Program Description: Friday Harbor Laboratories' Blinks - NSF REU Summer Internship Program seeks to link undergraduate students with scientist-mentors as collaborators in marine science research projects. The program takes advantage of the pristine environment, remarkable biodiversity, and the scientific and technical resources at University of Washington's marine science research facility. We have combined the NSF REU program with the Blinks Research Fellowship program, which targets groups who are historically underrepresented in the marine sciences. With support from the United Negro College Fund, the Andrew W. Mellon Foundation, the American Society for Cell Biology, the Federation of American Societies for Experimental Biology, and the Anne Hof Blinks Memorial Fellowship, the Blinks-REU Program offers a full immersion research experience for motivated undergraduates, post-baccalaureates and graduate students. In keeping with the University of Washington's policy of encouraging diversity in its student body and including underrepresented groups, the program seeks 10-15 students of diverse backgrounds and interests to participate in a eight to twelve week summer research project in the marine sciences. By linking fellows with marine scientists in a 1:1 research experience, fellows learn both the process and the substance of scientific research. As the research progresses, fellows will be encouraged to become semi-independent collaborators. The experience will expose fellows to the life and work of a marine science research laboratory. The program will incorporate workshops, seminars and training sessions in addition to hands-on research.
The mentors and projects vary from year to year according to the developing research interests of faculty and graduate students. Research projects are designed by the scientists to be achievable projects which dovetail with their research plans. Project descriptions are posted below. Fellows will work semi-independently for approximately 40 hours per week.
For summer 2012, the BEACON Program will fund up to four students, bringing the Blinks-REU-BEACON cohort up to 15 or 16 students.
As participants in the FHL community, students will participate actively in FHL community activities, e.g. attend the weekly seminars, eat in the Dining Hall and live in the student dormitory. Early in the summer session there will be a meeting of student participants with graduate students and mentors to share perspectives on graduate programs and participation in academic life, with a brief description of ongoing projects, and a question/answer session. At the end of their internship, fellows will present their research in a short powerpoint talk. Fellows will also write a scientific paper describing their work, and revise it based upon feedback from the mentor.
The Setting: Friday Harbor Labs is University of Washington's marine science field research station. Located north of Puget Sound in the San Juan Islands, FHL takes advantage of a remarkable diversity of marine habitats and organisms. FHL hosts 10-12 courses per year and approximately 100 independent researchers during the year. The 484 acre campus is the site for thirteen lab buildings, a dining hall, 3 dorms and other housing units.
Research at FHL emphasizes marine invertebrate zoology, phycology, fisheries science, conservation biology, cell and molecular biology, biomedical sciences, oceanography and other scientific disciplines. Investigators and students use diversified field resources as well as modern analytical technologies such as a nucleotide sequencer, scanning laser confocal microscopes, scintillation counter, centrifuges, HPLC, TEM, SEM and other equipment. The Labs is equipped with a 58' research vessel, numerous smaller boats, cold rooms, and an extensive seawater system serving numerous lab buildings. The facility includes a computer lab, networked research labs, wi-fi connectivity, a well equipped stockroom, a 17,000 volume library, and SCUBA facilities.
Financial Support: Participants will be provided with financial support to meet costs of room, board, round trip travel and a monthly stipend of $1000.
Eligibility: The Blinks Endowment supports students who bring diversity to the FHL student body in any phase of their undergraduate or graduate career. The NSF REU Site grant supports U.S. citizens or permanent residents during their undergraduate careers.
Please e-mail all application materials to Scott Schwinge (schwinge@u.washington.edu).
Scott Schwinge
Dr. Sara Hiebert Burch
Swarthmore College
shieber1@swarthmore.edu
While hummingbirds have been the subjects of field investigations on behavior, energy management, and flight mechanics for some time, the amenability of these tiny birds to endocrine investigation has been less appreciated. It might seem impossible to collect enough blood from one of these tiny birds to quantify the level of circulating hormones, much less obtain repeated samples over a period of minutes or hours. However, there is another, less invasively obtained, source for this information: Hormones or their metabolites are voided in the copious urine that hummingbirds produce because they must drink large quantities of relatively dilute nectar to meet their energy needs.
We have also shown that it’s possible to collect urine from a captive bird that is free-flying in its cage. While captive birds can teach us many things, the next step is to take these techniques into the field so that we can study birds that are living their natural lives in their natural environment. Using radio-frequency transponders and techniques that we are developing for collecting urine samples without handling the birds, we will investigate the hormonal correlates of behaviors in free-living hummingbirds, focusing on the question of whether behavioral personalities are correlated with particular hormonal profiles. In addition, we will be banding hummingbirds as part of a larger effort to understand the evolving patterns of migration in rufous hummingbirds, which are showing up in increasing numbers in the eastern United States during the winter, hundreds or thousands of miles from their traditionally known wintering grounds in Mexico. This project will involve field and computer skills, bird-handling, hormone and metabolite analysis, experimental design, statistical analysis, scientific writing and presentation skills.
Hiebert, S.M., M. Ramenofsky, K. Salvante, J.C. Wingfield and C. L. Gass. 2000. Noninvasive methods for measuring and manipulating corticosterone in hummingbirds. Gen. Comp. Endocrinol. 120:235-247.
Dr. David Duggins
University of Washington
dduggins@uw.edu
While it is well established that kelp forests (communities dominated by brown seaweeds belonging to the order Laminariales) have extremely high rates of primary production, very little is known about the ultimate fate of kelp biomass or how important it is to the broader nearshore ecosystem. Research published by Duggins et al. (1989) has demonstrated that in areas within and surrounding kelp forests, organic carbon produced by kelp photosynthesis is not only important as a food source to primary consumers but is actually more important than phytoplankton as the basis of local food chains. Although the vertical range of kelps extends only to 18 m depth, detrital kelp (i.e. drift algae) is present in deep subtidal habitats to depths of several hundred meters and its role in those deep food webs is unknown. Our broad project examines the influence of kelp detritus on deep-water (>100 m) benthic and planktonic assemblages. As kelp biomass decays and degrades, it is broken into small particles, which are subsequently colonized by bacteria and other micro-flora. This enriched detritus is potentially an excellent food source for other organisms.
Our lab is using a wide variety of observational and experimental techniques to test the importance of drift algae in nearshore food webs, including the use of biomarkers (multiple stable isotopes and fatty acids) that show what kinds of foods marine organisms have been eating. An REU student this summer will become involved in one of several planned or ongoing lab and field experiments as part of this larger project. Summer tasks include experiments to tease out the contribution of phytoplankton versus particulate organic matter (derived from kelp) in the diet of benthic suspension feeders; growth and reproduction of small crustaceans fed on fresh versus aged kelp detritus; and growth rates of outplanted suspension feeders in shallow versus deep water.
REU applicants should be interested in Marine Ecology and food webs. Useful (but not required) skills include basic carpentry and fabrication (for assistance in the construction of experimental arrays), and SCUBA certification and open water diving experience (for assistance in shallow water deployments and retrievals).
Duggins, D.O., C.A. Simenstad and J.A. Estes 1989. Magnification of secondary production kelp detritus in a coastal marine ecosystems. Science 245:170-173
Dr. Sophie George
Georgia Southern University
georges@georgiasouthern.edu
A regular occurring event in the coastal waters of the Pacific Northwest is a decrease in salinity to less than 15‰ in some areas, as a result of increased precipitation and ice melts. Studies by George and Walker (2007) and George, Pia, and Johnson (in preparation) indicate that Dendraster excentricus (right top picture) and Pisaster ochraceus larvae (bottom left) can develop to metamorphosis at 22‰ and 20‰ salinity (bottom right, juvenile P. ochraceus). However, larvae exposed to 20‰ for 14 days were shorter, wider, had smaller stomachs, developed slowly and produced smaller juveniles than those exposed for 7 days. This is rather intriguing given that echinoderms cannot regulate the osmolarity and ion content of their internal fluids. These studies also indicate that the timing, magnitude and duration of ice melts and rainfall in the Pacific Northwest could alter larval morphology, larval feeding and swimming efficiency, and ultimately the quality of new P. ochraceus recruits into the intertidal zone in the Puget Sound.
During the summer of 2012, research will continue looking at larval behavior of P. ochraceus in haloclines with different food patches. This project will illuminate the complex interactions between nutrition, salinity, and growth rates of an asteroid with bipinnaria and brachiolaria larval forms. Knowledge on larval behavior in haloclines would enhance our understanding of how echinoderm larvae will respond to a decrease in ocean salinity as a result of climate change. The participating student would be directly involved in preparing algal cultures; rearing larvae to metamorphic competency, preparing and observing larvae in haloclines, photographing echinoderm larvae etc. Past students have presented their research at regional (GAS) and international meetings (SICB), and are coauthors on 2 recent articles from research at FHL with one in preparation.
George, Sophie B. & Walker, Devoc. 2007 Short-term fluctuation in salinity promotes rapid development and metamorphosis of Dendraster excentricus larvae Journal of experimental marine Biology and Ecology. 348:113-130.
George, Sophie B., Fox Colleen & Wakeham, Stuart 2008. Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reflect FA composition of the diets Aquaculture 285: 167-173.
George, Sophie, Tanya Pia and Tiffany Johnson Single and multiple fluctuations in salinity affect growth, development and metamorphosis of the sea star Pisaster ochraceus. In prep.
Daniel Lee and Sophie George Vertical distribution of brachiolariae larvae in haloclines is influenced by prior exposure to low salinity. In prep. (past Blinks-REU scholars or grad students in bold).
Dr. Danny Grunbaum
University of Washington - School of Oceanography
random@uw.edu
Most marine invertebrates and many fishes have planktonic larval stages. In many species, especially those in which adults are sessile or slow moving, these larval stages are the primary mechanism for colonizing new habitats and for genetic exchanges between existing populations. Larval populations undergo extreme fluctuations in transport and survival on timescales of days to weeks; as a result, recruitment to adult populations is also highly variable and is so far unpredictable. On longer timescales, the impacts on larvae of environmental variations such as climate change and ocean acidification are even less predictable.
One of the most important limitations in improving our understanding and prediction of dispersal of planktonic larvae is that it is currently virtually impossible to find them in the natural environment. Larvae are abundant overall but very dilute compared to other plankton. Recently, genetic methods are being developed can help quantify larval abundance in fixed plankton tow samples. However, genetic methods do not provide a way to identify, isolate and characterize live planktonic larvae, or to characterize their fine scale distributions or behaviors.
This project uses new sensors based on embedded processor technology to image larvae and to quantify characteristics of marine invertebrate larvae. Depending on their interests, the student(s) can develop an independent investigation using imaging technology in one of several areas that are foci of our research: (i) using imagers to detect larvae in the natural environment, both in the water column and as they approach and metamorphose on settlement sites; (ii) using imagers to quantify larval swimming behaviors, coupled with oceanographic modeling to predict dispersal of larvae with observed behaviors; (iii) using hydrodynamic models to understand how changes to larval morphologies caused by environmental stresses impact swimming, dispersal, and ultimately adult populations.
In this project, the student(s) will learn and exercise skills in larval biology, computer analysis, oceanography and engineering. No previous experience in any of these areas is required, but an eagerness to engage with the unknown is highly desirable.
Dr. Danny Grunbaum
University of Washington - School of Oceanography
random@uw.edu
On land, we are accustomed to frequent, detailed and fairly accurate observations and predictions of atmospheric conditions. In water – by far the largest environment on Earth – the "weather" involves not only physical characteristics but also a spectacular array of organisms, from bacteria to whales. Compared to land, we have only a tiny capacity to sense and predict ocean conditions, especially those involving the number and well-being of plankton, fish and other organisms that are most directly important to human societies.
Ocean data are so limited because the primary means of collecting them – ship surveys and, recently, large-scale cabled observatories – are expensive and very restricted in their spatial and temporal scope. The recent availability of inexpensive, low-power but highly capable computers and imaging devices is likely to transform both the amounts of data from the marine environment and the methods for collecting it in the near future.
This project is to develop and implement prototype new ocean sensing instruments based on low-cost computing, imaging and networking – essentially, smart phones in the ocean. These instruments collect video images of organisms, process the video to extract useful information such as size, shape and movement characteristics, and transmit the resulting data to a central data repository for interpretation and analysis. In earlier work, we deployed sensors of this kind to survey plankton distributions off the Hawaiian Islands, and to remotely detect Harmful Algal Blooms at a salmon farm in Puget Sound. Potential projects include studies of spatial and temporal patterns in the distribution of important plankton groups such as copepods, diatoms, dinoflagellates and ciliates; marine invertebrate larvae; and fish. In the future, this approach will amount to a weather detection system for marine environments and, with incorporation into ocean models, an ecological prediction system as well.
In this project, the student(s) will learn and exercise skills in plankton and fish biology, computer analysis, oceanography and engineering. No previous experience in any of these areas is required, but an eagerness to engage with the unknown is essential.
Metamorphic Timing in Marine Invertebrate Larvae
Dr. Molly Jacobs
McDaniel College
mjacobs@mcdaniel.edu
Many benthic marine invertebrates reproduce via swimming planktonic larvae. These larvae swim for some period of time, and then metamorphose into juveniles. Metamorphosis is both an ecological and a developmental transition: the organisms transition from the larval habitat (the plankton) to the adult habitat (the benthos), and from the larval body plan to the juvenile body plan. The timing of this transition is interesting, because it is controlled by both internal and external factors.
Internally, before larvae can metamorphose they must be developmentally able (‘competent’) to complete the rapid morphological changes that are necessary. For most larvae, competence occurs when they reach a certain age, developmental stage, or (in the case of feeding larvae) size. Once a larva has become competent, it must locate an appropriate adult habitat and then initiate the metamorphosis. This means that the length of time between when a larva becomes competent and when it actually metamorphoses is controlled by external factors such as settlement cues.
My lab studies how external and internal factors control the timing of metamorphosis, and the physiological consequences of variation in metamorphic timing, in two very different invertebrate groups: ascidians and crabs. The REU student selected for this project will design and carry out her or his own novel experiment within this broader framework, using one of these systems. An example of an ascidian project would be to investigate the consequences of delaying metamorphosis by manipulating larval period in the laboratory, and then explanting juveniles (Fig 1) into the field into different environments. An example of a crab project would be to measure settlement behavior and metamorphic timing of wild-caught crab megalopae in large mesocosms (Fig 2).
The student will gain experience in experimental design and data analysis, embryo and larval culture, microscopy, comparative morphology, taxonomy, and other skills depending on the exact nature of the project selected.
Dr. Rachel Merz
Swarthmore College
rmerz1@swarthmore.edu
Examining how organisms move through water has long been studied both to understand the lives and evolution of swimming organisms and to evaluate the mechanisms they use, in some cases for potential application to human needs. What is much less well known is how aquatic organisms hang on to wet surfaces - knowing how organisms meet this mechanical challenge is important for the same reasons – to understand how the animals work and to look for possible applications for other uses.
Building on my previous research on the architecture of worm tubes and polychaete morphology, the task this summer will be to quantify the frictional interaction between the bodies of tube-dwelling worms and tube walls – where those tube walls are both natural and artificially constructed to vary texture. We already have good data on the morphology and ability of these worms to adhere to the insides of their natural tubes, what we want to do this summer is to compare the behavior and ability of worms in their natural tubes and artificial tubes made with different surface qualities. Accomplishing this goal will likely require careful observation of the worms in order to design good experiments and construct experimental apparatus. It will also involve video analysis and use of scanning electron microscopy.
Dr. Chris Neufeld
University of Washington - Friday Harbor Laboratories
cneufeld@uw.edu
Forecasting the impacts of anthropogenic climate change requires an understanding of how species ranges are defined, because species ranges ultimately determine local and global patterns of biodiversity. To predict how climate change will impact species ranges, studies have largely focused on how organisms cope with high temperatures, yet climate models also forecast widespread changes to minimum temperatures and to the breadth of temperatures experienced. Given that concurrent adaptation to high and low temperatures may be limited by physiological tradeoffs, determining how organisms will respond to changes in temperature breadth is critical to accurately forecasting the impacts of climate change on species ranges and population sizes.
I am currently investigating thermal tolerance using the intertidal copepod Tigriopus californicus as a model system. In T. californicus, genetically distinct populations show a clear trend for greater heat tolerance with decreasing latitude from Canada to Mexico, a pattern consistent with local adaptation to latitudinal variation in heat stress. Although patterns of adaptation suggest copepods may be able to adapt to increasing mean temperatures, it is unclear whether populations will be able to adapt to cope with a broader temperature range. It is also unknown how cold winters shape patterns of thermal tolerance in the northernmost Alaskan populations.
Laboratory cultures of the harpacticoid copepod Tigriopus californicus. Each culture may contain as many as 800 individuals.
By studying thermal adaptation in a species with a generation time of twenty days, we can ask a number of critical questions relevant to other long-lived species for which direct assessment of evolution in the laboratory isn’t possible.
Female bearing an egg mass. Females only mate once but produce multiple egg masses. Males clasp females prior to mating so parentage of embryos is known. Embryos develop into mature adults in 20 days at 20°C.
Photo: Gustav Paulay. Scale 1 mm.
The REU student selected will help design and carry out a study within this broader framework, and assist with several ongoing field surveys and laboratory experiments in this system. The student will gain experience designing field and laboratory experiments, maintaining laboratory cultures, assessing behaviour and morphology of laboratory-reared cultures, manipulating and analyzing data in the powerful open-source statistical programming language called R, and preparing data for presentation to the broader scientific community.
Dr. Charley O'Kelly
University of Washington - Friday Harbor Laboratories
cjokelly@uw.edu
So how come you can’t yet fill up at the pump with gasoline made from algae? There are lots of reasons, but one you may not have thought of is contamination. Farmers on land move earth, and try to move heaven, so that they can harvest their corn before the weeds and the rats and the birds get it. Algal farmers are discovering that they have to do the same thing. Without being able to tell which one of those things in their ponds and bioreactors is a weed, or a rat, or a bird. Until it’s too late.
Image: Dr. Charles O'Kelly. Algae-eating amoebae surrounding diatom prey.
We know little about the “rats” in marine ecosystems, and especially about the smallest ones, the protozoa, because they are the hardest to study. But these protozoa are also the ones that are most likely to get through the water filtration systems of aquaculture facilities and wipe out crops. In order to protect those crops, we need to be able to identify the rats and know what they will eat (and how fast) and what they will spurn. The bad news is that practically every time we find a protozoon that eats algae, it’s new to science, so we can’t look it up and find out what to do. The good news is that, most of the time, these protozoa are picky eaters. If only we had a better handle on just how picky they are.
We have several of these “rats” in culture, some obtained from a working algal biofuels facility, others isolated from the waters around San Juan Island. The principal questions that the student engaged on this project will attempt to answer are:
Dr. Charley O'Kelly
University of Washington - Friday Harbor Laboratories
cjokelly@uw.edu
If someone told you that there was an environment in nature that is pumping into the water, and eventually the atmosphere, approximately 20% of the carbon that’s being dumped into the biosphere by human activities, you’d probably say “That’s not boring”.
And you’d be right. And wrong.
Right, because that much carbon entering into the biosphere certainly must be significant.
Wrong, because the organisms that are doing this are boring.
Image: Dr. Charles O'Kelly. Live alga in a mollusk shell.
OK, they’re borers. Borers into calcium carbonate. Which, of course, are dissolving the carbonate as they bore, and releasing the carbon into the biosphere. Yes, that means that these organisms – algae, fungi, bacteria, sponges – aren’t living on a rock. They live in it.
We’re beginning to understand more about the communities of organisms that bore into calcium carbonate in tropical reef ecosystems. But very similar communities exist in temperate waters, where they inhabit shells of molluscs and barnacles, the skeletons of hydroids and bryozoa, and even concrete and native limestones. We know very little about what’s in these communities, and what if anything they contribute to that big load of carbon that their cousins in the tropical carbonate reefs are dumping.
We are trying to understand what species are present in three types of carbonate-boring algal communities: intertidal, shallow subtidal, and deeper subtidal. Each of these communities consists of a different array of algal species. We have cultures, and DNA signatures, for some of these algae. But we don’t know how much of the community we have captured in culture. And unless you can see the whole football field, it’s kinda hard to know which player’s got the ball. Or, in this case, which of the algae that are present in any given community is the one doing most of the carbonate dumping.
Image: Dr. Charles O'Kelly. SEM cast preparation of the same species of algae, also in a mollusk shell.
The principal questions that the student engaged on this project will attempt to answer is:
The student will take and examine samples from a carbonate-rich community from one of the three principal stations (intertidal, shallow subtidal, deep subtidal) of interest, and attempt a species assessment using morphological criteria, aided by an atlas of morphologies that we have created from the literature, other local field work, and laboratory cultures. This assessment will involve taking resin casts of the boreholes made by the algae, and examining these casts with the scanning electron microscope. The student may also attempt a DNA-based assessment of the species present, obtaining bulk DNA from field-collected specimens and using that DNA to assess species diversity, for example by probing the DNA with species-specific primers designed from algae isolated from similar habitats and growing in our culture collection of carbonate-boring algal strains.
Dr. Scott Santagata
Long Island University
scott.santagata@liu.edu
Specific Aims
1) Gather mitochondrial and nuclear sequences from various unidentified types of phoronid
larvae
2) Match these larval types with known adult forms based on published phylogenetic
sequences
3) Estimate the true worldwide diversity of phoronids
4) Investigate the genetic diversity among Pacific populations of Phoronis pallida
Background
The phoronids include two genera and at least 10 universally recognized species that are
largely supported by molecular phylogenetic data (Santagata and Cohen, 2009). Although
the evolutionary relationships within phoronids and brachiopods are still under debate,
phoronids and brachiopods clearly reside within the assemblage of protostome animals
known as the Lophotrochozoa or Spiralia. Individual species of adult phoronids often occur
in conspecific aggregations that may facilitate cross-fertilization, and, in general, most
species exhibit cosmopolitan geographic distributions. All but one phoronid species produce
a distinctive larval form known as the actinotroch, and at the time of metamorphic
competence actinotroch larval forms develop distinctive larval and presumptive juvenile
traits that allow for accurate discrimination among species types (Santagata and Zimmer,
2002). Based on these data there are more discrete larval types than described adult types.
The worldwide diversity of phoronid species is likely underestimated due to in part to the
greater ease of collecting larval types from the plankton rather than finding adults that
typically occur in cryptic subtidal habitats.
Methodology
Currently one undergraduate student in my laboratory is working on a DNA barcoding
project of phoronid larvae from my samples. We have successfully isolated mitochondrial
sequences from individual phoronid larvae and plan to isolate other taxonomically
informative nuclear sequences in the future. These sequences will be compared to those
available on Genbank isolated as part of a previous phylogenetic project (Santagata and
Cohen, 2009). These procedures would be easily carried out at Friday Harbor Laboratories,
and the geographic location would allow several other unidentified actinotrochs types to be
collected and included in the study. A Blinks scholar participating in this study would learn
various molecular techniques such as DNA isolation, primer design, PCR, and molecular
phylogenetic analyses. We would also conduct field sampling on San Juan Island, and collect
plankton samples from various locations in Washington and Oregon. As a secondary project
(time allowing) we would also investigate the genetic diversity among Pacific populations of
Phoronis pallida.
Santagata S, Cohen B: Phoronid phylogenetics (Brachiopoda; Phoronata): evidence from morphological cladistics, small and large subunit rDNA sequences, and mitochondrial cox1. Zoological Journal of the Linnean Society 2009, 157:34-50.
Santagata S, Zimmer R: Comparison of the neuromuscular systems among actinotroch larvae: systematic and evolutionary implications. Evol Dev 2002, 4:43-54.
Dr. Adam Summers
Friday Harbor Laboratories
University of Washington
fishguy@uw.edu
Several marine fishes have suction cups they use to attach to a substrate. We would like to know the effect of fouling on suction cup performance and also the effect of surface roughness. The student will learn force measurement, surface replication, profilometry, and scanning electron microscopy.
Dr. Michaelangelo von Dassow
Duke University Marine Lab
mvondass@gmail.com
Many important biological systems use local feedback between mechanical cues and development to control the structure of the system. The human circulatory system is one well-known example. Colonies of the bryozoan Membranipora form a two-dimensional analogue to a circulatory system. The development of this system involves feedback rules similar to the feedback rules found in other biological fluid transport systems, including human blood circulation: faster fluid flow induces the formation of larger conduits (von Dassow, 2006).
The long term goal of this project is to develop Membranipora colonies as a new model system for studying how feedback between physiological function and development affects organisms. Membranipora colonies have a very different structure, function, and mode of development than most other biological fluid transport systems, yet they share similar physics and similar feedback rules. Therefore they provide a unique perspective on how these feedback rules contribute to the development and performance of fluid transport systems in general. This summer I hope to test two possible mechanisms that may stabilize the structure of this system. One is that the subunits of the system may lose their responsiveness to flow as they age; the second is that they may respond to flow reduction less quickly than they to flow increases.
The student will gain experience with designing and conducting experiments in organismal biomechanics while working with a fascinating and beautiful organism. The student will also gain experience with data analysis, scientific writing, and presentation. The student will be encouraged to take the project in new directions that suit the student's interests.
Dr. Michaelangelo von Dassow
Duke University Marine Lab
mvondass@gmail.com
Does embryo biomechanics influence how environmental variation affects development? By studying this, we can gain a better understanding of how organisms withstand the normal environmental variation that they have evolved to cope with, and how mechanical processes contribute to developmental defects.
The changes in embryo shape that convert a single celled egg into a complex animal are driven by mechanical forces. Echinoderm embryos (e.g. sea urchins, starfish, and brittle stars) provide beautiful and tractable systems for investigating how environmental factors influence this biomechanical process. Early in development, echinoderm embryos form a hollow ball, the blastula. Previous studies suggest that blastula expansion depends on osmotic pressure from the fluid inside the cavity of the blastula. The osmotic pressure acts against the mechanical resistance of extracellular matrix layers that surrounds the layer of cells. Environmental factors such as salinity, temperature, and pollution are likely to affect both the osmotic pressure and the extracellular matrix properties.
The primary goal for this summer is to use step changes in osmotic pressure to investigate whether blastula expansion can be described using different models of the blastula wall. These models make different testable predictions about the sensitivity of the morphogenetic process to perturbations that affect the timing of force generation (von Dassow and Davidson, 2011). Such perturbations could include temperature differences and salinity fluctuations.
The student will gain experience with embryological techniques (e.g. rearing embryos and light microscopy) and developmental biomechanics, while learning to integrate cellular and developmental biophysics with larger organismal and ecological scale processes. The student will contribute to all aspects of the project including experimental design, conducting experiments, data analysis, writing, and data presentation.