Yellowwood Lake Lab Report

Distribution of Plankton in Yellowwood Lake

Introduction:

Over the duration of two lab periods we collected an assemblage of plankton and tested whether plankters are actively moving or are passive in bodies of fresh water. While working in paddleboats on the Yellowwood Lake in Brown County, IN, we assembled a collection of samples of protists, rotifers, and arthropods. Before starting our study we produced a null hypothesis: plankters are passive. This null hypothesis predicts, where water is mixing uniformly, plankton distribution will be uniform (Clara Cotton, personal communication, October 6, 2016). After coming up with a null hypothesis we then formed our alternate hypothesis: plankters are active. This hypothesis forms the prediction

This body of water is located in the Yellowwood State Forest, Brown Co., IN. on Thursday September 17th, 2015 from the time of 2:15-3:30 P.M. Our samples taken from the lake are from the South end side of the lake and in different ranges of depth. The Yellowwood Lake is a very long and narrow body of water that runs from the South end to the North end. Because of its narrower characteristics the wind plays a key factor in the samples taken. If the wind is blowing either East or West the plankton are more likely to be distributed because the lake runs North to South. The air temperature on September 17th, 2015 was 27 degrees Celsius with a cloudless sky and winds blowing from the West at 10 mph. To test the temperature profile of the water column we used the water sampler to collect water starting from the surface and taking it a half-meter down each time. After performing this at multiple depths you record the temperature after 2 minutes from each sample and any relative information about that water. We counted for a hundred protists at each depth (2, 3, and 4 m), 5 rotifer cells at each depth (2, 3, and 4 m), and 5 arthropod cells at each depth (2, 3, and 4 m). When identifying the plankters we were given many different images of plankton within the different phyla and background knowledge in the

This table represents all the species from three different taxa at the depths of 2, 3, and 4 meters. We examined the data from those three depths because that’s the region where there was a uniform temperature of 23 degrees Celsius. 12/19 taxa were selected because they showed counts at all three depths. Once I narrowed it down to 12/19 taxa I then used my non-statistical approach that states if there isn’t a 2-fold increase from the lowest number of taxa to the highest number of taxa they aren’t considered to show an uneven distribution. 11/12 of the taxa showed an uneven distribution where we would expect passive plankters to have even