A tale of two Gulf spills: A research consortium of 19 institutions from 5 countries studying the impacts of oil spills on the Gulf of Mexico.
Steve Newborn of WUSF radio (NPR affiliate for Tampa, St. Petersburg and Sarasota) travelled to Sarasota on Friday, Nov. 6, to learn about a few different parts of the C-IMAGE research happening at the Mote Aquacutlure Park. He spent the day with our researchers, and produced a great piece for our NPR affiliate.
Understanding the immediate impact of oil spills on fish is one of the goals of GoMRI researchers in the coming months during new C-IMAGE fish exposure program.
Through a series of experiments, using sub-lethal exposure levels of oil and three species of unexposed adult marine fishes, answers to questions about biochemical and physiological changes in the days and weeks following an oil blowout will aid researchers in understanding potential short and long-term impacts on the Gulf of Mexico ecosystem.
The Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE) and partners at Mote Marine Laboratory began a ground-breaking study to evaluate sub-lethal responses in targeted marine fish species to oil contamination.
During oil spills, like Deepwater Horizon, skin lesions (open sores) on fish may be attributed to prolonged contact with oil. Fishermen from the northern Gulf of Mexico first reported these lesions in their catches beginning in winter 2010 and researchers followed with studies in 2011. However, the status of these fisheries prior to the oil spill was a mystery due to a lack of baseline data in the region.
Dr.’s Dana Wetzel and Kevan Main from Mote Marine Laboratory are leading their team of researchers at the Mote Aquaculture Park in Sarasota, FL. Wetzel and Main will study effects of oil on hatchery reared species of adult pompano, red drum, and flounder, which occupy different habitats, in the open ocean, nearshore, or bottom, respectively.
“Most oil exposure studies target early life stages of animals because they are considered to most vulnerable,” said Dr. Wetzel, C-IMAGE’s ecotoxicology task lead. “However, we believe that determining sublethal responses in adults that suggest a decline in immune status, ability to reproduce, and gene integrity are critical for ecosystem conservation.”
These designed studies will test three different species of marine fish to oil through four pathways: ingestion, sediment contact, water contact, and direct injection. The experiments will measure changes in immune function, reproduction and DNA damage along with many other biological parameters.
On July 7th, Mote Marine Laboratory began their first exposure study to understand the extreme effects of oil exposure to a fish. Through an intra-peritoneal injection (body cavity injection; IP), all three species of fish were acutely exposed to a mixture of Louisiana crude oil and corn oil (corn oil acting as a carrier).
Following 24, 48, and 72 hour exposure periods, fish were sampled for blood, muscle and organ tissue, otoliths (ear bones), and bile. Careful analysis of these samples will be critical for understanding the extreme cases of oil exposure and what might be observed during the other exposure trials.
Wetzel acknowledges that, “Direct injection of oil is not a realistic oil exposure pathway. However, by carrying out this IP study, we will be able gain insight to confirm which biological health markers may be compromised or damaged during the remaining exposure scenarios.”
One pathway by which fish could be exposed to oil is through their diet. Oil in seawater can be adsorbed onto potential food particles (plankton, detritus, etc.) making its way into the food web and into fish. One question the Mote exposure studies will address is the efficiency of the metabolization of ingested oil – how well the fish breaks down oil compounds – in addition to other health impact assessments. Researchers will use oil-coated food pellets to investigate how fish, in these trials red drum, respond to hydrocarbons by ingesting sub-lethal levels of oil.
Ingestion experiments are set to begin in Fall 2015.
A fishes lifestyle determines the pathway of oil exposure; bottom-dwelling fish have contact with sediments, while open-water fish, or pelagic fish, are exposed by the water soluble components from spilled oil. The effect of an oil-water mixture (water accommodated fraction or WAF) on pelagic fish like pompano will be studied as part of the new exposure studies.
Adult pompano in this study will be exposed to a moderate concentration of WAF, which will decline to zero oil concentration levels as new sea water is cycled through, known as a spiked-declining exposure method. These results will show the potential impacts of spilled oil exposure to open-water, pelagic fish species.
Following the oil-water exposure studies, pompano will be moved into spawning tanks to reproduce. Reproductive fitness will be measured by the researchers through sperm and egg counts, hatch success, development abnormalities and egg/embryo biochemical composition. This information will be valuable in predicting possible impacts of spilled oil on the next generation of oil-exposed fish.
Trials for the WAF studies are set to begin in early 2016
Flounder are bottom-dwelling (benthic) fish spending their adult lives in contact with the ocean floor and sediments. During oil blowouts, sediments trap and retain oil in layers on the sea floor. Benthic dwelling fish are at risk of chronic oil exposure through these sediments.
This exposure study will expose flounder to oil-tainted sediments for several weeks to observe low level chronic conditions of exposure through contact with contaminated sediments. Sediment exposure studies are planned for Fall 2016.
“Exposure trials with sub-adult and adult fishes are challenging to carry out because of the large water volume required to implement these studies,” said Dr. Kevan Main, a Mote Marine Laboratory research focusing on fish reproduction. “Exposure trials will be conducted at Mote Aquaculture Park in tanks that are connected to a water treatment system; this system will filter and remove waste and oil from the allowing the reuse of clean water for exposure trials.”
The main goal of C-IMAGE is to advance understanding of the processes, mechanisms, and environmental consequences of marine oil spills. The results of these planned exposure studies have broad contributions to C-IMAGE II research by providing survival and reproduction information to the team’s ecosystem modelers for help in estimating population level responses to oil spills.
This research was made possible by a grant from BP/The Gulf of Mexico Research Initiative. Founded in 1955, Mote Marine Laboratory & Aquarium is celebrating its 60th year as an independent, nonprofit 501(c)3 research organization. Mote’s beginnings date back six decades to the passion of a single researcher, Dr. Eugenie Clark, her partnership with the community and philanthropic support, first of the Vanderbilt family and later of the William R. Mote family.
Acute catastrophic events can cause significant damage to marine environments in a short time period and may have devastating long-term impacts. In April 2010 the BP-operated Deepwater Horizon (DWH) offshore oil rig exploded, releasing an estimated 760 million liters of crude oil into the Gulf of Mexico. This study examines the potential effects of oil spill exposure on coral larvae of the Florida Keys. Larvae of the brooding coral, Porites astreoides, and the broadcast spawning coral, Montastraea faveolata, were exposed to multiple concentrations of BP Horizon source oil (crude, weathered and WAF), oil in combination with the dispersant Corexit® 9500 (CEWAF), and dispersant alone, and analyzed for behavior, settlement, and survival. Settlement and survival of P. astreoides and M. faveolata larvae decreased with increasing concentrations of WAF, CEWAF and Corexit® 9500, however the degree of the response varied by species and solution. P. astreoides larvae experienced decreased settlement and survival following exposure to 0.62 ppm source oil, while M. faveolata larvae were negatively impacted by 0.65, 1.34 and 1.5 ppm, suggesting that P. astreoides larvae may be more tolerant to WAF exposure than M. faveolata larvae. Exposure to medium and high concentrations of CEWAF (4.28/18.56 and 30.99/35.76 ppm) and dispersant Corexit® 9500 (50 and 100 ppm), significantly decreased larval settlement and survival for both species. Furthermore, exposure to Corexit® 9500 resulted in settlement failure and complete larval mortality after exposure to 50 and 100 ppm for M. faveolata and 100 ppm for P. astreoides. These results indicate that exposure of coral larvae to oil spill related contaminants, particularly the dispersant Corexit® 9500, has the potential to negatively impact coral settlement and survival, thereby affecting the resilience and recovery of coral reefs following exposure to oil and dispersants.
Florida SeaGrant has implemented a "Friday Interview Series" with the 2014 Guy Harvey Scholars. What are the marine scientists of tomorrow doing? See the full interview with our very own Kristina Deak from the University of South Florida and Mote Marine Laboratory.
Who will be the marine scientists of tomorrow?
It's Friday and that means it's time for another interview with one of our amazing 2014 Guy Harvey Scholars!
Meet Kristina Deak. She's a master's student at USF and is studying how the Deepwater Horizon oil spill affected the immune system of fish.
Q. Can you tell us a little bit about your research?
A. I study how the oil spill affected the immune system of fish, particularly red snapper and golden tilefish. My primary focus is on cytokines, which are key regulators of the inflammatory response.
Q. Is there a particular event or memory that made you interested in the ocean?
A. I read “Shark Lady,” a book about Eugenie Clark, when I was a kid and became absolutely obsessed with sharks and other fishes. It still boggles my mind when I walk past her door at the lab now – she was the woman who built Mote and the reason we all get to do what we do there.
Q. What do you do in your free time?
A. Between being a full time chemist at Mote and a full time graduate student at USF, I don’t have a great deal of free time. When I do, I like to explore our beautiful state, scuba dive, run, and visit all of the local parks and trails.
Q. What are your career plans?
A. I currently handle the Biomarker portion of the Environmental Forensics Lab at Mote Marine Laboratory. It’s a great place to work and has reaffirmed my interest in being a research scientist and applying biochemistry to environmental problems.
Mind Open Media reporter David Levin sits down with C-IMAGE co-PI Dr. Dana Wetzel to learn more about her research interests and her motivation for her studies. Dana is a senior scientist at Mote Marine Laboratory in the Environmental Laboratory Forensics Program. Her laboratory detects oil compounds, analyzes fatty acids for health and feeding ecology studies and develops biomarkers for effects of stressors, both chemical and non-chemical, on marine organisms. Immune function, fertility potential and DNA damage are currently some of the biomarkers that they use to help answer questions about the status of the environment.
By using cutting-edge technology to detect trace levels of persistent organic contaminants, she can evaluate possible effects toxic substances have on marine life — from low-level chronic exposures that could hinder reproduction and development, to acute exposures leading to immediate illness and death.