Research by Lucy McGinty and Marissa Jacobs

02/28/22 – 05/10/22 

Abstract

Local Pennsylvania streams are becoming more polluted due to chemical runoff, littering, and sewage dumping. Because of this, diversity in streams is beginning to decline. Popular ways researchers determine the quality of the stream is by species counts and various chemical testing. Macroinvertebrates are important bioindicators for stream health, as many macroinvertebrates are more tolerant of pollution than others. Additionally, pH and dissolved oxygen tests are useful tools for measuring pollutant levels in streams. Both of these strategies are able to give researchers a better understanding of the extent of pollution in certain locations. Besides species counts and chemical testing, documenting temperature changes and erosion rates can give a good insight into changing macroinvertebrate counts. 

Objectives 

1. Use macroinvertebrates as bioindicators of pollution.
2. Perform chemical testing on stream to determine stream health in more depth.
3. Observe the physical characteristics of the stream and document the rate of bank soil erosion.

Hypothesis

The tests and observations performed on the Honey Hollow Creek will result in healthy stream measurements as the creek and areas surrounding it are protected and monitored by Bucks Audubon.

Materials: 

• PH indicator strips
• Dissolved oxygen titration
• Small net
• Magnifying glass
• Measuring tape
• Thermometer
• Camera

Methods 

Once a week for nine weeks, we gathered stream information at the same location (lat. 40.37, lon. 75.01). We determined the level of erosion on our first day and then took weekly width measurements of the stream in order to document the erosion. We then used a thermometer for approximately 10 minutes to document temperature changes, pH strips for documenting pH changes, and a dissolved oxygen test kit for dissolved oxygen changes by using the Winkler method. Once chemical testing was complete, we spent 15 minutes counting macroinvertebrates by flipping over rocks, logs, and leaf litter and catching them with nets. 

Results

The creek showed significant signs of soil erosion where there were little to no root systems (Figure 1). From the data we collected, there were no significant signs of  further erosion.

Our pH strips indicated that the levels moved from 7-9, and our D.O. levels indicated that they moved from 8.5-10. pH and D.O. levels were both inside of a healthy range for the ecosystem to be sustained, as a healthy pH for a stream are between 5-9 and a healthy D.O. range is between 7-10. During our macroinvertebrate counts, we found large numbers of pollutant-intolerant species such as stoneflies, caddisflies, and mayflies. 

Conclusion

Because of the healthy pH and dissolved oxygen levels, the large counts of pollution-intolerant macroinvertebrates, and the number of frogs thriving in the creek, we can conclude that the Honey Hollow Stream at Bucks Audubon is a healthy aquatic habitat. However, it is important to note that the erosion along the bank could become an issue by smothering life in the water, and it may be beneficial to scatter native plants with deep root systems along the soil to reduce soil displacement.