Anyone lost in a desert hallucinating mirages knows that extreme dehydration discombobulates the mind. But just two hours of vigorous yard work in the summer sun without drinking fluids could be enough to blunt concentration, according to a new study.
Cognitive functions often wilt as water departs the body, researchers at the Georgia Institute of Technology reported after statistically analyzing data from multiple peer-reviewed research papers on dehydration and cognitive ability. The data pointed to functions like attention, coordination and complex problem solving suffering the most, and activities like reacting quickly when prompted not diminishing much.
“The simplest reaction time tasks were least impacted, even as dehydration got worse, but tasks that require attention were quite impacted,” said Mindy Millard-Stafford, a professor in Georgia Tech’s School of Biological Sciences.
Less fluid, more goofs
As the bodies of test subjects in various studies lost water, the majority of participants increasingly made errors during attention-related tasks that were mostly repetitive and unexciting, such as punching a button in varying patterns for quite a few minutes. There are situations in life that challenge attentiveness in a similar manner, and when it lapses, snafus can happen.
“Maintaining focus in a long meeting, driving a car, a monotonous job in a hot factory that requires you to stay alert are some of them,” said Millard-Stafford, the study’s principal investigator. “Higher-order functions like doing math or applying logic also dropped off.”
The researchers have been concerned that dehydration could raise the risk of an accident, particularly in scenarios that combine heavy sweating and dangerous machinery or military hardware.
Millard-Stafford and first author Matthew Wittbrodt, a former graduate research assistant at Georgia Tech and now a postdoctoral researcher at Emory University, published their meta-analysis of the studies on June 29 in the journal Medicine & Science in Sports & Exercise.
It can happen quickly
There’s no hard and fast rule about when exactly such lapses can pop up, but the researchers examined studies with 1 to 6 percent loss of body mass due to dehydration and found more severe impairments started at 2 percent. That level has been a significant benchmark in related studies.
“There’s already a lot of quantitative documentation that if you lose 2 percent in water it affects physical abilities like muscle endurance or sports tasks and your ability to regulate your body temperature,” said Millard-Stafford, a past president of the American College of Sports Medicine. “We wanted to see if that was similar for cognitive function.”
The researchers looked at 6,591 relevant studies for their comparison, then narrowed them down to 33 papers with scientific criteria and data comparable enough to do metadata analysis. They focused on acute dehydration, which anyone could experience during exertion, heat and/or not drinking as opposed to chronic dehydration, which can be caused by a disease or disorder.
One day to lousy
How much fluid loss adds up to 2 percent body mass loss?
“If you weigh 200 pounds and you go work out for a few of hours, you drop four pounds, and that’s 2 percent body mass,” Millard-Stafford said. And it can happen fast. “With an hour of moderately intense activity, with a temperature in the mid-80s, and moderate humidity, it’s not uncommon to lose a little over 2 pounds of water.”
“If you do 12-hour fluid restriction, nothing by mouth, for medical tests, you’ll go down about 1.5 percent,” she said. “Twenty-four hours fluid restriction takes most people about 3 percent down.”
And that begins to affect more than cognition or athletic abilities and concentration.
“If you drop 4 or 5 percent, you’re going to feel really crummy,” Millard-Stafford said. “Water is the most important nutrient.”
She warned that older people can dry out more easily because they often lose their sensation of thirst and also, their kidneys are less able to concentrate urine, which makes them retain less fluid. People with high body fat content also have lower relative water reserves than lean folks.
Don’t overdo water
Hydration is important, but so is moderation.
“You can have too much water, something called hyponatremia,” Millard-Stafford said. “Some people overly aggressively, out of a fear of dehydration, drink so much water that they dilute their blood and their brain swells.”
This leads to death in rare, extreme cases, for example, when long-distance runners constantly drink but don’t sweat much and end up massively overhydrating.
“Water needs to be enough, just right,” Millard-Stafford said.
Also, she warned that while salt avoidance may be good for sedentary people or hypertension patients, whoever sweats needs some salt as well, or they won’t retain the water they drink.
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Media Relations Contact: Ben Brumfield (404-660-1408)
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Anyone lost in a desert hallucinating mirages knows that extreme dehydration discombobulates the mind. But just two hours of vigorous yard work in the summer sun without drinking fluids could be enough to blunt concentration, according to a new study.
Cognitive functions often wilt as water departs the body, researchers at the Georgia Institute of Technology reported after statistically analyzing data from multiple peer-reviewed research papers on dehydration and cognitive ability. The data pointed to functions like attention, coordination and complex problem solving suffering the most, and activities like reacting quickly when prompted not diminishing much.
“The simplest reaction time tasks were least impacted, even as dehydration got worse, but tasks that require attention were quite impacted,” said Mindy Millard-Stafford, a professor in Georgia Tech’s School of Biological Sciences.
Less fluid, more goofs
As the bodies of test subjects in various studies lost water, the majority of participants increasingly made errors during attention-related tasks that were mostly repetitive and unexciting, such as punching a button in varying patterns for quite a few minutes. There are situations in life that challenge attentiveness in a similar manner, and when it lapses, snafus can happen.
“Maintaining focus in a long meeting, driving a car, a monotonous job in a hot factory that requires you to stay alert are some of them,” said Millard-Stafford, the study’s principal investigator. “Higher-order functions like doing math or applying logic also dropped off.”
The researchers have been concerned that dehydration could raise the risk of an accident, particularly in scenarios that combine heavy sweating and dangerous machinery or military hardware.
Millard-Stafford and first author Matthew Wittbrodt, a former graduate research assistant at Georgia Tech and now a postdoctoral researcher at Emory University, published their meta-analysis of the studies on June 29 in the journal Medicine & Science in Sports & Exercise.
It can happen quickly
There’s no hard and fast rule about when exactly such lapses can pop up, but the researchers examined studies with 1 to 6 percent loss of body mass due to dehydration and found more severe impairments started at 2 percent. That level has been a significant benchmark in related studies.
“There’s already a lot of quantitative documentation that if you lose 2 percent in water it affects physical abilities like muscle endurance or sports tasks and your ability to regulate your body temperature,” said Millard-Stafford, a past president of the American College of Sports Medicine. “We wanted to see if that was similar for cognitive function.”
The researchers looked at 6,591 relevant studies for their comparison, then narrowed them down to 33 papers with scientific criteria and data comparable enough to do metadata analysis. They focused on acute dehydration, which anyone could experience during exertion, heat and/or not drinking as opposed to chronic dehydration, which can be caused by a disease or disorder.
One day to lousy
How much fluid loss adds up to 2 percent body mass loss?
“If you weigh 200 pounds and you go work out for a few of hours, you drop four pounds, and that’s 2 percent body mass,” Millard-Stafford said. And it can happen fast. “With an hour of moderately intense activity, with a temperature in the mid-80s, and moderate humidity, it’s not uncommon to lose a little over 2 pounds of water.”
“If you do 12-hour fluid restriction, nothing by mouth, for medical tests, you’ll go down about 1.5 percent,” she said. “Twenty-four hours fluid restriction takes most people about 3 percent down.”
And that begins to affect more than cognition or athletic abilities and concentration.
“If you drop 4 or 5 percent, you’re going to feel really crummy,” Millard-Stafford said. “Water is the most important nutrient.”
She warned that older people can dry out more easily because they often lose their sensation of thirst and also, their kidneys are less able to concentrate urine, which makes them retain less fluid. People with high body fat content also have lower relative water reserves than lean folks.
Don’t overdo water
Hydration is important, but so is moderation.
“You can have too much water, something called hyponatremia,” Millard-Stafford said. “Some people overly aggressively, out of a fear of dehydration, drink so much water that they dilute their blood and their brain swells.”
This leads to death in rare, extreme cases, for example, when long-distance runners constantly drink but don’t sweat much and end up massively overhydrating.
“Water needs to be enough, just right,” Millard-Stafford said.
Also, she warned that while salt avoidance may be good for sedentary people or hypertension patients, whoever sweats needs some salt as well, or they won’t retain the water they drink.
Like this article? Get our email newsletter here.
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Atlanta, Georgia 30332-0181 USA
Media Relations Contact: Ben Brumfield (404-660-1408)
Writer: Ben Brumfield
The College of Sciences has named Jennifer Hom, Takamitsu Ito, and Scott Moffat as the 2018 recipients of the Cullen-Peck Faculty Fellowship Awards in the College of Sciences. The awards recognize innovative research by faculty at the associate professor or advanced assistant professor level. The goal is to help recipients take their research programs in new directions.
The fellowships are made possible by a generous gift to the College of Sciences from alumni Frank H. Cullen (B.S. in Mathematics with Honors 1973, M.S. in Operations Research 1975, Ph.D. Engineering 1984) and Libby Peck (B.S. in Applied Mathematics 1975, M.S. in Industrial Engineering 1976). The alumni couple wish to recognize and support faculty development in the College of Sciences
“We continue to be grateful for the generosity of alumni who encourage our faculty to take intellectual risks in their research,” says College of Sciences Dean and Sutherland Chair Paul M. Goldbart. “The Cullen-Peck fellowships help ensure that our research is pushing the frontiers of knowledge. Congratulations to the latest Cullen-Peck fellows.”
Knot Theory
Jennifer C. Hom is an associate professor in the School of Mathematics. The award recognizes her outstanding research in knot theory, which has led to fundamental contributions to the study of knots and development of powerful tools in topology.
Knots can be conceived as loops of strings with ends glued together. Their study is a beautiful subject, central to understanding low-dimensional space, as well as some modern trends in physics. Hom’s work centers on knots in three-dimensional space. She has enriched the field by introducing deep new ideas.
A much-studied question asks whether a knot can bound a disk in four-dimensional space in certain nice ways. Such knots were previously known. But Hom was able to find a huge new family of such knots, inspiring a flurry of activity in the use of Heegaard-Floer theory to study such objects.
The Heegard-Floer theory is a much-studied technique that revolutionized low-dimensional topology. Yet, Hom found new subtle features, which she formalized as the epsilon invariant. The epsilon invariant is a number associated to each knot. By using the properties of these numbers, Hom proved that an infinite number of knots could bound certain disks in four-dimensional space and not others.
Her work inspired leaders in the field, including the developers of Heegaard-Floer theory themselves, to pursue new avenues of research. Among other things, this work gives a new proof that in a sense there is more than one way to do calculus in four dimensions.
The epsilon invariant is now part of the Heegard-Floer theory; it is taught in graduate courses around the world; it is considered one of the top five spectacular advances in the past decade. A mark of top-notch mathematics is that it inspires other people and takes a life of its own. Hom’s epsilon invariant belongs to this category.
“It's a great honor to receive this award,” Hom says. “I look forward to using this fellowship to help develop new techniques for studying knots and low-dimensional spaces.”
Biogeochemical Cycling and Ocean Deoxygenation
Takamitsu “Taka” Ito is an associate professor in the School of Earth and Atmospheric Sciences. The Cullen-Peck award recognizes his outstanding research in biogeochemical cycling and ocean deoxygenation.
Ito uses models to better understand the interactions of physical, chemical, and biological processes that regulate the cycling of chemical elements in the ocean. He develops theories of the partitioning of dissolved gases between the ocean and the atmosphere. He is renowned for recent work on the distribution of dissolved oxygen in the subsurface ocean.
In the 2017 paper “The Upper Ocean Oxygen Trend: 1958-2015,” Ito analyzed historical, global datasets of dissolved oxygen. He found that the amount of dissolved oxygen in the water – an important measure of ocean health – has been declining for more than 20 years.
This paper garnered media attention for the implications of declining oxygen in the ocean: It could affect the habitat of marine organisms worldwide. It could lead to more frequent “hypoxic events,” which kill or displace populations of fish, crabs, and other organisms.
Furthermore, the analysis showed that ocean oxygen is falling more rapidly than anticipated from the rise in water temperature due to climate change.
Ito has also been exploring the previously under-appreciated role of polluted aerosols in altering ocean biogeochemistry. In a 2016 paper in Nature Geoscience, he and his collaborators showed that air pollution can deliver additional iron and reactive nitrogen to the ocean and affect oxygen levels.
The transport of highly insoluble iron to the ocean and its availability for biological productivity are not well understood. Ito’s modelling approach will help translate into new insights the oceanic iron data from the large observational program GEOTRACES. His research could reveal how iron cycling affects ocean productivity, carbon uptake, and oxygen concentrations over various time scales.
Cognitive Neuroscience of Aging
Scott Moffat is an associate professor in the School of Psychology. His selection as Cullen-Peck fellow is based on his outstanding research in the cognitive neuroscience of aging.
With aging comes cognitive decline, which affect mental faculties including memory and the ability to navigate. Moffat has embarked on research addressing metabolism and aging. In particular, he studies the role of diabetes in cognitive aging.
Peripheral insulin crosses the blood–brain barrier to modulate memory processes. Insulin resistance in the periphery goes with insulin resistance in the brain and memory impairment. The hope is to associate variations in peripheral insulin secretion and insulin sensitivity to cognitive and neural endpoints.
Meanwhile, type 2 diabetes is a public health crisis in the U.S. and many developed countries. The disease is a risk factor for other serious health conditions, such as brain and cognitive dysfunction, as well as Alzheimer’s disease. Using functional magnetic resonance imaging, Moffat is examining the association of glucose and insulin metabolism with cognitive and brain function.
The research is still in its early days, but already Moffat and his colleagues are realizing remarkable results. For example, they’ve found that individuals with higher fasting glucose levels or insulin insensitivity – even within the non-diabetes range – have poorer performance in episodic and working memories. They also have thinner gray matter in key prefrontal cortical areas.
The implications for prediabetes are profound. Prediabetes is prevalent among adults; the National Center for Chronic Disease Prevention reports that majority of all adults older than 65 have prediabetes. Discovering the impact of prediabetes on cognition and cognitive decline could bring about interventions, pharmaceutical or otherwise.
Shana Kerr didn’t always want to be a teacher. In fact, after completing her undergrad in applied biology at Tech, she chose to attend grad school at Emory University partially because it required the least amount of hours as a teaching assistant. “I wanted to be a lab rat,” Kerr says.
But midway through her PhD program, Kerr found her days spent buried in her own research unfulfilling. A fellow grad student urged her to try being a teaching assistant (TA) in a lab. Kerr did—and was instantly hooked. “It was the light bulb going off in students’ minds when you help them grasp an idea they didn’t see before,” she says. “Sharing that joy is one of the things I love most about teaching.
Kerr got her doctorate in biochemistry at Emory and, in 2012, promptly returned to Tech, where she teaches introductory and upper level biology classes and, ironically, the TA development and pedagogy course. Still, at first, Kerr found those “light bulb” moments with students relatively few and far between.
“I had so much fun putting together these PowerPoints with all the details and I thought my students would get it and it’d be magical,” she says. “But then I’d grade their quizzes and see they hadn’t gotten it.”
This sent Kerr, ever the researcher, in search of alternative teaching methods. The result is what is called a “flipped” class, in which the focus is on the student and not the instructor. The traditional method was to assign long readings in advance of class—“which no one does,” Kerr says. As a result, students would be introduced to the material for the first time during her lectures.
“Under the traditional lecture approach, some students will take good notes,” she says. “But most won’t. The next time they see the material in their homework, it’s when they’re alone and can’t ask for help. And then they’re tested.”
To make her classes more effective for students, Kerr has thrown out the text book (and in doing so eliminated a cost for students). Instead she assigns short readings, online videos and practice quizzes before the class, and then uses class time for students to work through activities—essentially testing themselves on the subject. Then she poses an after-class assessment to give the pupils one more chance to think about what they’ve learned. All of this before they are given a midterm exam.
The approach has proven so successful and well-received by her pupils that Kerr was recently given the 2018 Class of 1940 W. Roane Beard Outstanding Teacher Award.
“She put in the work to design each class and lab to tell a coherent story,” says Alicia Lane, one of Kerr’s former students and now a research specialist at the Emory School of Medicine. “It was so much easier to learn and retain that material. We did have a lot of work to do outside of class, but it was all related to the course. Whereas sometimes other classes’ assignments just feel like busy work.”
“The first year is challenging for students not used to it,” Kerr says. “But Tech students care about learning and being better at learning. Yes, they want the grade. But by and large, when we tell them why we’re teaching class this way, they appreciate it.”
READ ABOUT GEORGIA TECH'S OTHER TRANSCENDENT TEACHERS HERE.
From liquid laundry detergent packaged in cardboard to compostable plastic cups, consumer products these days are increasingly touting their sustainable and renewable origins.
Now researchers at Georgia Institute of Technology have created a material derived from crab shells and tree fibers that has the potential to replace the flexible plastic packaging used to keep food fresh.
The new material, which is described July 23 in the journal ACS Sustainable Chemistry and Engineering, is made by spraying multiple layers of chitin from crab shells and cellulose from trees to form a flexible film similar to plastic packaging film.
“The main benchmark that we compare it to is PET, or polyethylene terephthalate, one of the most common petroleum-based materials in the transparent packaging you see in vending machines and soft drink bottles,” said J. Carson Meredith, a professor in Georgia Tech’s School of Chemical and Biomolecular Engineering. “Our material showed up to a 67 percent reduction in oxygen permeability over some forms of PET, which means it could in theory keep foods fresher longer.”
Cellulose, which comes from plants, is the planet’s most common natural biopolymer, followed next by chitin, which is found in shellfish, insects and fungi.
The team devised a method to create a film by suspending cellulose and chitin nanofibers in water and spraying them onto a surface in alternating layers. Once fully dried, the material is flexible, strong, transparent and compostable.
“We had been looking at cellulose nanocrystals for several years and exploring ways to improve those for use in lightweight composites as well as food packaging, because of the huge market opportunity for renewable and compostable packaging, and how important food packaging overall is going to be as the population continues to grow,” Meredith said.
The research team also included Meisha Shofner, an associate professor in the School of Materials Science and Engineering and the interim executive director of the Renewable Bioproducts Institute, John R. Reynolds, a professor in the schools of Chemistry and Biochemistry and Materials Science and Engineering, and Chinmay Satam, a graduate student at Georgia Tech.
The team had been looking into chitin for an unrelated reason when they wondered if it might have use in food packaging.
“We recognized that because the chitin nanofibers are positively charged, and the cellulose nanocrystals are negatively charged, they might work well as alternating layers in coatings because they would form a nice interface between them,” Meredith said.
Packaging meant to preserve food needs to prevent oxygen from passing through. Part of the reason the new material improves upon conventional plastic packaging as a gas barrier is because of the crystalline structure of the film.
“It’s difficult for a gas molecule to penetrate a solid crystal, because it has to disrupt the crystal structure,” Meredith said. “Something like PET on the other hand has a significant amount of amorphous or non-crystalline content, so there are more paths easier for a small gas molecule to find its way through.”
Environmentalists have long looked for renewable ways to replace petroleum-based materials in consumer products. With the amount of cellulose already produced and a ready supply of chitin-rich byproducts left over from the shellfish food industry, there’s likely more than enough material available to make the new films a viable flexible-packaging alternative, Meredith said.
Still, there’s more work to be done. To make the new material eventually competitive with flexible packaging film on cost, a manufacturing process that maximizes economy of scale will need to be developed. Additionally, while industrial processes to mass produce cellulose are mature, methods to produce chitin are still in their infancy, Meredith said. And, more research is also needed to improve the material’s ability to block water vapor.
This work was supported by the Georgia Tech Renewable Bioproducts Institute and the Georgia Research Alliance. Any conclusions or recommendations are those of the authors and do not necessarily represent the official views of the sponsoring organizations.
CITATION: Chinmay C. Satam, Cameron W. Irvin, Augustus W. Lang, Jerel Cedric R. Jallorina, Meisha L. Shofner, John R. Reynolds, J. Carson Meredith, “Spray-Coated Multilayer Cellulose Nanocrystal – Chitin Nanofiber Films for Barrier Applications,” (ACS Sustainable Chemistry and Engineering, July 2018). https://doi.org/10.1021/acssuschemeng.8b01536
School of Physics Assistant Professor Martin Mourigal has received a National Science Foundation (NSF) Faculty Early Career Development (CAREER) award for research on so-called frustrated quantum materials. The $621,772 funding will support the research and education efforts of Mourigal’s team for the next five years.
From wood and glass to magnets and superconductors, the behavior of materials is rooted in the quantum mechanical interaction between their atomic-scale constituents: nuclei and electrons. Although the laws of the quantum world are known, predicting the macroscopic properties of materials from their atomic structure is a formidable challenge.
Entanglement is a central quantum phenomenon at the origin of chemical bonds in materials. It usually averages to zero on human length and time scales.
This is not the case with quantum materials such as superconductors, exotic metals, or frustrated quantum magnets. In such systems, the concerted behavior of many electrons propels quantum entanglement beyond the atomic-scale.
Thus, quantum materials present a unique opportunity to understand the fundamental properties of the universe while forming the building blocks to fabricate future quantum devices that may revolutionize the harvest and control of charge, light, heat, and information.
“This CAREER award will not only support my team’s efforts in the area of quantum materials; it will also support the training of the future quantum workforce by involving graduate and undergraduate students and high-school teachers.”
Mourigal’s team focuses on frustrated magnetic materials. In these materials, spins – which are atomic-scale compass needles attached to electrons – display collective quantum dynamics despite simple properties as individuals.
“By designing and studying magnetic materials in which spins occupy periodic lattices with triangular patterns, we frustrate individual spins,” Mourigal says. “Our goal is to suppress their tendency to align with their neighbors. Instead we seek to promote cooperation between spins and obtain richer collective dynamics. This is a promising route to bootstrap entanglement beyond the atomic-scale.”
Mourigal adds: “Our research is multidisciplinary, in our labs at Georgia Tech, we work on preparing and perfecting new materials and measuring their properties at very low temperatures, while simultaneously conducting a lot of theoretical calculations and analyzing large quantities of data”.
A recurring tool in Mourigal’s approach is neutron scattering, a specialized technique that can be performed only at major government-run facilities such as Oak Ridge National Laboratory, in nearby Tennessee, and the NIST Center for Neutron Research, in Maryland.
“Neutrons are an incredible tool to study magnetic materials because neutrons penetrate deep inside our samples and can tell us where spins are, where they point, and if they dance to the quantum tempo,” Mourigal says. But there is a catch, Mourigal adds: “Neutron sources tend to be relatively faint, at least compared to photon and electron sources. Therefore our experiments require large samples, often in the form of crystals.”
Such crystals can be hard to come by. Mourigal says the NSF CAREER award will allow his team to strengthen collaborations with U.S.-based research groups with expertise and tools to grow large, high-quality crystals of quantum magnetic materials.
“I am very grateful to the NSF for its support,” Mourigal says. “This CAREER award will not only support my team’s efforts in the area of quantum materials; it will also support the training of the future quantum workforce by involving graduate and undergraduate students and high-school teachers.”
A previously overlooked predator— a thumbnail-sized snail—could be increasing the pressure on coral reefs already weakened by the effects of overfishing, rising ocean temperatures, pollution and other threats. The snail attacks a key coral species that may offer the last hope for bringing back degraded Pacific reefs.
The snail damages coral by sucking fluid from it like a tick, and may have been ignored because it camouflages itself on reefs and doesn’t move around to leave obvious signs of its attack. In experiments done directly on Fiji Island reefs, scientists quantified the impact of the snails, and found that snail attacks could reduce the growth of Porites cylindrica coral by as much as 43 percent in less than a month.
Scientists at the Georgia Institute of Technology conducted the research and reported it July 26 in the journal Ecological Applications. The research was supported by the National Institutes of Health, the National Science Foundation and the Teasley Endowment to Georgia Tech.
“Once the reefs are down and nearly out, these snails are piling on,” said Mark Hay, a Regents and Teasley professor in Georgia Tech’s School of Biological Sciences. “The Porites coral is kind of the last man standing, the last hope for some of these reefs coming back, and they are the ones these snails selectively prey on. As you get fewer and fewer corals, the snails focus on the fewer and fewer of these colonies that remain. This is part of the downward spiral of the reefs.”
In areas protected from fishing, Postdoctoral Fellow Cody Clements never found more than five of the creatures – whose scientific name is Coralliophila violacea – on a single coral colony. But on degraded reefs where fishing was permitted, he found hundreds of the snails on some declining coral colonies, as much as 35 times more than colonies in the protected areas. To assess the damage, he devised an experiment to measure how the snails affected coral growth.
On the reefs near Votoa Village on Fiji’s Coral Coast, Clements isolated coral branches and attached snails to them. After a period of 24 days, he compared the growth of snail-infested coral branches to comparable branches that had no snails. During that three-week period, the predators reduced coral growth by approximately 18 to 43 percent, depending on snail size.
“A single snail can do a considerable amount of damage,” Clements said. “They are sucking the juice out of the coral. If you have a lot of snails feeding on a single coral colony, it can be very hard for the colony to thrive.”
In coral ecosystems, fish help keep many predators and seaweeds under control. For that reason, fishing is forbidden in marine protected areas to maintain species diversity. To confirm their suspicions that overfishing was related to the snail problem, Clements tethered individual snails to reefs in a paired protected and unprotected areas.
When they returned to examine the experiment, they found that snails in the protected areas had been eaten, and evidence left behind suggested they had been consumed by triggerfish and other species with teeth able to crack the snail shells. Predation of the snails was 220 percent higher in the marine protected areas compared to unprotected areas with few remaining fish, they found.
“From the predation evidence, it looked like the fish were eating the snails,” said Clements. “It seemed like the main element driving the difference was the protection status of the area where the snails were tethered.”
One unexpected finding was that the shells of larger snails had been taken over by hermit crabs. “The hermit crabs were very direct about getting the shells that they wanted,” Hay said. “This may or may not be ecologically important on a large scale.”
The study began with an accidental discovery while Clements was working on another project in a heavily degraded reef area. “I was fragmenting branches from colonies and noticed these snails,” he said. “I wondered why I had never seen them before, then I started looking around and noticed they were everywhere.”
The snail shells are covered with marine growth, so they’re difficult to see – unless you know what to look for, Clements said. During the research, Clements removed more than 2,000 of the snails with needle-nosed pliers.
The Porites coral often provides the foundation for reefs, and is considered one of the most hardy species because it is less susceptible to disease, less attractive to crown-of-thorns sea stars, and more resistant to damage from seaweeds. For that reason, researchers believe it may provide a way for reefs to recover if conditions improve. Unfortunately, that coral is also a favorite for the small snail.
The findings reinforce a lesson Hay and Clements have been working to explain for years.
“Protecting coral reef areas and keeping food webs intact is really important to maintaining these communities,” Hay said. “Overfishing takes a lot of key species out of the communities so that all you have left is the marine equivalent of cockroaches and dandelions. Taking out the fish takes away the functions the fish have been providing to the community.”
This research was supported by the National Science Foundation under award OCE 0929119, the National Institutes of Health under award 2 U19 TW007401-10, and the Teasley Endowment to the Georgia Institute of Technology.
CITATION: Cody S. Clements and Mark E. Hay, “Overlooked coral predators suppress foundation species as reefs degrade, (Ecological Applications, 2018). https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.1765
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Brian Hammer and Joel Kostka have been named American Society for Microbiology (ASM) Distinguished Lecturers. Hammer is an associate professor in the School of Biological Sciences. Kostka has joint appointments in the School of Biological Sciences and the School of Earth and Atmospheric Sciences. Both are members of the Parker H. Petit Institute for Bioengineering and Bioscience.
Hammer and Kostka are two of the eight ASM Distinguished Lecturers recently named to serve until 2020. Selection is based on a competitive process. Only the most distinguished individuals are named to the ASM Distinguished Lecturer Program.
The two microbiologists study microbe-microbe microbe-host interactions important in humans and in ecosystem health. Georgia Tech is emerging as a leader in this burgeoning research area.
As distinguished lecturers, Hammer and Kostka will speak at ASM branch meetings throughout the U.S. Their visits to various parts of the country will provide opportunities for students and early-career research microbiologists to interact with prominent scientists.
A Passion for Training Young Researchers
Hammer's research aims to understand the mechanisms bacteria use to cooperate and compete in niches they occupy. His work focuses on the waterborne microbe Vibrio cholerae, which causes outbreaks of cholera disease in places like Yemen where people have no option but to consume contaminated water.
His lab has identified components of regulatory networks in this bacterium that control secreted enzymes, biofilm matrix material, a molecular harpoon for toxifying neighboring cells, and an apparatus to take up foreign DNA.
Next, his lab aims to identify new genes and regulatory connections of these networks, characterize the behaviors they control, and determine the contribution of these activities to the fitness and adaptability of this waterborne microbe in host and ecological settings.
“I enjoy the challenge and excitement of engaging students and postdocs in conversations – about my lab’s research, about microbiology, and about being a research scientist,” Hammer says. “My passion for training young researchers stems from the mentoring I received from my own advisors, who are extraordinary scientists and communicators. As an ASM Distinguished Lecturer, I will relish the opportunity to serve as a model for students and postdocs discovering their unique career paths.
On the lecture circuit, Hammer will be talking about the following topics:
- Control of Bacterial Biofilms by Quorum Sensing Small RNAs
- Natural Transformation in Vibrio cholerae
- Type VI Secretion Alters the Organization of Bacterial Communities
- Carving Out Your Niche (in Microbiology)
On a Mission to Catalyze Students
Kostka is well-known for his research in environmental microbiology. His lab characterizes the role of microorganisms in the functioning of ecosystems, especially in the context of bioremediation and climate change. He is co-principal investigator of C-IMAGE-III. This consortium is funded by the Gulf of Mexico Research Initiative to study the environmental consequences of the release of petroleum hydrocarbons on living marine resources and ecosystem health.
“I was first introduced to ASM by attending a branch meeting in Gatlinburg, Tennessee, while I was a master’s student. My experience there was largely responsible for my decision to enter the field of environmental microbiology,” Kostka says. “I wanted to participate in the ASM Distinguished Lecturer Program so that I can give back the support and encouragement that I received at many ASM meetings. I very much believe that it is my professional mission to excite students about the myriad ways that microbes benefit society, thereby catalyzing their entrance into the field.”
On the lecture circuit, Kostka will be discussing the following:
- A Moveable Feast: The Response of Benthic Microbes to the Deepwater Horizon Oil Well Blowout in the Gulf of Mexico
- The Sphagnum Phytobiome: A Team of Ecosystem Engineers in Resource Limited Peatlands
- Can Peat Beat the Heat?: Stability of the Peatland Carbon Bank to Deep Warming
- New Pathways of Organic Matter Decomposition Limit Methane Emission from Wetland Soils
- Biogeography of Benthic Microbial Communities in the Gulf of Mexico
Many college students on summer break likely binge on Netflix and other streaming services. In a way, Melissa Ruszczyk did the same in summer 2015.
That’s when Ruszczyk watched videos of copepods in the lab of Georgia Tech biologist Jeannette Yen. Ruszczyk was among the participants of Georgia Tech’s Aquatic Chemical Ecology REU (Research Experiences for Undergraduates) program.
Copepods are small marine crustaceans; some are visible to the naked eye. “You can tell the males from the females,” Ruszczyk says. When they move, copepods leave a trail. To find mates, males follow the trails of females.
That summer, Ruszczyk looked for males tracking females. If she found them, she would analyze the trails to find environmental cues that affect male copepods seeking a sexual partner. She watched about 60 hours of copepods swimming. “It was great,” she recalls.
Fast forward to 2018. This month, Ruszczyk starts her second year as a Ph.D. student in Yen’s lab. The REU experience was a big factor in her decision to attend Georgia Tech for her doctorate.
The benefit goes both ways. Host institutions find REU programs to be prime recruiting tools for graduate students. Yen says one other REU participant has returned to her lab for graduate studies.
Supported by the National Science Foundation, REU programs provide early exposure to real-world research work. Additional funding from 3M extended the program to more students, including Ruszczyk.
“The REU experience started to get me used to the fact that not everything in science is going to be successful. You will have to overcome a lot of hurdles to discover something interesting.”
Ruszczyk grew up in Western New York. She went to Allegheny College, in Western Pennsylvania. The Great Lakes spurred her interest in the outdoors and aquatic pursuits. As a biology major, she knew she’d like to do aquatic research in graduate school. But she wasn’t sure whether it would be a good fit. So she looked for internships to test the water.
Because of Yen, Georgia Tech stood out from the REU programs to which Ruszczyk applied. “I was a fan,” she says.
Early on, Ruszczyk decided she would focus on small marine animals. “Fish are cool, but they are big, and a lot of people work with them,” she says. Copepods, zooplankton, and microinvertebrates would be the right subjects for her. Yen works with some of those organisms.
In college, Ruszczyk read lots of papers about microinvertebrates. “Eventually you start seeing a few names recur frequently,” she says. “You get attached to what they do. You like how they think and how they go about solving problems.” That’s how Yen became a minor celebrity for Ruszczyk.
Alas, after binging on copepod videos, Ruszczyk couldn’t get answers to the research question. Because of poor video quality, she couldn’t tell males and females apart. Even though she saw the small crustaceans tracking each other, she couldn’t identify those of males following females.
Ruszczyk would have liked concrete results. “But in the grand scheme of things, I learned a lot,” she says. “The REU experience started to get me used to the fact that not everything in science is going to be successful. You will have to overcome a lot of hurdles to discover something interesting.”
After that summer, Ruszczyk and Yen kept in touch. When Ruszczyk was deciding about graduate school, an email from Yen clinched the decision for Georgia Tech.
As Ruszczyk recalls, the email went like this: “Hey you might be interested in this. If you apply and get in, I have a place in my lab available for you.” Yen had sent information about the Ocean Science and Engineering interdisciplinary Ph.D. program, which launched in 2016.
Because of the REU experience, Ruszczyk says, “I felt good about Georgia Tech. I knew people on campus.” She had worked in Yen’s lab and liked what Yen she was doing. It was a good fit.
In August 2017, Ruszczyk joined the inaugural students of the new Ph.D. program.
Ruszczyk is now studying the hydromechanical cues to which copepods respond. These are physical changes resulting from movements in water. An example is wakes – the waves that a boat leaves behind as it slices through the water. “At the scale copepods live, hydromechanical wakes reside in the water longer than we are aware of,” she says.
The REU experience was “really great” – from the science, to the tools she learned, and the tricks of the trade, Ruszczyk says. However, what was most beneficial was the networking opportunity, not just with Yen, but with other students in her cohort. She remembers someone in the cohort who was mulling Georgia Tech for his Ph.D. “That would have been supercool; but he’s going to British Columbia.”
Kevin Arne, Paulette Richards, Ryan Snelling, and Rachel Tierney have completed the first year of the Innovators-in-Residence program at M.R. Hollis Innovation Academy. The group worked for the Georgia Tech Center for Education Integrating Science, Mathematics, and Computing (CEISMC) as part of the academy’s partnership with CEISMC’s School and Community Engagement program.
During the 2017-18 school year, the innovators-in-residence helped STEM (science, technology, engineering, and mathematics) teachers at Hollis integrate technologies such as robotics kits and 3D printers into their classrooms.
For example, Snelling helped teachers run their own printers. Snelling is an aerospace engineer and member of Decatur Makers. “We showed them not only how to use tools like Tinkercad and Onshape to create designs,” he said, but also how to operate and use the printers in class and perform routine maintenance.
Tierney, an undergraduate studying computer science at Georgia Tech, helped develop a class project for an Earth Science class. Using a seismograph she made out of K’NEX pieces and Hummingbird Robotics Kits as a model, the students built their own devices. Because Tierney left the design to the students, “the seismographs all looked different, which was very cool,” she said.
Tierney also assisted the all-girls after-school program Technovation. She helped girls build their own apps using App Inventor. In May, the students presented their apps to information technology and marketing professionals at Chick-fil-A.
Georgia Tech alum and civil engineer Arne worked with a Hollis STEM teacher to develop a robotics activity for fifth and sixth graders, similar to the Discovery network series BattleBots.
“We came up with “SumoBots,” Arne said. It features two robots trying to push each other out of a ring. Unlike BattleBots, this style of robotics does not damage the robots or require frequent replacement of parts. Students can use higher quality controllers, “rather than having to patch together cheaper parts that may not work,” Arne said.
Meanwhile, Richards worked with the art teacher. A teaching artist herself, Richards learned that most K-12 students do not know how structures work. At Hollis, she assembled kits demonstrating cardboard construction techniques, which students applied to a project she likes to think of as “Art meets engineering.”
“Most of the houses in this neighborhood are craftsman bungalows,” Richards said. So she researched the craftsman movement and the features of typical craftsman houses. The art teacher presented the information to the students. Then, the students imagined what the houses could look like if they were renovated.
The students designed their renovations on architecture paper brought by two students from the Georgia Tech School of Architecture. “The kids really enjoyed drawing on that and working with the rulers,” Richards said. She saw that the students felt good about themselves when they managed to assemble and paint their cardboard houses according to their own vision.
All four innovators-in-residence worked on a final project based on the film Black Panther. Inspired by the use of wearable technology in the fictional Kingdom of Wakanda, the project incorporated art, 3D printing, and coding.
“We came up with this Wakandian fashion idea,” Richards said. She incorporated Black Panther’s use of West African symbols known as Adinkra by finding analogs for the six “Habits of Hollis” – Communication, Collaboration, Creativity, Empathy, Perseverance, and Self-Discipline.
In art class, the students used 3D-printed Adinkra stamps to transfer the symbols onto cloth panels. The panels were fashioned into costumes that incorporate brooches, which the students programmed to light up.
The Black Panther project encompassed cultural studies, design, and coding. "When you bring all that together, now you're seeing a much more real-world example,” Snelling said. “Multidisciplinary types of work are becoming more and more common. The best websites have graphic designers — so it’s not just code; it’s art. The more we build those kind of learning experiences, the more they directly translate into work you could be doing in the future.”
Rosemary Pitrone - CEISMC Communications
CEISMC is currently seeking four dynamic individuals for its 2018-19 Innovator-in-Residence cohort. If you are interested, please email your resume and a cover letter to Alba Gutierrez, Educational Outreach Manager, at alba.gutierrez@ceismc.gatech.edu.
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