Preston Wilson and Professor Russell Rader, Department of Biology

My experiment was to test the effect Diadumene lineata has on the marine life of the intertidal rock pools in the northwest.

However, due to unfortunate circumstances there were not any Diadumene Lineata in the area of Coos Bay, Oregon. After discovering that they did not exist within our limits, we decided to test how terrestrial vegetation effects aquatic and marine environments. These nutrients are naturally introduced into the marine environment via streams that empty into the ocean. Any terrestrial vegetation near estuaries has potential to fall into rivers and be swept into the estuary were marine life has the opportunity to feed on these introduced nutrients. The most likely vegetation to be introduced are leaves so we decided to use them for our study.

The samples comprised of bricks which we attached leaves to. We would place the bricks at randomly selected areas throughout the estuary and at intervals of the river. Each area contained two bricks which were each divided into three sections totaling to six sections which was comprised of the six different types of samples we were using. We used two different types of vegetation; leaves taken from the same species of tree found along the river emptying into the estuary and kelp found in the estuary. The vegetation was attached to the bricks using a small gauge plastic wire which was threaded into the vegetation and wrapped around the brick. The samples were covered in three different manners. One of each type of vegetation was left uncovered, another was covered with a 250 mm mesh and the third was covered with the mesh which had half inch squares cut out of it at 1 inch intervals. The purpose of the mesh was to discover which aspect of the estuary was having the greatest effect. The samples without mesh were exposed to all elements including large feeders, small feeders, and wave action. The mesh with holes cut into it was intended to eliminate the large feeders. Finally the intact mesh eliminated the majority of macroscopic feeders leaving the vegetation to be broken down primarily by microscopic feeders and wave action.

To test the river system we took leaves that were close to the river dried them and then took 10 grams of the dried leaves to go in each of the pouches. The river samples did not include the kelp so it was only comprised of 3 samples per area. For the marine system we took kelp fresh from the ocean and leaves from the same trees in the river samples and dried them out as well and took the 10 grams and placed them in each of the pouches to go in the ocean.

Once the pouches were all sown and stuffed, I took them down to the steam and put them in random locations in the river and in the estuary. We then recorded the GPS locations. Using a random simulator online to decide which bricks should be picked up on which weeks. We picked a set of two up each week in week one, week two, and week three.

After each pouch was picked up, they were cut open and all the leaves were washed. It would have also been done to the kelp but beggining on week one all of the kelp was gone in every kind of mesh. The leaves were washed by hand under cold water and they were then placed in a low temperature oven to dry them. Afterwards, the leaves were weighted again to see the difference in mass between the leaves originally and after they had been feed on by various animals.

However, there we discovered issues after we had dried and weighed the leaves. The samples that were collected early on did not decrease in weight and actually increased in weight in many of the samples. By the time we collected the last set of bricks some of the samples had decreased in weight but some still had increased. The leaves we used were fuzzy and we hypothesized that this resulted in a large amount of inorganic material getting stuck to the leaves despite our efforts to wash the leaves. Many of the leaves appeared to have been partially eaten and many of the samples had a large amount of aquatic insects that we suspected to have been eating the leaves. After we had disposed of the leaves we realized that we could have burned off the organic material (the leaves) which would have left behind any inorganic material allowing us to gather more accurate data. Our mentor professor is keeping the data we have collected in case groups who return to the area can renew the research and potentially use the data.