The third week of this course we spent exploring the oyster reefs, sea grass beds, and current patterns of Estero Bay. On the first day we snorkeled four different oyster reefs located in Estero Bay. At each site we used lift nets to collect what species inhabited the area then took them back to the lab for identification. Before this week I never realized how many different species lived within oysters. A majority of our findings were crabs and snapping shrimp. Once all the species had been identified we could use this data to measure biodiversity by using Shannons diversity, evenness, and species richness.
On the second day we went out to Horseshoe Key and took a core sample of an oyster reef. To do this we put a long hollow aluminum pole into a flat spot of the reef at about sea level and slowly pushed it down until you could see the sediment inside the pole. To remove the pole from the ground we had to pull it out slowly so that the sediment layers didn’t shift and mix. Sadly ours had but we still had the chance to look at the other groups and see the difference in sediment from the surface layer to the bottom layer. We also visited Mound Key, a large mangrove island in the middle of Estero Bay, the same day and got to meet an archeologist and his group of graduate students that are doing research on the Calusa Empire that once inhabited the land.
On the third day, my favorite day, we snorkeled at six different soft bottom/seagrass bed locations in Estero Bay. We took core samples, seagrass samples, and took the percent coverage of the bottom using a quadrat at all six sites. To do the core sampling we used a small PBC pipe and a sieve to collect the organisms living within the sediment. For our seagrass samples we used a homemade device, calledVirnstein. This device was a little box connected to a pair of scissors that could cut the seagrass and collect it within the box. To find the percent coverage of the bottom of the bay we used a quadrat, which is essentially, a square made out of PBC pipes with string in the center making smaller squares within the larger square. This was my favorite day because at the last site the bottom of the bay was COVERED in brittle stars, so it was really cool to get to see all the different species all in one location.
On the fourth day we took out canoes all in different locations of the bay and dropped a grapefruit in ten different locations over a ten-minute drop period. The objective was to study how winds, currents, and tides effect the movement of the grapefruit. To keep track of the distance the grapefruit traveled we used GPS to plot its latitude and longitude on a map once we got back to the classroom. This week seemed to have gone by faster compared to the first two weeks but it wasn't any less fun!