Georgia Southern University
Blinks Fellow working with Dr. Terrie Klinger
The effect of limpet grazing and their preference for hard substrate
The oyster Crassostrea gigas is commonly found in the rocky intertidal zone of the San Juan Islands, where it is an invasive species. Various species of limpets are often found on the surface C. gigas, and Fucus is very rarely seen growing on the oyster valve. To determine whether macroalgal distributions on oysters are influenced by grazers, we quantified the number of limpets and littorine snails on oyster valves and the surrounding rocky substrate. In addition to the field study, a lab experiment was performed to determine if limpets exhibit a preference of substrate. Fucus was grown in the lab in the presence of different extracts (C. gigas shell, barnacle shell, and enriched seawater). We found that limpets in the field are more dense on the oyster valve than on surrounding hard substrates. Our results indicate that limpets prefer the oyster valve of C. gigas more than other hard substrates (including Mytilus trossulus, Semibalanus cariosus, and rock). Limpet density on the oyster valve may be limiting Fucus distribution onto the oyster. Culture growth demonstrated that germination and growth of Fucusin the oyster extract was equal to or better than growth in the enriched seawater. This implies that there is no negative effect of oyster shell chemicals on Fucus germination and growth. This finding also further supports the importance of grazers keeping the oyster valve void of algal overgrowth.
University of Victoria
Blinks Fellow working with Dr. Shaun Cain
Magnetic Orientation Behavior in Tritonia diomedia
At FHL I learned many skills and techniques useful for research in biology. Starting with literature research and identifying an area of interest, to designing an experiment, learning experimental techniques and presenting my results to a scientific audience.
With Dr. Shaun Cain's instruction and supervision I became familiar with electrophysiology, immunocytochemistry as well as a host of other techniques.
My main project this summer was to find out if the nudibranch Tritonia diomedea had magnetic particles and if so, where in its tissues were they located. After two months of learning, experimenting, and meeting other biologists, our research yielded some interesting results which I presented at a seminar and plan to present as a poster next spring.
Colorado College
Blinks Fellow working with Dr. Shaun Cain
Magnetic Orientation Behavior in Tritonia diomedia
I spent the summer of 2002 in Shaun Cain's lab studying the magnetic orientation behavior and neuroethology of the sea slug Tritonia diomedea. I spent the first couple of weeks learning techniques with which I had not yet been acquainted. I was introduced to electrophysiological techniques, and learned how to do intracellular recordings from neurons. I also gained experience in performing immunohistochemistry on tissue (the animals' brains), and using confocal microscopy to image fluorescent labeled cells.
Near the end of the fellowship everyone presented their work in the form of a PowerPoint presentation. This also gave me an opportunity to learn important skills I will undoubtedly use often in pursuit of an academic career. While preparing this presentation I learned to use a variety of software programs I had not used previously, including PowerPoint.
The project I chose involved studying the neurological pathway that is stimulated in Tritonia diomedea by changes in the ambient magnetic field. This animal has been used as a model system for studying this behavior for years at the Labs. While the responses of a few reidentifiable cells have been observed, the underlying pathway is still unclear. I hoped to use immunohistochemical techniques to identify other cells involved in this process, so their responses could then be studied through other techniques.
While attempting to find an antibody against an early activated protein, whose presence indicates a cells activity, I learned how to do Western Blot analysis. Unfortunately, I have had little luck with this part of the process, and moved on to look for specific staining in whole-mount tissue samples using all three antibody options. I have had one unclear result, and the others will be done as I am leaving. Ah, the joys of lab science.
University of New Hampshire
Blinks Fellow working with Drs. Adam Summers
and Eliot Drucker
Measuring Intramuscular Pressure in the Spiny Dogfish, Squalus acanthias
The basis of my research this summer was the question of fast swimming. In particular, how do cartilaginous fishes such as sharks, achieve high speeds without a bony skeleton? In the teleost fishes, speed can be achieved because of the balance between rigidity and flexibility that is inherent in their overall skeletal morphology. The more rigid a body is the easier it is to swim fast (e.g. Tuna). If you have a bony skeleton, becoming rigid is easy. So how do sharks get around the problem?
Dr. Adam Summers, Dr. Eliot Drucker and I hypothesized that cartilaginous fishes were pressurizing their bodies in order to achieve enough rigdity to gain speed. We were interested in characterizing the pressure wave intramuscularly while a shark was swimming, something which has not been done previously. We used the spiny dogfish, Squalus acanthias, because they are relatively easy to capture in the waters around Friday Harbor and because of their size. We measured intramuscular pressure by inserting small pressure transducers on either side of one of the dorsal fins. We then placed the fish into a flume and swam them at various speeds. Dr. Summers wrote a data acquisition program that enabled us to get large amounts of data in a short period of time.
We discovered that indeed, as we increased the swimming speed, the fish increased their internal pressure.
Oakwood College
Blinks Fellow working with Dr. Billie Swalla
This summer I worked with Dr. Billie Swalla and studied the innate immune system in the ascidian Boltenia villosa. Boltenia is a sea squirt and the innate immune system is for antimicrobial defense. When I began my project, I knew very little about ascidians. I started the internship by reading about ascidians and learned about its life cycle. The stage I worked on was from precompetent larva to competent larva. By the end of the summer I understood the development of the embryo and metamorphosis.
My research experience was rewarding because I learned more than I expected. Along with learning the basics about ascidians I was able to improve my basic laboratory skills. My skills improved for writing a laboratory notebook by remembering to document dates, times, and materials used for experiments. Sometimes experiments had to be done over again but it only helped me to improve the skills I was using.
This internship helped me to think about science in a new light. I was able to put the principles of science to use by seeing them in action. Embryology, Molecular, and Cellular biology became more relevant to me and I was able to understand these subjects better.
Georgia Southern University
Blinks Fellow working with Dr. Sophie George
The ability of Dendraster excentricus larvae to capture and ingest small, intermediate and large algal cells and convert the energy acquired into building larval and adult structures was investigated in the lab, through 3 experiments. The first experiment tested the effect of single and mixed algal diets on growth and development of Dendraster larvae. Two single diets Dunaliella tertiolecta and Rhodomonas sp. and 3 mixed diets-D. tertiolecta and Isochrysis galbana, Rhodomonas sp. and I. galbana and D. tertiolecta and Rhodomonas sp. were used. Larval body parameters, survival rates and metamorphosis success were recorded. Towards the end of the experiment 3 samples of 1000 larvae/treatment were collected and stored at -80°C for protein analysis.
Simultaneously, a second experiment was run with larvae maintained under the same treatment conditions as experiment 1 and 4, 6 and 8-arm larvae were collected and stored at -80°C for fatty acid analysis. Larvae were starved 3 days prior to collection. At the time of each collection, survival rates were determined. In addition, the algae used in the diet treatments were cultured to the exponential growth phase, centrifuged and algal cells collected and stored at -80°C for fatty acid analysis.
The third experiment tested the ability of larvae to ingest different sized algal cells. Larvae were cultured under the same diet treatments as the previous experiments and tested at the 4, 6 and 8-arm stage after being starved for 3 days to make sure their stomach was empty.
Dept. of Earth Sciences, Univ. of California,
Riverside
Blinks Fellow working with Dr. Richard R. Strathmann
Does scarcity of sites for egg deposition limit reproductive success?
Estimated mortality rates are higher for planktonic larvae than for benthic embryos of marine invertebrates. However, since not all marine invertebrates are benthic developers, there must be some limitations associated with this mode of reproduction. One such limitation may be availability of substratum for attaching eggs. We examined this possibility for the opisthobranch snail Haminaea vesicula in False Bay, San Juan Island. At low tide False Bay empties almost completely, and large tidepools are distributed throughout the bay. H. vesicula lives in the tidepools and forages on the mud surface for diatoms. The snail attaches its egg ribbons to firm substrata, not mud or sand. Even the most common substrata, bivalve shells and algae, are relatively rare in False Bay. Eelgrass (Zostera marina) is scarcer yet in most of the bay, occurring as small clumps of a few shoots or single drifting blades. Where eelgrass is abundant, large numbers of ribbons are attached to the grass blades. Where eelgrass is absent, there are fewer egg ribbons, even where the snails are abundant. Given the overall rarity of substrata, we decided to test the hypothesis that the snails' reproductive output is limited by the amount of substratum available. We also tested the snails' preference of different substrata.
To find out if substratum availability limits egg deposition, we added artificial eelgrass to some of the pools in False Bay. The artificial eelgrass was made of duct tape attached to a stake buried in the mud, and the blades were the same length and width as the average blade of real eelgrass. The results were that the number of egg ribbons laid per square meter in the experimental areas (with duct tape) was 21 to 428 times that in control areas (without duct tape). This means that the snails' actual reproductive output is much less than their potential reproductive output.
Choice experiments established the snails' preferences for deposition sites. In multiple-choice experiments, they preferred a rare branched red algae (Ceramium) most, followed by eelgrass, then bivalve shell (Macoma), then green algal blade (Enteromorpha growing on shell). The order of preference was the inverse of the order of abundance in the bay. In a pairwise comparison, the snails strongly preferred eelgrass to bivalve shell. Overall, we found that H. vesicula prefers to lay its eggs on Z. marina, but the rarity of that substratum in the bay limits reproductive output.
Our results are important for two main reasons. First, they provide a clear example of a limitation on benthic development-that is, availability of suitable substratum to lay eggs on. Second, they show a potential direct effect of habitat loss. Seagrasses are in decline worldwide due to pollution and other factors, and animals like H. vesicula that depend on seagrass for food or shelter may face declining population size, or even extinction, as a result.
University of South Florida
Blinks Fellow working with Dr. Christiane
Biermann and doing independent research
I'm a Master's student studying molecular evolution in sea urchin genes. The Blinks program exposed me to the world of marine biology and enabled me to work with a professor with years experience in the same field of study all while collecting DNA samples essential for my thesis. It was an amazing experience!
I spent the first five weeks enrolled in the Marine Invertebrate Zoology course. I learned about 20 new phyla, found out animals exist where I didn't think they could, saw incredibly bizarre and amazing things, and learned more about the spiny sea urchin I study. It was unbelievable.
After the class Christiana Biermann and I collected tissue samples and extracted DNA from hundreds of sea urchins. We experimented with collecting and preserving methods, and tested a high out-put DNA extraction kit. Although I already knew many laboratory techniques, the filed component was completely new to me. Christiana taught me how to look for potential collection sites, collect the urchins, extract tissue with a non-lethal method, and store the tissue so DNA could be extracted years later. We split the DNA samples when I left. This collaboration allowed me to gain samples from locations I otherwise would not have had access to, and assisted Dr. Christiane Biermann in her huge population project.
My Blinks experience opened my eyes and opened doors for me. Every day this past summer I woke up thinking "I must be one of the luckiest people alive". And although I am now at my home university plowing through data, the memory of his summer inspires me to work harder with the hopes that I can return some day to that wonderful little island in the Pacific.
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