Research at SEA


Scholarly Research

SEA faculty and staff are active in their fields and contribute regularly at professional conferences and to scholarly journals. We encourage SEA Semester students to stay involved in the research projects they contribute to during their time at SEA, and many have been included as authors on papers resulting from this work. See the list below for recent scholarly work by SEA staff and students. Scientific research aboard SEA vessels has contributed to over 50 publications in oceanography, environmental science, biology, geology, chemistry, physics, and other fields. Click here for a complete list of scientific publications.

#denotes SEA faculty author
^denotes SEA Semester student author
*denotes SEA Semester alumnus

March 2014

Seasonal and decadal changes in distribution patterns of Halobates (Hemiptera: Gerridae) populations in the eastern tropical Pacific

Mary Engels#, Liann Correia*, Sarah Piwinski*, Lanna Cheng, Erik Zettler#: Mar.Biol.: DOI: 10.1007/s00227-014-2414-x

Distributions of the marine insect Halobates collected aboard SSV Robert C. Seamans were compared to historical data from 40 years earlier. We observed differences in species distributions over time, but these were not due to climate change. Our analyses show that the patterns observed show substantial but previously undescribed seasonal shifts that occur each year in the ranges of these small water striders. There is substantial overlap in ranges during seasonal shifts, but very little co-occurrence of species in individual net tows, suggesting biological mechanisms rather than physical factors are restricting distribution and co-occurrence.

The article has just been published and is available as ‘Online First’ on SpringerLink. Click to read more.

February 2014 - Ocean Sciences Meeting

Monday, 24 February


08:15 in 316B: Lavender Law, K.#; Moret-Ferguson, S. E.*; Zettler, E. R.#; DeForce, E.; Proskurowski, G.;

We present Sea Education Association’s extensive survey of floating plastic debris in the eastern North and South Pacific Oceans, comprising more than 2500 plankton net tows conducted on annually repeated cruise tracks between 2001 and 2012.


From these data we define an accumulation zone (25° to 41°N and 130° to 180°W) in the North Pacific subtropical gyre that closely corresponds to several modeled regions of accumulation predicted from the convergence of ocean surface currents. Maximum plastic concentrations from individual surface net tows exceeded 106 pieces km-2, with overall concentrations decreasing with distance from the model-predicted accumulation zone center. Outside of the defined accumulation zone the median plastic concentration was 0 pieces km-2. Spatio-temporal variability in sampling can impose order of magnitude differences in summary statistics, such as mean and median concentrations, calculated over short time periods or limited geographic areas. Such sampling variability also obscures potential trends in plastic concentration over time. Comprehensive monitoring efforts must continue to critically access these biases while synthesizing available data to maintain a dynamic and robust understanding of plastic marine debris.


10:30 in 316B: Amaral-Zettler, L. A.; Boyd, G.; Slikas, B.; Zettler, E. R.#; Mincer, T. J.;

Plastic Marine Debris (PMD) is the most abundant form of marine debris found in all of the ocean’s gyres. The Plastisphere is defined as the thin layer of life found on the outer surface of PMD.


Plastisphere microbial communities on microplastics (<5 mm) collected from open ocean surface waters are distinct from the surrounding seawater and harbor a diversity of microbial species including potential pathogens. However, the variability of the Plastisphere over space and time remains underexplored. We completed collection and next-generation amplicon sequencing of 16S rRNA gene V6 hypervariable regions on samples from two open-ocean transects in the North Atlantic Subtropical Gyre and the North Pacific Subtropical Gyre, giving us good data sets for comparing regional differences within and between oceans. Our data reveal that many of the same bacterial Operational Taxonomic Units (OTUs) inhabit the Plastisphere of Atlantic and Pacific gyres, but dominant OTUs are often distinct on different pieces of plastic regardless of ocean basin. Our sampling strategy allows us to compare and contrast Plastisphere biogeography along marine longitudinal and latitudinal gradients.


10:45 in 316B: Mincer, T. J.; Guzzetta, V. S.; Slikas, B.; Zettler, E. R.#; Amaral-Zettler, L. A.;

Plastic Marine Debris (PMD) persists much longer than any natural floating substrate and provides an attachment surface for thin layers of life (termed the Plastisphere).


Our previous amplicon sequencing surveys of 16S rRNA genes have shown that Bacteria of the genus Vibrio can comprise a major portion of the Plastisphere – at times nearly 25% of the bacterial community. We adapted a 96-well plate format biofilm quantification assay to survey over 50 Vibrio spp. cultivars for attachment ability to various plastic resins. Some vibrios demonstrated cell density-dependent attachment and/or a preference for plastic resin type. Strikingly, ‘super-colonizer’ vibrios were discovered to form measureable biofilms on plastic in a matter of minutes. In general, biofilm formation phenotypes clustered within Heat Shock Protein 60 (HSP 60) gene phylogenies. We generated a metagenomic dataset of a Vibrio-dominated PMD sample and analyzed it for key adherence and virulence genes. Characterizing Vibrio attachment to plastic will provide a model for PMD colonization and clues to the ecological function of this prevalent group of Plastisphere inhabitants.


10:45 in 316B: Zettler, E. R.#; Morrall, C.; Proskurowski, G.; Mincer, T. J.; Amaral-Zettler, L. A.;

Recent studies have revealed a diverse microbial community on plastic marine debris in the Atlantic and Pacific oceans, the so-called “Plastisphere”. How this community develops over time on different types of plastic and in different geographic areas of the world ocean is unknown.


We immersed sterile polyethylene, polypropylene, polystyrene, and glass samples in temperate (Woods Hole, MA, USA) and tropical (St. Georges, Grenada) coastal surface waters, and then monitored the development of microbial communities on these substrates using quantitative counts of scanning electron micrographs and next-generation amplicon sequencing. A variety of pennate diatoms colonized plastic marine debris within the first week and diatoms dominated the early communities in both locations, followed by bacteria. Over time the community changed and other groups such as sessile ciliates colonized the plastic. Communities on expanded polystyrene developed more slowly than on the other substrates, and total coverage increased more quickly in temperate waters than tropical waters. Changes in the diversity and composition of communities over time may provide clues to the age of plastic marine debris, which is currently difficult to determine.


12:15 in 304AB: Goodwin, D. S.#; Schell, J. S.#; Siuda, A. N.#*;

Interdisciplinary teaching and course design encourage critical thinking, promote cognitive development, acknowledge the complexity of real world problems and solutions and, lastly, utilize a problem-solving narrative as the unifying framework providing purpose and relevance to discipline-specific content and methodologies.


Building upon this foundation and aiming to maximize student learning, Sea Education Association (SEA) assembled faculty teams from the traditionally separate disciplines of oceanography, history, policy, and nautical science, to develop 10+ interdisciplinary teaching (IDT) modules. Each IDT module addresses an established marine environmental problem, incorporates problem-solving through a case study approach, emphasizes the challenges and complex pathways inherent in moving towards a solution, and continues to disseminate disciplinary content, skills, and analytical strategies in an integrated way. We will present three IDT modules (iron fertilization, marine debris, and cruise planning in a changing climate) implemented in SEA Semester programs to illustrate their pedagogic components and highlight student outcomes. Most surprising, this teaching initiative, planned for a single course, has guided the evolution of further curriculum design resulting in institution-level change and the development of an entirely new interdisciplinary multi-course semester.


16:00-18:00 poster session: Amaral-Zettler, L. A.; Yingxin, Y.^; Ong, B.^; Siuda, A. N.#*; Zettler, E. R.#;

Science education combining classroom work with field and laboratory research engages students and can make real contributions to ongoing research projects.


As an example, SEA Semester: Marine Biodiversity and Conservation requires students to take classes combining theory and training in conservation science and policy, including molecular biology, ecological statistics, microscopy, morphology-based taxonomy, conservation planning, GIS, cultural landscape analysis, and marine spatial planning. Students propose a research project that ties into ongoing long-term studies, then live, work, and study aboard a sailing research vessel for 5 weeks to collect samples and data for their projects. Students carry out biodiversity research projects and develop conservation plans for High Seas protection with the Sargasso Sea as a backdrop. Following the first offering of the curriculum, two students continued their research on bacteria associated with plastic marine debris during summer internships in Woods Hole and as part of senior capstone theses at their home campuses. We use these case studies to show how this educational model challenged the students, provided valuable training for their development as young scientists, and contributed to ongoing research projects.

Wednesday, 26 February


09:30 in 301AB: Goodwin, D. S.#; Schell, J. S.#; Siuda, A. N.#*;

Sargassum natans and S. fluitans, pelagic drift macroalgae species, are distributed across surface waters of the North Atlantic Gyre (Sargasso Sea), Caribbean Sea and Gulf of Mexico.


These floating ecosystems host diverse biological communities including ecologically and commercially important organisms. As a result, pelagic Sargassum is the focal organism of a new policy initiative to make the Sargasso Sea a high-seas Marine Protected Area. Though observations of Sargassum date back centuries, certain basic questions about distribution and species-specific community composition remain unanswered. This study employs a dataset archived by Sea Education Association (SEA) to examine the distribution and concentration of S. natans and S. fluitans collected from approximately 6000 surface net tows conducted on more than 300 cruises between 1993 and 2013. Distinct seasonal and geographic patterns exist for each species, suggesting that Sargassum in the Sargasso Sea may have multiple source populations each regulated by separate yet overlapping biophysical dynamics. Presently utilized satellite observation methods cannot differentiate between species and thus may not provide sufficient information to guide regional management strategies.

February 2014

A Review of Observations of Floating Tar in the Sargasso Sea

Peters, A.J., and A.N.S. Siuda. 2014. A review of observations of floating tar in the Sargasso Sea. Oceanography 27(1):217–221,

Floating tar balls are a product of weathering of crude oil in the marine environment. They have been found to be prevalent in the world ocean, particularly in the 1960s and 1970s before stricter controls on petroleum transport and handling were in effect. Much of the early research on the occurrence and composition of pelagic tar balls was conducted in the North Atlantic Ocean. Research and time-series assessments in the Sargasso Sea since that time have documented that floating tar balls sampled by neuston nets in the open ocean and washed up on shorelines have declined in the past two decades.

December 2013

Two SEA alumni (Edson and Sehein) presented research posters and two SEA faculty members (Siuda and Zettler) presented talks at the 7th annual BioNES (Biology New England South) meeting at Roger Williams University on 6 December:

  • Ethan Edson (SEA C247/Northeastern Univ.)-Genetic Diversity of Vibrio on Natural Versus Artificial Substrates Across the Sargasso Sea
  • Taylor Sehein (SEA C241/Northeastern Univ.)-Slender Sargassum Shrimp (Latreutes fucorum) Population Genetic Structure in the Sargasso Sea
  • Amy NS Siuda-Sargassum sp. Distributions in the Western North Atlantic: Implications for Conservation and Management
  • Erik Zettler-Life in the ‘Plastisphere:’ The Ecology of Plastic Marine Debris

The results are based on a combination of student projects during the SEA program ‘Marine Biodiversity and Conservation’, current NSF grants, and SEA’s long term data sets.

October 2013

Gooseneck barnacles (Lepas spp.) ingest microplastic debris in the North Pacific Subtropical Gyre

Miriam C. Goldstein​ and Deborah S. Goodwin. PeerJ: DOI 10.7717/peerj.184

The latest research findings from SEA Semester plastic marine debris research by Miriam Goldstein (Scripps Institution of Oceanography) and SEA oceanographer Deb Goodwin describes and quantifies ingestion of plastic particles by Gooseneck barnacles attached to floating marine debris. Miriam and Deb sailed together on SEA Semester trips multiple times and this study integrates samples collected during a Scripps voyage that Miriam led (SEAPLEX 2009), a SEA Semester voyage that Deb led (S-242), and the recent Plastics at SEA 2012 expedition in the Pacific (S243). They found that 33.5% of the 385 barnacles examined had plastic particles in their gut, ranging from one plastic particle to a maximum of 30 particles.

Research Abstract: Click for Details

Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG) since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp.), which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

June 2013

Life in the "Plastisphere": Microbial communities on plastic marine debris

Zettler, E.R., T.J. Mincer, and L.A. Amaral-Zettler. Env.Sci.&Tech.: DOI: 10.1021/es401288x.

This study of the microbial community that develops on plastic marine debris is based on samples collected during SEA Semester voyages and was published in Environmental Science & Technology. SEA scientists and students are contributing to this collaborative research project between three Woods Hole organizations: SEA, Marine Biological Laboratory, and Woods Hole Oceanographic Institution.

Research Abstract: Click for Details

Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

March 2013

SEA Semester Marine Biodiversity and Conservation: Improving Stewardship Capacities through Field based Undergraduate Education

John Jensen, SEA (presenter); coauthors Amy Siuda, Sea Education Association;  James McDonald Western Michigan University; Caleb McClennen Wildlife Conservation Society; Linda Amaral-Zettler Woods Hole Marine Biological Laboratory; Erik Zettler Sea Education Association

Presented at the 2013 GWS Biennial Conference on Parks, Protected Areas, and Cultural Sites: "Protected Areas in a Changing World", Denver, Colorado • March 11-15, 2013

Research Abstract: Click for Details

The goal of SEA Semester: Marine Biodiversity and Conservation (MBC) is to make a significant and continuing contribution to improved ocean stewardship by developing a new generation of leaders in ocean science and public policy dedicated to understanding, preserving, and restoring our global ocean commons. Funded by NSF and the Virginia Wellington Cabot Foundation, the MBC curriculum integrates science, conservation policy, and place-based management through a field-based study of the potential of the Sargasso Sea as a high seas protected area. The new curriculum combines instruction in classical and cutting-edge techniques in marine biodiversity research, practical tools from conservation, and emergent concepts in placebased management. Initial analyses of first year results suggest a 34-point increase in conservation science and policy content knowledge, improved capacities in written and oral communication, and --most important--an increased engagement and interest among the strongest students in careers related to coastal and ocean stewardship.

February 2013

Designing a Seabird Observation Protocol for the Sea Education Association

Michael B. Schrimpf*1, Erik R. Zettler1, and K. David Hyrenbach2; 1Sea Education Association, P.O. Box 6, Woods Hole, MA 02543 USA,; 2Hawai’i Pacific University, Waimanalo, HI 96795, USA

Presented at the Pacific Seabird Group annual meeting, Portland, OR.

Research Abstract: Click for Details

The Sea Education Association (SEA) is dedicated to marine exploration, understanding, and stewardship, and to the study of humanity's relationship with the oceans. SEA offers high school and undergraduate students an interdisciplinary curriculum, with on shore and at sea components aboard oceanographic sailing school vessels. Cruises are primarily conducted in the tropical and subtropical eastern Pacific Ocean, the northwestern Atlantic Ocean, and the Caribbean Sea. Studies of seabirds on these cruises have been limited in the past, primarily due to constraints of identification for inexperienced students, especially in tropical – subtropical areas of generally low bird abundance. We wish to augment these past efforts by developing standardized survey protocols and identification guides that will allow students to collect meaningful distributional data. Visiting scientists have also participated in some of our past cruises, providing opportunities to collect traditional transect survey data while introducing motivated students to topics in seabird biology and conservation. Our primary goals are to: (1) determine what level of taxonomic identification and ancillary data are both required by researchers and feasible for students, and (2) design a protocol that will enable the collection of survey data valuable for collaborative projects. Another goal of this presentation is to explore whether members of the Pacific Seabird Group research community are interested in joining future SEA cruises.

Sweepstakes Reproductive Success of the Caribbean Spiny Lobster (Panulirus Argus) in the Sargasso Sea

Pivor, J.; Daniel, J.; Siuda, A. N.; Bucklin, A.; Blanco-Bercial, L.; Amaral-Zettler, L.; Zettler, E.

Research talk presented at the ASLO (Association for the Sciences of Limnology and Oceanography) meeting in New Orleans, LA, Feb 2013.

Research Abstract: Click for Details

The Caribbean spiny lobster (Panulirus argus) is widely distributed across the Atlantic Ocean and the fishery is highly economically important. Long-range dispersal of the long-lived planktonic larvae and consequent complex and variable recruitment patterns have generated persistent difficulties in prediction of recruitment and design of effective management strategies. Similar to other highly- fecund and highly abundant marine species, P. argus has lower genetic diversity than expected from abundance and census population size. One explanation may be the Sweepstakes Reproductive Success (SRS) hypothesis, which poses that high variance in individual reproductive success results in smaller effective population size. In particular, SRS predicts less genetic diversity in larval cohorts compared to adult spawning stocks. Life stage and genetic analysis of phyllosome larvae of P. argus collected from the Sargasso Sea has revealed spatial patchiness and genetic differentiation among life stages of similar cohorts. Time/space patterns of population genetic diversity and structure allowed us to test the SRS hypothesis for P. argus and provide new understanding to inform management and policy strategies for this important fishery.

October 2012

Amy Duarte, an alumna of PEP (Partnership Education Program) presented a poster at the national Society for Advancement of Chicanos and Native Americans in Science (SACNAS) meeting held in Seattle, Washington from October 11-14, 2012. Amy’s poster was based on a research internship she did in collaboration with scientists at SEA, Woods Hole Oceanographic Institution, and Marine Biological Lab:

“Analysis of Plastic in the Sargasso Sea and Vibrio Interactions with Plastic” by Amy Duarte1, Erik Zettler2, Linda-Amaral Zettler3, Tracy Mincer4
(1Humboldt State University, CA, 2Sea Education Association, 3Marine Biological Laboratory, 4Woods Hole Oceanographic Institution, Woods Hole, MA)

April 10, 2012

SEA scientists and students are authors on a new publication in Geophysical Research Letters. Proskurowski. Morét-Ferguson and Law are SEA scientists, and Meyer did this work as an SEA alumnus while enrolled at Eckerd College in St. Petersburg, FL.

Kukulka, T., G. Proskurowski, S. Morét-Ferguson, D.W. Meyer, and K.L. Law. The effects of wind mixing on the vertical distribution of buoyant plastic debris. GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L07601, 6 PP., 2012, doi:10.1029/2012GL051116

March 2012

SEA Education Association received a National Science Foundation collaborative research grant “Microbial Interactions with Marine Plastic Debris: Diversity, Function, and Fate”. This 3 year project is being directed by Tracy Mincer (Woods Hole Oceanographic Institution), Linda Amaral-Zettler (Marine Biological Laboratory), and Erik Zettler (SEA). The research will use a combination of culturing, molecular biology, and microscope imaging to explore the diversity and function of the unique microbial community that develops on plastic marine debris. The field component of this proposal takes advantage of SEA’s ongoing plastic debris research and is built around independent projects by undergraduate students participating in SEA Semester research cruises in the Atlantic and Pacific Oceans.

Featured Research: Plastics at SEA

Click here to go to the Plastics at Sea Pacific Expedition website.

Since 1971 SEA students and faculty have been sailing and studying the oceans, towing nets to collect planktonic organisms from the surface waters. In addition to microscopic plankton, scientists have found these nets also collect small pieces of floating plastic debris. It was not long before this plastic "trash" was of scientific interest itself.

For more than 20 years SEA has been carefully measuring the abundance of plastic marine debris in the North Atlantic and Caribbean Sea on the sailing oceanographic research vessels SSVs Westward and Corwith Cramer, and also in the North and South Pacific since the arrival of the SSV Robert C. Seamans in 2001.

More than 6150 surface net tows have been carried out from Nova Scotia to the Caribbean Islands, collecting 64,000+ plastic pieces that have been handpicked from net samples. On cruises from Hawaii to the west coast of the U.S. samples have been collected in the much-popularized "Great Pacific Garbage Patch".

Plastic has emerged as a major contaminant in the ocean, yet the most basic questions about its sources, abundance, distribution, and fate in the open ocean remain largely unanswered.

Marine debris poses significant threats to marine life, such as:

  • injury or death to large marine mammals due to entanglement by large debris
  • ingestion of smaller plastic debris by seabirds, turtles, and even zooplankton
  • transport of marine organisms to regions where they may be invasive
  • plastic materials attracting some chemical pollutants from the ocean, while releasing other harmful compounds into the water

By understanding where in the ocean the plastic collects and the oceanographic reasons why, SEA is taking the first step in tackling these threats to living marine resources.

This work was supported by the National Science Foundation.