Christine Walder ’15 on Rockweed Harvesting

2014-07-07 10.29.59I am studying Rockweed (Ascophyllum nodosum) harvesting in the Gulf of Maine, both at the Coastal Studies Center in Harpswell, ME and on Kent Island in the Bay of Fundy. Rockweed is harvested commercially for use in fertilizers, food additives, and some other minor industries; landings have been increasing in recent decades and there is a growing concern over how harvesting activities are affecting the ecosystem.

Rockweed beds are essentially the old-growth forest of the intertidal zone, much like the Amazon rainforest in South America. Young algae sporelings settle onto rocks only during rare low-flow conditions, and once attached grow very slowly (approximately 6-10 cm per year). For a plant that regularly reaches two meters in length, this means that the fronds alone are several decades old, while holdfasts have been shown to live for centuries.

Although rockweed beds may look like a nondescript slimy olive-green mass just waiting to sprain an ankle the second one sets foot on their slippery surface, it is far from the “weed” that its name suggests. Rockweed is tough and chemically well defended, making it unappetizing for the run-of-the-mill intertidal herbivore. It forms an important habitat for a variety of organisms: periwinkles, crab, dog whelks, amphipods, isopods, bryozoans, and nudibranchs are all found within its holdfasts and fronds, while shorebirds and Eider ducklings forage in it. Juvenile fish, many of which are commercially important, spend part of their life cycle in the rockweed. It acts as an important buffer against the stress of extreme temperature fluctuation, desiccation, and wave stress of the intertidal zone, and it is also important for cycling nutrients and energy through the ocean ecosystem. While A. nodosum plays many important roles within the ecosystem, it is still important to note that it is the competitively dominant seaweed of the intertidal zone and reduces other algal diversity (but few intertidal seaweeds have the same mature biomass and complexity levels of rockweed).

2014-07-07 10.25.42

Because of the complex role of Ascophyllum nodosum in the intertidal ecosystem, its harvest naturally begs the question—what is the ecological impact of cutting rockweed? My research is focused on answering this question in a general sense. I am using a BACI (Before, After, Control, Impact) experimental design where I have set up paired 2x2m plots. I survey both, cut one to the 16 inch minimum length required by the Maine DMR, then survey them again immediately following and at one-month intervals after harvest. Surveys involve noting plot characteristics (slope, substrate, vertical height, etc.), identifying all algal species present, and identifying and counting all other organisms in a 1 m2 quadrat placed in the center of each 2x2m plot.

In addition to this I am monitoring the regrowth of the Ascophyllum after it has been cut. I generally find a few staple organisms in each plot—Littorina spp.(periwinkles), Carcinus maenas (green crabs), Nucella lapillus(dog whelks), Semibalanus balanoides (barnacles), Mytilus edulis (blue mussels), amphipods and isopods (small crustaceans which look very much like insects) Fucus vesiculosus (another type of rockweed), Chondrus crispus (a red algae), and Lithothamnium (an encrusting pink algae). However, sometimes other creatures also are found in lower densities and add a pop of excitement to my day—nudibranchs (sea slugs) are my personal favorite, and I have also found sea stars, sea urchins, scale worms, and a rock gunnel.

My work at the Coastal Studies Center is part of a comparative study between Maine and Kent Island, located in the Bay of Fundy on the border between Maine and Canada. My experimental design is essentially the same at the two study sites, although I established study plots on Kent Island in 2013 and have been tracking them for a year at this point. My hope is to collect long-term data from Kent Island, and also to compare the effects of cutting Ascophyllum nodosum between to relatively different locations. Kent Island experiences 28-foot tides (as compared to the 9-foot tides in Harpswell), and the intertidal zone supports a very dense, mature rockweed bed that has never been harvested, while the rockweed at the Coastal Studies Center is much less prolific. Past studies looking at rockweed harvesting have drawn varied conclusions, and conducting a comparative study will help to determine whether some of these differences are due to site-specific variation.

2014-07-07 10.40.55I do not have any results for my work at the Coastal Studies Center as of yet, but the data from Kent Island indicates that the harvested plots have regained little of the length and biomass that was removed a year ago. A general reduction in most invertebrate abundances (amphipods, periwinkles and crabs being the most outstanding) that persists a year following harvest was observed. Algal biodiversity increases after a year, suggesting that removing the competitively dominant algae stimulates other algal growth. I plan to follow the Kent Island plots into September, and the Coastal Studies plots for as long as the weather permits (Maine winters being what they are, this might not be much later than September). My data will be used for a Senior Honors Project.

For a review of rockweed harvesting, see Seeley and Schlesinger (2012): Sustainable seaweed cutting? The rockweed (Ascophyllum nodosum) industry of Maine and the Maritime Provinces. Annals of the New York Academy of Sciences. 1249: 84-103.

My research has been supported by the Bowdoin Scientific Station Fellowship and the Rusack Coastal Studies Fellowship.

Project Advisors: Damon Gannon, PhD and Amy Johnson, PhD.

Student Research Symposium

The 2014 Coastal Studies Fellows and Faculty Members
The 2014 Coastal Studies Fellows and Faculty Members

After six weeks of conducting their own research projects, the Coastal Studies Center’s summer fellows were eager to share their research with each other and visiting audience members at the Coastal Studies Summer 2014 Research Symposium.

With research projects ranging from studies of green crabs eating habits to lobsters’ cardiac responses to specific peptides, the short presentations given by 15 students and 7 faculty members span 7 different academic departments, showcasing the varied nature of Coastal Studies fellowships.

Fellowships that support student research in the coastal sciences include the Rusack Coastal Studies Fellowship, the Doherty Coastal Studies Research Fellowship, the Freedman Summer Research Fellowship, and the NSF Faculty Student Research on Computational Sustainability. Research topics ranged from studies that use marine organisms as models for understanding fundamental biological processes – locomotion in sea stars, for instance, or cardiac neural control in lobsters – to investigations of how coastal organisms and ecosystems are responding to environmental shifts such as rising ocean temperature and acidity.

lobster (Illustration credit: Abby McBride)

In his introductory remarks, Coastal Studies Center director and Associate Professor of Biology David Carlon described not only the ecological changes that are taking place in the Gulf of Maine but also the changes in store for the Center and its on-site Marine Lab.

“The lab is growing already,” Carlon said, with new dry- and wet-lab spaces scheduled to open in time for classes this fall, not to mention the pending acquisition of a new research vessel that will join the R/V Laine at the Coastal Studies Center dock. In the works is a marine science semester targeted at juniors and seniors, planned for fall 2015.

Associate Professor David Carlon presents

Following Carlon’s introduction, faculty members from Biology, Chemistry, Earth and Oceanographic Science, and Environmental Studies described their research and shared perspectives from their areas of expertise, while students supported by summer research fellowships reported on progress they’ve made so far and previewed their plans for the rest of the summer, opening up the floor for questions after each talk.

These students and faculty are making use of field sites throughout Maine and beyond, with a concentration of activity at the Coastal Studies Center itself, only twelve miles from Bowdoin’s campus – where they can take advantage not only of aquarium tanks and other laboratory facilities, but also the natural lab that is Harpswell Sound.

Coastal Studies Center 2014 Summer Research Symposium

The Coastal Studies Center is hosting a one day Research Symposium this Monday, July 14th. As in previous years, this meeting will be a friendly forum for students supported by summer fellowships to present an overview of their project, and their progress to date. New to this year, we are opening up the floor to postdocs and faculty who would like to tell us about their work in any aspect of marine or environmental science.


Shuttles will depart campus from the Druckenmiller loading dock at 8:00 AM. We expect shuttles will depart Coastal Studies by 3:30.


Please download a copy of your presentation the Bowdoin scratch drive [microwave/scratch/COASTAL STUDIES PRESENTATION JULY 2014] by Monday morning at 6:00 AM. Please plan to upload by this time so we can be sure to load your presentation in time. You can also bring a back-up copy on a thumb drive if you wish. Let Rosie Armstrong know if you have trouble accessing this folder. 


Time Speaker Topic
9:00 Dave Carlon, Director of the Coastal Studies Center Welcome and research remarks
9:15 Sarah Kingston, Doherty Marine Biology Postdoctoral Scholar “Genotype and phenotype in a changing ocean, how much is standing genetic variation influencing mussel populations’ reaction to ocean acidification?”
9:30 Christie Jewett ‘15
Doherty FellowshipAdvisor: Patsy Dickinson
“Does the presence of modulators alter the ability of the American lobster heart to generate a stable output pattern over a range of temperatures?”
9:45 Nathaniel Wheelwright, Professor of Biology “The effect of trait type and strength of selection on heritability and evolvability in an island bird population “
10:00 Michèle LaVigne, Assistant Professor of Earth & Oceanographic Science “Acidification Research on Maine Clam Flats: A Partnership between Bowdoin and The Kennebec Estuary Land Trust.”
10:15-10:30 Lloyd Anderson’16, & Bailey Moritz ‘16
Rusack Fellowships
Advisor: Michele LaVigne
“An Assessment of pH and the Effects of Ocean Acidification in Phippsburg Clam Flats”
10:30 Jack Mitchell ‘17(Remote presentation)
NSF/Computational Sustainability
“Analysis of long-term trends in DNA Barcoding sets from tropical marine zooplankton from the Hawaiian Islands”
11:15 Xuan (Circle) Qu ‘17
Doherty Fellowship
Advisor: Patsy Dickinson
“Pyrokinin peptides’ effect on the stomatogastric nervous system in the American lobster, Homarus americanus”
11:30 Tricia Hartley ‘15
Doherty Fellowship
Advisor: Patsy Dickinson
“Does the neuropeptide GYS modulate stretch feedback pathways in the lobster cardiac neuromuscular system?
11:45 Sophie Janes ‘16
Doherty Fellowship
Advisor: Patsy Dickinson
“Does nitric oxide alter the modulation of the cardiac system in the American lobster, Homarus americanus, via a peptide (GYSDRNYLRFamide)”
12:00 Amy Johnson, Professor of Marine Biology “What puts the bounce in the gait of the seastar Protoreaster nodosus.
12:15-12:30 Samantha Garvey ’16, & Brendan Soane ’16, Doherty Fellowships
Advisor: Amy Johnson
“How does tube foot coordination generate a novel bouncing gait in the Indo-Pacific seastar Protoreaster nodosus and the North Atlantic seastar Asterias rubens?”
12:30-1:30 LUNCH
1:30 Aidan Short ‘15
Doherty Fellowship
Advisor: Dave Carlon
“What’s for dinner? A molecular analysis of the feeding habits of the green crab Carcinus maenus in Harpswell Sound”
1:45 Sabine Berzins’16, Rusack Fellowship
Advisor: John Lichter
“Vulnerability of eelgrass (Zostera marina) to green crab (Carcinus maenas) invasion”.
2:00 Nora Hefner ‘16
Cook Fellowship
“GIS Analysis of the Historical Ecology of Gulf of Maine Cod Fisheries”
2:15 John Lichter, Professor of Biology & Environmental Studies Informal research remarks
2:30 Anna Hall ’15,
Freedman Fellowship
Advisor: Phil Camill
“Investigating the effects of climatic change on peatland C accumulation and fire dynamics in coastal Labrador, Canada”
2:45 Emily Tucker ’15 Hughes Fellowship
Advisor: Phil Camill
“Effects of Climate Fluctuations in Labrador on Indigenous Populations, 8,000 BCE- present”
3:00 Amanda Howard’15
Doherty Fellowship
Advisor: Beth Stemmler
“Localization and post-translational modifications of crustacean AST-C peptides: a mass spectrometric study using the lobster, Homarus americanus”
3:15 Beth Stemmler, Professor of Chemistry Informal research remarks

Bowdoin Marine Science Semester Fall 2014

In the Fall of 2014 we will run a pilot program for the Marine Science Semester, offering two courses at the Bowdoin Marine Laboratory and Coastal Studies Center. Transportation will be provided.

Each of course counts as an elective in the Biology Major. In addition, Biology 2330 will count as a Group 3 core course. Pre-requisites: Bio 1101, Bio 1102 or 1109, and one semester of Math.

Course to be taught Fall 2014

Dimensions of Marine Biodiversity – Biology 3301. Dave Carlon.
Class: Tuesday 2:30-3:55, Lab: Thursday 1:00-3:55
This inquiry driven field course examines the significance of marine biodiversity through the lenses of systematics, genetics, and functional ecology. Each semester we consider major contemporary scientific problems by confronting student-generated hypotheses with data sets from multiple dimensions of biodiversity in coastal Maine. For Fall 2014, we will examine the impacts of invasive species on native shellfish populations, build a longitudinal data set of coastal plankton, and investigate potential impacts of coastal aquaculture on marine ecosystem functioning. Taught at the Coastal Studies Center, Orr’s Island (Same as ES 2234).

Marine Molecular Ecology & Evolution – Biology 2330.  Sarah Kingston.
Class: Tuesday 1:00-2:25, Lab: Friday 1:30-4:30
Features the application of molecular data to ecological and evolutionary questions in coastal and marine contexts. Hands on work will introduce students to field sampling, data generation, and analysis of molecular data sets (using both Sanger-based and Next Generation Sequencing technologies). The course will emphasize robust sampling design in both ecological and population genetic contexts. Theoretical foci will include evolutionary and population genetic concepts and analytical tools: tenets of Hardy-Weinberg Equilibrium, Wright-Fisher model, the coalescent, evolutionary processes and signatures in the genome, speciation: maintenance and breakdown of reproductive isolation, spatial patterns and phylogeography, selection and linking genotype to phenotype. Lectures, discussions, data analysis, and computer-based simulations will demonstrate the relevant theoretical principles of population genetics and phylogenetics. A class project will begin a long-term sampling program that uses molecular tools to understand temporal and spatial change in the ocean. During the course of the project, students will learn to apply bioinformatic analyses to population-level genomic data.  Taught at the Coastal Studies Center, on Orr’s Island. (Same as ES 2233)

Questions? Contact Dave Carlon or Sarah Kingston

Dave Carlon, Associate Professor of Biology, and Director of the Bowdoin Marine Laboratory
232 Druckenmiller Hall
Phone: 207-798-4364, e-mail:

Sarah Kingston, Doherty Marine biology Postdoctoral Scholar
109 Bannister Hall

Message from the Director


Dave Carlon, Director of the Bowdoin Marine Laboratory
Dave Carlon, Director of the Bowdoin Marine Laboratory

The Bowdoin Marine Laboratory  is the scientific component of Bowdoin’s Coastal Studies Center. Our amazing site includes 118 acres of coastal spruce-pine forest and 8 miles of coastline. Our accessible location, and diversity of natural habitats opens up a wide range of marine, estuarine, and terrestrial research and teaching possibilities.

As the Bowdoin Marine Laboratory’s new Director, my job is to facilitate an expansion of research and teaching programs. Our growth will require new infrastructure and instrumentation. I am working with the Bowdoin administration, faculty, and staff on a strategic plan that includes a new “dry” teaching and research building, new housing, and new instrumentation to monitor climate change. This year we will begin work increasing the capabilities of our wet lab and building our small boat program. Our short history includes outstanding research from our Bowdoin community and friends from other institutions (see our list of publications). I would like to build on this intellectual platform and grow the breadth and depth of the research and teaching activities anchored by the BML by recruiting new researchers and new students from Bowdoin and beyond.

The Bowdoin Marine Laboratory has an outstanding geographical and ecological position for understanding the biological impacts of climate change. We are located within the Gulf of Maine ecosystem, a historically cold and productive body of water that has undergone a recent warming. Our coastal location and 8 km shoreline on Harpswell Sound, provide immediate access to tidally driven coastal and estuarine habitats, predicted to uniquely respond to increased warming due to high productivity and close linkages with terrestrial systems. Speaking of land, our peninsula on Orr’s Island includes 118 acres of upland forest, and I am strongly encouraging new courses and research that can capitalize on the terrestrial side of the Coastal Studies Center on Orr’s Island.

Come visit us on Orr’s Island to tour the facilities and see our stunning linkages between land and sea.

Dave Carlon, Director of the Bowdoin Marine Laboratory