Posts Tagged ‘Science’

UGA Skidaway Institute scientists study microbial chemical warfare

April 18, 2017

In the battlefield of the microbial ocean, scientists have known for some time that certain bacteria can exude chemicals that kill single-cell marine plants, known as phytoplankton. However, the identification of these chemical compounds and the reason why bacteria are producing these lethal compounds has been challenging.

Now, University of Georgia Skidaway Institute of Oceanography scientist Elizabeth Harvey is leading a team of researchers that has received a $904,200 grant from the National Science Foundation to fund a three-year study into the mechanisms that drive bacteria-phytoplankton dynamics.

Researcher Elizabeth Harvey examines a part of her phytoplankton collection.

Understanding these dynamics is important, as phytoplankton are essential contributors to all marine life. Phytoplankton form the base of the marine food chain, and, as plants, produce approximately half of the world’s oxygen.

“Bacteria that interact with phytoplankton and cause their mortality could potentially play a large role in influencing the abundance and distribution of phytoplankton in the world ocean,” Harvey said. “We are interested in understanding this process so we can better predict fisheries health and the general health of the ocean.”

This project is a continuation of research conducted by Harvey and co-team leader Kristen Whalen of Haverford College when they were post-doctoral fellows at Woods Hole Oceanographic Institution. They wanted to understand how one particular bacteria species impacted phytoplankton.

A microscopic view of a population of phytoplankton

“We added the bacteria to the phytoplankton and the phytoplankton died,” Harvey said. “So we became very interested in finding the mechanism that caused that mortality.”

They identified a particular compound, 2-heptyl-4-quinlone or HHQ, that was killing the phytoplankton. HHQ is well known in the medical field where it is associated with a bacterium that can cause lung infections, but it had not been seen before in the ocean. The team will conduct laboratory experiments to determine the environmental factors driving HHQ production in marine bacteria; establish a mechanism of how the chemical kills phytoplankton; and use field-based experiments to understand how HHQ influences the population dynamics of bacteria and phytoplankton.

“This project has the potential to significantly change our understanding of how bacteria and phytoplankton chemically communicate in the ocean.” Harvey said.
The project will also include a strong education component. The researchers will recruit undergraduate students, with an effort to target recruitment of traditionally under-represented groups, to participate in an intense summer learning experience with research, field-based exercises and some classroom work.

“The idea is for the students to return to their home institutions at the end of the summer, but to continue to work with us on this project,” Harvey said. “This will be a unique opportunity to offer students cross disciplinary training in ecology, chemistry, microbiology, physiology and oceanography.”

In addition to Harvey and Whalen, the research team includes David Rowley of the University of Rhode Island.

NOTE:  A complementary video with an interview with Dr. Harvey is available at http://www.skio.uga.edu/news/videos/

 

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Microplastics article in Savannah Morning News

February 20, 2017
Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

Reporter Mary Landers wrote a very nice article about Dr. Jay Brandes’s research into microplastic and microfiber pollution on the Georgia coast.

http://savannahnow.com/news/2017-02-19/skidaway-researchers-track-plastic-fibers-coastal-food-chain

Tiny but voracious marine organism studied — video

February 8, 2017

Tiny but all-consuming marine organism focus of UGA Skidaway Institute study

February 8, 2017
Marc Frischer

Marc Frischer

Doliolids are tiny marine animals rarely seen by humans outside a research setting, yet they are key players in the marine ecosystem, particularly in the ocean’s highly productive tropical and subtropical continental margins, such as Georgia’s continental shelf. University of Georgia Skidaway Institute of Oceanography scientist Marc Frischer is leading a team of researchers investigating doliolids’ role as a predator in the marine food web.

Doliolids are small, barrel-shaped gelatinous organisms that can grow as large as ten millimeters, or about four tenths of an inch. They are not always present in large numbers, but when they bloom they can restructure the marine food web, consuming virtually all the algae and much of the smaller zooplankton.

A doliolid with a cluster of juvenile doliolids on its tail. Actual size is approximately three millimeters, or one eighth inch.

A doliolid with a cluster of juvenile doliolids on its tail. Actual size is approximately three millimeters, or one eighth inch.

“The goal of this particular study is to find out what the doliolids are eating quantitatively,” Frischer said. “This is so we can understand where they fit in the food web.”

Scientists know from laboratory experiments what doliolids are capable of eating, but they don’t know what they actually do eat in the wild. They are capable of eating organisms as small as bacteria all the way up to much larger organisms.

“What they are eating and how much are they eating from the smorgasbord that is available to them, that is the question,” Frischer said. “We are investigating how much of those different prey types they are really eating out there across the seasons.”

The project involves intensive field work, including 54 days of ship time on board UGA Skidaway Institute’s Research Vessel Savannah. During the cruises they conduct trawls using special plankton nets to collect the doliolids. They also collect water samples to understand the conditions where the doliolids thrive.

Graduate students Lauren Lamboley and Nick Castellane deploy a plankton net from the Research Vessel Savannah.

Graduate students Lauren Lamboley and Nick Castellane deploy a plankton net from the Research Vessel Savannah.

“We take the doliolids and the water samples back to the laboratory, and that is where the magic begins,” Tina Walters, Frischer’s laboratory manager said.

Because the animals are gelatinous and very delicate, the researchers cannot use classical microscopic techniques to dissect the animals and analyze their gut content. Instead they extract DNA from the animals’ gut and use sequence-based information to determine what the doliolid ate.

“We go through a process called quantitative PCR,” Walters said. “So even though we can’t see the prey in a doliolid’s gut, because the prey have unique DNA sequences, we can identify and quantify them using a molecular approach.”

The three-year project is funded by a $725,000 grant from the National Science Foundation and will run until February 2018. Frischer’s collaborator on the project is Deidre Gibson from Hampton University. Gibson received her Ph.D. from the University of Georgia in 2000, and did much of her graduate research at Skidaway Institute with Professor Gustav Paffenhöfer.  In addition to Walters, Savannah State University graduate student Lauren Lamboley is part of the team, along with a number of students at Hampton University. Several undergraduate research interns have also participated in the project, gaining hands-on research experience. Frischer is also working with the Institute for Interdisciplinary STEM Education at Georgia Southern University to engage K-12 teachers by inviting them to participate in the research cruises.

Scientists track microplastic pollution on the Georgia coast

January 31, 2017

In recent years, the public has become attuned to the problem of trash in the ocean, especially plastic, as images of the Great Pacific Garbage Patch have spread through media and the Internet. Now, University of Georgia Skidaway Institute of Oceanography professor Jay Brandes is leading a team investigating another issue closer to home on the Georgia coast: microplastics.

Jay Brandes

Jay Brandes

These are tiny pieces of plastic—smaller than  five millimeters, or about a fifth of an inch—that have either been manufactured small or have broken down from larger pieces. They can be found in our beaches, water and in the digestive systems of aquatic wildlife.

“Five millimeters is still something you can see with the naked eye, but if you are out at the beach you aren’t going to pick up on it easily,” Brandes said. “So we say anything smaller than 5 millimeters is considered a microplastic.”

A few pieces of microplastic collected from the Georgia coast.

A few pieces of microplastic collected from the Georgia coast.

 

Funded by Georgia Sea Grant, Brandes and UGA Marine Extension and Georgia Sea Grant educator Dodie Sanders are in the first year of a two-year study to ascertain the extent of microplastic pollution in Georga’s coastal waters.

“Right now we are just trying to get an idea if there is a problem, and if there is, how prevalent it is,” Brandes said.

Microplastics come from several sources. Beginning in 1972, cosmetics manufacturers started adding plastic microbeads to exfoliating body washes and facial scrubs, which often pass freely through water treatment plants. When scientists reported finding these microbeads in rivers, lakes and oceans, it prompted a worldwide discussion on the issue. In 2015, Congress enacted legislation requiring the cosmetics industry to remove microbeads from rinse-off cosmetics by July of this year.

The sun also contributes to the production of microplastics. Plastic exposed to sunlight eventually fades, becomes brittle and breaks down into smaller pieces.

“All of us have probably seen a Styrofoam cup break down and the little beads come out,” Brandes said.  “So there is the physical breakdown of the plastics into smaller and smaller pieces as they grind against each other and sand grains.”

To assess the extent of microplastic pollution on the Georgia coast, the research team makes use of the regular trawls conducted by UGA Marine Education and Aquarium staff. They collect the fish, shrimp, squid and other animals captured in the trawl and take them back to a laboratory where they will dissect them and analyze the contents of their gut.

Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

Students from Pierce County Middle School sort through the results of a trawl as part of an education program at the UGA Marine Education Center and Aquarium.

“The first thing we have to do is to subject the gut contents to some extremely harsh chemicals to destroy the flesh and leave us mostly with the plastics,” Brandes said. “When dissecting even a small fish, it’s like looking for a needle in a haystack if you don’t get rid of all the other stuff.”

What is left is examined under a microscope and the plastic pieces identified and counted. The researchers have already found some surprises. Everywhere they look, whether it is beach sand or the contents of a fish’s stomach, they are seeing microfibers, extremely fine synthetic fiber used to create textiles.

According to Brandes, microfibers are pervasive—so much so that when the researchers take samples to the laboratory they have to take special measures to prevent contamination of their samples from microfibers floating in the air. It is not clear, however, if the microfibers are causing any harm to the marine organisms that ingest them.

“We are not finding fish with their stomachs packed with microfibers,” Brandes said. “It’s hard to tell if they are causing any real problems.”

The project also has an educational component. Brandes has taught workshops in which he takes  groups of K-12 teachers to Tybee Island to collect sand and return it to the laboratory for microscopic analysis. He says the teachers are usually shocked with what they see.

“Hey, you thought that sand was clean, and from a tourist standpoint it is,” he said. “But there is still stuff in there and then you start talking about where it came from and what kinds of effects it may have.”

The project is expected to be completed and the results published by early 2018.

New imaging lab in the news

January 23, 2017

There was a nice article in Saturday’s Savannah Morning News regarding a new imaging lab at UGA Skidaway Institute.

http://savannahnow.com/news/2017-01-20/automated-microscopes-aid-crucial-ocean-work-skidaway

UGA Skidaway Institute’s Jay Brandes interviewed on public radio

January 19, 2017
Dr. Jay Brandes

Dr. Jay Brandes

UGA Skidaway Institute’s Jay Brandes was a featured interview guest on Georgia Public Broadcasting this week, talking about his work with microplastics in the marine environment.

http://www.gpb.org/blogs/community/2017/01/17/community-conversations-skidaway-scientist-on-mission-measure-ocean?utm_source=eGaMorning&utm_campaign=b51e5a8395-1_18_17&utm_medium=email&utm_term=0_54a77f93dd-b51e5a8395-86742941

WSAV airs story on UGA Skidaway Institute black gill research

December 16, 2016

Savannah NBC affiliate, WSAV-TV aired an update on Dr. Marc Frischer’s ongoing research into the problem of black gill in Georgia shrimp.

Research reveals black gill kills shrimp

UGA Skidaway Institute develops cutting-edge microbial imaging laboratory

December 7, 2016

A team of researchers from the University of Georgia Skidaway Institute of Oceanography has received a $226,557 grant from the National Science Foundation to acquire state-of-the-art imaging equipment to investigate microorganisms from the tiniest viruses to larger zooplankton. The equipment will be housed in UGA Skidaway Institute’s new Laboratory for Imaging Microbial Ecology, or LIME.

Researcher Elizabeth Harvey leads the research team that also includes UGA Skidaway Institute scientists Julia Diaz, Marc Frischer, James Nelson and James Sanders.

The equipment will improve Skidaway Institute’s capability to conduct field and laboratory experiments by automating many viewing methods.

“Anyone who uses a microscope will tell you that it is both tedious and time consuming,” Harvey said. “This equipment will allow us to enumerate and analyze microbes and other planktonic organisms much faster, and will allow us to do more large-scale projects than we could in the past.”

UGA Skidaway Institute researchers Tina Walters, Marc Frischer and Karrie Bulski practice running zooplankton samples on the FlowCam, a new instrument that is part of LIME.

UGA Skidaway Institute researchers Tina Walters, Marc Frischer and Karrie Bulski practice running zooplankton samples on the FlowCam, a new instrument that is part of LIME.

Much of the equipment will also have imaging capability so researchers will be able to do more detailed measurements on the size and shape of the tiny organisms and how that might relate to the health of an ecosystem.

Marine microbes are an essential component of all marine ecosystems and they play central roles in mediating biogeochemical cycling and food web structure.

“They are the things that drive all other processes in the ocean,” Harvey said. “They play a really important role in the way nutrients, oxygen and carbon are cycled through the ocean. We care a lot about those processes because they impact our climate, fisheries and the ocean’s overall health.”

A sampling of phytoplankton   imaged by the LIME's FlowCam.

A sampling of phytoplankton imaged by the LIME’s FlowCam.

The benefits of LIME will be shared beyond Skidaway Institute’s science team. Harvey envisions it as a regional center for microbial imaging, available to any other researchers who need the capability.

“Anyone is welcome to come here and get trained to use them,” she said. “They just need to contact me and we can make arrangements.”

Some of the equipment is already in place, while other pieces have not been delivered. Harvey anticipates all the equipment being functional by mid-2017.

UGA Skidaway Institute associate professor cited for top research articles

December 2, 2016

University of Georgia Skidaway Institute of Oceanography associate professor Aron Stubbins is one of just a handful of researchers cited in the journal Limnology and Oceanography for authoring two of the journal’s top scientific papers over the past 60 years.

Skidaway Institute's Aron Stubbins

Skidaway Institute’s Aron Stubbins

Limnology and Oceanography is an official publication of the Association for the Sciences of Limnology and Oceanography and is considered a premier scientific journal. In its recently published 60th anniversary issue, the journal collected and republished the 10 most cited research papers for each of the last six decades. Stubbins authored or co-authored two of those papers, one in 2008 and the other in 2010.

“It came as quite a surprise to see two articles show up on the list,” Stubbins said. “I was at a conference and wasn’t really checking my email when one of my colleagues let me know.”

The journal used the number of times a paper was cited in future studies as the yardstick to determine which papers should be included on the list. It is one commonly used method for measuring the impact of a scientist’s work.

“The list isn’t really about popularity,” Stubbins said. “It’s about usefulness. That people have found some of my work useful over the years is rewarding.”

The 2008 paper was titled “Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter.” The lead author was John Helms. Stubbins was a co-author along with four other scientists. The research team developed a new method for extracting new information from a relatively common and simple test of the color of dissolved organic matter.

Stubbins was the lead author, along with nine co-authors, of the second paper, “Illuminated darkness: Molecular signatures of Congo River dissolved organic matter and its photochemical alteration as revealed by ultrahigh precision mass spectrometry.” The study examined organic carbon carried to the ocean by the Congo River — after the Amazon, the second largest river in the world in terms of carbon and water flow. The research team studied how sunlight degrades organic material, including which compounds are degraded, which are not and what new compounds are created when sunlight shines on river water.

“His inclusion in this seminal volume is quite an honor for Dr. Stubbins,” UGA Skidaway Institute Interim Director Clark Alexander said. “This recognition validates what we have always known, that he is conducting groundbreaking and meaningful research that is recognized around the world.”

All 60 papers can be found at http://aslopubs.onlinelibrary.wiley.com/.