Furnace Brook Lab Report

Furnace Brook Lab Report

Introduction:  The amount of macroinvertebrates in a body of water can be an important sign for the quality of that body of water, according to a Penn State study.  If a body of water is clean and functional, that means the entire ecosystem around it will be healthy.  Certain macroinvertebrates, like aquatic worms, can survive with high water pollution levels, where others cannot.  This lab was conducted to test the health of the water and the ecosystem based on pH, turbidity, dissolved oxygen levels, and macroinvertebrate levels.  If the level of dissolved oxygen is high enough, there will be a large amount of macroinvertebrates in the water.  According to a study by Utah State University, most macroinvertebrates require a large amount of dissolved oxygen in the water in order to survive and thrive.  This lab requires two parts to be completed, which for my group began with testing flow rate of the stream, and the second part being testing the macroinvertebrate population of the stream.  Two different locations were tested in both areas, and every time we went to both areas, the turbidity, pH, dissolved oxygen, and temperature levels were taken.  The flow rate was found by dropping a plastic practice golf ball into the stream and timing how long it took the ball to travel 40 feet.  The macroinvertebrate population was found by a group member putting a piece of screen door under a rock and waiting a set amount of time for macroinvertebrates to flow into the screen, and were then put in a controlled area of water.

Research Question:  What kind of impact will the water quality of Furnace Brook have on the macroinvertebrate population?

Hypothesis:  The dissolved oxygen levels and water quality will be high enough to sustain a high level of macroinvertebrates.  Again based on the Utah State study, the high dissolved oxygen levels would lead to a high population of macroinvertebrates.

Variable Identification:

Controlled Variable	Method to control the variable
Creek Flow Rate Distance of ball flow	Flow rate is uncontrollable. 40 feet was previously measured, same distance was always used.

Experimental Setup :  My group conducted our experiment in two different places.  Our first location was almost directly under the bridge over Furnace Brook that connects the parking lot of Corcoran High School and the path that leads up to the football field.  Our second location was a few hundred feet up stream, and we were based on a very distinctive rock.  In the lab, the materials used were pH and dissolved oxygen tablets, a water thermometer, metal door screening, a plastic golf ball, a stop watch, a plastic paint tray, and two different sized vials, one for pH and one for dissolved oxygen. 

Procedure: 

1.  Picked two locations to sample flow rate and macroinvertebrate populations.

2.  Look around at locations, observe water clarity.

3.  Develop a hypothesis based on the appearance of the water.

4.  Test the pH.  This is done by filling up the smaller vial with water and placing two pH tablets in the vial and agitating the vial for four to five minutes. Check the color of the water, and record the pH based on the color of the water.                                                                                                                 5.  Test the dissolved oxygen.  This process is the same except for the fact that the larger vial is used and only one tablet is placed in the water.  Make sure the vial is filled to 10mL.

6.  Take the cup that contained most of the materials, and fill it with water.  Look at the circle at the bottom with is divided into quarters and determine the turbidity based on the reference sheet.

7.  Place water thermometer in the water and record temperature in degrees Celsius.                            8.  Repeat steps 4-7 for both locations on both days.                                                                           

9.  Measure width of stream using measuring tape, recorded width.                                                          

10.  Take six different measurements of depth, making sure they are equidistant, along the width of the stream.  Record the depths.                                                                                                              11.  Convert the depth from inches to feet by dividing each by 12.                                                   

12.  Find the average depth of the stream by adding all of the depths up and dividing by 6.

13.  Have one person stand at a location in the stream.  Have another person stand 40 feet downstream form the first person.                                                                                                                           

14.  Have person one drop the plastic golf ball.                                                                                      15.  Record how long it takes for the ball to travel from the first person to the second person.               16.  Repeat steps 14 and 15 five times.                                                                                                  

17.  Repeat steps 9 through 16 at both locations.                                                                                

18.  Find the average flow rates for both by adding the five trials together and dividing by five.  Repeat for both locations.                                                                                                                 

19.  Calculated the stream velocity and discharge.                                                                              20.  Give person 2 the screen kick net and have them move about 10 feet away from person 1.  Have person 1 kick up rocks and debris.                                                                                                        21.  The person with the screen will collect any macroinvertebrates.                                                   22.  Remove the macroinvertebrates and place them in the paint tray.  Record the amount of species you find.                                                                                                                                                 23.  Put the macroinvertebrates back in the stream.                                                                                                                                         

Data:  Each piece of data collected in this lab was collected from two different locations on two different days.  The turbidity on each day was recorded at zero.  On both days, both locations had a pH of seven.  On the first day, both locations had a dissolved oxygen level of four, and it was five on the second day.  The temperatures of the first location were 11 degrees on the first day and 10 degrees on the second.  For the second location, the first day was 11 degrees and the second day was 8.  The first site had a width of 15.0 feet, while the second had a width of 9.2 feet.  The average stream depth for the first location was 0.4217ft and for the second it was 0.49 ft.

Site 1:

Trial	1	2	3	4	5	6
Depth (in)	2.7	2.7	2.5	2.0	4.5	16.0
Depth (ft)	.225	.225	.208	.167	.325	1.333
Time (sec)	129	141	138	135	130	NA

Site 2:

Trial	1	2	3	4	5	6
Depth (in)	5.5	3.8	4.5	1.5	9.0	11.0
Depth (ft)	.458	.317	.375	.125	.750	.917
Time (sec)	65	55	28	34	38	NA

Site 1:

	Day 1	Day 2
pH	7	7
Dissolved Oxygen (ppm)	4	4
Temperature (Degrees Celsius)	11	10
Turbidity (JTU)	0	0

Site 2:

	Day 1	Day 2
pH	7	7
Dissolved Oxygen	4	5
Temperature (Degrees Celsius)	11	8
Turbidity (JTU)	0	0

Results :

Site 1:

Site 2:

Discussion:  In the first site, only two types of macroinvertebrates were present at the time of our testing.  Stonefly nymphs and midge larvae floated into our net, where in the second site, scuds and caddisfly larvae were also present.  The population of the macroinvertebrates in the two streams was different as well, because the first and second sites had considerably different populations of midge larvae.  Since midge larvae are very tolerant of pollution, the population difference based on the graphs leads me to believe the first site is much more polluted than the second.  That would also explain the very slight increase in stonefly nymphs in the second location, along with the presence of scuds and caddisfly larvae. 

Evaluation:  To improve this experiment, I would repeat each step of the process multiple times.  There is no such thing as enough when it comes to experiments, so more trials would be a more realistic representation of the population of macroinvertebrates in Furnace Brook.  Also, testing at five or ten different locations instead of two would be helpful, so differences in pollution and the types of species in different areas will be even greater.  The main limitation of this lab was the amount of trials we were held to while doing field work.  Human error can possibly be found while rounding answers while recording data such as depth.  Exact answers are more precise, but cannot always be used.  A group error made could’ve been making accurate measurements under water.  Since the bottom of the creek is not totally flat, measurements can be misread or mistaken by group members. 

Conclusion:  The data collected in this lab did indeed support my hypothesis.  The dissolved oxygen levels were high enough to support at least four different types of species in the stream.  Throughout the stream I am sure there are many more different kinds of species, but based on where my group was located, only four species were present.  The dissolved oxygen levels were always measured at 4 or 5, which is high enough to sustain a small population of different species.  The different species were also limited by the amount of pollution in the water, which varied form location to location.  According to the Macroinvertebrate Identification Key, midge larvae are very tolerant of pollution, making it easy to understand why there was such a high population at the first location.

References – http://extension.psu.edu/natural-resources/water/news/2013/macroinvertebrates-as-indicators-of-water-quality                                                                                                            

http://extension.usu.edu/waterquality/htm/whats-in-your-water/aquatic_macroinvertebrates