August 11, 2009
Today I was asked to helped Victoria Burdett-Coutts. As mentioned earlier on, Victoria is a visiting scientist in the Wahle lab. She has been here for a couple of weeks trying to finish up collecting data so she can get a journal article written on her work. She is leaving tomorrow to return to Nova Scotia so time was of the essence for her today. She had but one more experiment that she wanted to run before she left.
Victoria is looking at the different factors that contribute to lobster larvae settlement. It is already well known that lobsters before to settle on rocky, cobble bottoms where they have places to hide and protect themselves. It is also well known that this is not the only factor that determines settlement. Victoria is trying to find out what else the lobsters prefer when deciding to settle. One idea she has is they the larva may prefer to settle in areas where there are already settled lobsters. The larva may have a way to detect and respond to the presence of other lobsters.
The experiment that Victoria and I ran today was designed in order to help answer Victoria's question as to whether lobsters prefer to settle in areas where other lobsters are already present. Her set-up consisted of 12 Tupperware containers that were filled with natural seawater. Six of the containers contained rocks in order to mimic the cobble bottom of the ocean. Three of the six lobsters containers held juvenile lobsters. The other six containers had sand on the bottom in order to mimic a sandy bottom ocean. Three of these containers also held juvenile lobsters.
The experiment began when we added one stage 4 lobster larva to the Tupperware container one at a time. After the larva was added, one of us watched and recorded it before for 10 minutes. We then checked their behavior again at 20 and 30 minutes. We recorded how much time the lobster larva spent swimming, on the bottom, or diving. The test was run in the dark because the natural environment they live in amongst the rocks is typically dark. In order to observe each lobster container Victoria and I observed them using headlamps with red lights in order to disturb them as little as possible while the experiments were run. Victoria will use the data gathered during our experiment by looking to she how much time each lobster spent doing the previously described behaviors. If the lobster spent most of its time on the bottom, this would indicate that it prefers to settle in that habitat. We ran 24 trials for this experiment. It took up from about 10 a.m. until 6 p.m. to set-up and clean up the entire experiment. Now, all Victoria has to do it analyze the data to see if there are any trends present.
Victoria had to finish this last experiment today because she is leaving to go back to Nova Scotia tomorrow. She is a dive instructor there and she must be back home to teach her dive classes. Victoria is also employed as a teaching assistant at Dalhousie University in Halifax, Nova Scotia. I asked her what her most exciting or memorable experience was during her career in the field of marine biology. Victoria could not decide on just one! She enjoys being a liaison between the scientific community and the public. Specifically, she had a chance to do this when she was a naturalist for an adventure cruise that ran from Greenland to Labrador. She enjoyed getting people excited about ocean invertebrates and echinoderms that they might not normally notice because they are not as well known as the dolphins and whales. It is very important to her that she spread a love for the ocean and its inhabitants. She also enjoyed a job she had in Newfoundland where she got to raise her own baby lobsters. This job just increased Victoria's desire to learn more about the lobster species.
I wanted to share one interesting fact that I learned today. I asked how to determine the different between the different stages within a lobster life cycle. Since we were working with stage 4 lobsters today, I was shown how to distinguish whether a lobster larva was in the stage. During stage 4, the lobster larva no longer resembles the look of a typical larva as they do in stage three. The lobster looks like a miniature lobster during this stage. Stage 4 lobsters typically have a carapace length ranging from 4 to 5 mm in length. The carapace is a section of the lobster exoskeleton that is easily located by observing the backside of the lobster. It begins at the eye sockets and runs to the tall.