MAVERICK SCIENCE
  The University of Texas at Arlington College of Science 2012-13  
College of Science faculty members Laura Gough, Arne Winguth and Laura Mydlarz, from left, all took an early interest in science, particularly in the environment.
Hot topic
The debate about global warming isn't whether it's real, but about how fast it's causing changes in Earth's climate, and what the consequences will be on people and the environment. Through their research, Laura Gough, Laura Mydlarz and Arne Winguth are providing evidence to help answer those questions.
 

By Greg Pederson

The Earth is getting warmer. There can be no disputing that fact.
The global average temperature increased by more than 1.4°F over the last century. Last year was the hottest year on record in the contiguous United States. According to the National Oceanic and Atmospheric Administration (NOAA), the decade from 2000-10 was the warmest on record. While the Earth has always gone through natural cycles of warming and cooling – caused by factors such as changes in the sun or volcanic activity – the warming of the past century cannot be explained by natural factors alone. An overwhelming majority of scientists believe that recent global warming is primarily a result of greenhouse gas emissions from human activities.
According to a National Academy of Sciences report released in 2008, "Most scientists agree that the warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere."
A report by the United Nations Intergovernmental Panel on Climate Change (IPCC) in 2007 – the largest and most detailed summary of climate change situation ever undertaken, produced by thousands of authors, editors, and reviewers from more than 120 countries – stated that "warming of the climate system is unequivocal", and "most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."
These human activities are causing profound changes in ecosystems around the world, such as increases in temperatures and sea levels and decreases in sea ice, glaciers and snow cover. Studies by researchers have demonstrated the tremendous changes that global warming has already wrought. A trio of UT Arlington College of Science faculty members – Laura Gough and Laura Mydlarz in biology and Arne Winguth in earth and environmental science – are among those conducting research which is adding to the sizable body of evidence about climate change.
Gough has spent years studying how Arctic tundra plant communities in northern Alaska respond to long-term manipulations of factors associated with climate change, including air temperature and soil nutrients. Mydlarz examines coral reef ecosystems, coral interactions with the environment and how climate change and warming of the oceans may be promoting coral diseases by causing the immune systems of corals to be suppressed. Winguth devotes much of his research to studying hothouse climates and climate extremes in the distant geologic past, and to discovering how such data can be applied to better understanding the climate change of today.
 
The Arctic: Barometer for global climate change
Laura Gough has seen the effects climate change can have on ecosystems firsthand in one of the most environmentally vulnerable areas of the world – the Arctic. Since 1996, she has been investigating plant communities in the Arctic tundra of northern Alaska and how they respond to climate change as part of the Arctic (ARC) Long-Term Ecological Research (LTER) project. She has served on the ARC LTER's executive committee since Fall 2011 and has two currently funded research projects in the tundra.
The first project is funded by a four-year, $225,550 grant from the National Science Foundation (NSF) and focuses on how an increase in nutrient availability in Arctic soils causes a shift to dominance by shrubs and, in particular, how this may be further affected by simultaneous changes in the soil community.
"We are using results of this experiment to develop a model to better predict changes in carbon and nitrogen cycling in Arctic tundra as nutrients are increased in the soil with global warming," Gough said.
Laura Gough scouts a field site near the Sagavanirktok River on the North Slope of Alaska in May 2010. She was determining the height and species composition of the shrubs to decide if it would make a good site for "shrub tundra" research.
The other project is funded by a five-year, $346,230 NSF grant and also looks at how an increase in shrubbiness affects Arctic ecosystems, but uses shrub- and non-shrub-dominated plots of land to examine patterns of vegetation, arthropods, and associated migratory songbirds.
After all the research she's done in the Arctic, there is no uncertainty in Gough's mind about the effects of global warming on the climate there.
"There is no doubt that landscape-level changes are occurring in the Arctic as a result of global warming," she said. "From the global perspective, there are two changes that I think we should be most concerned about in the short term. First, the melting of the polar ice cap is altering Earth's climate in ways that climate scientists are just beginning to understand. It may seem counter-intuitive, but there is evidence that when the ice cap is particularly low, like this year, in North America and Europe we will have much more severe winters. These extreme events are occurring more frequently now, and what is happening to the ice in the Arctic is affecting that.
"The second is the increased production of methane and carbon dioxide from tundra soils. These greenhouse gases will only serve to enhance the greenhouse effect, thus leading to additional warming. My research is focused on trying to understand the implications of these changes, particularly with the increase in shrubs. We can imagine that more shrubs mean more wood, which may trap more carbon in plant tissues and prevent it from getting to the atmosphere. However, empirical data and models have shown that the plants quickly run out of the nutrients they need to continue to grow (especially nitrogen) so that they can only grow more for so long before that carbon dioxide bypasses the plants and goes to the atmosphere."
"There is no doubt that landscape-level changes are occurring in the Arctic as a result of global warming," she said. "From the global perspective, there are two changes that I think we should be most concerned about in the short term. First, the melting of the polar ice cap is altering Earth's climate in ways that climate scientists are just beginning to understand. It may seem counter-intuitive, but there is evidence that when the ice cap is particularly low, like this year, in North America and Europe we will have much more severe winters. These extreme events are occurring more frequently now, and what is happening to the ice in the Arctic is affecting that.
The project on nutrient availability in soil is focused on these interactions, on what happens when nutrients increase and finding out what the long-term ramifications for carbon and nitrogen cycling are, Gough says. The migratory songbird project is focused more on the results of what is occurring now, and as shrubs continue to increase in dominance; it seeks to answer the question of how changes in the plant community will affect organisms that rely on shrubs for shelter or food. Hundreds of thousands of migratory birds breed in the Arctic during the summer, thus changes to that part of the Earth has ramifications for the other places in North and South America where these birds winter.
"As the pressures of human society on natural systems increase, I feel that ecologists must focus our research in areas that can help inform resource management and policy making," she said. "For example, my studies in the Arctic will always center on the effects of global change. A major goal of this work is to understand how Arctic organisms are responding to increased temperature and how altering their communities may further feedback to cause greater change, particularly through the carbon and nitrogen cycles."
Gough knew early on that she wanted to study biology because of a lifelong fascination with nature.
"I have always loved being outdoors," she said. "I have a drawing that I made in kindergarten where I wrote that I wanted to grow up to be a ballerina or a biologist. I drew a picture of myself walking down a path in the woods. My parents both have graduate degrees in biology, so I grew up in a house full of science."
She went to Brown University and originally was in a pre-med program, but that ongoing fascination with nature eventually led her down a different path.
"I decided that I wasn't interested enough in medicine and in the clinical aspect of that field, but was more interested in being outside and trying to figure out how natural systems work," Gough said.
After graduating from Brown with a B.S. in Biology with Honors in 1990, she went on to pursue a doctoral degree in Plant Biology at Louisiana State University.
She received her Ph.D. in 1996 and spent the next two years as a postdoctoral scientist at The Ecosystems Center of the Marine Biological Laboratory, in Woods Hole, Mass., where she began working in the Arctic in the summers. That was followed by three years as an assistant professor in biology at the University of Alabama. In 2002, she moved to UT Arlington.
While much of her previous research has involved examining specific ecological changes brought on by the warming climate, Gough says a new component of her current research – measuring the effects of human activities in urban ecosystems on local organisms and communities – is of equal importance. One of her Ph.D. students is looking at how patterns of urbanization in Dallas-Fort Worth have affected breeding bird communities, and another is determining how air quality associated with urban areas is affecting growth of native grass species and their interactions with insect herbivores.
"One of the reasons that I am developing a research program in urban ecology is because what I am seeing happen in the Arctic is a result of human activities, which are concentrated in cities," Gough said. "I believe that people in Dallas-Fort Worth are rather isolated from their environment for the most part but that enhancing understanding of what is happening right here in our backyards will help us acknowledge how our activities have far-reaching consequences. This is also one of the reasons why teaching is so important to me. We need an educated, scientifically literate public to get engaged in these issues and to understand what the science tells us."
 
Coral reefs: Losing the fight against global warming
For years, Laura Mydlarz has examined another part of the environment which has been negatively affected by climate change – coral reefs. She studies how temperature stress directly affects coral resistance to disease, as well as how rising temperatures may be affecting the pathogens themselves, causing them to be more virulent.
"I have seen that the effects of a warmer climate have been devastating to coral reefs, especially those in the Caribbean," she said. "We see many coral dying due to increases in disease outbreaks and bleaching events, where the coral loses its symbiotic algae due to stress responses from high temperatures. My work does show that temperature stress can negatively affect a coral's immune system and cause marine bacteria and fungus to be more virulent and infect a host easier. So in many ways, my research shows that the effects of climate change on ecosystems are as disturbing as many scientists originally thought."
Mydlarz uses coral-pathogen models as the main study systems in her lab. Two examples are the sea fan – an order of corals common in the tropics and subtropics which is infected with a common soil fungus – and a large, reef-building coral which is infected by a group of bacteria.
Mydlarz is in the second year of a $409,537 National Science Foundation grant to study coral disease, especially associated with environmental stress and climate change. The study is a collaboration between Mydlarz, Ernesto Weil of the University of Puerto Rico at Mayaguez, and John Bruno of the University of North Carolina at Chapel Hill. In her lab, Mydlarz and her students are analyzing coral samples from Puerto Rico for disease resistance markers.
Laura Mydlarz collects a fragment of sea fan coral in the Florida Keys for use in her lab.
"I'm really interested in why some coral species are more resistant to diseases and temperature stress than others," she said. "We are looking at the genes and protein expressed in these corals to see what they are doing right while more sensitive species around them are dying."
The project focuses on coral in the Caribbean which are affected by numerous bacterial and fungal diseases. One particularly destructive disease is Caribbean Yellow Band disease, a bacterial infection which attacks colonies of coral at a time when the coral is already stressed by pollution, overfishing, and climate change. It is characterized by large blotches or patches of bleached, yellowed tissue on Caribbean scleractinian corals, also called stony corals.
Mydlarz and her collaborators are examining the effects of environmental stressors on the Montastraea species complex, one of the more important species of reef-building coral in the Caribbean. They are looking at how coral immune and self-defense mechanisms are affected by temperature, nutrient and pathogen stress.
"We are working to describe the basic innate immune responses of reef-building corals," Mydlarz said. "Specifically, characterizing how environmental stressors such as temperature affect the corals' ability to fight pathogens."
Caribbean Yellow Band disease often leads to coral death. Scientists fear that the disease has already seriously affected reef-building corals in the Caribbean and believe it has been worsened by the effects of climate change.
Mydlarz had a strong interest in marine science from an early age and did everything she could to further that interest, but being born and raised in Montreal presented geographical and logistical challenges which limited her. That all changed when she moved to Boca Raton to attend Florida Atlantic University.
"When I started at Florida Atlantic, I really was able to get involved in many marine projects and jumped at the chance to work tracking sea turtles and on coral reefs," she said.
One of her mentors at FAU was looking at new drugs that came from coral near the reefs in Florida and the wider Caribbean. The subject intrigued her and, after earning a B.S. in Marine Biology in 1996, Mydlarz stayed at FAU for her master's degree, which she earned in 1998. She went to the University of California at Santa Barbara for her doctoral work, and there she learned how to use all of the techniques she had mastered to answer bigger ecological questions about coral declines, mainly due to new diseases and climate change.
She earned her Ph.D. in 2004 and spent two years as a post-doctoral associate in Ecology at Cornell University, then joined the UT Arlington Department of Biology in 2007.
Before getting involved in research that was directed at conserving corals and figuring out why reefs are dying as water temperatures warmed, Mydlarz studied corals as sources of natural products for human use. This continues to be an area she is interested in, and she has been working with UT Arlington associate professor in chemistry/biochemistry Kevin Schug on projects to use corals as sources for new antibacterial compounds.
"These projects have renewed urgency since many of us believe that there are many potential drug candidates on the reef," she said. "But if reef loss continues at its current rate, we may not get the chance to find them."
Mydlarz says the continued loss of coral reefs due to global warming is having a profound effect on marine life and, as a result, on the economies of those living near them.
"A lot of people ask why the average American should care about coral reefs, especially since they may never visit one," she said. "Coral reefs are extremely important for local islands to protect the shoreline and as a part of their local economy due to the fisheries and tourist dollars. Most importantly, coral reefs are extremely rich in biodiversity and house some of the most unique and beautiful animals in the world. The corals build the reef ecosystem and provide habitat for many reef creatures and nursery grounds for many larger open ocean fish and sharks."