Seneca Lake Lab Report

Introduction: The pH and DO of the water in an aquatic ecosystem is very important to the plant and animal life living there. According to the USGS Water Science School, a pH below five can affect the reproduction of fish. If it is below 4, adult fish will begin to die. According to Lenntech, a water with too high alkalinity can also affect fish. In water with a pH of about 9.6, gills and eyes may be damaged and the fish may die. The Science on Seneca manual says that a pH of less than 5 or higher than 8.5 will place a strain on plant life. Dissolved oxygen is also important in an aquatic ecosystem because plants and animals need the oxygen in the water to use for respiration. When it falls below 3 ppm, (Science on Seneca manual) fish cannot survive. Water with a high DO level is considered healthy. Low DO can affect an ecosystem in many ways, such as harming the biodiversity (oocities.org) and allowing dangerous chemicals to dissolve into the water. An example is cadmium, which stays solid in the presence of oxygen and sinks to the bottom of lakes. If the water lacks much oxygen the cadmium will dissolve, which is a problem because it's poisonous to fish.

Research question: How does the water quality of Seneca Lake affect the plant and animal life in the lake?

Hypothesis: The pH and DO will both be at safe levels for the support of plant and animal life in the lake, and both will be healthy.

Variable identification:

Controlled Variable	Method to control variable
Amount of water	The amount of water used for each sample was measured
Methods used to collect data	The same tools were used for each group
Areas data was collected from	The latitude and longitude was used to make sure each group collected data from the same spots

Experimental setup: The lab was performed on Seneca lake on the 5^th of November. Three locations, a deep, medium depth, and shallow area, were used to collect data from. At each of the three locations, one of the three groups on the boat performed a certain test. This happened twice; in the morning and afternoon.

Procedure:

·  Collect water sample to perform pH test

·  Turn pH meter on, remove cap to expose glass bead

·  Pour at least an inch of water into a glass beaker rinsed with lake water and place pH meter in the beaker

·  Let number on readout stabalize for 5-10 seconds and record

·  Rinse off pH meter with distilled water, replace protective cover, and turn off

·  Find LaMotte sample bottle. Add 8 drops of the manganese(II) sulfate solution (bottle 4167) followed by 8 drops of the alkaline potassium iodide azide solution (bottle 7166).

·  Carefully cap the bottle and mix by inverting gently. Allow precipitate that has formed to settle on shoulder of the bottle. Wait 3-4 minutes for this.

·  Add one gram of sulfamic acid (bottle 6286) to the solution. Cap the bottle and mix until the white crystals and precipitate have completely dissolved.

·  Pour solution into the titration tube, up to the 20 mL line. Add 8 drops of starch solution.

·  Fill the Direct Reading Titrator (0337) up to the 0 mark with the sodium thiosulfate solution (bottle 4169).

·  Insert titrator though the small hole in the cap of the titration tube and titrate solution slowly. Swirl the solution until the blue color disappears permanently with one drop of titrant. You may have to fill the titrator more than once. Record how much titrant you used before refilling. 

·  Dump remaining contents of the LaMotte bottle and titratration tube into labeled waste container. Rinse with distilled water and place back into kit.

Data: The weather for the morning samples was partially cloudy. There was a bit of sun towards the end. The water was choppy but clear, with the secchi disk visible at about 8 meters. The dredge sample for group 2A had a temperature of 50 degrees Fahrenheit with quagga mussels scattered throughout and some plant material. It had distinct layers. The bottom was black while the top was brown.

Plankton Collection

	Species #	1	2	3	4	5	6	7	8
Sample
1A		2	2	2	3
2A		2	2	1	7	2	1
3A		1	1	3	1	1	1	1
1P		1	1	1	16+	2
2P		1	1	1	2	5	2	4	1
3P		6	1	7	3	1	1

Water Chemistry

	1A	2A	3A	1P	2P	3P
Latitude	42°50 N	42°51 N	42°51 N	42°49 N	42°50 N	42°50 N
Longitude	76°57 W	76°58 W	76°57 W	76°57 W	76°57 W	76°57 W
Sample temp (°C)	13	13	13	7	14	13
Sample depth (m)	46.6	22.7	8	62.6	22.3	7.5
pH	7.3	7.4	7.5	7.4	7.4	7.3
Chloride (ppm)	200	300	200	180	143	140
DO (ppm)	30	6	10	10	10	10

                                                             

                                                                      Data Logger Graph


                                                        DO and Chloride Graph

Discussion: The data is mostly consistent for each area. The temperature and pH are almost the same for every one, showing that they are similar throughout the whole lake regardless of depth or specific spot. The DO and Chloride levels vary, though it could be due to the time the data was collected or the depth.

The data logger graph printed on the boat shows the temperature and conductivity levels of the water as it gets deeper. They are steady until about 45 feet, when they change. The conductivity could be due to the salt mines that the lake was exposed to. There were many of them around the lake in past years and much of the salt ended up in Seneca Lake, where it mixed in with the water. Salt increases the water's conductivity. It can also be due to salt deposits in the water. Because New York was once a shallow ocean, it's possible there may be some deposits under the lake that's getting into it. The temperature changes could be due to the density. Dense water is colder and at the bottom, so it would make sense that the temperature changes where it's deeper.

Evaluation: The largest limitation in this lab was human error. As this was the first time any of the students have done this kind of testing, there was room for many mistakes. To fix this, more than one test at each station could have been done. Then, the students could compare all the data they collected and be sure they did it correctly. There was also very little time to do each station. The students could have done the testing more accurately and carefully if they were given more time to. At each location, the depths were not exactly the same. For example, the “deep” location had a different depth for every group – 46.6m and 62.6m. This led to variations in the data.

To test my hypothesis, more information on the plant and animal life in the lake was needed. Tests needed to be done on how healthy they were and how well the lake supported them to be able to draw any conclusions about the effect of pH and DO.

Conclusion: The data collected from Seneca Lake shows that it is very healthy. The pH and DO levels that were found are in the standard for human drinking water. On this trip we did not find anything pertaining to the life in the lake, except for the mussels living there. To test the research question more data would need to be collected on how healthy the plants and animals are.

References:

"Dissolved Oxygen." Dissolved Oxygen. Utah State University, n.d. Web. 28 Oct. 2015.

"Effects of Changes in PH on Freshwater Ecosystems." DissolvedOxygen. Lenntech BV, n.d. Web. 28 Oct. 2015.
Halfman, B., J. Halfman, C. De Denus, T. Curtin, and S. Myers. Science on Seneca. Geneva, New York: HOBART AND WILLIAM SMITH COLLEGES, 2008, 2011. PDF.

"PH -- Water Properties." PH: Water Properties, from the USGS Water-Science School. USGS, n.d. Web. 28 Oct. 2015.

"Water Treatment Solutions." Effects of Acids and Alkalis on Aquatic Life. Lenntech BV, n.d. Web. 28 Oct. 2015.