New DROPPS Researchers at the University of Texas Marine Science Institute

By Lalitha Asirvadam, DROPPS Program Coordinator

The New Year brings new talent to the Dispersion Research on Oil: Physics and Plankton Studies (DROPPS) consortia! Since last fall, DROPPS has added three new post-doctoral researchers and one PhD student to the team at the University of Texas Marine Science Institute (UTMSI). Maud Moison, Tatiana Severin, Charles Tang and Sarah Cosgrove are working with Dr. Ed Buskey and Dr. Deana Erdner on research involving various zooplankton and phytoplankton-bacteria interactions in relation to oil exposure. They each bring a wealth of diverse knowledge to our consortia. Read about their past experiences, research interests and what inspired them to work with DROPPS at UTMSI.

Maud Moison

 I was born and raised in France, in a small city by the sea in Brittany. After graduating from high school, I went to a two-year college in the south of Brittany and then transferred to the University of Rennes 1 where I obtained a B.S. in biology. After a short stint as a laboratory assistant in IFREMER in Brest, France, I moved back to the University IUEM for graduate school. I obtained my PhD in marine ecology from the University of Lille 1. I then moved to Germany, and later to Taiwan to continue my research work. I finally arrived at UTMSI as postdoctoral researcher in September 2015.

My research interests have focused on marine zooplankton behavior. I am particularly interested in small scale mechanisms that drive individual behavior change under both anthropogenic and climatic forces. For example, My PhD thesis provided a quantitative description of the seasonal change of copepod swimming activity, as well as evaluated the impact of different environmental factors on the copepod behavior.

My research also aims to analyze multiscale ecological responses of plankton communities to external forcing. Specifically, this part of my research involves using adequate methodologies to face the challenge of scale-dependent processes in plankton ecosystem, and the nonlinearity and non-stationarity of time series data.

Within the DROPPS consortium, I am going to study the sublethal effects of low concentrations of crude oil and dispersants on marine zooplankton. More specifically, my current research topics will try to answer to these questions: (1) Does the exposure to PAHs decrease the behavioral adaptations ability of zooplankton and then disturb their migration, feeding or mating activity? (2) Does the exposure to PAHs increase the vulnerability to other stress such UV? (3) What are the long term consequences (i.e. consequences over generations) of a short exposure to PAHs?

Working at UTMSI with Dr. Buskey gives me the opportunity to broaden my experience in individual animal behavior using state of the art optical techniques, while playing an active role in understanding and protecting the marine environment.

Tatiana Severin

I finished my PhD in 2015 at the Oceanological Observatory of  Banyuls-sur-mer, France. I worked on the impact of the convection process in the Northwestern Mediterranean Sea on the nutrient budget and the microbial compartment. The nutrient supply driven by the upwelled deep waters during one convection event revealed to be significantly higher than the annual rivers discharges of the Northwestern basin, and was able to sustain the entire spring bloom. Sequencing analyses of the 16S rRNA gene revealed that the bacterial community structure was deeply mixed in the convection cell, with the presence of both surface and deep OTUs from 0 to 1500 m depth. This mixed community persisted after the water column stratification and was entrapped in the new-formed deep waters.

To reinforce my specialization in the ecology of phytoplankton and prokaryotes, I came to UTMSI to work with Dr. Deana Erdner and Dr. Edward Buskey. In DROPPS-II, I aim to understand the impact of oil on the phytoplankton-bacteria interactions. After an oil spill, some phytoplankton species turned out to be resistant, while others were not. The strong interactions existing between bacteria and the host-phytoplankton could be at the origin of this resistance. During my researches in DROPPS-II, I will characterize these interactions and follow the physiological responses of some xenic and axenic phytoplankton strains after an oil exposition.

Chi Hung "Charles" Tang

I graduated from the Chinese University of Hong Kong (CUHK) as a marine ecologist.  I decided to pursue a research career in the field of marine plankton. I am impressed by the faculty team at UT Marine Science Institute, as it comprises many well-established research scientists in this field. Particularly, I am interested in the work of Dr. Edward Buskey. The first time I heard about Dr. Buskey was when I came across an article about the interaction between persisting brown-tide alga and planktonic grazers when I was in CUHK. Since my previous research experience is related to the grazing impact of micrograzers on algal blooms, I found the article very insightful. Later, I learned more about Dr. Buskey's work by reading his publications about the effects of dispersant-treated petroleum on marine plankton. I have become interested in how the treated oil affects planktonic organisms and animas up the trophic levels. Therefore, it is my pleasure to take part in the DROPPS research program as a doctoral student. I plan to investigate the effects of crude oil and dispersant on the eco-toxicology, adaptive behavior and population community of marine zooplankton and micrograzers.

Sarah Cosgrove

I completed my Marine Science degree at The National University of Ireland, Galway along the West Coast of Ireland during the period of 2006 - 2010. It was during my final year when I became increasingly interested in the smaller things in life i.e. plankton! My undergraduate thesis focused on the resting ‘cyst’ stage of dinoflagellate species in an archipelago region located north of Scotland known as the Shetland Isles.

My supervisor Dr. Robin Raine was an incredibly enthusiastic and supportive mentor and I ended up sticking around following the completion of my degree to work in his department as a research assistant. I continued to develop a passion for marine microbiology studies, especially within the area of Harmful Algal Blooms (HABs) and I became part of an on-going monitoring effort along the south coast of Ireland involving the saxitoxin producing species Alexandrium minutum. From here I gained funding for a three year PhD project where my primary objective was to take a closer look at the life history stages of A. minutum and at how both asexual and sexual reproductive phases can impact upon their population dynamics. A. minutum bloom initiation and termination were modeled based on observed variations in environmental parameters and sexual reproductive stages. Aside from the role physiological changes played in A. minutum cell behavior and population dynamics, an attempt was also made to determine the level of control parasitism exerted on the functional ecology of the population. It was after the completion of my PhD that the road to oil studies began. Following my thesis submission, I became employed as post-doctoral researcher as part of a European project called ‘Kill-Spill’. Involving over 30 organizations, the motive of ‘Kill-Spill’ is to develop environmentally and economically viable bio-technological tools to combat marine oil spills. My area of work focused on the eco-toxicology testing of bio-surfactants and plant-derived dispersants.

During the end of this research, I applied for the position of post-doctoral researcher with DROPPS-II and here I am! I’m delighted to be part of the team and under the supervision of Prof. Buskey. I have been following developments and research undertaken regarding the Deepwater Horizon oil spill since its occurrence and feel privileged to be contributing to on-going studies of such importance.

My research while at UTMSI is predominately aimed at utilizing mesocosm experimentation to analyze natural alterations in planktonic community structures following oil pollution events. As all planktonic groups are linked through complex direct and/or indirect interactions, it is important to focus on the long term impacts caused by oil pollution under a variety of environmental parameters. The physiological changes and recovery abilities of various protozoan and phytoplankton species will be assessed over time following the introduction of oil and dispersant to the controlled systems. As both of these groups play crucial roles in the tropic food chain, I will also aim to determine their level of contribution in the bio-transfer of Polycyclic Aromatic Hydrocarbons to higher tropic levels. Overall, the research intends to gain a greater understanding of the interactions between oil droplets and key planktonic organisms by means of mimicking the natural environment.

Research Experiences for Undergraduates (REU) Student Chris Payne Presents DROPPS Research

Every summer, the University of Texas Marine Science Institute (UTMSI) admits Research Experiences for Undergraduates (REU) interns to participate in exciting research, giving them valuable experience that will prepare them for careers in marine science. After choosing a research topic and mentors, they spend the summer working on their projects and give a final presentation at the REU Symposium at the end of the summer. 

Chris Payne, a marine biology major from Boston University, is one such student. He decided to work with DROPPS because he realized the value of studying oil spills and wanted to help be a part of the solution to this complicated problem.

There have been many studies on how oil affects macrofauna, but not as many studies on the impacts it has to the base of the marine food chain: plankton.  These tiny organisms are important for many reasons. Plankton are important contributors to primary and secondary production. Also, toxic species can cause harmful algal blooms when they are in large numbers. They also form important links in the marine food web, and finally, they provide organic matter to deep sea ecosystems through marine snow.

Research Questions

Chris Payne presents at the REUfest
2015 Summer Symposium
Credit: Lalitha Asirvadam

Chris’ research focused on these questions: What effect does oil and dispersant have on natural plankton populations? How do changes in oil and dispersant concentrations affect natural plankton communities? Chris worked closely with his mentors, Dr. Brad Gemmell and Dr. Ed Buskey from DROPPS, to try and find answers to these questions.

Background

In preliminary experiments, Dr. Gemmell has looked at the dinoflagellate Prorocentrum and its ciliate grazers. He exposed them to oil and dispersants and observed changes in populations. His results indicated that dispersants inhibit ciliate growth which led to population increases in dinoflagellates. Chris wondered if similar results can be seen in natural plankton populations.

Methods

His study consisted of three experiments: two using nearshore water and one using offshore water. The water was filtered to remove large zooplankton. Each experiment used three treatments: filtered sea water, seawater with crude oil, and seawater with crude oil and dispersant. Both offshore and nearshore experiments were exposed to 20 µL Lˉ̄ ¹ of crude oil, while an additional treatment was conducted for nearshore water with 50 µL Lˉ̄ ¹ concentration of oil. A 20:1 ratio of crude oil to dispersant was used in all three experiments. For the nearshore experiments, 10 mL samples were taken daily and Chris counted diatoms, dinoflagellates, and ciliates using microscopy, FlowCAM, and flow cytometry. The offshore samples had to be settled in 50 mL settling chambers and were counted using microscopy.

Results

For the 20 µL Lˉ̄ ¹ crude oil nearshore experiment, Chris found no significant differences among the total populations of the control, oil, and oil plus dispersant treatments. The 50 µL Lˉ̄ ¹ nearshore experiment, however, showed significant differences among the total populations of each treatment.

Conclusion

In summary, Chris observed that oil and dispersants have a negative effect on diatoms; however, dinoflagellates appear to be resistant to the toxicity of oil and dispersants. In addition, higher concentrations of oil have a more significant impact on plankton populations while offshore populations were more affected by 20 µL Lˉ̄ ¹ concentration of crude oil than the nearshore populations.  And finally, a population of small (approximately 2 micron) organisms becomes much more abundant in oil and oil + dispersant treatments. It may be that small nanoplankton (such as Synechococcus) are resistant to oil and dispersant.

Chris gave his final presentation on August 5, 2015. He said that he learned a lot and enjoyed his time as an REU student at UTMSI. He is currently thinking about a future in marine conservation.

Research sponsored by the Gulf of Mexico Research Initiative 

Oil and Plankton: DROPPS Takes a Closer Look Using Laser Technology

The interactions of plankton with oil droplets is a fascinating but relatively unexplored area. Scientists in the DROPPS Consortium previously looked at oil droplets rising though thin layer of plankton to see how they interact with oil. This time DROPPS wanted to look further into what may have happened in the dispersed oil layers between the well head, at approximately 5000 feet below sea level, and the ocean surface. DROPPS Scientists used holography technology, small scale experiments in the lab, and a recently constructed tower tank, measuring approximately 4 meters tall, for their latest experiments.

During the week of June 22^nd 2015, DROPPS scientists Ed Buskey, Brad Gemmell, Jian Sheng, Joe Katz, David Murphy, Cheng Li, Larry David, Vincent d'Albignac and Jeffrey Cordero convened at the University of Texas Marine Science Institute (UTMSI) in Port Aransas, Texas to participate in the experiments.

DROPPS’ recent experiments involved holography technology which allows you to construct volume in 3D. This shows a 3D distribution of water and how it interacts with particles. DROPPS scientists were able to take a closer look at what could have happened to plumes of oil released from the Deepwater Horizon well head that had been mixed with dispersant. Studies showed dispersants created subsurface plumes of tiny oil droplets.  DROPPS recreated this in the laboratory by creating a layer of microscopic droplets (by adding dispersant to oil and mixing it up with seawater using stir plates), mimicking the subsurface layers associated with the Deepwater Horizon. They also created varying density layers in the water (by slightly changing the salinity), with the most dense water at the bottom, intermediate water in the middle, and lighter water at the top. They wanted to see how quickly oil would diffuse through these layers. Seawater density can change throughout the water column, with the most rapid changes often occurring near the bottom of the thermocline.  With the tower tank experiments, they set up layers to see how the micro oil droplets would disperse naturally, with and without small organisms swimming through it or with larger organisms stirring up the water.  This would help measure the importance of biogenic mixing (mixing of the ocean by animals), an idea that has recently been of great interest to biologists and oceanographers.

Small scale experiment in lab. Photo by Jeffery Cordero

First, DROPPS scientists conducted small scale experiments in the lab. In these experiments, they added small zooplankton, copepods mostly, and used PIV to examine how or if they mixed a layer of oil. The copepods did not seem to have much effect on the dispersion of the oil layer, probably because they were too small.  Tiny oil droplets have natural fluorescence so they glow when exposed to certain wavelengths of light. This allows DROPPS scientists to measure how well the animals mix the oil-water emulsion layer in comparison to natural diffusion.

A ctenophore suspended in water. Photo by Jeffery Cordero

 In the large tower tank experiment, they produced physical dispersion by using larger organisms (jellyfish), which had more of an effect on the layer containing dispersed oil.

Tower Tank. Photo by Jeffery Cordero

 In the future they hope to use intermediate sized organisms such as shrimp and small fish to examine their effects of biogenic mixing of dispersed oil. In the future, DROPPS scientists also wanted to study how these organisms interact with the dispersed oil layers; do copepods and other small zooplankton feed on the oil? Does this make them more susceptible to their predators (jellyfish and small fish)?

Video by Jeffery Cordero

Research sponsored by the Gulf of Mexico Research Initiative 

Hi everyone! My name is Colbi Gemmell and I am the Outreach Coordinator for DROPPS. I conduct outreach and educational activities related to our research such as: K-12 classroom visits, participation in local events, keeping up with social media, and coordinating news about our team members. I have also been organizing the DROPPS reading group which is comprised of ten DROPPS graduate students, post-docs, and staff members. Participants are from the University of Texas Marine Science Institute (Hernando Bacosa, Meredith Evans, Brad Gemmell, Colbi Gemmell, and Tracy Harvey), Johns Hopkins University (Cheng Li and David Murphy), Texas Tech University (Maryam Jalali-Mousavi), and the University of Pennsylvania (Tagbo Niepa and Liana Vaccari).

In December of 2013, the DROPPS reading group began as a monthly meeting where members got together to discuss papers relevant to the field of oil spill science. After a few of these meetings, the group determined that we wanted to do more than simply discuss the current literature. DROPPS Research Associate Dr. Brad Gemmell came up with the idea of conducting an extensive oil spill literature review with the goal of putting together a publishable manuscript on global, long-term trends. The idea was based on reading groups that he had previously been involved in. The group agreed that this was an exciting direction that allowed group members exposure to a large portion of oil spill literature across a wide variety of years and disciplines. The group worked together to develop a plan for obtaining, analyzing and completing such a large literature review. 

After determining the keywords to use, important questions to be addressed and doing several rounds of controls to ensure consistency, the DROPPS reading group started the official literature review. Each participant had to review a predetermined number of papers for assigned years to ensure that we were reviewing at least 10% of the available literature during each 5-year period dating back to 1968. Data collection took a total of six weeks and included the review of approximately 1100 papers. Currently, participants are in the process of analyzing the data in order to start putting together the manuscript. We are really excited to see what story our data tells. 

Reading group members discuss oil spill papers during a recent meeting. 

Research sponsored by the Gulf of Mexico Research Initiative 

Hi! My name is Sarah Horn and I’m an undergraduate Biology student at University Wisconsin-Milwaukee. I’m working with Professor Rudi Strickler at the Global Water Center. I was given the opportunity to work with DROPPS through the UW-Milwaukee’s Undergraduate Research Opportunity Program. I began working in the spring semester of 2014. 

Me feeding Daphnia an algae mixture.

I’m working on a project to observe how the freshwater zooplankton Daphnia pulex will react to oil droplets. Oil droplets of a set size are generated to simulate dispersed oil. Daphnia are placed in a Kreisel tank filled with oil droplets and algae. Water is pumped into the Kreisel tank creating a current along the edges of the tank, which keeps the Daphnia from getting too close to the edge. Daphnia behavior when surrounded by oil droplets is documented by taking a high speed video using laser holography. Using holography means that the Daphnia can be out of focus while it is being filmed, and reconstructed with imaging software later. This is necessary because of the Daphnia’s constant movement. After the video is taken, the size of oil droplets is measured to see if the Daphnia have attempted to eat the dispersed oil. Additionally, the behavior of Daphnia when surrounded by oil droplets is observed.

A Kreisel tank

Freshwater zooplankton are used because they are easy for us to access. We get our zooplankton from the Menomonee River, Milwaukee River, Kinnickinnic River and Lake Michigan, all which are located less than a mile away from the lab. Once we obtain adequate results using the freshwater zooplankton, a species of saltwater zooplankton will be used.

Hi, everyone! My name is Meredith Evans; I am a graduate student at the University of Texas Marine Science Institute (UTMSI) and of course, a DROPPSter. Here at UTMSI, I have had the opportunity to get involved with the DROPPS consortium thanks to my research on oil spills.

An oil sheen on the Gulf Coast in Port Aransas, TX.

As an aspiring Texan scientist, I have always had a critical view of the oil and gas industry. Although it is an established part of our culture and economy, I have come to recognize many of the negative ramifications it can have on our environment. With a large portion of drilling taking place offshore, many of these consequences occur in our oceans. Outside the devastation oil spills cause to marine plants and animals, crude oil input can cause major chemical shifts in the water column and sediment. Crude oil is a complex mixture of trace metals and hydrocarbons of varying length and shape. As the oil degrades from a variety of weathering processes, these compounds start to separate and transform. Some components will completely disappear, others will be modified, and some will be retained in the water and/or sediment for years. The story is never the same between oil spills; the remaining mixture of toxic compounds varies by location, bacterial composition, and a variety of other factors. I am interested in teasing apart these relationships and improving the methods scientists use to study oil spills so the industry can continue to thrive, but in a more environmentally responsible way.

Studying the chemistry of oil spills is an exciting field. Recently, I (like many beach goers) was combing the beach for interesting organisms. To my surprise, I found a significant number of tarballs on our beaches here in Port Aransas, TX. Tarballs are exactly what they sound like: sizeable lumps of rubbery tar. They are typically associated with offshore oil spills and formed after crude oil has been rolled around in the ocean. They come in all shapes and sizes and, in my opinion, are pretty unsightly for the beach.

A few of the tarballs I collected on the Gulf side of Mustang Island.

Most people who find them may assume them to be a unique rock or piece of coal from a barbecue. Individuals who are familiar with tarballs may think about the possible spill source, and how it may have affected species living in the area.  I, on the other hand, think about the compounds composing that tarball and what they can tell us. In our lab, we not only have the capacity to study tarball components to determine how much that tar has degraded, but we can also trace the source of that tar ball to see exactly where it came from and possibly how long it has been roaming the ocean. The tarballs I collected are currently in the freezer at UTMSI and will be analyzed soon. These kinds of discoveries are small, but give scientists and activists a better picture of how our oceans are responding to our oil consumption.

One of the algae beds I collected small tarballs from. 

Outside of tarballs, my current research focuses on using a new technique to study oil spills, ramped pyrolysis. Under the advisement of Dr. Zhanfei Liu, I am exploring the possibilities on what this technique can tell us about contaminated sediments and waters. Recently, ramped pyrolysis has been used to distinguish oil-based hydrocarbons from natural organic content in contaminated sediments and water. This technique is fast, efficient and is very useful when trying to explain organic matter in an oil-affected environment. Expanding on previous research, I hope to show how we can better use ramped pyrolysis to explain the oxygenated partition of degraded oil, which has recently been shown to be a significant product of weathering.

Some Summer Science students and me mimicking surface currents after an oil spill. 

In addition to the time I spend in the lab, I love participating in outreach opportunities where I can share my research and passions with the public. Recently, I was invited to participate in a program here at UTMSI called Summer Science. In this program, elementary and middle school students spend each day with a scientist, learning about what they do and why it is important. In my time at Summer Science, I taught students about how currents can affect oil spills. Working with 3^rd – 5^th graders, I was not expecting them to be knowledgeable about oil spills, but these students were sharp - they already knew a lot about how oil spreads and the damage it causes. This shows me that education and outreach about oil spills had already benefitted them (and hopefully, other students their age across the nation)! Personally, I hope to have expanded their knowledge even more and encouraged them to share the information with their friends and family, who may not have had similar exposure.

Summer Science students watching how and where the currents are moving the oil.

With expanding opportunities to learn and teach about oil spills, such as Summer Science and the DROPPS consortium, I am optimistic that scientific investigations and outreach about offshore drilling and oil spill clean up protocol can continue to improve into the future.

Hello, my name is Lambert Aryee. I was one of 1783 finalists, from over 70 different countries and territories, that qualified for the Intel International Science and Engineering Fair (ISEF) held in Los Angeles, California. I met numerous people of various ethnicities and backgrounds. I presented my science project on the dispersal of oil spills, which I worked on at the Johns Hopkins Oil Spill Lab during the past year.

Day One:

After arriving at the hotel in L.A., finalists were given the opportunity to officially meet with each other for the first time at the Pin Exchange Party. As a finalist from Maryland, my pins had the Maryland flag on them, and I was able to trade pins with 100s of finalists from countries like China, Japan, Mexico, Germany, Russia, Puerto Rico, and the Philippines. Additionally, the United States was heavily represented as nearly all 50 states had finalists from local and regional fairs. I met people from Texas, Ohio, California, Virginia, Tennessee, Florida, Louisiana, Illinois, Connecticut, Hawaii, and numerous other states.

Day Two:

This day was designated for set-up and inspection of the finalists' boards. The judging halls were open at 9am for finalists. All stations and boards were inspected by an ISEF staff member. Once I had passed my inspection and made sure that everything was in perfect condition, I was able to explore the city of L.A. with Darius Johnson, another finalist, and our mentors. We drove through the mountains and up into the valley, saw the Hollywood sign, explored Beverly Hills, and visited the Getty Museum which is filled with some of the best art pieces in the world. That night, a party was hosted for the finalists in front of the Staples Center at Club Nokia. This was the time for finalists to have a little fun because the next day was Grand Prize and Special Awards judging day.

Day Three:

The day officially began at 8am and ended at 5pm. All judges evaluated projects within their area of expertise. I had approximately 8-12 judges, of which 6 were scheduled to judge my project. The rest were either special awards judges or just spectator judges on break. After judging was over, ISEF rented out Universal Studios for all finalists, student observers, and mentors to go and celebrate the long and stressful day of presenting. We were at Universal from 7pm to 12pm.

Day Four:

This day was open to the public, so schools and science fair enthusiasts from the L.A. area came and listened to our presentations. This was also an opportunity for the media to come and interview the finalists and know more about their projects. I had the honor of being interviewed by a local news crew and an Innovations blogger. It was a more relaxed day. That night was the special awards ceremony. Many finalists received awards from organizations, universities, and research groups.

Day Five:

This day was the grand prize award and closing ceremony. I won a fourth place award in the category of Environmental Management with my project Dispersing Oil Slicks: Impact of Droplets on a Floating Oil Layer!