Saturday, July 31, 2010

Day 3 Identifications


I was able to most confidently hypothesize an identification for the following two species of plants (and maybe a third?):

Group 2 pulled several samples from under the dock of a large green leaf, which measured between 8inches to over a foot. It resembled a piece of lettuce, and was floating away from the dock, only attached by its stem. It was slimy to the touch, and had wavy edges. Using Peterson’s guide I was able to venture a guess that this plant is Sea Lettuce, or Ulva Lactuca, which can grow to 3ft and is native to the area. Apparently it is also edible.

The second and third species that I think I was able to identify may have been the same or two different species. We all saw the brownish-black sea weed on the wall of the Long Wharf, which was in the upper inter-tidal zone and exposed at low tide. I think I found something similar under the docks. This weed was the same color, and hung in bunches in the same way, but it was wet/alive and was not inhabiting an inter-tidal zone since it remained submerged all day. This plant, however, had small air sacks along its stalks, which I did not observe on the brown weed on the wall. Perhaps this is because I couldn’t see it, or perhaps it was a similar species that lacked the air sacks. In fact, Peterson describes several varieties of Rockweed, one has air sacks like the Fucus Vesiculosus, and others don’t like Fucus Spiralis. He notes that these two are often difficult to differentiate if the air sacks are not visible, he goes on to say: “When Spiralis and Vesiculosus occur together, the former is usually zoned at a higher level” (36). This would support the conclusion that the one high up on the wall may have been Spiralis, and lacked air sacks.


Owing to our superior field research skills, the members of Group 2 were able to catch a crab. It was fairly small, measuring only about an inch across. Thanks to a hint by professor Berman, who said he was speaking Chinese to the crab, I immediately examined the description of the Asian Shore Crab, Hemigrapsus San Guineus. Sure enough, this crab, inhabits the area, lives in intertidal and subtidal zones, has three marginal “teeth,” and can measure up to an inch wide. The coloring, with spots on the shell and bands on the legs, also resembled our crab. The easiest identifying aspect was the “teeth,” which I was able to zoom in on and view on my camera.

Another animal we examined was a tiny stick like creature, which we first thought was a baby sea horse. Upon further inspection we began to refer to it as a “water praying mantis.” It was just under an inch long and, later with the group we used the Audubon guide to identify it, we reached a consensus that it was a type of Skeleton Shrimp (Caprella). At home, when I consulted Peterson’s guide, I found that apparently the comparison to a praying mantis is common “form and behavior suggest miniature praying mantises”(229).

The first animal which was immediately recognizable to me was a mussel. Having eaten many of them, I was familiar with the general shape and size of the larger ones we found, which measured over 3 inches. Some were dead (empty) while others seemed alive (closed and heavier). They had all bunched together under the dock and were serving as a platform for other life to inhabit. Using my guides, I determined that these larger, smooth, blueish-black bivalves were in fact Blue Mussels, Mytilius Edulis. The Latin name tells us that this is the same type of mussel we eat.

Group 2’s most intriguing discovery was a group of three “blobs” these squishy spheres measured about 1 inch in diameter. They were covered in fouling growth, but parts were visible, and translucent. We immediately assumed these were some sort of egg sack for a different looking creature. We cleaned one as best we could and then sliced it open. The insides looked a lot like a slug covered in mucus. Our best guess was that this was a snail egg? Professor Berman quickly reminded us that we didn’t even know if it was an egg, how did we know the “shell” wasn’t the skin of an already developed organism. I was able to identify this creature as a part of the sea squirt family (Molgula). It was even easier to narrow down the identification, since all of the squirts identified by Peterson were much smaller than an inch in diameter, therefore, I was able to conclude that we found a Sea Grape, Molgula Manhattensis, which is often covered in “debris.”

A fifth species that we found resembled a worm. It was about 2 inches long, and had a brownish color to it. Parts of it were translucent, and we observed some reddish tint at its tail end. While trying to measure it, we accidentally chopped it in half, which actually gave us a clue to what it was, since we observed it secrete a reddish liquid. I think this may be a Blood Worm (Glycera), although I was not able to see how many fangs it has, and most Blood Worms are much longer. Could this one have been a juvenile? Or perhaps a similar species like the Chevron Worm (Goniada), which shares traits with the Blood Worm, but is much smaller, 1 3/8 inches to 2 inches.

As for the “orange daisies.” I have no idea, but my gut tells me that this is an animal species, partly because it is growing as separate organisms in a colony, like coral, and also because at first glance it reminds me of a sea anemone.

Here are pictures of the Asian Shore Crab, as well as the before and after shots of the Sea Grape. I’ve also included a drawing of a small fish we caught, which I was unable to identify.



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