Monday, July 16, 2012

Seashore adventure!

Today we took an in depth look at the intertidal zone of Peddocks Island. We started out by taking a short trail through the inner island to the south shore, where we observed pebble, cobble, and rocky beach habitats. The pebble beach had small stones that appeared to be less than half an inch long. We investigated this shore line for any signs of life, digging a few inches under the pebbly surface, but there was nothing to be found. We then took a closer look at the different rack levels on the shore and what they could show us about the habitat. The lighter objects, such as small shells, seaweed, and dried plants that looked like straws were pushed to the top of the shore, indicating the highest the tide has ever gotten. There was about a foot long space between the top rack and second rack as well as the second and third rack, which contained heavier shells and bigger rocks closer to the water. Our class was able to identify all of the different shells on the shore, without our guide books! There were varying sizes of blue mussels, oysters, clams, razor clams, and periwinkles. All these shells indicated that there was life in the area, but it was either farther out in the water or on a different location on the beach.

The rocky beach proved to be more fruitful for our search for seashore life. As the tide was going out more of the the shore was exposed. When we turned over large flat rocks there were many Asian Seashore Crabs living under them. The largest one I saw appeared to be less than 2 inches wide. Although they were more than eager to try and pinch my fingers, when I picked them up I was able to get a good look at their shell, which was brown with two lines of raised bumps and green spots. We also looked at live periwinkles, which are a type of snail that live in small swirly shells. Although these were by far the most passive and uninteresting creature I've encountered this week, I learned that they were highly decisive and destructive in changing the shape of the harbor's shore line. Although it is hard to determine whether or not this is a "good" or "bad" thing, these creatures are an important part of this habitat.

 Samples of seaweed and shells found on the middle rack of the pebbly beach on Peddocks Island/
 A periwinkle coming out of its shell!
 The top of a spider crab shell.
 A mermaids purse! I remember seeing these at the touch tank in the aquarium near my home town; they are the egg sack for a type of creature but I don't remember which one...
 Razor clam.
 Horseshoe crab.
 Dead skate...
 Asian shore crab.
 Oyster shell.
 Clam shell.
 Some type of red seaweed dried on a rock.
 Professor with a periwinkle =)

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