Sunday, August 2, 2009
Aug. 2, 2009
Lovell's Island, MA, 75 degrees, partly cloudy
Stop #1 10:30 AM
Our first stop today was at a cobble beach on the island. The tide had begun to go out. We collected various shells scattered throughout the beach including Blue Mussel shells as well as shells from Common Periwinkles.
Stop #2 approximately 11:30 AM
Next we moved on to what used to be a salt marsh but is now dried up do to the new man-made sea wall. Here we observed Pepper Weed which is an invasive plant species taking over the salt marsh. The root smells like horseradish.
Stop #3 approximately 12:00 PM
We then walked to the Tide Pool. Canadian Geese, a Spotted Sandpiper, Sea gulls, an a Herring Gull were all hanging out around the little bit of moist salt marsh left near the tide pool. We also observed and caught Asian Shore Crabs who were hanging out in the tide pool underneath rocks. As the MIT Sea Grant website states, "Originally introduced from Asia, it now ranges from Maine to North Carolina, preferring rocky cobble floors in the intertidal and subtidal zones."
Stop #4 approximately 12:45 PM
The class then followed a path through the more forested area of Lovell's Island. Here we searched for land snails which I believe can be identified as either Grove (Brown-Lipped) snails or White-Lipped Snails.
Stop #5 1:30 PM
We then returned to the tide pool where one of our fellow classmates found an American Lobster.
1. What made holes in the periwinkle's shells?
We discussed how Starfish are natural predators of the Periwinkles, but I believe the organism that preys on the Perwinkle by drilling a small hole in the shell's side is a Moon Snail. Moon snails are known to prey on smaller snails and drill holes into the victim's side.
2. What were the unusual snails and how did they get onto the beach?
I believe these so called "unusual" snails we found on the beach were actually just land snails possibly Grove or White-Lipped snails. I believe they could have gotten onto the beach, other than Bruce putting them there, by some type of predatory bird.
3. What kind of crabs did we find in the tide pool?
We found Asian Shore Crabs which are an invasive species from Asia. As the MIT Sea Grant website states, "Originally introduced from Asia, it now ranges from Maine to North Carolina, preferring rocky cobble floors in the intertidal and subtidal zones.
4. Why the difference between the live and dead snail shells?
The snail shells that we collected which have been dead longer had much more bleached out eroded shells than their live counterparts. What was once bright yellow is now pale yellow after laying on the ground or beach dead under the sun. The shells of the live snails have brighter colors due to more nutrients than the dead snail shells and more moisture.
Re-Do of Barking Crab Journal
I believe I was mistaken when I said we found Red Beard Sponge on the docks. I now know that it is indeed Tunicate. Possibly Orange Sheath Tunicate as well as Star Tunicate.