On Sunday, July 24, 2011 we took a field trip to Georges and Lovell’s Island. Weather was cloudy at 8:30 AM with light drizzling. We were on-board by 9:00 AM, so we can reach the tidal pool at Lovell’s Island for low tide at about 12:30 PM. At first we stopped at Gorges Island d and explored the Fort Warren which was built in 1850 as a Civil War fort that was also utilized as a prison for Confederate military and political prisoners. One of the rangers narrated the tragic story of “the lady in black” who haunts the Inside “Corridor of Dungeons” where her ghost has appeared over the years. However, I was about to faint in the darkness of that damp corridor, it was horrifying. Furthermore, we the outskirts of the neighboring Islands from the top of the fort, as well as Boston Light House.
Rocky Shore Habitats
Later on our class and some other passengers took the Water Taxi to Lovell’s Island. After our brief meeting with the ranger we followed the dirt trail to the beach to find, identify and observe different animal and plant species; which were there in abundance. First, professor mentioned the “wrack line” which is the top of the tide line and it usually brings dried brownish poppy sea weed, empty slipper and periwinkle shells, crab legs, blue mussels, and Sea Lichen Bryozoans. We had a little discussion how native species such as periwinkles and humans have impacted, rather changed the habitat from a sandy beach to a rocky and cobble stone one. The organisms which attach themselves to stones find this type of rocky shore to be their home. The average tidal exchange in Boston is 9.5 feet (3 m). The habitat we examined were Tide pools, pools of water left in rocky crevices and depressions down to the water line.
Observing Isopods (Green, Asian Shore, Hermit and Atlantic Rock Crab, Scud)
Moving forward into the tidal pools we found Green crab under the rock almost 3.6” long, fan shaped with blackish mottling above, with 5 marginal teeth. Green crabs were introduced from Europe and lives in tide pools and brackish water. We also managed to find Asian shore crabs which were much more aggressive in behavior, because they shed their skin at random times throughout the year, while displacing the other exposed crabs. They were blackish with banded legs, and red spots on claws, 3 marginal teeth and almost 1 in long. They were introduced from Asia and prefer rocks, cobble and live in intertidal zones. I also found a Hermit crab which was hiding under the periwinkle shell almost half an inch long. Which was brown to grayish in color, pincers were tannish-gray with white edges. It was long, and soft with segmented body. These Hermit crabs are common in Atlantic waters. Of all the miniature crabs we found a bigger one which was almost 5.5” wide and 3.5” long. It resembles the description of Atlantic Rock crab in the guide book with upper side yellow and dotted with reddish spots. Pincers were stout, short, fingers bent downward, black at tips, walking legs short and hairy at edges. This kind of crabs lives in low tide line. One of our classmates also found a shrimp like tiny specie which matched the characteristics of a Scud in our guide book. It was 1” long and ¼” tall. It was arched, brownish in color with pairs of long antennae, back smooth and segmented. This creature lives among seaweeds above low-tide line and feeds on mostly worms.
Observing Mollusks (Common Periwinkle)
The specie that is a native and has hugely impacted the shore slowly yet steadily are periwinkles (Littorina saxatilis) these are grayish, or brown with spiral nearly oval in shape. The surface is smooth to touch. It lives in intertidal zone, rocky and mud flats and feeds on alga. It is usually 1.7” in length but there could also be bigger periwinkles. They are invasive species introduced from Europe.
Northern Rock Barnacles (Semibalanus balanoides)
These were attached on the rocks in colonial pattern; I saw both white and yellowish barnacles which were flat at top but rough to touch. These are most commonly found in New England in intertidal zone they are up to 1 in” in width. They are also native species came from northern Atlantic to Delaware, and are in abundance in New England.
Kelp, Brown Seaweed, Enteromorpha , Sea Lichen Bryozoan:
Kelp is found in Sub-tidal zone. It was brownish in color. Kelps can range in size from the two-foot-tall to the giant kelp, which grows to over 150 ft long. They are an important constituent of some brackish water ecosystems. The brown leathery kelps and seaweeds were the most common fauna and flora found on the shore. Only next to green string lettuce with thin tabular strands, lime greenish in color, and very slippery algae which covered the rocks. Enteromorpha is common in the intertidal zone. I also found a colony of sea lichen bryozoans which was straw colored. The texture was rough and bushy, shaped like a ribbon on the edges, yet flexible. It was 1.5” long and 1” wide. It usually resides in low-tide line and widely found in New England.
Then after the lunch break we decided to search some land snails so that we can differentiate between the water and land snails. The first one we spotted on the tree was Yellow White- Lipped snail which was slightly smaller than the Grove or Brown-Lipped snail. The shell is usually 1” in dimension and shell has color banding of yellow and black, while it is brown and black for grove snail. The two species share many of the same habitats, such as woods, dunes and grassland, but the white-lipped snail tolerates wetter and colder areas than the grove snail can.
This is the end of my observations that I did at the Lovell’s island and also learnt that if I took the snail home I would need calcium for it to survive. On our way back, me and Janelle swam in the chilly Boston Harbor, until we saw our boat coming and quickly ran out of the water. It was a good learning experience over all.
P.S I am posting the pictures separate i think it is much easier that way