Life in Plastic, It’s not Fantastic

Samuel Daughenbaugh, DePauw University

2DA71FE7-975A-4AA8-8A78-DF3D1E545F05The Problem: We live in a plastic world. Plastics have saturated all aspects of our daily lives and, as a consequence, have also entered the natural world.  About 8.3 billion metric tons have been produced in the past 60 years, playing a pivotal role in the advancement of modern society (Parker, 2018). Although they are used to create many things we enjoy and benefit from, there are serious consequences for the health of humans and the environment that are associated with their use.

We have found plastics in unexpected places, everywhere from human guts to the most remote locations on earth (Schwabl, 2018; Woodall, 2014). Plastics have a long list of negative effects on living organisms, but their impact in the ocean is of special concern. Pictures of turtles with straws up their noses, bottle caps spilling out of dead bird stomachs, and penguins strangled in plastic beverage rings are often posted on social media sites. Less widely known are the chemical additives that leach from plastics. Phthalates are one such group of additives that pose threats to the health of humans and marine life.


Current Fort Johnson REU Interns (Julianna Duran not pictured) collecting plastic and sand dollars on Otter Island. (Photo credit: R. Podolsky)

Phthalates have been valuable to the plastic industry because they promote flexibility and durability in many plastics (EPA, 2017). An astounding 470 million pounds of phthalates are used in the United States every year (EPA, 2017). This presents a significant problem because phthalates interfere with the production of important hormones that regulate growth and metabolism in humans and other animals (Boas et al., 2012).

This summer I am exploring the effects of three different phthalates– dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP)–on the larval development of marine invertebrates, using the purple-spined sea urchin (Arbacia punctulata) as a model. Sea urchin larvae float freely in the water column for an extended period of time and, therefore, are vulnerable to many marine pollutants.


Purple-spined sea urchin (Arbacia punctulata)

Sea urchins are an important model because they are closely related to humans. Both humans and sea urchins use a signaling hormone called thyroxine, which is especially important for growth in early developmental stages (Heyland et al., 2006). Exposure to phthalates can disrupt the production of thyroxine. Additionally, larvae are very important to study because they form the base of food webs. Being at the bottom of the food chain means they feed animals at higher levels, many of which humans rely on for protein. Therefore, understanding how phthalates affect sea urchin growth and metabolism can lead to new insights into how these pollutants directly and indirectly impact human health.


I would like to thank my mentor, Dr. Robert Podolsky, for his continued support, guidance, and encouragement. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.


Boas, M., Feldt-Rasmussen, U., & Main, K. M. (2012). Thyroid effects of endocrine disrupting chemicals. Molecular and Cellular Endocrinology, 355(2), 240-248. 

Environmental Protection Agency (Ed.). (2017). Phthalates. America’s Children and the Environment, 3, 1-19.

Heyland, A., Price, D. A., Bodnarova-Buganova, M., & Moroz, L. L. (2006). Thyroid hormone metabolism and peroxidase function in two non-chordate animals. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 306B(6), 551-566.

Parker, L. (2018, December 18). A whopping 91% of plastic isn’t recycled. Retrieved from

Schwabl, P. (2018, October). Assessment of Microplastic Concentrations in Human Stool. Conference on Nano and microplastics in technical and freshwater systems, Monte    Verità, Ascona, Switzerland.

Woodall, L. C., Sanchez-Vidal, A., Canals, M., Paterson, G. L., Coppock, R., Sleight, V., . . . Thompson, R. C. (2014). The deep sea is a major sink for microplastic debris. Royal      Society Open Science, 1(4), 140317-140317. doi:10.1098/rsos.140317


Pinniped Problems: Domoic Acid Diatom Denotes Death

Jackson Eberwein, Sonoma State University

The Problem: Imagine a new disease spreading through your community, and it is deadly. It injures the kidneys, affects heart muscles, and causes parts of the brain to wither away. Scientists and doctors know that it is caused by a toxin made by a microscopic organism that loves to suddenly appear with force in unpredictable restaurants across the country. Despite this knowledge, doctors have no good way of knowing that a person has the disease until it is too late.
This is the reality for California sea lions. Along the west coast, large blooms of algae have been producing a toxin called domoic acid, and sea lions have been getting stomachs full of it through their diet of alga-eating fish. According to California Marine Mammal Stranding Network records from 1998 to 2006, around one out of every four California sea lion beach strandings or deaths along most of the California coast were due to exposure to the biotoxin. Since 2006, blooms of the algae have increased, with stranding numbers rising along with them.

California Sea Lion (Zalophus californianus) spooked about eating bad fish.
Photograph by Pixiabay

No good blood test exists for Domoic Acid Toxicosis, as the biotoxin that causes it rapidly clears from the body of sea lions. This means veterinarians can’t see if a sea lion has it unless they use outdated or expensive tests, or guess based on how an animal acts. Since veterinarians don’t have a good way to measure how bad the disease is, they don’t really know for sure if what they do helps a sick sea lion. If they wait to use the behavior of the animal to judge, then it is already too late because the disease has done permanent damage.
So how do we get a viable blood test? Can something be measured in blood when it is simply not there? In this case, we think it can, though not directly. While the domoic acid is in the body, it will be doing what toxins do best: messing with a lot of things that should not be messed with. This will cause changes in the body, such as more or less of a protein being made than it usually is. An unusual change in production of a protein could be measured instead of the toxin that caused that change. In this situation, the protein is called a “biomarker”, or a proxy for measuring the real target. By finding a biomarker protein in sea lion blood, it will actually be possible to make a cheap and effective blood test for the impacts of domoic acid!


I would like to thank Dr. Michael Janech, Dr. Benjamin Neely, Alison Bland, The Marine Mammal Center, & College of Charleston. Supported in part by the Fort Johnson REU Program, NSF DBI-1757899.

Neely BA, Ferrante JA, Chaves JM, Soper JL, Almeida JS, Arthur JM, et al. (2015) Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis. PLoScONE 10(4): e0123295. doi:10.1371/ journal.pone.0123295

Bejarano, A.C., Gulland, F.M., Goldstein, T., Leger, J.S., Hunter, M.S., Schwacke, L.H., VanDolah, F.M., & Rowles, T.K. (2008). Demographics and Spatio-Temporal Signature of the Biotoxin Domoic Acid in California Sea Lion ( Zalophus californianus ) Stranding Records.

Laake JL, Lowry MS, DeLong RL, Melin SR, Carretta JV (2018) Populationgrowth and status of California sea lions.J Wildl Manage82: 583–595 .

America’s Continuing Toxic Legacy: Quantifying the Impact of PCBs

Carolina Rios, New York University

The Problem: Polychlorinated biphenyls (PCBs) are a legacy contaminant that pose a threat to human health. PCBs are classified as possible carcinogens and are known to affect neurological development and contribute to diabetes (Xue et. al 2014). Additionally, PCBs are known to alter liver function, impact immune and thyroid function and effect reproduction, as well as gastrointestinal and respiratory health (Hansen 1987). Humans are largely exposed to PCBs by consuming contaminated animal products, such as contaminated fish or dairy (Xue et. al 2014). Similarly, dolphins sampled near Brunswick, Georgia were found to have elevated levels of PCBs, likely due to the consumption of contaminated fish (Wirth et. al 2014). The hydrophobic properties of PCBs mean that they bioaccumulate and can be found in aquatic organisms in concentrations thousands of times greater than the surrounding environment (Nimmo et. al 1974). PCBs also biomagnify up trophic levels in the web, and can be found in even greater concentrations in predator species, as they consume contaminated prey. Thus, the effects of PCBs can be felt throughout the ecosystem.

As PCBs are still relevant contaminants, it is important that we are able to quantify injury associated with PCB levels found in the coastal environment. It is particularly difficult to assess this risk to benthic marine invertebrates (organisms that live in the interface between the bottom of the ocean and the sediment). Therefore, a model has been proposed that predict rates of injury to benthic marine invertebrates (Finkelstein. et al 2017). This model was created through an extensive literature search. However, the data collected as the basis of this mathematical model dates back to the 1970s. In order to verify this model, it is important that we generate new data to verify the accuracy of the model in predicting benthic marine invertebrate injury.

Biphenyl structure. PCBs consist of a biphenyl structure of varying degrees of chlorination. Created using Chemdraw

PCBs were produced for industrial use, such as dielectric fluids, hydraulic fluids, and heat transfer fluids. From 1929 to 1977, PCBs were produced by the Monsanto Corporation in the US, before being removed from production due to negative effects on human health and the environment. Of the 1.4 billion pounds of PCBs produced in the US, it is estimated that one third has entered the environment (Safe et. al 1987). Though they are no longer being produced, their stability and long half-life means that PCBs are still present and continue to pose a real threat to the environment.


I would like to thank Dr. Ed Wirth and Brian Shaddrix for their continued guidance and support, as well as my co-mentor Dr. Paul Pennington. Supported by the Fort Johnson REU Program, NSF DBI-1757899.


Finkelstein, K. & Beckvar, N. & Dillon, T. (2016). Benthic injury dose-response models for PCB-contaminated sediment using equilibrium partitioning. Environmental toxicology and chemistry, 36 (5), pp. 1311-1329. doi:10.1002/etc.3662.

Hansen, L. (1987). Polychlorinated Biphenyls: Environmental Occurrence and Analysis. In S. Safe (Ed.), Polychlorinated Biphenyls (PCBs): Mammalian and Environmental Toxicology, pp. 15-48. Berlin, Heidelberg: Springer Berlin Heidelberg.

Nimmo, D. & Forester, J. & Heitmuller, P & Cook, G. (1974). Accumulation of Aroclor 1254 in grass shrimp (Palaemonetes pugio) in laboratory and field exposures. Bulletin of environmental contamination and toxicology. 11 (4) pp. 303-308. 10.1007/bf01684932.

Safe S., & Safe, L., & Mullin, M. (1987). Environmental Toxicology of Polychlorinated Biphenyls. In S. Safe (Ed.), Polychlorinated Biphenyls (PCBs): Mammalian and Environmental Toxicology, pp. 1-13. Berlin, Heidelberg: Springer Berlin Heidelberg.

Wirth, E.F., & Pennington, P.L., & Cooksey, C., Schwake, L., & Hyland, J., & Fulton, M.H. (2014) Distribution and sources of PCBs (Aroclor 1268) in the Salepo Island National estuarine research reserve. Environmental Monitoring and Assessment. 186 (12) pp. 8717-8726. doi:10.1007/s10661-014-4039-4

Xue, J., & Liu, S., & Zartarian, V., & Geller, A., & Schultz, B. (2014). Analysis of NHANES measured blood PCBs in the general US population and application of SHEDS model to identify key exposure factors. Journal of Exposure Science and Environmental Epidemiology. 24 (6) pp. 615-621. doi: 10.1038/jes.2013.91

Meddling with Mysterious Macroalgae

Pressley Wilson, University of South Carolina Aiken

The problem: If you have ever been in the ocean, you have probably come across a piece of seaweed, which is a type of macroalgae. Macroalgae are simply algae that can be seen without a microscope. These organisms undergo photosynthesis, produce carbon, and can reduce the levels of phosphates and nitrates in water (Champagne et al. 2015).

Although algae are one of the most important parts of marine ecosystems, the algae microbiome (the bacteria that live in and around algae) is highly unknown and further research is needed to uncover this critical macroalgae information. Is there a relationship between bacteria and algal species? Is there a relationship between the algae’s physical features and the bacteria? Or is the microbiome the same throughout the algae, regardless of variation in species and physical features?

In order to answer these questions, I am conducting a research project this summer looking at the bacteria that are associated with intertidal macroalgae from One’ula Beach, Hawai’i.

Intertidal region of One’ula Beach, Hawaii

The five species below were chosen from the intertidal region of One’ula: Asparagopsis taxiformis (1), Avrainvillea sp (2), Halimeda discoidea (3), Padina sanctae-crucis (4), and Dictyota sandviscensis (5). These species were chosen because they range from red, brown, and green algae; have varying physical features; and all currently grow on the intertidal region of One’ula Beach.

Macroalgae from One’ula Beach, Hawaii (Photo credit: Dr. Heather Spalding)

Asparagopsis, Avrainvillea, and Dictyota are uncalcified, Halimeda is calcified, and Padina is lightly calcified. Asparagopsis has fluffy upright filaments, Avrainvillea and Padina have a fan-shaped thallus, Halimeda has flattened segments, and Dictyota has dichotomous branches. All species are native to One’ula Beach, Hawaii, except Avrainvillea which is an invasive species, meaning it is not native to the area. These species represent a diverse array of brown algae (Padina and Dictoyta), green algae (Avrainvillea and Halimeda) and one red alga (Asparagopsis).

This research will lead to a better understanding of algae, which could lead to a better understanding of all photosynthetic marine organisms. Furthermore, this research will be used as preliminary results for Dr. Heather Spalding’s work in the Northwestern Hawaiian Islands determining if there is a relationship between spatial patterns and the algae microbiome, beginning in August.


I would like to thank Dr. Heather Fullerton for her guidance and support with this project and Dr. Heather Spalding for her sample collection. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899. 


Champagne P, Hall G, Liu X, Wallace J, Yin Z. 2015. Determination of Algae and Macrophyte Species Distribution in Three Wastewater Stabilization Ponds Using Metagenomics Analysis. MDPI – Water. 7(7): 3225-3242.

Invisible Neighbors: How Gracilaria Changes Bacterial Communities

Lilia Garcia, Illinois Wesleyan University

The Problem: It only takes a walk along the mudflats to notice large patches of wiry, red seaweed. The seaweed is called Gracilaria vermiculophylla, an invasive organisms that is native to East Asia (SERC, 2019)  The seaweed is hard to miss, but its effects on the ecosystem are not easily seen. This summer I will be studying how Gracilaria affects a bacterial community invisible to the naked eye.

Mudflat with Gracilaria, taken by L. Garcia

According to previous studies, Gracilaria is found to increase the amount of a bacteria called Vibrio (Gonzalez, et al., 2014). This may not mean much at first, since most of us don’t think about microscopic interactions. Bacteria, however, are important in maintaining the health of complex environments like estuaries. They cycle and break down nutrients and organic matter, influencing oxygen, carbon, and nitrogen levels. An increase in one group of bacteria, such as Vibrio, can change these patterns. And like most of us know, bacteria tends to spread easily. There are a few strains, or types, of Vibrio, such as V. vulnificus, V. parahaemolyticus, and V. cholera, that are dangerous to human health. An increase in these strains may cause an increase in disease from swimming or eating infected food.†

Vibrio growing on petri dish, taken by L. Garcia

We known Vibrio levels increase with Gracilaria, but we do not know how this happens. We also don’t know if all Vibrio strains increase together, or if only a few strains grow. To understanding the relationship between Gracilaria and Vibrio, I will record how much total Vibrio and how many strains of Vibrio grow in and away from patches of Gracilaria. In order to preserve its own health, Gracilaria produces compounds that promote or stop organisms from growing around it (Assaw et al., 2018). These are compounds I will test against different strains to study the mechanism Gracilaria uses affect specific Vibrio levels. I want to see how the growth of each strain is affected by different extracts. Will the strains further away from the Gracilaria be unable to grow when exposed to a certain type of extract? Will other strains grow better with the extract?

We tend to think about invasive species on a large scale, assessing the damage it causes to other familiar animals and plants. The ecosystem relies on tiny, cellular organism and studying how bacteria changes leads to a deeper understanding of environmental health. An invisible community is changing as Gracilaria flourishes, and there is a lot left to learn about it. 


Thank you to my mentor Dr. Erik Sotka, and our collaborator Dr. Erin Lipp. I would also like to thank Dr. Alan Strand and Kristy Hill-Spanik for their supporting guidance. Lastly, thank you to Dr. Loralyn Cozy (IWU) for preparing me to succeed in the lab. All research is funded by Grice Marine Lab and College of Charleston through the Fort Johnson REU Program, NSF DBI-1757899


Assaw S, Rosli N, Adilah N, Azmi M, Mazlan N, Ismail N. 2018. Antioxidant and Antibacterial Activities of Polysaccharides and Methanolic Crude Extracts of Local Edible Red Seaweed Gracilaria sp. Malays Appl Biol. 47(4): 135-144. 

Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT. 2019. National Exotic Marine and Estuarine Species Information System. 

Gonzalez D, Gonzalez R, Froelich B, Oliver J, Noble R, McGlathery K. 2014. Non-native macroalga may increase concentrations of Vibrio bacteria on intertidal mudflats. Mar Ecol Prog Ser. 505: 29-36.

From Female to Male – Mud Snails Tell All!

Kelsey Coates, Duquesne University

The Problem: Remember the big fuss over a chemical called tributyltin? Tributyltin (TBT) was used as an antifouling agent in paint on ships’ hulls (De Mora et al., 1997). Antifouling agents prevent marine organisms, such as barnacles, from growing on the bottom and sides of ships. TBT did that and more. In fact, it was banned in the United States in the 1980s when it was found to be a biocide – meaning it unintentionally killed marine plants and animals that were not on the ships’ hulls (De Mora et al., 1997). Long after being banned, TBT is still detectable in marine environments, categorizing it as a ‘legacy’ contaminant. It is also considered an endocrine disrupting chemical (EDC). EDCs are contaminants that mimic hormones in the bodies of people and other organisms, like the mud snail. EDCs can change the effects of hormones which can alter health and physical development.

Me at Grice Beach in Fort Johnson, SC collecting mud snails to examine their sexual organs and patterns of gene expression. Each bump in the mud is a snail! We verified that the snails were no longer in their reproductive season. Photo taken by Edwina Mathis.

The eastern mud snail, Tritia obsoleta, is abundant on the mud flats of the estuaries and rivers around Charleston, SC. They live in groups in the same intertidal zones for all 20 – 40 years of their lives. Mud snails use the winter season to reproduce and the summer season to feed and grow. Mud snails are detritivores, meaning they feed on decaying plant and animal matter bound to sediments and in the water column. This makes mud snails especially susceptible to chemical contaminants that associate with sediments, like TBT. One of the endocrine disrupting effects of TBT on mud snails is the induction of imposex, where female snails develop male sex organs to varying degrees (Sternberg et al., 2008). Because mud snails are so sensitive to TBT, elevated exposures lead to more extreme changes and infertility. This can happen to female snails of all ages over time! Mud snails are an ideal alert system for contamination because they stay in the same location all their long lives, spend months of the year solely focused on feeding, and show a spectrum of imposex based on exposure level. If there is any contaminant in the harbor water or sediment – the mud snail is sure to take it up.

TBT and other similarly acting EDCs may be of major concern due to the Charleston Harbor Dredging Project. The dredging project is going to make Charleston harbor the deepest harbor in the east coast (USACE, 2015). Dredging will likely resuspend sediments that had long past settled on the bottoms of waterways. Disturbing the sediment in this way could potentially release legacy contaminants, like TBT, into the water column and along the mud flats. This may increase imposex rates as well as other effects on a wide range of organisms and people. In the body, TBT acts like a hormone that binds to a receptor called the Retinoid X Receptor (RXR) (Iguchi et al., 2007). RXR in the mud snail is expected to come in three different forms called isoforms. My goal this summer is to sequence those isoforms to determine how different chemicals or different concentrations of the same chemical can change the relative levels of the RXR isoforms. By accomplishing this goal, mud snails can be used in the future to detect contaminants that affect marine organisms because their pattern of isoform expression might suggest which contaminants are present in the environment where they live.

Graduate student Edwina Mathis and I doing a NanoDrop to determine the purity of the mud snail DNA product we want to sequence. Photo taken by Katie Hiott.

Imposex is a concern for mud snails because interference with female snails’ sex organs can lead to infertility. Also, mud snails inhabit the same areas as crabs and juvenile fish. If crabs and small fish become contaminated, the larger fish and birds that prey on them would become contaminated in higher levels by the process of biomagnification. This could limit the amount and types of fish that humans can eat and sell which would disrupt the local marine economy. If the contaminants go undetected, it could lead to human reproductive and other health disorders. It is important to study imposex for the sake of all marine species and humans that use the harbor for food, shelter, and recreation.


I would like to acknowledge Dr. Demetri Spyropoulos, Edwina Mathis, Dr. Bob Podolsky, The Fort Johnson REU Program, The Hollings Marine Lab, NOAA, and The Grice Marine Lab. This research was supported by the Fort Johnson REU Program, NSF DBI-1757899.


  1. de Mora, S. J., and E. Pelletier. “Environmental Tributyltin Research: Past, Present, Future.” Environmental Technology 18, no. 12 (1997/12/01): 1169-77.
  2. Sternberg, Robin M., Andrew K. Hotchkiss, and Gerald A. LeBlanc. “Synchronized Expression of Retinoid X Receptor Mrna with Reproductive Tract Recrudescence in an Imposex-Susceptible Mollusc.” Environmental Science & Technology 42, no. 4 (2008/02/01): 1345-51.
  3. Iguchi, Taisen, Yoshinao Katsu, Toshihiro Horiguchi, Hajime Watanabe, Bruce Blumberg, and Yasuhiko Ohta. “Endocrine Disrupting Organotin Compounds Are Potent Inducers of Imposex in Gastropods and Adipogenesis in Vertebrates.” Molecular and Cellular Toxicology, Vol. 3, (2007): 1-10
  4. US Army Corps of Engineers. “Charleston Harbor Post 45 Final Integrated Feasibility Report/Environmental Impact Statement.” (2015/06)

Calling All Corals

Jordan Penn, Millersville University

The Problem: On average, light cannot penetrate ocean waters beyond a depth of 200m. This region of the world ocean is commonly named the “deep sea.” These depths are characterized by enormous pressure and frigid temperatures. However, the deep sea has become an area of increasing interest as we have come to learn about the unique habitat it provides as well as the abundance and diversity of species it supports. Researchers estimate that the deep sea may be home to as many as 100 million species, most of which are still unrecorded.

Adelogorgia phyllosclera, one of my five corals of interest. Image credit: NOAA Southwest Fisheries Science Center, Advanced Survey Technologies Group

Although corals are most commonly known to be found in shallow tropical waters, many exist in the deep sea. Because of the lack of photosynthesis in the deep sea, survival of the corals in the deep is dependent upon “marine snow,” the rain of phytoplankton and other organic material from the ocean’s surface to the sea floor. Dense clusters of corals are termed “coral gardens,” and these gardens provide refuge for many bottom-dwelling species.

Cold water corals are vulnerable to habitat destruction by human influence because their locations are generally undocumented. We’re working to identify and protect these slow-growing aggregations of coral and the communities that they support!

ROV Beagle, remotely-operated vehicle used to collect samples in the Channel Islands, CA. Image credit: MARE Group.

Offshore drilling, commercial bottom trawling (a form of fishing that severely degrades bottom habitats), and dumping of waste are the greatest threats to deep sea corals and the species that take advantage of the habitat that they provide. The deep sea has become a popular fishery and drilling prospect, so it has become increasingly important to protect these habitats so that any profitable resources there may be harvested sustainably. My project this summer focuses on sea pens as well as an order of cold water corals called gorgonians in the Channel Islands, CA. I will be analyzing video data from an ROV (remotely-operate vehicle) in order to record the locations and quantify the abundance of my study organisms. The results of this research should provide the scientific community and commercial managers with information on how to protect these vulnerable habitats.

Thank you to the members of the Etnoyer Lab for their guidance and assistance as well as the Grice Lab and College of Charleston for funding this project. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.


Marine Applied Research and Exploration. (n.d.). ROV Beagle. Retrieved June 17, 2019, from

NOAA Southwest Fisheries Science Center, Advanced Survey Technologies Group. (2015, June 10). Southern California Bight. Retrieved June 27, 2019, from