My Days with the Shrimp

Deanna Hausman, The University of Texas at Austin

me with ray

 

 

 

 

In “What can baby shrimp teach us about oil spills,” I discussed the problem of UV enhanced toxicity of oil. In other words, the fact that UV rays can cause molecules in oil known as PAHs to become more harmful than they would be otherwise. I also discussed the fact that this summer, I will be studying the effects of oil toxicity on grass shrimp, or Palaemontes pugio, an important estuarine species that cycles nutrients through the food chain. Because oil spills are always complex, and organisms can be exposed to oil in many different ways, from the sediment they walk on to the water they swim through, a variety of experiments are needed to get a better understanding of this issue.

PAHs

A few of the many PAHs- the compounds in oil that harm marine life Photo from: http://www.crawfordscientific.com/newsletter-2008-12-dedicated-HPLC-GC-columns-PAH-analysis.htm

The first and simplest of the experiments I conducted was the developmental test. In this test, I basically mixed oil and seawater in a giant blender, then took out the water with the oil dissolved in it. Then, I made several dilutions, creating several concentrations of the oily water. Then, I took 6-well plates and filled them up, and placed a single, 24-hour old shrimp in each well. Then, I put these plates in an incubator under UV and non-UV light, and waited for 4 days. After that, I moved the shrimp into clean water, counted how many died, and am currently monitoring them to see how the oil exposure in early life impacts their ability to grow into healthy juveniles.

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Shrimp being monitored after initial oil exposure

Another experiment I conducted essentially followed the same procedure as above, but instead of watching them as they grew, I analyzed the shrimp after their 96-hour oil exposure to see whether the oil affected the concentration of a hormone, known as an ecdysteroid, that controls their molting. Essentially, if the concentrations of this steroid are off in a shrimp it can’t grow properly, so it’s very important!

I’m also conducting an oil sheen test. In this experiment, I place 40 larval shrimp in an aquarium, some caged on the bottom and some swimming freely, and then place an extremely thin oil sheen on top. One aquarium goes under UV light and the other goes under fluorescent light, and after exposure I analyze whether the sheens have had a harmful effect. Whether thin oil sheens are toxic is something that’s not very well understood in this species, so it will be very interesting to see the results.

Finally, I’m conducting an experiment to see what occurs when oil is mixed in with sediment. Essentially, this involves putting sediment from an estuary in a jar, adding oil, and tumbling it around so that the oil is completely mixed in. Then, the sediment is placed into beakers along with water and 24-hour old shrimp, and put under UV and non-UV light for 24 hours, in order to see what mortality occurs. This will perhaps be the most informative experiment, as grass shrimp spend most of their time on the seafloor, so if they’re going to be exposed to oil, it will likely be from the sediment they’re walking on.

In short, I have my hands full this summer! It will be very interesting to see the results. Hopefully, this will increase our knowledge of the harmful impacts oil spills can have to estuarine organisms, and allow NOAA and oil spill analysts to make better predictions of the long-range impacts of oil spills. Ultimately, this may help them make better clean-up decisions.

Thank you to my mentors, Dr. Marie Delorenzo and Dr. Paul Pennington, for their guidance. I’d also like to thank Katy Chung for all her help and expertise. This research is funded through the National Science Foundation.

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Are Manatees the Key?

Kady Palmer, Eckerd College

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Contaminants. One word, countless different connotations. Therefore, the exposure to contaminants is a constant concern to both the public and the scientific community. The study I will be performing this summer focuses on perfluorinated chemicals, or PFCs. PFCs are a class of contaminants that are utilized in many commercially available products (ex: non-stick pans, stain resistant sprays, and water-resistant materials) and have been classified as highly abundant and persistent chemicals of concern, in relation to overall environmental and, subsequently, human health.

teflon

Photo from: “Should You Ban Your Teflon Pan? California.” Savvy California, January 1, 2015. https://savvycalifornia.com/teflon-pan-toxic-or-not/. 

Through various mechanisms, PFCs have been noted to integrate into the environment and end up in the air, soil, and water. As this is happening, the organisms living in these areas become exposed and are put into a precarious situation. Little research has been performed on examining exactly what the effect these compounds have on organisms in these types of environments. Although it would be just as interesting to scoop water samples from different places to determine a basis for this environmental change, my project will be delving a bit deeper. Because previous studies have shown data supporting PFC accumulation in the bloodstream of different marine animals and their subsequent health consequences, I will be expanding this research by analyzing the types and abundance of PFCs in the Florida manatee.

The Florida manatee (Trichechus manatus latirostris) inhabits areas of warm water, close to the shoreline. Unfortunately, manatees have a history of endangerment, as a result of human impacts (boat strikes, entanglements, drowning due to drainages) and environmental changes. Perfluorinated chemicals, as described above, could very well be impacting manatees in ways currently unknown. This study aims to isolate the types and abundance of PFCs in Florida manatees and potential health concerns associated with this exposure. While the health of manatees is undoubtedly important, the results of this research could provide insight as to the overall health of the ecosystems examined. Manatees could function as a model for other organisms, demonstrating the possible repurcussions of PFC exposure. If that is the case, the knowledge gained from this organism, living so close to the shoreline of human inhabited areas, may be applicable in aiding future human research.

manatee-cow-and-calf

Photo from: “West Indian Manatee.” Southeast Region of the U.S. Fish and Wildlife Service. Accessed June 23, 2017. https://www.fws.gov/southeast/wildlife/mammals/manatee/.

I’d like to sincerely thank everyone involved in the National Institute of Standards and Technology laboratories who have been a wealth of information and guidance, specifically Dr. Jessica Reiner, Jackie Bangma, and my mentor, Dr. John Bowden. This project would not be possible without samples and information provided by Robert Bonde with USGS, funding from the National Science Foundation, and the College of Charleston’s Grice Marine Laboratory.

References:

Bangma, Jacqueline T., John A. Bowden, Arnold M. Brunell, Ian Christie, Brendan Finnell, Matthew P. Guillette, Martin Jones, et al. “Perfluorinated Alkyl Acids in Plasma of American Alligators (Alligator Mississippiensis) from Florida and South Carolina.” Environmental Toxicology and Chemistry, no. 4 (2017): 917. doi:10.1002/etc.3600.

“CDC – NBP – Biomonitoring Summaries – PFCs.” Accessed June 19, 2017. https://www.cdc.gov/biomonitoring/pfcs_biomonitoringsummary.html.

West Indian Manatee”. Southeast Region of the U.S. Fish and Wildlife Service. Accessed June 23, 2017. https://www.fws.gov/southeast/wildlife/mammals/manatee/.

Grac Attack!

Aaron Baumgardner, The University of Akron

The only thing more pervasive than the constant thoughts of, conversations about, and stress from Gracilaria vermiculophylla in Dr. Erik Sotka’s lab is the invasion of this red alga that is occurring along the coasts of North America and Europe (Sotka, et al. 2013). After only a few short weeks in Charleston, I have seen how prevalent and successful this seaweed is. The success of G. vermiculophylla along the southeastern coasts of the United States is due in part to the established mutualism between it and the decorator worm Diapatra cuprea. This mutualism provides a secure site for the seaweed to grow (Kollars, Byers, and Sotka unpublished manuscript), but it does not explain the success of G. vermiculophylla to thrive in environmental conditions that differ from its native Japanese range.

G. vermiculophylla colonizes a mudflat in Charleston Harbor by clinging to tube-building decorator worms. Credit, Erik Sotka

G. vermiculophylla colonizes a mudflat in Charleston Harbor by clinging to tube-building decorator worms. Credit, Erik Sotka.

Researching G. vermiculophylla can help us understand how aquatic invasions occur. Do introduced populations evolve novel characteristics or do they simply benefit from the phenotypic plasticity of their source populations? To answer this question, it is necessary to test plasticity in response to varying environmental conditions on native and non-native populations (Huang, et al. 2015). Since G. vermiculophylla has spread outside its latitudinal range and into high salinity environments (Kollars, et al. 2015), I will be testing the plasticity of native and non-native G. vermiculophylla populations to a range of temperatures and salinities. Photosynthetic efficiency will be measured using a PAM fluorometer to provide a more objective way to quantify stress (Rasher and Hay 2010).

I would like to thank the College of Charleston for this internship opportunity, Dr. Erik Sotka for mentoring me on my project, and the National Science Foundation for funding REU programs.

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References:

Huang, Q. Q., et al. (2015). Stress relief may promote the evolution of greater phenotypic plasticity in exotic invasive species: a hypothesis. Ecology and Evolution 5(6), 1169-1177.

Kollars, N. M., Byers, J. E.,  & Sotka, E. E. (unpublished manuscript). Invasive décor: a native decorator worms forms a novel mutualism with a non-native seaweed.

Kollars, N. M., et al. (2015, in review). Development and characterization of microsatellite loci for the haploid-diploid red seaweed Gracilaria vermiculophylla. PeerJ.

Rasher, D. B., & Hay, M. E. (2010). Chemically rich seaweeds poison corals when not controlled by herbivores. PNAS 107(21), 9683-9688.

Sotka, E. E., et al. (2013). Detecting genetic adaptation during marine invasions. Grant proposal to the National Science Foundation.

New Philadelphia to Charleston

Aaron Baumgardner, The University of Akron

Coming from the landlocked small town of New Philadelphia in the Midwest, I feel like I’m dreaming when I realize I’m spending my summer researching in Charleston, SC. I’m thankful for the opportunity that my mentor, the College of Charleston, and the National Science Foundation has given me to learn and grow in my scientific ability.

However, I do not believe I would be where I am today if it weren’t for my Aunt Jane. She is the only member of my family with a background in science, and even though she is hundreds of miles away at UPenn, she is always an email or phone call away. She has always shown an interest in my academics and will always be there for any advice I may ask. She has helped me develop my professionalism and offered insight on which graduate schools are worth going to.   Because of her, I can finally realize it’s not a dream. It’s reality that I’m spending my summer in Charleston, SC. It’s because I’ve worked hard in school and reached out for opportunities for me to mature as scientist. And I owe her so much for pushing me to succeed.

Thank you Aunt Jane!