On April 6th 2013, our Biology II lab evaluated the health of two freshwater streams in the Denver area. Both creeks flow to the South Platte River but are situated in different environments (urban and suburban) which cause variance in biotic and abiotic indicators of stream health. The presence or absence of bioindicators is dependent on the water chemistry.
Through the study of stream health, we can gain insight on the stress that humans cause to freshwater habitats. I think that Bear Creek is healthier than Cherry Creek because it is in a less urban environment and is less affected by human influences.If the stream is unhealthy, there will be fewer organisms inhabiting it. The presence or absence of bioindicators depend on the water chemistry. Urban stream syndrome is the term used to describe a stream located in an urban environment that has undergone high levels of stress from city runoff (N.
A Benthological Society 2005). Urban streams can be adversely affected by the increasing amounts of contaminants, channelization, clearing of the riparian zone, and runoff from storm drains, making the waterway uninhabitable for it’s native species.I expect that Cherry Creek is an example of urban stream syndrome due to it’s location. Some examples of abiotic indicators of stream health are water temperature, pH, dissolved O2 , nitrite and nitrate levels. The organisms that live in freshwater streams a re sensitive to certain environmental changes.
For example, dissolved O2 is present in streams due to photosynthesis. If the concentration of O2 is too high or too low, the stream becomes uninhabitable for many organisms but is still useable as drinking water. High levels of nitrite and nitrate indicate fertilizer runoff.Benthic invertebrates are sensitive to pollutants and are an easy indicator of the health of a stream (MSD 2010). The presence or absence of different organisms indicate specific qualities of the health of the stream (Hodkinson, Jackson 2005). Bioindicators of stream health include blackfly larvae, caddisflies, and algae.
The presence of blackfly larvae indicates sewage pollution. Caddisflies indicate higher O2 concentrations. The presences of algae can indicate different things. If algae is absent, there may not be enough nutrients to support its growth.
Thick algae indicates eutrophication. Previous studies by the Colorado Department of Health Water Quality Control Commission in 1981 show comparable amounts of dissolved O2 as well as pH, nitrite, and nitrate levels in both Cherry and Bear creek. The NH 3 levels were much higher in Cherry Creek at . 10 mg/L compared to Bear creek where the NH 3 levels were at . 06 mg/L (Colorado 1981). In today’s society, it is important to find a balance between preserving the natural ecosystem and accommodating the wants, needs, and desires of the humans who affect it.
(Meyer 1997).Pollution is inevitable but should be considered and kept as low as reasonably achievable. Materials and Methods The following procedures were carried out carried out at both Cherry Creek and Bear Creek 04/06/2013. The Colorado Department of Health Water Quality Control Commission 1981 provide abiotic standards for both creeks will be used as control for the chemical data collected. The first task was to seek out an area that included a pool and a riffle.
The pool was identified as an area that is fairly deep with slowflowing water. A riffle was found with fairly shallow, faster moving water.At Cherry Creek, we found an area that fit this criteria near the corner of Speer Boulevard and Lawrence Street in Denver, Colorado. The area studied at Bear Creek was a short walk from 2900 S. Estes Street in Lakewood. We walked over a bridge and down the stream about 100 yards and found an area fit for study.
Using measuring tape, an area ranging 10meters that included both the pool and riffle was measured. This was the stretch of the creek from which data was collected. Next, prelabeled nalgenes were used to collect water samples from the pool, riffles, and midstream.Then, the samples were tested.
We measured and recorded the temperature of each water sample using a thermometer. Ph was obtained from each sample using a Melter Toledo 7 Go Pro pH meter and a CHEMetrics chemistry kit as directions indicated. Salinity and total dissolved solids were found using a meter. Any trash left from this experiment was disposed of in a container labeled “trash” and any broken ampules were placed in a container labeled “sharps”. We measured a transect running across the bank at the top of the 10meter length that has been designated for study.
