH3) is a by-product of fish urine, solid waste, and decaying organic matter (such as after an algal bloom) If ammonia is present in significant quantities, it can indicate that the water column does not have sufficient oxygen to oxidize ammonia to nitrite and nitrate. In an established lake or other aquatic ecosystem, ammonia should be at or near 0 ppm

pH The pH scale measures how acidic or basic a substance is. It ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic, and a pH greater than 7 is basic. Each whole pH value below 7 is ten times more acidic than the next higher value. For example, a pH of 4 is ten times more acidic than a pH of 5 and 100 times (10 times 10) more acidic than a pH of 6. The same holds true for pH values above 7, each of which is ten times more alkaline—another way to say basic— than the next lower whole value. For example, a pH of 10 is ten times more alkaline than a pH of 9. http://www.epa.gov/acidrain/measure/ph.html

pH As with our temperatures, if the pH of your creek begins to change, then you might suspect that something is going on somewhere that is affecting the water, and possibly, the water quality. So, often, the changes in water measurements are more important than the actual measured values.

Alkalinity Alkalinity is the capacity of water to neutralize acids (or in terms of a lake or stream, the capacity to “heal” itself after a rainfall or other acid increasing event). This capacity is caused by the water's content of carbonate, bicarbonate, hydroxide and occasionally borate, silicate and phosphate. pH is an expression of the intensity of the basic or acid condition of a liquid as measured by the presences of H+. Furthermore, alkalinity and pH are different because water does not have to be strongly basic (high pH) to have a high alkalinity Normal alkalinity readings of a pond, lake, or stream should be between 100 and 120 mg/L

Phosphates Since phosphorus is the nutrient in short supply in most fresh waters, even a modest increase in phosphorus can, under the right conditions, set off a whole chain of undesirable events in a stream including accelerated plant growth, algae blooms, low dissolved oxygen, and the death of certain fish, invertebrates, and other aquatic animals. There are many sources of phosphorus, both natural and human. These include soil and rocks, wastewater treatment plants, runoff from fertilized lawns and cropland, failing septic systems, runoff from animal manure storage areas, disturbed land areas, drained wetlands, water treatment, and commercial cleaning preparations (especially laundry detergent) Abnormal conditions: More than 0.1 ppm http://water.epa.gov/type/rsl/monitoring/vms56.cfm

Temperature The temperature of a body of water influences its overall quality. Water temperatures outside the “normal” range for a stream or river can cause harm to the aquatic organisms that live there. It is for this reason that the change in the temperature of the water over a section of a stream is measured, not just the temperature at one location. If the water temperature changes by even a few degrees over a one-mile stretch of the stream, it could indicate a source of thermal pollution. Thermal pollution may be responsible for decreased amounts of dissolved oxygen.

Temperature (cont.) Water temperatures in lakes during summer months is not uniform from top to bottom. Three distinct layers develop: The top layer stays warm at around 65–75 °F (18.8–24.5 °C). The middle layer drops dramatically, usually to 45–65 °F (7.4–18.8 °C). The bottom layer is the coldest, staying at around 39–45 °F (4.0–7.4 °C). Since light does not penetrate to the bottom, photosynthesis is limited to the top layer. Because of the warmer waters and more plentiful food supply, almost all creatures spend the summer months in the upper layer. In the spring time, the top layer mimics the air temperature and can be expected to be around 45-65 °F http://www.mbgnet.net/fresh/lakes/pond.htm

Taking the Temperature of River’s Edge Lake Use the Vernier temperature probe and LabQuest to get a reading in at least three different areas in two different locations. Use the glass/alcohol thermometers to confirm the readings. Please be careful with these thermometers so we do not have broken glass to contend with! Record in your notebook