Monday, August 3, 2009

Lovell's Island, Day 2

Yesterday morning we took boat to Lovell's Island where we spent the entire day. We learned that Lovell's Island is cobble beach (both rock and sand) and that there was a 9 foot tide that was going out about 1 1/2 feet per hour. The larger rocks were on top of the smaller rocks and sand, and Bruce informd us that this was because of the Brazil nut phenomenom where the larger things come to the top and the smaller stuff (sand) goes under the rocks. We also learned that there are 3 types of island catergories, 1. used (George's) 2. less used (Lovell's) and 3. outer, which are largely untouched.

When we arrived at Lovell's Islnd we mde our way to the shore where we found periwinkles, which are very common. While these periwinkles are very common and the average person believes they are native they are actually invasive originating from Canada. The theory of how the came to our shores is that they gradually traveled down the coastline and turned sandy beaches into rocky beaches over 200 years, and they are the Most destructive invasive species. We were able to find some live periwinkles (picture below), but we also found many dead ones. A number of these empty periwinkle sheels had a small hole drilled in it, leeting us know that it had been attacked by a predator. Bruce mentioned that one of it's predators was the satr fish but asked to find out what else could have drilled the hole in the shells. Upon some reseach online I found that it was most likely the green crab (
We then walked down the shore a bit and stop to have lunch, where Bruce found an unusual type of land snail that he asked to identify. We later found these snails on a trailt that we were walking along trying to find some ripe blackberries. After some looking I believe that these snails are Cepaea nemoralis (grove snail or brown lipped snail) and their dfferent coloring is due to the fact that they are polymorphic. The color of the snail can vary from yellow to pink to a brownish, and it can be as a darker more noticable color or pale and sometimes almost white. They can be found with and without bands and the bands vary in color and size. One reason of thinking for the variations n coloring for protection from predators, such as birds which could be one way that the empty shells found their way to the beach that or Bruce planted them there.

After lunch we walked through the marsh to the other side of the island, where we were able find some crabs. I;ve been having a hard time trying to identify the type of crab that we were found. But I have few thoughts to what it type it could be. Initally I thought maybe Carcinus maenas (green crab) but from the guidebooks description the ones we found maybe too small. My other possibility was the Planes minutus (Gulfweed crab) which would be about the right size and is peckled but it's not very clear to me where they are typically found.

Redo of Saturday's assignment
I looked at my photos of the tunicates and the guide book again and I still think that what I found was a Golden Star Tunicate (Botrylus schlosseri) which according to the books description is found in Boston, is 3-4 inches in size, are often golds, purples and browns, are often abundant in summer along the coast, and adhere to to seaweed, eelgrass, and other firm substratum. And a Sea Pork (Amaroucium stellatum) which can have 6-20 bright red or orange zooids, is found from Cape Cod to the Gulf of Mexico.

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