Seneca Lake Lab Report

Plankton on Seneca Lake

Introduction: In Seneca Lake there is an abundance of plankton. In the experiment, it will test if different depths (and possibly other variables) affect the plankton in that area. The plankton do no harm to the ability to drink the water. The plankton could vary in amounts, to types of plankton. Temperature impacts seasonal variation of plankton. So, if you were to do this experiment in the spring, you would get different results. The lake has a great diversity, so hopefully many different types of plankton are found.

Research Question: How does water depth affect the number, and types of plankton on Seneca Lake?

Hypothesis: Depth and water conditions will affect the number of plankton and the type of plankton. 

Variables: Controlled- Location, instruments, boat

Independent- Locations and depths

Relevant- pH, DO, chloride ion, hardness, number of plankton, soil samples

Method to Control Variables: I will take down coordinates of all the locations. Then do the technique from the manual: "In order to establish a fix of one's position using radar one needs to know the ranges (distance) to at least two known targets. Place the pin leg of a drawing compass on the chart at the location of one of the targets and construct a circle or arc whose radius is equal to the range determined to that target. Similarly, scribe an arc which is centered on the second target and which has a radius equal to the range to that target. The observer's position lies on both arcs and the two arcs will intersect at, at most, two points. Inspection will probably make clear which of the two intersection points the observer’s position is, in fact. It may, however, be necessary to determine the range to a third target in order to resolve any ambiguity." Then I will follow all of the procedures to get the pH levels, temperature, dissolved oxygen, and the number of plankton.

Experimental Setup: In the experiment a boat with the ability to collect water samples, test the sample, and get a dredge sample was used. This boat on Seneca Lake gives the ability to get the samples needed and do the procedures necessary for the lab. A pH meter, thermometer, DO kit, Chloride kit, net, microscope, dredge, and water from the lake were used to get the necessary data.

Procedure:

1. Find pH level

2. Find the temperature
3. Find dissolved oxygen

1. When you get to the lab bench, gather the dissolved oxygen kit. To the 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). Some water may drip off the sides, this is expected! Carefully cap the bottle, mix by gently inverting (do not generate bubbles inside the glass sample bottle), then allow the orange-brown precipitate that has formed to settle below the shoulder of the bottle (about 3-4 minutes).

2. Using the 1 gram spoon provided in the kit (0697), add one level spoonful of sulfamic acid (bottle 6286) to the solution in your LaMotte sample bottle. Cap the bottle and mix until both the reagent (white crystals) and precipitate (brown crystals) have completely dissolved and you obtain a clear brown-yellow solution. CAUTION: Sulfamic acid will burn if you get it on your skin. Be careful!!

3. Pour this clear brown-yellow solution from the LaMotte bottle into the titration tube and fill it up to the 20 ml line. Then, using the plastic eye-dropper provided in the kit, add 8 drops of the starch solution to the titration tube. At this point, the solution should change color to a bluish-green.

4. Fill the Direct Reading Titrator (0337) up to the 0 mark [looks like a syringe, marked 0-10 ppm] with the sodium thiosulfate solution (bottle 4169).

5. Insert the titrator you just filled through the small hole in the cap of the titration tube and titrate the solution slowly. Swirl the titration tube until the blue color of the solution disappears permanently with one drop of titrant (i.e., you are looking for a color progression from green-blue to blue to light blue to colorless). You may have to fill the titrator more than once. Be sure to record how much titrant you used before refilling. The direct reading titrator is calibrated in units of parts per million (ppm) dissolved oxygen, therefore, be sure to record all of these units.

4. Do plankton collection procedure

1. Twist the end of the rope around one hand 2-3 times and grasp with a fist. Don't let go! This grip is to ensure the net isn't tossed overboard when it is cast 

2. Make sure the clasp at the bottom of the net is closed! If it isn't, the sample will not be captured and the net will need to be recast.

3. Lower the net over the side of the boat until it floats freely in the water. Walk slowly from the stern to the bow of the boat and then back again, gently dragging the net behind you. Try to walk at a steady pace so that the net stays at a fairly constant depth and does not scrape the side of the boat. Since water clarity is an indication of the presence of phytoplankton, use your secchi disk reading as an indicator of productivity. If the secchi disk reading is less than 7 meters, traverse the length of the boat twice. If it is greater than 7 meters, make 3-4 trips to make sure you collect enough plankton in your net.

4. Back at the stern of the boat, gather the line up until the net is vertical, hanging freely, and level with the railing. Using the provided wash bottle (filled with tap or lake surface water, not distilled water), wash down any plankton clinging to the sides of the net into the small grey cup attached to the lower end of the net.

5. Raise the net slightly, keeping it vertical. Grasp the grey sample cup and swing it on board, making sure not to spill the sample.

6. Hold the provided plastic beaker under the sample cup and attached rubber tubing and release the tubing clamp, allowing the sample to flow into the beaker. If it appears that some sample has clung to the inside of the grey sample cup, carefully use a small amount of water from the wash bottle to rinse it into the beaker. You don't want to dilute the sample.

7. The beaker can now be taken to the lab for analysis. Remember to rinse it out when the plankton sample is no longer needed (using either tap or distilled water) and replace it in the net box.

5. Do inventory and counting procedure

 For samples with slowing agent (DETAIN):

- Put 9 – 10 drops of sample on Sedgewick-Rafter cell.

- Put 5 – 6 drops of DETAIN from marked dropper bottle onto sample. It is a very viscous

liquid, avoid getting the Detain anywhere other than the sample cell.

- Carefully mix with dissecting needle along entire length of the slide without scratching

the Sedgewick-Rafter cell.

- Carefully cover Sedgewick-Rafter cell with cover slip. Try to minimize air bubbles.

For samples without slowing agent (DETAIN):

- Put approximately 14 drops of plankton sample on Sedgewick-Rafter cell.

- Carefully cover Sedgewick-Rafter cell with cover slip. Try to minimize air bubbles.

6. Count the plankton

Data:

Sample 1

SaSam	AM	PM
Latitude	N 42° 49.94’	N 42° 49.97’
Longitude	W 76° 59.972’	W 76° 57.94’
Sample Temperature	13°C	7°C
Sample Depth	38.9 m	54 m
pH Level	7.3	7.4
Chloride Level	200 ppm	180 ppm
Dissolved Oxygen Level	30 ppm	10.4 ppm
Depth to Bottom	46.6 m	62.6 m

Sample 2

	AM	PM
Latitude	N 42° 51’	N 42° 50.84’
Longitude	W 76° 58’	W 76° 57.52’
Sample Temperature	13°C	14°C
Sample Depth	10 m	10 m
pH Level	7.4	7.4
Chloride Level	300 ppm	143 ppm
Dissolved Oxygen Level	6 ppm	10 ppm
Depth to Bottom	22.7 m	22.3 m

Sample 3

	AM	PM
Latitude	N 42° 51.50’	N 42° 52.55’
Longitude	W 76° 57.76’	W 76° 57.57’
Sample Temperature	13°C	13°C
Sample Depth	0 m	0 m
pH Level	7.5	7.3
Chloride Level	200 ppm	140 ppm
Dissolved Oxygen Level	10 ppm	10 ppm
Depth to Bottom	8 m	7.5 m

	1	2	3	4	5	6	7	8
Sample 1 AM	2	2	2	3
Sample 1 PM	1	1	1	16	2
Sample 2 AM	2	2	1	7	2	1
Sample 2 PM	1	1	1	2	5	2	4	1
Sample 3 AM	1	1	3	1	1	1	1
Sample 3 PM	6	1	7	3	1	1

Results:

Number of Plankton

Discussion: In the graphs, the different locations for the most part align with the time of day. They stay mostly similar across the day.  If we were to go across seasons, the data would most likely change from season to season. Our data does not line up very well with the logger graphs, but one is very close. Temperature and pH were almost the same across all locations and samples, whereas chloride varies greatly across the locations and time of day.

Evaluation: In this experience there may be a large amount of human error. We were not in the exact same place every time. The chloride levels were most likely wrong due to inexperience of the testers. To improve this you could get exact location and make it exact. You could also remove as much human error as possible. The chloride levels could have been re done with more knowledge of what was going on. For my hypothesis and research question I would need exact species names and count, not just a rough estimate that we gathered our data as.

Conclusion: The data does slightly support my hypothesis. The problem is that I do not have exact data for what kinds of species were counted. If we had more class time and were able to deliver exactly what types of plankton and numbers that were found, my data might support my hypothesis even more. The number of individual species and the number of those species (running on the vague data) did fluctuate from location and time as I hypothesized.

References:

Kaplan, Jeremy A. "What's in Your Water? Probably Tiny Invisible Shrimp | Fox News." Fox News. FOX News Network, 02 Sept. 2010. Web. Oct. 2015.

My Pure Water. "New York Tap Water, Water Distillers by Pure Water." My Pure Water. N.p., 13 Sept. 2010. Web. Oct. 2015.

"Science on Seneca Manual.pdf." Google Docs. Woodrow, Ahrnsbrak and Carle, n.d. Web. Oct. 2015.

(Sub procedures taken directly from the Science on Seneca Manual)