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, called
Virnstein. 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!
I liked the brittle stars, too. I'm still not quite sure why there were so many at that one site compared to the others.
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