Corals create potions that fight bacterial attackers, but warming appears to tip the scales against the potions as they battle a bacterium common in coral bleaching, according to a new study. Reef conservation may offer hope: A particular potion, gathered from reefs protected against seaweed overgrowth, proved more robust.

The protected Pacific reefs were populated by diverse corals and shimmered with colorful fish, said researchers who snorkeled off of Fiji to collect samples for the study. Oceanic ecologists from the Georgia Institute of Technology compared coral potions from these reefs, where fishing was prohibited, with those from heavily fished reefs, where seaweed inundated corals because few fish were left to eat it.

The medicated solutions, or potions, may contain a multitude of chemicals, and the researchers did not analyze their makeup. This is a possible next step, but here the researchers simply wanted to establish if the potions offered any real defense against pathogens and how warming and overfishing might weaken it.

Conservation matters

“I thought I probably wouldn’t see antibiotic effects from these washes. I was surprised to see such strong effects, and I was surprised to see that reef protections made a difference,” said the study’s first author, Deanna Beatty.

“There is a lot of argument now about whether local management can help in the face of global stresses – whether what a Fijian village does matters when people in London and Los Angeles burn fossil fuels to drive to work,” said Mark Hay, the study’s principal investigator, Regents Professor and Harry and Linda Teasley Chair in Georgia Tech’s School of Biological Sciences.

“Our work indicates that local management provides a degree of insurance against global stresses, but there are likely higher temperatures that render the insurance ineffective.”

^{[Ready for graduate school? Here's how to apply to Georgia Tech.]} 

Adding heat

The researchers collected three coral species along with seawater surrounding each species at protected reefs and at overfished reefs. In their Georgia Tech lab, they tested their solutions against the pathogen Vibrio coralliilyticus at 24 degrees Celsius (75.2 Fahrenheit), an everyday Fijian water temperature, and at 28 degrees (82.4 F), common during ocean heating events.

“We chose Vibrio because it commonly infects corals, and it’s associated with coral bleaching in these warming events. It’s related to other bleaching pathogens and could serve as a model for them as well,” Hay said.

“We chose 24 C and 28 C because they’re representative of the variations you see on Fijian reefs these days. Those are temperatures where the bacteria are more benign or more virulent,” Beatty said.

The data showed that warming disadvantaged all potions against Vibrio and conservation aided a potion from a key coral species. The team, which included coauthor Kim Ritchie from the University of South Carolina Beaufort, published its study in the journal Science Advances on Oct. 2. The research was funded by the National Institutes of Health’s Fogarty International Center, the National Science Foundation, and the Simons Foundation.

Deeper dive into the experiment

Seaweed hedges

The unprotected reefs’ shabby appearance portended their effects on the one potion associated with a key coral species.

“When you swim out of the no-fishing area and into the overfished area, you hit a hedge of seaweed. You have about 4 to 16% corals and 50 to 90% seaweed there. On the protected reef, you have less than 3% seaweed and about 60% corals,” Hay said.

Hay has researched marine ecology for over four decades and has seen this before, when coral reefs died off closer to home.

“Thirty years ago, when Caribbean reefs were vanishing, I saw overfishing as a big deal there, when seaweed took over,” he said, adding that global warming has become an overriding factor. “In the Pacific, many reefs that were not overfished have been wiped out in warming events. It just got too hot for too long.”

Distilling potion

The potions are products of the corals and associated microbes, which comprise a biological team called a holobiont.

To arrive at potions focused on chemical effects, the researchers agitated the coral holobionts and ocean water then freeze-dried and irradiated the resulting liquid to destroy remnants of life that could have augmented chemical action. Some viruses may have withstood sterilization, but it would have weakened any effect they may have had, if there were any.

Then the researchers tested the potions on Vibrio.

“All of the solutions’ defenses were compromised to varying extents at elevated temperatures where we see corals getting sick in the ocean,” Hay said. 

But reef protection benefited the potion taken from the species Acropora millepora.

“The beneficial effect in the solution tested in the lab was better when Acropora came from protected areas, and this difference became more pronounced at 28 degrees Celsius,” said Beatty, who finished her Ph.D. with Hay and is now a postdoctoral researcher at the University of California, Davis.

Acropora architecture

Of the three species with potions that were tested, Acropora millepora may be a special one.

It is part of a genus – larger taxonomic category – containing about 150 of the roughly 600 species in Pacific reefs, and Acropora are core builders of reef structures. They grow higher as sea level rises, helping maintain healthy positions for whole reefs.

“Acropora are big and branching and make lots of crevices where fish live. The evolution of lots of reef fish parallels the evolution of Acropora in particular,” Hay said.

If fish can hang on, they may buy Acropora more time, and coral reefs perhaps, too.

Also READ: When Coral Species Vanish, Their Absence Can Imperil Surviving Corals

These researchers coauthored the study: Deanna Beatty, Jinu Valayil, Cody Clements, and Frank Stewart of Georgia Tech. The research was funded by the National Institutes of Health (grant 2 U19 TW007401-10), the National Science Foundation (grant OCE 717 0929119), the Simons Foundation (grant 346253), and the Teasley Endowment. Any findings, conclusions, or recommendations are those of the authors and not necessarily of the sponsors. DOI: https://doi.org/10.1126/sciadv.aay1048

Writer & Media Representative: Ben Brumfield (404-272-2780), email: ben.brumfield@comm.gatech.edu

Georgia Institute of Technology
177 North Avenue
Atlanta, Georgia  30332-0181  USA

The College of Sciences held its annual summer dinner on Sept. 18, hosted by Susan Lozier, the new dean and Betsy Middleton and John Clark Sutherland Chair of the College of Sciences. The gathering has become a tradition for welcoming new members; recognizing excellence in research, instruction, and service; and affirming the College’s special community of scholars.

Tim Cope, Christine Heitsch, and Marvin Whiteley received the 2019 Faculty Mentor Awards. Cope and Whiteley are professors in the School of Biological Sciences; Heitsch is a professor in the School of Mathematics.

Nominations for these awards come from early-career faculty. Nominators cite mentors’ willingness to make introductions, review proposals, and develop professional training programs as extremely helpful as they get familiar with and navigate their environment and roles.  

"[Y]our recognition also shines a bright light on your school and the College of Sciences, for which we are grateful.”

Also celebrated at the 2019 Summer Dinner were recipients of distinguished faculty awards, funded through the generosity of alumni and friends.

Greg Blekherman, Martin Mourigal, and Ronghu Wu received the Cullen-Peck Fellowship Awards. These are made possible by a gift from alumni couple Frank Cullen and Libby Peck. The goal is to encourage the development of especially promising mid-career faculty. Bleckherman is an associate professor of mathematics, Mourigal is an assistant professor of physics, and Wu is an associate professor of chemistry and biochemistry.

Kim Cobb, professor of Earth and atmospheric sciences, received the 2019 Gretzinger Moving Forward Award. This is made possible by a gift from alumnus Ralph Gretzinger and his late wife, Jewel.  The award recognizes leadership of a school chair or senior faculty member who has played a pivotal role in diversifying the composition of faculty, creating a family-friendly environment, and providing a supportive environment for early-career faculty.

Jennifer Glass, associate professor of Earth and atmospheric sciences, received the 2019 Eric R. Immel Memorial Award for Excellence in Teaching. This award is supported by an endowment fund given by alumnus Charles Crawford to recognize exemplary instruction of foundational courses.

“I am pleased that your distinction in research, teaching, and mentoring brings recognition your way,” Lozier said. “But your recognition also shines a bright light on your school and the College of Sciences, for which we are grateful.”

Lozier also welcomed faculty who joined in the 2019-20 academic year, herself included as professor of Earth and atmospheric sciences. Also present were Meghan Babcock and Keaton Fletcher, School of Psychology; Marcus Cicerone and Joshua Kretchmer, School of Chemistry and Biochemistry; and Glen Evenbly, School of Physics. Unable to attend were Alex Blumenthal, School of Mathematics, and Alonzo Whyte, School of Biological Sciences.

“As you set out on your academic journey, please know that we are here to support, mentor, and advise you along the way,” Lozier said.  “Your good fortune will be ours as well.”

The Office of International Initiatives announces the launch of the Georgia Tech Guide for Responsible International Activities, a new online resource regarding guidelines, policies, and procedures around the Institute’s global activities and partnerships.

This summer, the Office of International Initiatives convened a working group of members of the Office of the Executive Vice President for Research and the Office of the Provost to develop a resource to guide educational and research activities that happen abroad. The major deliverables of the working group were designed to help Georgia Tech make decisions and ensure proper planning, compliance, and transparency around all international activities.

“Georgia Tech is proud to engage with researchers, scholars, and institutions all over the world as an expression of the Institute’s motto of Progress and Service,” said Chaouki T. Abdallah, Georgia Tech’s executive vice president for Research. “We remain wholeheartedly committed to those important global collaborations, but we must safeguard the Institute, and ensure all activities are fully transparent and in compliance with Georgia Tech policies, as well as applicable government laws and regulations.”

Site users can find direct links to Georgia Tech resources, policies, and relevant campus contacts for offices and units that manage a variety of issues, including export control; managing conflicts of interest; appointments at other institutions; intellectual property; materials, data, and confidential information; the Foreign Corrupt Practices Act (FCPA); international agreements; disclosing foreign relationships; lab tours; hosting foreign visitors; and international travel.

“Georgia Tech promotes a culture of global engagement and believes that our community is enriched through opportunities to study, work, serve, or do research abroad,” said Rafael L. Bras, provost and executive vice president for Academic Affairs. “Thanks to the working group, the guide now provides access to Tech’s standing policies and procedures governing international activities in one centralized location.”

The guide will be maintained by the Office of International Initiatives and will be available on faculty and staff resource pages at several touchpoints, including global.gatech.edu, research.gatech.edu, and provost.gatech.edu, among others.

The working group also refined Georgia Tech’s Guiding Principles for International Activities, a standard set of objective criteria used by the Office of International Initiatives for measuring each international activity’s impact on academic activities, value to the Institute, compliance with applicable policies, sustainability and viability, and risk assessment and mitigation concerns.

Georgia Tech is also in the process of creating an International Advisory Committee comprised of representatives of the administration, faculty, and staff. The committee will be chaired by Yves Berthelot, vice provost for International Initiatives, and will provide guidance and advice regarding how Georgia Tech engages internationally (e.g. research, MOUs, master research agreements, etc.).

“Our success in international activities must be assessed in full consideration of geopolitical factors, as well as current and potential state and federal regulations and legislation,” said Berthelot. “With those considerations in mind, the work of the committee will prove vital for Georgia Tech as we continue to grow our relationships across the world and explore new opportunities to engage globally.”

Nominations for the committee are currently being accepted through Oct. 7. Faculty and staff are encouraged to submit self-nominations or nominations for a colleague. Details on the final committee roster will be made available via the online tool, once finalized. To self-nominate or nominate a colleague for the committee, or for more information on the working group’s activities, contact Monique Tavares, director of Global Operations at mtavares@gatech.edu.

Editor's Note: This story by Nilde Maggie Dannreuther was originally published on Oct. 1, 2019, by the Gulf of Mexico Research Initiative. It is reposted here with permission. 

Researchers at Florida State University and the Georgia Institute of Technology analyzed degradation processes of oil that was deposited along Gulf of Mexico beaches following Deepwater Horizon. They found that small millimeter-size oil particles and thin oil films that coated sand grains disappeared within a year, facilitated by the large surface-to-volume ratio of the small particles and films that allowed space for microbial colonization and biodegradation. In contrast, the degradation of golf-ball sized sediment-oil-agglomerates (SOAs or tarballs) with a smaller surface-to-volume ratio is a lengthier process.

Using a novel in-situ experimental setup, the researchers followed the degradation of buried SOAs for three years and, based on decay rates, estimated that the SOA decomposition would take about 30 years. The degradation of the same SOAs kept in a dark lab environment would take approximately 100 years, highlighting the key role of the beach environment and its microbial community in the oil degradation process.

The researchers published their findings in two studies, one in Marine Pollution Bulletin: Degradation of Deepwater Horizon oil buried in a Florida beach influenced by tidal pumping and one in Scientific Reports: Decomposition of sediment-oil-agglomerates in a Gulf of Mexico sandy beach.

Oil associated with Deepwater Horizon reached the Florida panhandle sandy beaches of the Florida panhandle on June 22, 2010. Waves generated by the distant passage of Hurricane Alex, deposited oil mousse high onto the beaches and strong winds blew an oily sea spray across the beach, coating the sands with oil.

Mixing of oil and sand in the swash zone produced large SOAs that were buried in the beach. The deposition of oil continued, and by the end of July, sands in the upper 70 cm of the beach were stained brown and veined by dark compacted layers of SOAs. Questions arose about the length of time that this oil would persist in Florida beaches.

To assess the degradation of the oil particles and oil films coating the sands, the teams of Markus Huettel and Joel Kostka quantified concentration changes of aliphatic and aromatic oil components; assessed microbial communities’ abundance, composition, and succession; and determined the transport of oxygen and carbon dioxide from June 2010-July 2011. To assess oil degradation in buried SOAs, the team conducted an in-situ experiment from October 2010-December 2013 using golf-ball size standardized SOAs that were embedded in the beach. They compared oil decomposition in buried SOAs to laboratory-incubated SOA material to determine the beach environment’s contribution to oil degradation.

Study author Markus Huettel explained the method for their in-situ experiment, “We combined and homogenized Deepwater Horizon SOAs that we collected at Pensacola Beach one week after the oil came to shore and filled the resulting SOA material in 100 golf-ball-size stainless steel teaballs. Five pairs of such standardized SOAs were attached to a vertical PVC pipe and buried in the beach, positioned at 10, 20, 30, 40 and 50 cm sediment depth, respectively. The ten arrays were removed from the beach one at a time over a period of 3 years. Using this method, we could follow the degradation of the SOAs at different sediment depths over time.”

Huettel emphasized the role of beaches as biocatalytical filters at the land-ocean interface, “Microbial degradation activities typically are most efficient when oxygen and warm temperatures are present, and this was supported by the tidal groundwater table oscillations in the beach. When the ebb tide sets in, the groundwater level in the beach drops, drawing air into the highly permeable beach sand. This ‘beach inhaling’ carries oxygen and heat into the sand, boosting the biodegradation activities within the beach. The rising groundwater table of the following flood acts like a piston pump, pushing air enriched in carbon dioxide out of the beach and moisture from deeper sands into the upper drier beach layers. This ‘beach exhaling’ is beneficial for the decomposition processes in the beach as gases resulting from the oil decomposition can reduce aerobic microbial degradation processes, and microbes need moisture to ‘drink.’ The beach, breathing in tidal rhythm, thus has similarities to an organism that aerobically ‘digests’ the buried oil, inhaling oxygen and exhaling carbon dioxide. After most oil had been decomposed, the microbial community of the beach reversed to a community typical to an unpolluted beach environment.”

Data for the study published in Marine Pollution Bulletin are archived at the National Center for Biotechnology Information (NCBI) under BioProject ID PRJNA294056 and publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at DOI 10.7266/N7765CV9, DOI 10.7266/N7XW4HBZ, DOI 10.7266/N7BZ64J8, DOI 10.7266/N73J3BGD, DOI 10.7266/N7PZ56VV, DOI 10.7266/N7PG1Q83, DOI 10.7266/N7T72FZZ, DOI 10.7266/N78C9TSB, and DOI 10.7266/N7MG7N1S.

Data for the study published in Scientific Reports are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at DOI 10.7266/n7-wjj4-dq16, DOI 10.7266/n7-jjcn-y650, DOI 10.7266/n7-r0ca-f740, DOI 10.7266/n7-kzth-6056, DOI 10.7266/n7-jgbx-p395, and DOI 10.7266/n7-kavs-t279.

The Marine Pollution Bulletin study’s authors are Markus Huettel, Will A. Overholt, Joel E. Kostka, Christopher Hagan, John Kaba, Wm. Brian Wells, and Stacia Dudley.

The Scientific Reports study’s authors are Ioana Bociu, Boryoung Shin, Wm. Brian Wells, Joel E. Kostka, Konstantinos T. Konstantinidis, and Markus Huettel.

Editor's Note: This story by Nilde Maggie Dannreuther was originally published on Oct. 1, 2019, by the Gulf of Mexico Research Initiative. It is reposted here with permission. 

Researchers at Florida State University and the Georgia Institute of Technology analyzed degradation processes of oil that was deposited along Gulf of Mexico beaches following Deepwater Horizon. They found that small millimeter-size oil particles and thin oil films that coated sand grains disappeared within a year, facilitated by the large surface-to-volume ratio of the small particles and films that allowed space for microbial colonization and biodegradation. In contrast, the degradation of golf-ball sized sediment-oil-agglomerates (SOAs or tarballs) with a smaller surface-to-volume ratio is a lengthier process.

Using a novel in-situ experimental setup, the researchers followed the degradation of buried SOAs for three years and, based on decay rates, estimated that the SOA decomposition would take about 30 years. The degradation of the same SOAs kept in a dark lab environment would take approximately 100 years, highlighting the key role of the beach environment and its microbial community in the oil degradation process.

The researchers published their findings in two studies, one in Marine Pollution Bulletin: Degradation of Deepwater Horizon oil buried in a Florida beach influenced by tidal pumping and one in Scientific Reports: Decomposition of sediment-oil-agglomerates in a Gulf of Mexico sandy beach.

Oil associated with Deepwater Horizon reached the Florida panhandle sandy beaches of the Florida panhandle on June 22, 2010. Waves generated by the distant passage of Hurricane Alex, deposited oil mousse high onto the beaches and strong winds blew an oily sea spray across the beach, coating the sands with oil.

Mixing of oil and sand in the swash zone produced large SOAs that were buried in the beach. The deposition of oil continued, and by the end of July, sands in the upper 70 cm of the beach were stained brown and veined by dark compacted layers of SOAs. Questions arose about the length of time that this oil would persist in Florida beaches.

To assess the degradation of the oil particles and oil films coating the sands, the teams of Markus Huettel and Joel Kostka quantified concentration changes of aliphatic and aromatic oil components; assessed microbial communities’ abundance, composition, and succession; and determined the transport of oxygen and carbon dioxide from June 2010-July 2011. To assess oil degradation in buried SOAs, the team conducted an in-situ experiment from October 2010-December 2013 using golf-ball size standardized SOAs that were embedded in the beach. They compared oil decomposition in buried SOAs to laboratory-incubated SOA material to determine the beach environment’s contribution to oil degradation.

Study author Markus Huettel explained the method for their in-situ experiment, “We combined and homogenized Deepwater Horizon SOAs that we collected at Pensacola Beach one week after the oil came to shore and filled the resulting SOA material in 100 golf-ball-size stainless steel teaballs. Five pairs of such standardized SOAs were attached to a vertical PVC pipe and buried in the beach, positioned at 10, 20, 30, 40 and 50 cm sediment depth, respectively. The ten arrays were removed from the beach one at a time over a period of 3 years. Using this method, we could follow the degradation of the SOAs at different sediment depths over time.”

Huettel emphasized the role of beaches as biocatalytical filters at the land-ocean interface, “Microbial degradation activities typically are most efficient when oxygen and warm temperatures are present, and this was supported by the tidal groundwater table oscillations in the beach. When the ebb tide sets in, the groundwater level in the beach drops, drawing air into the highly permeable beach sand. This ‘beach inhaling’ carries oxygen and heat into the sand, boosting the biodegradation activities within the beach. The rising groundwater table of the following flood acts like a piston pump, pushing air enriched in carbon dioxide out of the beach and moisture from deeper sands into the upper drier beach layers. This ‘beach exhaling’ is beneficial for the decomposition processes in the beach as gases resulting from the oil decomposition can reduce aerobic microbial degradation processes, and microbes need moisture to ‘drink.’ The beach, breathing in tidal rhythm, thus has similarities to an organism that aerobically ‘digests’ the buried oil, inhaling oxygen and exhaling carbon dioxide. After most oil had been decomposed, the microbial community of the beach reversed to a community typical to an unpolluted beach environment.”

Data for the study published in Marine Pollution Bulletin are archived at the National Center for Biotechnology Information (NCBI) under BioProject ID PRJNA294056 and publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at DOI 10.7266/N7765CV9, DOI 10.7266/N7XW4HBZ, DOI 10.7266/N7BZ64J8, DOI 10.7266/N73J3BGD, DOI 10.7266/N7PZ56VV, DOI 10.7266/N7PG1Q83, DOI 10.7266/N7T72FZZ, DOI 10.7266/N78C9TSB, and DOI 10.7266/N7MG7N1S.

Data for the study published in Scientific Reports are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at DOI 10.7266/n7-wjj4-dq16, DOI 10.7266/n7-jjcn-y650, DOI 10.7266/n7-r0ca-f740, DOI 10.7266/n7-kzth-6056, DOI 10.7266/n7-jgbx-p395, and DOI 10.7266/n7-kavs-t279.

The Marine Pollution Bulletin study’s authors are Markus Huettel, Will A. Overholt, Joel E. Kostka, Christopher Hagan, John Kaba, Wm. Brian Wells, and Stacia Dudley.

The Scientific Reports study’s authors are Ioana Bociu, Boryoung Shin, Wm. Brian Wells, Joel E. Kostka, Konstantinos T. Konstantinidis, and Markus Huettel.