University of Maine graduate students use the DMC's facilities on a full-time, part-time or seasonal basis depending on their thesis advisor and research requirements. Most DMC graduate students are enrolled in the School of Marine Sciences Graduate Program and are pursing a MS or Ph.D. in Marine Biology, Oceanography or Marine Policy. Listed below are the current graduate students at the DMC and their research interests.
For more information about the SMS Graduate Programs, contact the program coordinators:
SMS Graduate Program of Oceanography
Dr. Larry Mayer • lmayer@maine.edu • (207) 563-3146, ext 237SMS Graduate Program of Marine Biology
Dr. Ian Bricknell • ian.bricknell@umit.maine.edu • (207) 581-4380SMS Graduate Program of Marine Policy
Dr. James Wilson • jwilson@maine.edu • (207) 581-4368SMS Marine Science and Policy Dual Degree Program
Dr. James Wilson • jwilson@maine.edu • (207) 581-4368
Current SMS Graduate Students Based at the DMC
Susie Arnold
Ph.D. candidate, Marine Biology
Advisors: Dr. Bob Steneck / Dr. James Acheson
Area of interest: coral reef ecology, ecosystem resilience, marine policy
Charlene Bergeron
M.S. candidate, Oceanography.
Advisor: Dr. Rick Wahle
Area of interest:
Nathan Briggs
M.S. candidate, Oceanography.
Advisor: Dr. Mary Jane Perry.
Area of interest: factors affecting phytoplankton abundance and carbon sequestration.
Meg Estapa
Ph.D. candidate, Oceanography
Advisors: Dr. Larry Mayer and Dr. Emmanuel Boss
Area of interests: Photochemical reactions of particulate organic matter (POM), carbon and pollutant cycling at river-dominated coasts, optical proxies for POM in turbid water.
margaret.estapa@maine.edu
Maine In-situ Sound and Color Lab • more info
Mahima Jaini
M.S. candidate, Marine Biology
Advisor: Dr. Rick Wahle and Dr. Andy Thomas
Area of interests: Marine ecology, Invertebrate zoology, Environmental drivers of settlement and Demographic connectivity in the American lobster (Homarus americanus) populations.
Mike Sauer
Ph.D. candidate, Oceanography
Advisor: Dr. Collin Roesler
Area of interest: Coastal primary productivity, DOM, optics, Ocean Observing Systems, Remote Sensing
michael.sauer@umit.maine.edu
More info
Anne Simpson
Ph.D. candidate, Marine Biology
Advisors: Dr. Les Watling & Dr. Kevin Eckelbarger
Area of interest: Reproduction in deep & cold water octocorals
anne.simpson@umit.maine.edu
Watling Lab Webpage
Recent Grads
Andrea Drzewianowski, M.S. Oceanography, 2008
Working with Dr. Mary Jane Perry, Andrea studied the diel patterns of ultraviolet absorption by phytoplankton in the Gulf of Maine. Phytoplankton need light for photosynthesis, but too much UV radiation is known to inhibit photosynthesis. MAAs (mycosporine-like amino acids) are believed to act as sunscreens, providing some protection to phytoplankton during periods of intense light. Andrea measured how much light is absorbed by MAAs and, in her thesis, reported that UV absorption was low in the morning and evening and high at midday. These data suggest that phytoplankton can respond very rapidly to changes in UV radiation. Upon completing her thesis, Andrea participated in the NAB08 cruise, page 1, and is currently working at the University of Rhode Island for Dr. Tatiana Rynearson.
Celeste Mosher, M.S. Oceanography, 2008
Working with Dr. Les Watling, Celeste studied the symbiotic relationship between an octocoral and a brittle star found on seamounts between 1500 and 3000 feet below sea level. On each octocoral specimen, Celeste found a solitary
brittle star. She found evidence that the the
brittle stars settle on the octocorals when both are young and that they continue to live together as they grow. Though the octocoral appears to neither benefit nor be disadvantaged by the
brittle star, she believes the brittle star is likely obligate to the octocoral, gaining feeding and protective benefits.
Celeste’s research shows that there is still much to be learned about seamount communities and reminds us that deep-sea trawling and other human impacts can cause irreparable harm, not to just one species to a host of others.
Celeste works for the Gulf of Maine Foundation
Lisa Pickell, Ph.D. Oceanography, 2008
Lisa completed her Ph.D. in September. Her advisor was Dr. Mark Wells. Using a novel continuous culture system at sea, Lisa exposed coastal and offshore phytoplankton populations to different forms of naturally occurring ligand-bound iron and copper. She found different algal assemblages in the different treatments suggesting that phytoplankton species have evolved various systems to maximize their uptake of these micronutrients. Pseudo-nitzschia, appears to have evolved a highly specialized iron uptake system powered by copper and domoic acid. In the presence of these compounds, the uptake of ligand-bound iron increases and Pseudo-nitzschia thrives, out competing other phytoplankton species in coastal environments.
Lisa is now an Assistant Research Scientist at Cellana Biofuels in Kona, Hawaii. The company, a subsidiary of British Dutch Shell, is developing techniques to culture phytoplankton rich in oil that can be converted into diesel fuel.
Susie Arnold, M.S. Marine Policy & Marine Biology, 2007
Working with Dr. Bob Steneck, Susie Arnold studied the processes of coral recruitment on the reefs of Bonaire. Parrotfish and other herbivorous reef fish keep algal abundance low. Damselfish, however, ward off such grazing fish from their territories, creating areas of increased algal biomass. Focusing on the role of algal biomass on potential coral nursery habitats, Susie placed standardized terra-cotta coral settlement plates inside and outside of Damselfish territories. After 27 months, baby coral densities were 73% higher in well-grazed treatments. This suggests that herbivory, or a lack thereof, explains a considerable portion of the variance associated with coral recruitment at a very local scale. Thus, careful management and monitoring of herbivores could improve the potential for coral reefs to recover from disturbances.
Susie is staying on at UMaine to pursue a Ph.D. in Marine Biology. Her dissertation research will focus on various aspects of coral recruitment from a more regional perspective, including larval choice experiments, juvenile survivorship rates and a manipulative demonstration of the importance of conserving particular species of grazing fish.
Curt Brown, M.S. Marine Policy & Marine Biology, 2007
Curt Brown worked with Dr. Rick Wahle, Bigelow Laboratory for Ocean Sciences and Graduate Faculty in the School of Marine Sciences, studying predation pressure on juvenile lobsters from Rhode Island to Maine. He used video monitoring as well as diver and ROV surveys to determine abundance and diversity of lobster predators, and tethering experiments to determine relative predation rates. Curt’s findings confirm that predation pressure increases from north to south, as does the diversity and abundance of predatory fish. The interesting twist to his story is that a recent episode of very high recruitment of crabs has made life more risky for newly settled lobsters in the Gulf of Maine.For the Marine Policy portion of his degree, Curt looked at lobster fishery regulations which were largely initiated and enforced by lobstermen; exploring the history behind this unique conservation ethic and why it persists today.
Curt now works as a research technician at the Gulf of Maine Research Institute in Portland and as a lobsterman out of Cape Elizabeth. He is also involved in www.catchapieceofmaine.com, a business venture with a new means of marketing Maine lobsters and the lobstering tradition.
Kelly Dorgan, Ph.D. Oceanography, 2007
Working with Dr. Pete Jumars, Kelly Dorgan studied the biomechanics of worm burrowing and discovered that a worm functions more like a wedge than a backhoe, using crack propagation rather than excavation, to tunnel though muddy sediments.
Gelatin is a suitable analog for mud, having many of the same mechanical properties. Like mud, it is a cohesive, elastic solid. Unlike mud, however, gelatin is translucent and birefringent. Using a video camera and polarized light Kelly was able to not only see crack propagation, but also quantify the stresses necessary for the sandworm, Nereis virens, to propagate cracks in the gelatin. The implications of Kelly’s findings may be far-reaching. In addition to “rewriting” textbooks on worm locomotion, her findings may also hold for other mud-inhabiting marine fauna including clams, small crustaceans and anemones, and may impact bioturbation models.
Kelly is now a postdoctoral fellow with Dr. Mimi Koehl at the University of California, Berkeley. With funding from the National Science Foundation, she plans to study the energetic (metabolic) cost of burrowing and the flux of materials through sediments due to burrowing/mixing.
Elizabeth Stephenson, M.S. Marine Policy & Marine Biology, 2007
Elizabeth Stephenson began her graduate studies in 2002, barely a year after the invasive Asian shore crab (Hemigrapsus sanguineus) was first detected in Maine waters. She was thus presented with the unique opportunity to study a bioinvasion from its beginning stages. Working with advisor Dr. Bob Steneck and Robin Hadlock Seeley of Cornell University, Elizabeth explored whether temperature may limit range expansion by this species.
Elizabeth’s results suggest that the invasion is progressing much more slowly in Maine than in the southern New England and Mid-Atlantic states. The crab’s range seems to be stalled at the terminus of the cold Eastern Maine Coastal Current, and rates of population growth have been slow even in the warmest, most southern locations of the state. She speculates that the summer temperatures of Maine waters are too low to allow for regular successful recruitment, but notes that a warming ocean may create a more hospitable environment for the Asian shore crab as well as other future invaders.
Elizabeth is currently working for the Maine Coastal Program, an extension of the work she did for the policy portion of her degree. She is involved in a variety of programs and projects including coordinating the Maine Marine Invasive Species Working Group and working on beach management and water quality issues.
Brandon Sackmann, Ph.D. Oceanography, 2006
Brandon Sackmann was awarded a Ph.D. in Oceanography for his dissertation “Remote Assessment of 4-D Phytoplankton Distributions off the Washington Coast.” For nearly three decades oceanographers have had access to sea surface data (including ocean color and temperature) collected by satellites. More recently oceanographers have come to use a variety of autonomous underwater vehicles to provide in-water measurements of chlorophyll-a fluorescence, optical backscattering, temperature, oxygen concentrations and more. Using data from Seaglider (an autonomous underwater glider) and from satellites for waters off the coast of Washington state, Brandon developed methods to combine the two data sets into a 4-dimensional model of the water column. The result offers a clear look at water column characteristics below the sea surface and improves regional estimates of phytoplankton biomass.
Brandon completed his Ph.D. with Dr. Mary Jane Perry and will be a postdoctoral fellow at the Monterey Bay Aquarium Research Institute (MBARI) working with John Ryan and Zbigniew Kolber.
Mei Sato, M.S. Oceanography, 2006
Emergence events were believed to be nighttime affairs, where under the cover of darkness, epibenthic organisms could safely swim up into the water column to feed and reproduce. Using acoustic profiling, Mei Sato found that diel migration was only part of the emergence story–tidal periods also played a role. Mei collected acoustic data over a longer time frame than previous researchers and was thereby able to track seasonal patterns of emergence and to differentiate between diel and tidal migrations. Mei’s data suggests that the mysid, Neomysis americana, has a diel pattern of emergence during the summer and a semidiurnal tidal rhythm in the fall. Such patterns reveal a more complex life history pattern of mysids as well as a greater degree of benthic-pelagic coupling.
Mei received a M.S. in Oceanography for her thesis titled “Diel and Tidal Rhythms of Emergence Events Based on Acoustic Observations in a Shallow Estuary." Her advisor was Dr. Pete Jumars.
Brian Thompson, M.S. Oceanography 2006
Brian Thompson investigated the variability of phytoplankton biomass in the Damariscotta River Estuary, as well as environmental factors, such as nutrients, light, and physical conditions, in order to assess the estuary's ability to sustain shellfish aquaculture farms. He found highest chlorophyll-a concentrations in the upper reaches of the estuary, above Glidden Ledge. Brian concluded that environmental conditions favoring phytoplankton production, and a longer residence time for water north of this constriction promoted these higher concentrations. Throughout the study Brian posted his chlorophyll-a data on the web. These continued postings have been a useful resource for local aquaculturists who need to make informed decisions about the management of their sea farms.
Brian Thompson received a Master’s degree in Oceanography for his thesis research titled “Phytoplankton Carrying Capacity in the Damariscotta River Estuary” and is currently a consultant for the Gulf of Maine Ocean Observing System.
Jeanne Brown, M.S. Marine Biology & M.S. Marine Policy, 2006
“Save the Parrotfish!” was the take home message of Jeanne Brown’s Master’s thesis “Multi-scale and Multi-species Interaction Strength of Damselfishes on Coral Reef Ecosystems.” Working with advisor Dr. Bob Steneck, Jeanne spent hours underwater scouring the coral reefs of Bonaire to study the damselfish in reef ecosystems.
Protected as national parks with only a limited hook-and-line fishery, Bonaire’s reefs are the healthiest on the planet and have significant herbivorous fish populations, including damselfish and parrotfish of all sizes. These herbivores eat the macroscopic algae that would otherwise overrun the corals.
Jeanne’s research showed that damselfish eat some of the algae, but their territorial nature actually keep other smaller herbivorous fish at bay. Large parrotfish, however, were not deterred by the damselfish, grazing voraciously on macroalgae when and where they like.
Jeanne received a dual degree in Marine Biology and Marine policy. She now works for NY Sea Grant/ Cornell University Cooperative Extension Program helping Long Island municipal leaders with coastal watershed and storm water management, abatement of non-point source pollution, and meeting requirements of the Clean Water Act.
Lisa Nigro, M.S. Microbiology, 2006
Lisa Nigro successfully defended her Master’s thesis titled “Distribution and Diversity of Bacterial Chemolithotrophs in Marine and Freshwater Sediments”, a topic not previously explored by scientists. Her advisor was Dr. Gary King. Chemolithotrophs can fix CO2 and use inorganic compounds as a food source. Lisa hypothesized that chemolithotrophs in sediments would differ based on the relative availability of sulfide. Using molecular techniques to look at RuBisCO, a CO2 fixation enzyme, she found that bacteria in sulfide-rich intertidal marine sediment mainly contained a RuBisCO gene type similar to that found in known sulfur-oxidizing bacteria. Sulfide-poor Damariscotta Lake sediment, however, largely contained a RuBisCO gene type mainly seen in carbon monoxide and hydrogen-oxidizing bacteria.
Lisa is currently working for Dr. Ann Bucklin at UCONN-Avery Point in Groton, CT. She is the lab manager of a zooplankton molecular ecology laboratory and part-time manager of COMMA (Center of Marine Molecular Analysis).
