Storms and Botany Experiments

The video above shows just how large the waves became in the past two weeks of the storm. Luckily we finished our Diving Research Methods class and did not have to dive in that weather. However for my Botany group project, consisting of Lauren, Steph, Ellen, and me, we have been unable to go diving.

Our Botany class had to design a research project and go out and study algae in the field. Our group idea was to go out to Joe's Beach, a sandy bottom, and Pumphouse Beach, a rocky bottom, and collect hermit crabs and count and identify the different algal species growing on their shells. We had planned to dive two weeks ago, but the storm forced us to change our plans. This morning the water was calmer so we decided to go out and dive and complete our transect. We went out out to Joe's and went down only to find that the visibility was less than 1 foot, and the bottom water was so dark with sand we couldn't see where the bottom actually was let alone find any hermit crabs. This dilemma has caused us to rethink our project idea to come up with something that will not involve diving. Science is in a constant state of change! We must always be thinking of new ideas!

Anything but mainstream

As usual, students in the Three Seas Program live by the motto, "work hard, play hard," as evidenced by their creativity in the annual Halloween party at the haunted house on Pleasant Street. This year's costume themes included Dog the Bounty Hunter

and a mash-up of Jersey Shore and the "Mario" universe.

An epic time was had by all,

even the hipsters.

"I saw the best minds of my generation destroyed by madness, starving hysterical naked, dragging themselves through the negro streets at dawn looking for an angry fix;

Angel-headed hipsters burning for the ancient heavenly connection to the starry dynamo in the machinery of night"

(Allen Ginsberg, Howl, 1956).

An Experimental Look

In addition to the exciting trips that we have been on and have yet to take, as Three Seas students we have been able to take part in running experiments related to our favorite topic, marine biology!

For our experimental design class (a nice way of saying statistics for scientists), we split into groups to set up and run three different experiments that our professor Geoff Trussell and TA Catherine Matassa (a former Three Seas graduate) introduced us to. Each of them examined the effects of the presence of the green crab (Carcinus maenas), a predator to local Nahant snails. The top down/bottom up group looked at whether chemical cues in the water from the crabs affected how much algae the snails ate, the mechanical damage group looked at differences between the effects of chemical cues and physical damage to snail shells on snail growth, and the respirometry group is still running their experiment on how water temperatures in addition to chemical cues from the crabs affect the snails' respiration rates.


Carcinus maenas, the green crab.

Photo from: uri.edu
Littorina obtusata, the snail used in the damage experiment.

In the damage group, we learned about the time and effort that goes into the care and keeping of an experiment. Multiple times a day, we had to go to the Marine Science Center (MSC) just to make sure the water was flowing into our tanks, so that our snails and crabs would survive. We even had to check on weekends! It became a routine, though, and it was exciting to have something of our own to take care of for 5 weeks. Just last week, it was time to take down our experiment and weigh out all 120 of our snails (yes, 120 of them), to determine how much they grew, or didn't grow, over the length of the experiment. Luckily, with a team of 10, tasks were split up, and the work went quickly and smoothly. By quickly, I mean about 4 hours. A little bit of music on the radio helped keep us entertained while we waited almost two hours for the snails to dry so we could weigh them.

Here are a few pictures documenting the process of taking down our experiment:

Bobby is cleaning one of the jars we used to transport our snails back to the lab.


Josh and Liz are carefully opening the containers with the snails to keep them underwater, so we could record whether they were feeding or not.


Everyone having a good time cleaning the buckets. Want to leave it looking better than when we started.


A demonstration of the buoyant weight technique, to determine the weight of a snail when it is in water. This helps us when we want to determine the weights of the shell and the snail body tissue separately, instead of just the total weight of the snail.


Piper recording the buoyant weights of the snails, then leaving them out to dry.


The set up we used to photograph each snail in the experiment, so we could visually see how much the damaged shells grew back over 5 weeks.

Running and maintaining the experiment was a great experience, and now we get to delve into the statistics. How much did our snails grow when they were exposed to a crab or no crab, and did the damaged snails grow their shells back more or less than the undamaged snails? Crunching the numbers may be difficult, but the results that come out at the end will be the most interesting and will tell us a little bit more about snails that we did not know before.

Counting Hermit Crabs

As part of our Diving Research Methods class, we surveyed Pumphouse Beach and Canoe Beach for hermit crabs (Pagurus spp.) to analyze their abundances and see if there was a difference between beaches.

Pumphouse Beach is exposed to more wave action than Canoe Beach and also has a rockier substrate compared to Canoe Beach which has a cobble bottom. We thought that these differences might contribute to more hermit crabs being present at one site than at another.

To find out, we split into two groups and went SCUBA diving at each site taking along transect tapes, T-bars, and rugosity chains. Each dive team swam along the 30-meter transect and and used the T-bars to count the number of hermit crabs seen in the one meter to either side of the tape. We used the rugosity chain to figure out how complex the substrate was. A pre-measured chain is laid on the bottom and is conformed to any variations in substrate, such as rocks or valleys. We compared the length of the conformed chain to the actual length to find out if it was the same (sandy bottom) or shorter (rocky bottom).

There was a lot of variation in the number 0f hermit crabs that we found; some groups found only 14 0r 18, but one group found over 100! We looked at the data using methods that we've learned in our Experimental Design statistics course, but found that there wasn't really a difference in where hermit crabs live. This might be because they don't have to worry about finding the perfect home, since they carry their homes with them.

Although bottom type and beach location didn't affect the number of hermit crabs, we still got to combine what we've been learning in our classes to carry out an observational experiment.

Dissections in Invertebrate Zoology