On the one hand, Kausch, a Ph.D. student based at Fordham’s Louis Calder Center biological field station, is studying the causes and consequences of harmful algal blooms (HABs) in New York metropolitan area lakes.

For the last six years, that has involved traveling to about 20 lakes in and around New York City and collecting water samples to determine concentrations of dissolved nutrients, chlorophyll, and phytoplankton species composition. Algal blooms are a big concern now, and in fact, the State of New York has dedicated $82 million to combat them in places such as Lake Carmel in Putnam County, one of Kausch’s sites. In addition to appearing as foam or scum on the surface of the water, the blooms can produce toxins that make people and animals sick. Preventing explosive growth of these microscopic organisms is so key to his work, that the tentative title of his dissertation is “Causes and consequences of cyanobacteria harmful algal blooms in New York metropolitan area lakes.”

On the other hand, despite trying to prevent the blooms, he happens to be fascinated by them.

“I’ve always been interested in the smallest life forms. I certainly think they’re the most interesting life forms, and many times, the most important ones,” said Kausch, a native of Queens who earned a master’s degree in applied environmental geosciences at Queens College.

“They can also cause some substantial problems for humans. Climate change and nutrient loading, which is when human activity triggers the release of nitrogen and phosphorus, are happening pretty much all over the world, so in the last few decades it seems like there’s been an explosion in the occurrence and the intensity of harmful algal blooms.”

Last month, Kausch, who goes by the Twitter handle @NYCMicrobes, tweeted out the view he’s had in the lab with the wider world. With the aid of an Em1 portable microscope and an iPhone, he created videos of several algae, including synura, oocystis, and his favorite, euglena, flitting and bouncing around in their aquatic world. The videos, which he set to music that he’s recorded with friends, are a side project, but have attracted some attention; the Quebec City newspaper Le Soleil included them in an article published in their science section in July.

“I think these could be good for teaching because I feel like people might be amused by the music, and then also seeing the cool algae moving around,” Kausch said.

When it comes to the research, which Kausch has conducted under the supervision of John Wehr, Ph.D., the most intriguing finding is that in the lakes with the highest concentrations of chlorophyll, the concentrations of nitrogen greatly affect the growth of algae. This is important because up until recently, the focus has been on the ways phosphorus can spur growth, rather than nitrogen.

“Historically, efforts to control HABs have focused on reducing phosphorus loads, but in the past decade or so, the literature has increasingly highlighted the importance of dual-nutrient management strategies targeting both nitrogen and phosphorus loading to control HABs,” Wehr said. Both come from waste created by humans.

“Sometimes it’s the nitrogen and phosphorus together, but the point is we as humans create waste in all sorts of ways, and that waste finds its way into water bodies,” he said.

He said one need not go further than Central Park to see how harmful algal blooms can be. Visit the boat rental area, and he noted that you’ll see signs warning against letting dogs swim there because some of the algae produce toxins. Excess use of fertilizer is one culprit; human waste can be another.

“Our use of the environment leads to these hyper-eutrophic, or sometimes hyper-productive situations, which people find aesthetically unpleasing, but in some cases, it’s also biologically undesirable,” he said.

“It changes the structure of the community, biodiversity goes down, we see unpleasant tastes and smells in water bodies, and then occasionally it produces toxins.”

Like Kausch, Wehr said he finds cyanobacteria to be fascinating—one of the remarkable features of some of them is their ability to draw nitrogen from the atmosphere when levels of it in the water start to dip.

“When there isn’t enough nitrogen in the system to keep supporting these blooms, certain species come to the fore and pull nitrogen from the atmosphere, convert it into usable forms, and keep on ticking. It’s quite a remarkable and amazing group of organisms with their adaptations,” he said.

Kausch’s enthusiasm translates into the lab, Wehr said, making him a natural to inspire and mentor undergraduate students. Like most researchers in the lab, he tends also to get more excited by algae-covered bodies of water than the average person would.

“I think his motivation to share some of what he’s been learning with videos and pictures is a good example of how he wants to share what he’s learning, and the excitement of discovery.”

At the Louis Calder Center, scientists explore ecological mysteries and study society’s impact on the natural world.

To the casual observer, Fordham’s Louis Calder Center might seem to be just another quiet tract of Hudson River Valley forest. But for natural scientists, it abounds with opportunity. Explore the 113-acre biological field station in Armonk, New York, and you’ll find a bounty of ecosystems and animals, from the four-legged to the microscopic. At the heart of the preserve is a 10-acre temperate lake teeming with a diversity of aquatic life. Go high enough and, way off in the distance, you can see another big player in the preserve’s ecology: New York City, which begins only 16 miles away.

Its proximity has never been more relevant. “Humans and our cities are the most dominant forces of contemporary evolution now,” says Jason Munshi-South, Ph.D., a Calder-based biology professor who recently co-authored a paper in the journal Science on how species are evolving within cities. Other scientists at Calder study invasive species that arrive via big-city commerce. And they tackle many other mysteries: why some animals survive new threats while others don’t, how nutrients flow beneath the soil, or how insects transmit disease.

The center was born 50 years ago when the land was given to Fordham by the Louis Calder Foundation, named for the paper and pulp magnate who maintained a summer home on the property. Today, that home is Calder Hall, one of several buildings in which students and professors analyze DNA samples, inspect plant and animal specimens, hold classes, and generate knowledge.

Among many other public services, the Calder Center supports the nation’s longest-running study of ticks and Lyme disease, and its scientists work to illuminate society’s impact on nature at a time of growing concern about biodiversity and climate change.

It is also a crucial training ground: “The most important thing we do here is make scientists,” says Thomas Daniels, Ph.D., an expert in tick- and mosquito-borne diseases who has served as the center’s director since 2014.

On a sparkling autumn day late last October, FORDHAM magazine tagged along as undergraduates, graduate students, professors, and visiting scientists went about their work—gently probing, collecting samples, and explaining the science behind their work and its potential impact.

Evolution in the Big City

In recent years, Fordham biologist Jason Munshi-South, Ph.D., and his team of graduate and undergraduate students have become known for their studies of urban wildlife and pest species, most notably rats.

“The initial idea was to understand what a New York City rat is, from all ecological and evolutionary angles,” he says of one project, which grew to a global scale and has public health implications. “We’re using DNA to understand how they move around the city and how they’re related to other rat populations.”

In a first-floor lab in Calder Hall, doctoral student Carol Henger uses similar methods to study coyotes, animals that only recently moved into the city for the first time, Munshi-South says. She’s looking at DNA markers from coyote scat collected in Pelham Bay Park and elsewhere to infer how individual coyotes are related, what they’re eating, and how they’re dispersing.

Meanwhile, Nicole Fusco, another doctoral student in Munshi-South’s lab, sequences DNA to study gene flow among populations of salamanders.

Biodiversity and Climate Change

In the Calder Center’s Lord & Burnham greenhouse, constructed on the property nearly a century ago, doctoral student Stephen Kutos has been growing pairs of potted trees and studying how they pass water and nutrients back and forth via subsoil networks of fungus.

“Tree stumps have been found that are still alive hundreds of years after the tree was cut down, quite possibly because surrounding trees send them nutrients,” he says. With further study, he adds, it may be possible to restore the wild population of one type of tree he’s growing, the American chestnut, which was eradicated from the wild 100 years ago by blight.

Restoring the tree could help combat climate change, scientists believe, because the American chestnut can absorb and store carbon quickly.

In an adjacent greenhouse, several researchers work on an evolutionary study initiated by Fordham biologist Steven Franks, Ph.D., and focused on Brassica rapa (field mustard). As Franks demonstrated in an earlier study, the annual plant evolved earlier flowering within just five years to cope with drought conditions in California.

The Mystery of the Red-Backed Salamander’s Survival

Late in the morning, undergrads Dan Khieninson and Erin Carter and doctoral student Elle Barnes enter Calder forest in search of red-backed salamanders.

“You can find them anywhere in the forest as long as the soil’s moist,” Barnes says before the group navigates a steep decline to the forest floor.

She indicates several flat, weathered pieces of wood she’s left behind. “You’re more likely to find them under here.” The three researchers crouch down and soon locate several specimens.

They’re trying to discover why red-backed salamanders are not affected by the chytrid fungus that is devastating other amphibian populations.

“It’s not enough to just study the ones that are going extinct,” Barnes says. “There are solutions in the ones that will survive. What do they have that other amphibians are lacking?”

The answer lies in their microbiome, Barnes says. She, Carter, and Khieninson use cotton swabs on the salamanders’ bodies to collect samples of microorganisms that they can test against chytrid fungus in the lab. The impact of their research could extend beyond conservation biology, Barnes says: “The discoveries we make about disease and microbiomes can be applied to multiple systems, including humans’.”

A Closer Look at a Ubiquitious, Ecologically Valuable Species

Michael Kausch, a doctoral student in aquatic ecology, rows a boat out on Calder Lake to take some water samples he can later test for cyanobacteria at the lakefront McCarthy Laboratories. Meanwhile, inside the lab, his fellow doctoral student Stephen Gottschalk is working with their Fordham supervisor, John Wehr, Ph.D. Gottschalk is studying green algae in the Characeae family.

“They’re an important food source for birds, a habitat for insects, and they support fisheries,” he says.

So far Gottschalk has collected samples in nine U.S. states, and he’s been working at the New York Botanical Garden under the supervision of Kenneth Karol, Ph.D., to examine his samples on a molecular level.

He’s finding that what scientists once thought were just subtle differences among green algae are in fact ecologically important distinctions. “They’re designated as one species,” Gottschalk says, “but what it looks like to me so far is these are very regionally distinct.”

Mosquitoes, Ticks, and the Pathogens They Carry

Insect-borne diseases are a big part of the research focus at Routh House, the vector ecology lab at the Calder Center that’s jointly run by Fordham and the New York state health department. Inside the lab, scientists study samples of various species, such as the aggressive and potentially disease-carrying Asian tiger mosquito. Outside, they collect specimens and conduct surveillance projects.

“We set up mosquito traps all around the lower Hudson Valley,” says Marly Katz, a state employee and Fordham doctoral student. “All the mosquitoes end up here, where I identify them, and then we send a bunch [to the state health department]for disease testing.” She and her colleagues are also collaborating with Columbia University scientists to “map the Asian tiger mosquito,” she says, and determine if changes in climate are affecting its migration patterns.

While Katz checks a mosquito trap, research technician Richard Rizzitello collects ticks by dragging a white cloth across the ground and then pulling them off with forceps (he uses a lint roller to collect any larvae).

One Calder scientist, Nicholas Piedmonte, displays egg-to-adult samples of the blacklegged tick, which can carry the bacterium that causes Lyme disease.

“These are great for education and outreach,” he says, particularly in central New York, “where ticks are kind of a new problem.”

View a timeline of the Calder Center’s history. And watch a July 2017 video celebrating the center’s recent golden anniversary.

Daniels, associate research scientist in Fordham’s Department of Biological Sciences, took the reins from John Wehr, Ph.D., professor of biology, on Jan. 1. Wehr, who has overseen the doubling of the center staff and the construction of a 3,800 square-foot, 12-bed, log cabin-style residence for graduate researchers, has served as Calder’s director since 1986. A renowned limnologist, Wehr has also overseen research projects in the center’s 10-acre lake and in lakes and streams across the nation.

Tom Daniels, left, will direct Fordham’s Calder Center, taking the reins from John Wehr, right. Both men are among Calder’s most senior researchers.
Photos by Bruce Gilbert (left) and Bill Denison

The Calder Center is 25 miles north of New York City and consists of 113 forested acres and a 10-acre lake. It is one of the few field stations in North America with relatively undisturbed natural communities near a large urban center. Calder supports scientific and interdisciplinary research in ecology, evolution, and conservation, and provides hands-on education for students of diverse backgrounds and academic levels. The center was established in 1967 on the former estate of Louis Calder, chairman of the Perkins-Goodwin Company.

Daniels earned his doctorate in biology in 1987 at the University of Colorado, Boulder, and joined Fordham as an adjunct professor in 1994. He is currently the co-director of the Vector Ecology Laboratory at Calder, where he and fellow co-director Richard Falco, Ph.D., lead a team of scientists and students in researching disease-carrying insects (vectors) such as ticks and mosquitoes.

In his own research, Daniels has focused on vertebrate-tick relationships and the ecology of Lyme disease in the northeastern United States, as well the ecology of the West Nile virus in the Northeast. He credits co-researcher Wehr with laying a successful foundation for the center.

“I’m flattered to be asked to take over as director when John steps down, and excited to begin the next stage in Calder’s growth. The center has untapped potential that we all see, and I’m committed to help move us along the path to reaching that potential,” Daniels said.
Daniels said his primary role would be “helping to facilitate the research efforts of our faculty and graduate students at Calder.”

“That, in turn, will generate opportunities for our undergraduate students to assist in active research and come away with a unique field experience. It is why Calder exists.”

Jonathan Crystal, Ph.D., associate vice president and associate chief academic officer in the Office of the Provost, said the office is “thrilled” that Daniels is taking the position. He likewise noted that “without the work of John [Wehr], there would have been no Calder Center.”

Wehr will stay on at the center and continue research in aquatic biology.

“The Calder Center is an important asset for Fordham, supporting research and educational opportunities not only for our own faculty and students, but for others across the region and nationwide,” Crystal said.

“We have a lot of confidence that, under Tom’s leadership, Calder will make great strides in fulfilling the field station’s potential.”

Currently, one in six of Fordham’s undergraduates are majoring in biology or pre-health, or both. In 2013, Calder’s Summer Undergraduate Research Program attracted 170 applicants for 10 positions. Calder’s graduate students regularly go on to careers that make use of their biological training, including positions at the Alaska SeaLife Center, the Central Park Zoo, the Malcolm-Pirnie environmental consultancy, the National Wildlife Federation, the New York Botanical Garden, New York Medical College, New York City’s Department of Environmental Protection and Department of Health, the U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service, and Woods Hole Oceanographic Institute.

For Nancy Busch, Ph.D., dean of the Graduate School of Arts and Sciences and chief research officer/associate vice-president for academic affairs, the transition is a good time to reflect on how Wehr’s work helped make the Calder Center a nationally and internationally recognized field station whose scientists are at the forefront of research and education on issues of ecological significance and global conservation.

“I believe that Tom Daniels will continue to establish Calder’s prominence as a center for the study of key issues in ecology involving urbanization and conservation, such as invasive species, water quality and vector borne illnesses like Lyme disease,” she said.

“Tom has great passion for Calder and understanding of its unique position as a biological field research station at the urban-rural gradient in one of the world’s foremost urban environments.”

John Wehr, Ph.D., sees the world’s network of watery veins and arteries for what it is: the vascular system of the Earth.

As a limnologist, Wehr, professor of biology and director of Fordham’s Louis Calder Center biological field station, has conducted numerous studies on the impact of humans on freshwater environments, most notably on water quality and critical levels of phytoplankton.

At Calder, Wehr oversees research projects in the center’s 10-acre lake and in lakes and streams across the state. He also mentors projects in the University’s Experimental Lakes Facility (ELF) tanks, a collection of two dozen 1,200-gallon tanks that can hold entire lake communities for research purposes.

The ELF tanks make it possible to replicate a “miniature lake” that can be controlled, yet result in environmental conditions with a fairly high level of realism. Recently, Wehr oversaw a project on how an increase in ultraviolet radiation levels, resulting from the thinning ozone layer, affected the lake’s algal and bacterial communities and, therefore, its food chain.

“In the past, we thought of fish and larger plankton as being most important, but it is actually these tiny microbes that are critical,” he said.

As the co-editor of Freshwater Algae of North America: Ecology and Classification (Academic Press, 2003), Wehr’s expertise in algae and phytoplankton has attracted projects beyond the confines of Calder. A few years ago, Wehr published a study on the health of channel regions of the Ohio River. Currently, he is partnering with the U.S. Geological Survey (USGS) to study a huge archive of phytoplankton samples from the upper Mississippi River, and helping to measure the importance of wetlands on the river’s ecosystem.

“The upper section of the Mississippi is basically still a natural river, expanding and contracting with rainfall and the time of year,” said Wehr, who divides his time between the Calder Center and the Rose Hill campus. “But the lower part of the Mississippi has been turned into essentially a channel of water, with few wetlands to buffer the water and no exchange.”

The result, he said, is catastrophic flooding and a “dead zone” that exists in the Gulf of Mexico at the river’s mouth, stretching for 5,000 square miles. There, an abundance of algae, feeding upon an excess of nitrate-based nutrient runoff, makes aquatic life unsustainable.

“Some scientists refer to wetlands and side channels of rivers as ‘the rivers’ liver,’” Wehr continued. “Our research asks the questions: does a river that has high connectivity and intact flood plains function better? Is it necessary to preserve intake wetlands and backwater habitats that previously were thought of as useless? We suspect wetlands matter because of how their phytoplankton and other microbes process nutrients.”

A few times a year, Wehr and his students travel to LaCrosse, Wis., to measure the activity and composition of aquatic organisms and water samples, using experimental enclosures that are dropped in different locations of the upper Mississippi.

Wehr and Jillian Decker, a doctoral candidate in biology, transfer the river samples into clear, one-gallon sunlit containers called mesocosms. Back at the center’s labs, they test hundreds of samples from a range of habitats on the river.

In addition to the experimental samples, Wehr and Decker are doing tests on the first round of a cross-section of 10,000 preserved, unstudied samples of river phytoplankton collected by the USGS over the past decade.

“There are very few agencies in the world that have such a huge archive just waiting for someone to analyze,” Wehr said.

Wehr and colleagues in LaCrosse are working on a paper, “Differences in Phytoplankton Species Composition Among Habitat Types in Pool 8 of the Upper Mississippi River,” based on their preliminary research. The long-range plan, Wehr said, is to get additional federal funding to complete a more comprehensive study on the upper river’s connectivity—and how it influences an ecosystem.

At Fordham, Wehr wears three distinct hats: as professor of biology, he teaches students on the Rose Hill campus; as Calder’s director, Wehr oversees the budget and staff of the forested, 113-acre facility; lastly, he is a vigorous mentor.

“There were three faculty and two grad students when I arrived [in 1986],” recalled Wehr, “Now we’re eight faculty and countless students.”

Each summer, the center hosts Fordham University’s Calder Summer Undergraduate Research (CSUR) Program, sponsoring 12 undergraduates from around the country in paid research internships. The program has been in existence since 1998 and is funded by the National Science Foundation (NSF). This past summer, six of the 12 students were from Fordham.

During the academic year, the center engages several undergraduates and about a dozen graduate research assistants on projects that often lead to honors, master’s or doctoral theses. Plans are underway to provide 12 housing spots for graduate students with the new construction of NSF-funded, log cabin dormitories.

“We tryto make Calder a place where students can do good science, one that is very collaborative,” said Wehr, who takes photos of his students after they defend their master’s theses or doctoral dissertations and posts them on the wall of his office.

“As with all of the scientists here, our labs don’t work unless we’ve got students happily joining us in our research. In fact, I can’t imagine doing a research project without having students involved.

“I think we have had a good impact on a number of people’s careers and lives,” he said.

– Janet Sassi

The all-day event featured a keynote address by Sarwan Dhir, Ph.D., program director of the Center for Biotechnology at Fort Valley State University. “You have worked really hard,” Dhir told the students. “This was just a seed for you—it’s up to you to grow now.”

The Calder Summer Undergraduate Research (CSUR) Program, which has been held at Fordham’s Louis Calder Center Biological Field Station in Armonk since 1998, is a highly selective 12-week initiative that attracts students from across the country to conduct research under the mentorship of Fordham ecology faculty members. Participating students have access to study sites at the station and nearby ecosystems, such as the Hudson River, the Catskill Mountains and Black Rock Forest.

The students ranged from Texas A&M University in College Station, Tex., to Medger Evers College in Brooklyn. Funding for the program is provided by a grant from the National Science Foundation’s Research Experiences for Undergraduates Site Program.

John Wehr, Ph.D., associate professor and director of the Calder Center, and James Lewis, Ph.D., associate professor of biology, direct the program. “As opposed to being told about science, they’re doing science,” Wehr said. “By the end of the summer, their hard work results in some excellent science. This was a very enthusiastic group of students.”

The students each delivered 20-minute presentations about their research on topics ranging from ectomycorrhizal fungi to negative geotaxis in rice and maize weevils.

The 12-week Calder Summer Undergraduate Research Program, which has been held at Fordham’s Louis J. Calder Center Biological Field Station in Armonk since 1998, is a highly selective program that attracts students from across the country to conduct research under the mentorship of Fordham ecology faculty members.

The summer program, funded by a grant from the National Science Foundation’s Research Experiences for Undergraduates Site Program, is under the direction of John Wehr, Ph.D., associate professor and director of the Calder Center, and James Lewis, Ph.D., associate professor of biology.

“The symposium is the culminating experience for these students, who come to our field station with great enthusiasm but often limited opportunities to conduct research projects of their own interest and design,” Wehr said. “Our program is hands-on learning for an entire summer. We have an excellent faculty, so it’s an amazing opportunity and our students really take advantage of the time they spend here. By the end of the summer, their hard work results in some excellent science. Some of their findings may also end up in peer-reviewed scientific publications—a great start to a young person’s scientific career. You can clearly see success and confidence in their talks in August.”

Dhir, the keynote speaker, has hosted a similar program at the Center for Biotechnology at Fort Valley State since 2001. Dhir, whose research interests focus on genetic engineering of plants for vaccine production, medicinal plant genetic engineering and biodegradable thermoplastic production, was the recipient of the 2005 Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring.

As part of Fordham’s program, students have access to study sites at the station and nearby ecosystems, such as the Hudson River, the Catskill Mountains and Black Rock Forest. This year, nine students from institutions ranging from Texas A&M University in College Station, Tex., to Medger Evers College in Brooklyn will present their research findings at the daylong symposium.