The Problem with PFCs- Seeking Answers in Plasma

Kady Palmer, Eckerd College


I previously outlined the problem of perfluorinated chemicals (PFCs) in the environment and their unknown health effects.  In order to gain this knowledge, it is essential to determine what types of PFCs are frequently used and the mechanisms by which an individual would be exposed to them. Here, we are measuring the presence or absence of 15 PFCs that are commonly associated with non-stick cookware, firefighting foam, and water-resistant materials.

This compiled list of PFCs is the basis of my research procedure. From here, I must learn how these compounds interact with biological components in organisms in order to understand their subsequent health effects. With that being said, the type of samples I am analyzing is a topic worth explaining. PFCs are known to be “proteinophilic” or, attracted to proteins in the bloodstream of organisms like humans and, in the case of my study, manatees. Therefore, I am using manatee plasma to test for the total individual burden of PFCs. 

PFAAs1       PFAAS2

Fig 1. 69 collection tubes containing manatee plasma samples (left). Aliquots of 22 samples of manatee plasma for future studies (right). Photos taken by me!

With 69 different plasma samples, I am performing a series of procedures that allow me to extract the PFCs. After completing multiple chemical processes (methodology proposed by Reiner et al., 2012), I am left with a liquid (containing the PFCs), measuring no more than 1 mL to be placed into a small vial. From here the vials are inserted into a liquid chromatography tandem mass spectrometer (LC-MS/MS), a machine that reads each of the 15 unique chemical structures of the outlined PFCs of interest and determines their abundance in each vial. This system isolates the concentration of each perfluorinated chemical for every one of the 69 manatee samples.

Mass Spec

Fig 2. The basic process a mass spectrometer performs in order to provide the concentration of chemicals being studied. Photo from:,nav?

The concentrations of these chemicals is the ultimate goal of my research study. This data will be compared to manatee location, morphometrics, body condition, sex, and more, in order to gain a better understanding of the overall PFC burden on these animals. These factors, or variables, may also provide insight into what may be influencing the burden intensity an individual may face. Once this knowledge is gathered, potential links to the health effects of PFC accumulation can be investigated in both manatees and humans.

I’d like to thank the National Science Foundation for funding this research opportunity and the College of Charleston’s Grice Marine Laboratory REU program for making this experience possible. A special thanks to the NIST team who has been teaching and supporting me throughout this process, specifically, Dr. Jessica Reiner, Jacqueline Bangma, and my mentor, Dr. John Bowden.

Note: These samples were collected as part of a health assessment of manatees by the USGS Sirenia Project. No manatees were harmed in the process of obtaining them.


Reiner, Jessica, Karen Phinney, and Jennifer Keller. “Determination of Perfluorinated Compounds in Human Plasma and Serum Standard Reference Materials Using Independent Analytical Methods.” Analytical & Bioanalytical Chemistry 401, no. 9 (January 15, 2012): 2899–2907. doi:10.1007/s00216-011-5380-x.z

Some Dramatic Microorganisms and Targeted Genetic Analysis

Emily Spiegel, Bryn Mawr College


Genetic analysis has become the name of the game in many fields of biological research. Genes encode proteins, and in biology, proteins are king. Proteins guide biological pathways throughout the entire organism, so if you can track the genes, you can understand how the animal functions. Advances in technology like CRISPR, RNA sequencing, and PCR have improved the accessibility and accuracy of high-level genetic analysis in laboratories across the world. Some scientists utilize this technology to study the entire genome of an organism, while others attempt to understand the response of specific genes to various environmental factors or other external influences. This summer, I’m conducting an experiment focused on the latter. I’ll be studying how the polar algae species, Fragilariopsis cylindrus (affectionately known as Frag) copes with environmental stress by reproducing sexually. To do so, I’ll use targeted RNA sequencing to track genes related to sexual reproduction.

In order to understand how a Frag, responds to environmental stresses, you need a lot of algae. I reared nearly 100 liters of this algae in different artificial conditions. These conditions varied by two factors: photoperiod (the length of day and night), and nutrient levels. If you missed my previous post, “Stressing Out My Algae,” you should check it out for more details on the background for this experiment. We suspect that in conditions of stressful light energy (24 hours of continuous light), Frag will respond by reproducing sexually as opposed to its normal asexual mode of reproduction. This could possibly be a mechanism to rid itself of excess energy in times of stress, since sexual reproduction is more energetically expensive than asexual reproduction. By reproducing sexually, Frag may improve its chances of survival against this stress. Compounded with this is our hypothesis on nutrient deprivation. Previous experiments have shown that when a major nutrient, nitrogen, is limited, the algae cannot grow at full capacity and sexual reproduction is inhibited. We predict that when the stress of nitrogen limitation is combined with the stress of high light energy, we’ll see a reduction in the algae’s ability to survive in the stressful conditions due to the inhibition of sexual reproduction. So if we stress out the Frag enough and take away their ability to have sex, they’ll probably die. They’re some very dramatic microorganisms.


24 bottles of algae were grown in six different experimental conditions varied by length of light exposure and nutrient levels. Algae was reared in 4-liter bottles filled with seawater.

So we grew our Frag, four bottles per six experimental conditions. Every day for eight days we extracted biomass from the bottle. From this sample we could test chlorophyll levels and cell counts, both of which give us a good idea of how well the algae in that bottle are growing in their conditions. We also took samples to be used for RNA extraction. Remember how genes encode proteins and proteins are king? Well before you can have your protein product, you need RNA. You’ve probably heard of DNA, which is the double stranded genetic cookbook. RNA is its single stranded offspring, which is then used as a the direct template to make proteins. A lot of genetic analysis therefore looks at RNA instead of DNA in order to understand how genes are being transcribed for protein production. We’re currently working on extracting the RNA from the original biomass sample and then running that pure RNA through a specialized machine called Nanostring. This is extremely targeted analysis, as Nanostring focuses in on the specific RNA we’re most interested in. In this case, we’re interested in RNA which is encoded from genes related to sexual reproduction. Using Nanostring will tell us how active the genes for sexual reproduction are in each bottle, which we can analyze to derive any correlation between our environmental stress factors and sexual reproduction.

If our hypothesis is correct, then we’ll see the greatest expression of sexual reproduction genes in the conditions of high light energy (24 hours of continuous light). We’d expect to also see low growth performance in nitrogen limited populations, indicated by low cell counts and chlorophyll levels. In these populations we predict we’ll see little if any expression of genes related to sexual reproduction. By the end, we’ll hopefully have a clearer picture of how phytoplankton like Frag deal with environmental stress.

Funding for this project is provided by the National Science Foundation in collaboration with the College of Charleston Grice Marine Laboratory and the National Oceanic and Atmospheric Administration. Acknowledgements to the entire lab of Dr. Ditullio and Dr. Lee in the Hollings Marine Laboratory facility.

Searching in the Sand

Christine Hart, Clemson University

Interim report picture

In “Exploring the Secret Garden” I discussed our studies of the benthic microalgae (BMA) that inhabit the intertidal regions of beaches. The goal of our study is to identify the mechanisms involved in the visually noticeable increase of BMA during low tide. This mechanism will be linked to changes in the type of BMA dominating the sand flat. To accomplish these goals our study will incorporate field work, molecular techniques, and DNA analysis.

During field work we will collect and manipulate sediment to distinguish between an increase in BMA by either vertical migration or growth mechanisms. The sediment will be collected on a sand flat in Grice Cove (Figure 1). Sand will be sampled using corers, which pick up a layer of sand without disturbing the vertical organization. The collected sand will be split between measurements of biomass, or BMA density, and DNA analysis. Biomass is measured by finding the concentration of chlorophyll a in the sediment. BMA synthesize chlorophyll a; therefore, the concentration of chlorophyll a is proportional to the density of BMA.

Sampling Site.png

Figure 1. Aerial view of Grice Cove sampling site with the approximate location of the 50 m sand flat transect site. Sampling sand flat is open to the Charleston Harbor. Source: “Grice Cove” 3244’58”N 7953’45”W. Google Earth. March 20, 2017. June 20, 2017.

The methods for field work are represented in Figure 2. There are two vertical migration treatments: filter and mesh. Filter treatments prevent vertical migration between cored and surrounding sediment. Mesh treatments permit vertical migration. If migration is important to the biomass increase, biomass measurements in mesh will be greater than in filter treatments. Filter and mesh treatments will also be exposed to shade and light conditions to interpret the impact of growth on biomass. Sunlight provides the energy necessary for BMA growth. Without sunlight growth will be limited. If growth is the mechanism of biomass increase, the shaded samples will have a lower biomass than the light exposed samples.

Field Work Diagram.png

Figure 2. Field work methods visualization. Locations of replicates along the 50 m transect are chosen using a random number generator and marked with flags. Random coordinates and a quadrat of 50 cm by 50 cm are used to determine where sediment will be sampled and treatments will be placed. Three controls (T0, TM, and TF) are taken at time intervals 1.5 hours apart after sand exposure. During TM and TF time points, samples are taken from the 4 treatments shown above: filter, mesh, filter + shade, and mesh + shade. Filter treatments prevent vertical migration, while mesh treatments permit vertical migration. Shaded and non-shaded filter and mesh treatments will be important in determining the role of sun exposure in biomass increase.

To link the mechanism of biomass increase to the BMA composition, we will use molecular techniques and analyze the DNA found in the sediment. DNA will be extracted from the sediment and amplified using a polymerase chain reaction (PCR). The DNA will be sequenced using High Throughput Ion Torrent technology. The results from sequencing will identify the BMA present at each time point and within each treatment. This information will link the mechanism of biomass increase to the changes in BMA composition. Our understanding of BMA dynamics will establish a basis for the BMA ecology in the Charleston Harbor. In the future, BMA dynamics could be compared to our study to assess changes caused by human influences in Charleston estuaries.


Thank you to my mentor, Dr. Craig Plante, and my co-advisor, Kristina Hill-Spanik, for their support and guidance. This project is funded through the National Science Foundation and supported by College of Charleston’s Grice Marine Laboratory.


Literature Cited:

Lobo, E. A., Heinrich, C. G., Schuch, M., Wetzel, C. E., & Ector, L. (n.d.). Diatoms as Bioindicators in Rivers. In River Algae (pp. 245-271). Springer International Publishing. doi:10.1007/978-3-319-31984-.

MacIntyre, H.L., R.J. Geider, and D.C. Miller. 1996. Microphytobenthos: the ecological role of
 the “Secret Garden” of unvegetated, shallow-water marine habitats. I. Distribution, abundance and primary production. Estuaries 19: 186-201.

Should we say no to Nonylphenol?

Meagan Currie, Swarthmore College


The ocean is approximately 1.3 billion cubic kilometers (Eakins, 2010). A single cubic kilometer can hold 400,000 Olympic-sized pools. So much does it really matter if human-made chemicals end up in our oceans? What could such small concentrations of chemicals really do to marine organisms?

These are the questions that are fueling my research project this summer at the Hollings Marine Laboratory. I have the privilege of working in the lab of Dr. Cheryl Woodley, who specializes in marine toxicology and coral health. Here I will be using two environmentally and biologically important marine organisms – sea urchins and coral – to understand more about the effects of manmade chemicals on the health and development of marine life.

Of course, given our limited time I am not going to investigate all of the over 70,000 different chemicals produced by the US. I will focus on the compound  nonylphenol, which has been recognized by the US Environmental Protection Agency (EPA) as a chemical of emerging concern (US EPA, 2012). This forbidding title is given to chemicals that have been recently detected in the natural environment that are believed to have harmful effects on humans and natural wildlife.

Nonylphenol is added to products as a detergent, as it helps dissolve oils and other compounds more easily in water, and is produced and distributed in very large quantities.  Approximately 500 million pounds of nonylphenol is produced every year, although in the last ten years the EPA has developed new rules to attempt to limit its application in products (Helmut, 2002; US EPA, 2016).  It is used in most commercial laundry detergents, soaps and cleaners, meaning that it often funnels down the drain and into wastewater treatment plants, or even directly into seawater . Unfortunately, nonylphenol isn’t broken down easily and is moderately bioaccumulative, meaning that it collects and remains in the systems of organisms that come into contact with the chemical.

Another element of nonylphenol’s chemical story is that it is an endocrine disruptor. This means that nonylphenol behaves like a common biological hormone, estrogen, and can negatively impact the hormonal systems of organisms. Marine invertebrates are particularly vulnerable to endocrine disruptors because many, including sea urchins and coral, exist as tiny, free-swimming organisms at early stages of development. Early embryos and larvae are known to be more susceptible to the effects of toxins, particularly hormonal disruptors, than adult organisms (Shirdel, 2016).

This summer I will work with the gametes (egg and sperm) and juveniles of the lovely sea urchin Lytechinus variegatus. This species of urchin is native to much of coastal South America as well as Florida and South Carolina.

IMG_0076 copy

Lytechinus variegatus in the lab

I will see how sea urchin sperm responds to nonylphenol at different concentrations, and whether or not exposure affects the ability of sperm to fertilize eggs. I will also watch the development of sea urchin larvae exposed to the chemical to see if nonylphenol changes the pace or physiology of developing urchins. Finally, I will investigate the effects of nonylphenol on regrowth and regeneration of one of the most important organisms in our oceans: coral. Coral reefs host nearly a quarter of all marine species and are critical to maintaining the biodiversity and resources that we derive from the oceans (Coral Reef Alliance, 2017).  If you want to know more about coral reefs and maintaining reef health, you can follow the Coral Reef Alliance blog, which releases recent information about efforts to protect coral.

I will be examining how a threatened species of coral, Acropora cervicornis, responds to nonylphenol. To do this I will see how nonylphenol influences the speed and effectiveness of recovery if the coral tissue is injured and then exposed to the chemical. I will also gauge how healthy the coral is by measuring how much the coral is photosynthesizing, which will tell us about how much energy it is producing.

I am very excited to be working with two incredible marine model organisms, and investigate such a prevalent and interesting compound! Our results will hopefully better inform the US EPA and other organizations about the threats of nonylphenol to marine aquatic environments and the many organisms that may be exposed at different stages of their lifecycle. Many thanks to Dr. Cheryl Woodley for welcoming me into her lab, and to the Fort Johnson Summer REU program for giving us this incredible experience.

Funding Sources



International Trade Administration. Chemical Spotlight: “The Chemical Industry in the United States.” Select USA; US Department of Commerce. Web. Accessed Jun 22, 2017.

US EPA., 2012. DfE Alternatives Assessment for Nonylphenol Ethoxylates. Design for the Environment. United States Environmental Protection Agency. pp. 2-27.

Helmut Fiege, Heinz-Werner Voges, Toshikazu Hamamoto, Sumio Umemura, Tadao Iwata, Hisaya Miki, Yasuhiro Fujita, Hans-Josef Buysch, Dorothea Garbe, Wilfried Paulus “Phenol Derivatives” in Ullmann’s Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a19_313

US EPA., 2016. Nonylphenol and Nonylphenol Ethoxylates: Assessing and Managing Chemicals under TSCA. United States Environmental Protection Agency, 2 Nov. 2016. Web. Accessed 12 Jun, 2017.

Kay, Jane. D4 and nonylphenol in textiles, plastics. Environmental Health News. May 6, 2013. Web. Accessed June 20, 2017.

Brown, Mark Anthony et al. Microplastic moves pollutants and additives to worms, reducing functions linked to health and biodiversity. Current Biology. 23 (23): 2388-2392.

Eakins, B.W. and G.F. Sharman, Volumes of the World’s Oceans from ETOPO1, NOAA National Geophysical Data Center, Boulder, CO, 2010.

Shirdel, Iman. Kalbassi, Mohammad Reza. Effects of Nonylphenol on Key Hormonal Balances and Histopathology of the Endangered Caspian Brown Trout (Salmo Trutta Caspius). Elsevier Inc. PubMed: 26811907 DOI: 10.1016/j.cbpc.2016.01.003

Coral reef alliance. 2017. Coral Reef Ecology: Biodiversity. url.

Fatal before fertilization?

Cecilia Bueno, Lewis & Clark College

frog calling

Male Squirrel Treefrog (Hyla squirella) calling for a mate (credit)

Amphibians, including frogs, toads, salamanders, newts, and others, are experiencing large declines in populations worldwide1. Many factors human-caused factors are contributing to this decline, including habitat loss, to climate change, and pollution1.

One way that habitats are being damaged is by increased salinity in normally freshwater systems. Salt is getting into freshwater by use of salt road deicers, poor land irrigation, rising tidelines, and increased storm surges2. Changes in water quality, such as salinity, is especially dangerous to amphibians such as frogs because of their permeable skin.

green treefrog amplexus

Breeding pair of Green Treefrogs (Hyla cinerea) in amplexus (credit)

In addition to increased salt levels harming adult frogs, it can damage developing frogs from fertilization onwards. Almost all frogs are external fertilizers- that is, when they breed, male and female join in amplexus and release sperm and egg into the water. Frogs require freshwater to breed and develop as tadpoles, so when freshwater is intruded by salt, there are problems for frogs from their earliest stages.

Many studies have shown that even low levels of salinity can cause tadpoles to develop abnormally, have lower adult weights, and die.While we already know that increased salinity has a bad effect on tadpoles, little is known about how this salinity affects frogs at the first stage of life: fertilization.

frog egg development

First stages of embryonic development (credit)


We hope to look at the effects of salinity on sperm and fertilization, an area which has very little research currently. Previous research has shown that in squirrel treefrogs, low levels of salinity can stop eggs from being fertilized4. A study on green treefrog sperm showed that as salinity increased, sperm function decreased incrementally5. These two closely related species live in the Coastal Plains habitat, which is at risk of salinization by rising tides and storm surges. Sperm function and fertilization rates have been shown to be negatively by increased salinity- we look at these two effects in squirrel treefrogs and see if a decrease in sperm function can explain at least part of how salinity hinders fertilization.

I would like to thank the National Science Foundation for funding this REU program, and the Grice Marine Lab of the College of Charleston for hosting us. In particular, I would like to thank my mentor Dr. Allison Welch for her help and support.



Stuart, S. N., J. S. Chanson, N. A. Cox, B. E. Young, A. S. L. Rodrigues, D. L. Fischman, and R. W. Waller. 2004. Status and trends of amphibian declines and extinctions worldwide. Science 306:1783–1786. CrossRefPubMed

2: Williams, W. D. 2001. Anthropogenic salinisation of inland waters. Hydrobiologia 466:329–337. CrossRef

Van Meter, R.J., Swan, C.M., Leips, J. et al. (2011) Salinity Acclimation Affects Survival and Metamorphosis of Crab-Eating Frog Tadpoles. Wetlands, 31: 843. doi:10.1007/s13157-011-0199-y

3:Alexander, Laura G., Simon P. Lailvaux, Joseph H. K. Pechmann, and Philip J. DeVries. “Effects of Salinity on Early Life Stages of the Gulf Coast Toad, Incilius Nebulifer (Anura: Bufonidae).” Copeia 2012, no. 1 (2012): 106-14.

Brown, Mary E., Walls, Susan C. (2013). Variation in Salinity Tolerance among Larval Anurans: Implications for Community Composition and the Spread of an Invasive, Non-native Species. Copeia, Sep 2013 : Vol. 2013, Issue 3, pg(s) 543-551 doi: 10.1643/CH-12-159

4:Unpublished data, Ruby and Welch

5: Wilder, Anneke E., Welch, Allison M. (2014). Effects of Salinity and Pesticide on Sperm Activity and Oviposition Site Selection in Green Treefrogs, Hyla cinerea. Copeia, 2014, No. 4, 659–667


What can baby shrimp teach us about oil spills?

Deanna Hausman, University of Texas at Austin

Pretty much everyone knows that oil is toxic, unfortunately. We’ve all seen images of birds or otters covered in oil, or seen wetlands destroyed due to an oil spill. But what many people may not know is certain factors, even rays from the sun, can increase the toxicity of oil. UV light—what gives us sunburns—can increase the toxicity of oil by over 1000 times in some cases, which allows it to kill more organisms and damage more of the ecosystem.

This is a big problem. And like in everything else, you can’t start solving a problem until you completely understand it. Before experts can start to clean up an oil spill, they have to make predictions, and determine how toxic the oil is going to be, what organisms are going to be more sensitive to it, and what conditions exist that could make the oil more toxic.

Which is where my research comes in! This summer, I’m studying the effects of oil on larval grass shrimp. They’re kind of cute little creatures: as larvae, they swim upside-down, and have giant eyes. Most importantly, as adults, they’re very important to the ecosystem. They’re an important food source for many larger fish and crabs, and they’re also detrivores, meaning they break down waste on the seafloor into smaller pieces, that tiny organisms such as plankton can eat. Therefore, they’re important for organisms both at the top and bottom of the food chain, and if their populations are harmed, it can have a huge negative impact on a large number of other organisms.


Adult grass shrimp

Specifically, my work this summer is focusing on the toxic effects of thin oil sheens and oil mixed in with sediment, as well as the developmental effects of oil. Previously, some studies have worked to determine that very thin oil sheens can be toxic, but they largely focused on deep-water organisms, not estuarine species. My study will work to determine how thin oil sheens can affect estuarine species.  In addition, the sediment tests will determine how estuarine species might be affected by oil sinking down after a spill- a situation they are often exposed to. Both these studies will also evaluate what impact UV light has on oil in these situations. Finally, studying the impact of oil on shrimp development will help determine what the long-term affects an oil spill may have.


The set-up of the oil sheen experiment. One tank contains pure seawater, to serve as a control, while the other contains the oil sheen. Some shrimp are caged and some are swimming free, in order to determine whether shrimp need to swim through the oil to be affected or not

All of this research will help people to make predictions about the damage that will occur in the event that an oil spill does occur in or near an estuary.

I’d like to thank my mentors, Dr. Marie Delorenzo and Dr. Paul Pennington, for their guidance and NOAA for providing me with lab space and equipment.

Works cited:

Finch, B.; Stubblefield, W. Photo-enhanced toxicity of fluoroanthene to Gulf of Mexico marine organisms at different larval ages and ultraviolet light intensities. Environmental Toxicology and Chemistry. 2015, 35, 1113-1122.

A Seaweed to beat them all

Killian Campbell, Eastern Washington University


“Gracilaria vemiculophylla”.

Does anything even remotely familiar come to mind when you read those words? If you’re like most people, the answer is probably “no”. However, this strange red seaweed is actually quite ubiquitous, and chances are it dwells somewhere along the coast of the country you live in.

To most of the world, Gracilaria vermiculophylla is an invasive organism—Unless of course you live in East Asia, where it is considered to originate from. Outside of East Asia however, human activities have carried this organism far and wide. Of those activities, the trading of Japanese oysters to the rest of the world is believed to play the biggest role in transporting Gracilaria to new environments.

Above all, what makes Gracilaria so remarkable is that it can thrive in many different types of conditions all over the world. For example, Gracilaria can easily be found along the coastline right here in Charleston, but the climate in Charleston is very different from its native environment in Japan. Gracilaria’s remarkable ability to adapt to its environment makes it an interesting organism to study.

gracGracilaria vermiculophylla found along Grice Beach, Charleston, South Carolina. Photo Credit: Melanie Herrera.

Given that, I will be researching Gracilaria with Dr. Erik Sotka at Grice Marine Laboratory. My research will attempt to uncover some of the reasons why Gracilaria is able to thrive in so many different environments, and what allows other invasive species to thrive in varying conditions. Past research has found that heat shock proteins (Hsps) may play a role in Gracilaria’s ability to survive. Hsps are molecules found inside most living organisms that regulate the functions of the cells and thus keep the organism alive during high stress events (extreme temperatures, or in the case of marine organisms, extremely high or salinity levels). In response to that, researchers have recently developed what are known as inhibitors. Inhibitors are tools that halt the functions of Heat Shock Proteins. We believe that giving inhibitors to Gracilaria can halt the functions of their Hsps, and we can use that information to gain insight about the stress tolerance of Gracilaria, and ultimately other marine organisms. To do this, I will be harvesting lots of Gracilaria form Charleston Harbor, giving them inhibitors, and subjecting them to extreme temperatures and salinity levels to see how they respond. Additionally, we hope that the data we generate can inform predictions about the health of other marine organisms as ocean temperatures rise due to climate change.

I want to dedicate some words of appreciation Dr. Erik Sotka, Benjamin Flanagan, Dr. Bob Podolsky, Grice Marine lab The College of Charleston, and the NSF for this wonderful opportunity.

Works Cited:

Sørensen, J. G., Kristensen, T. N. and Loeschcke, V. (2003). The evolutionary and ecological role of heat shock proteins. Ecol. Lett. 6, 1025–1037.

Queitsch, C., Sangster, T. a and Lindquist, S. (2002). Hsp90 as a capacitor of phenotypic variation. Nature 417, 618–24.

Krueger-Hadfield, S. A., Kollars, N. M., Strand, A. E., Byers, J. E., Shainker, S. J., Terada, R., Greig, T. W., Hammann, M., Murray, D. C., Weinberger, F., et al. (2017). Genetic identification of source and likely vector of a widespread marine invader. Ecol. Evol.