Bio-inspired chemistry, in which biological design principles are applied to the construction of man-made hybrid nano-chemical catalytic structures, is a rapidly emerging area that is attracting intense interest.

Baruch ’60 Center for Biochemical Solar Energy Research at Rensselaer was established to meet this challenge through the combined and iterative use of chemical, biochemical, physical, nanomaterials, and advanced computational approaches for the design of highly efficient and cost-effective bio-inspired photovoltaic devices. During the annual Rensselaer Reunion & Homecoming weekend, the Baruch ’60 Center hosted a poster session and laboratory tours for the School of Science alumni “experiences” event.

Below are a few images from the event.

Participants include students and postdoctoral research associates from the research groups of chemistry and chemical biology professors K. V. Lakshmi, Jacob Shelley, Peter Dinolfo, and Chulsung Bae in the Chemistry and Chemical Biology department. Sara Foreman, Vidas Kalendra, Kacey Kilpatrick, Jacob Palumbo, Brian Mark, Amanda Hoffman, Adrien Campbell, Brian Molnar, Courtney Walton, Montwaun Young, Anna Smallwood ,and Stefan Turan participated in the poster session where they described their research on bio-inspired strategies for the conversion and storage of energy as electricity or chemical fuels.

 

[Four years ago, Rensselaer Polytechnic Institute and the Ichan School of Medicine at Mount Sinai entered a relationship to promote personalized medicine and medical care through collaborations in education, research, and development of new diagnostic tools and treatments. Several innovative projects on Alzheimer’s disease, cancer, diabetes, and osteoporosis have already emerged from this partnership. As part of the relationship, the Icahn School hosted a Heath Hackathon, supported in part by the Rensselaer Center for Biotechnology and Interdisciplinary Studies, to explore transformative ideas in several areas of health-care delivery. The event, held October 13-15 in New York City, included Rensselaer students from all five schools, as well as students from Mount Sinai Medical Center, Columbia University, and CUNY, and hospital staff. Rensselaer students were part of all the three finalist teams who will compete for a Shark Tank-type showcase in February. In this post, the Approach spoke with Angela Su, a member of one of the finalist teams.]

As a doctoral candidate in computer science, Angela Su had been in hackathons before. But she’d never been to a health-care hackathon. So when she saw the notice about an event hosted at the Icahn School of Medicine at Mount Sinai, she signed up. Forty-eight hours after she walked in, she and a group of people she had never met had designed and pitched a new app for pediatric cancer patients. And that’s just the beginning.

Su was one of a dozen undergraduate and graduate students from Rensselaer Polytechnic Institute who entered the Mount Sinai Health Hackathon. Her team, which also included Rensselaer biomedical engineering student Alagu Chidambaram, is one of three finalists. Finalists were awarded $2,500, and will participate in an innovation “Shark Tank-type” showcase on February 15, 2018, during which the finalists and a fourth wild card team will present a five-minute pitch to a panel of entrepreneurs.

Two Rensselaer students were on each of the two remaining finalist teams. Lydia Krauss, a biomedical engineering undergraduate, is working on “Helping Stand,” a portable device to assist fatigued patients stand to get out of a car. And Michael Bramson, a graduate student in biomedical engineering, is working on “StreamLine,” an AI-based tool for streamlining the clinical trial protocol development process.

The multidisciplinary competition focused on creating novel technology solutions for assessing, monitoring, managing, and treating problems in health care, with a focus on cancer. Entrants were first given an overview of problems in cancer prevention, diagnosis, management, treatment, and recovery. Then entrants generated solution ideas, such medical devices and apps, and teams coalesced around the ideas. Teams designed and refined their solution during the event, and presented them before a panel of judges.

The format made it possible for teams with a diverse skillset to work together, said Su.

The hackathon started with problem statements, basically an overview of problems that hospital and patients face in cancer treatment. I don’t have a medical background, and I don’t know the leading-edge problems in cancer and cancer research, so hearing the problems made it easier for me to bring my skills to bear in a new field.

Su and her six-member team designed “On track,” a web-based school and socializing tool for pediatric cancer patients. The tool makes it possible for parents and teachers to keep kids connected with their classroom and peers as they undergo treatment.

Su said her team took a systematic approach to developing their solution.

My team ended up being super diverse, everyone came from different backgrounds – biomedical, education, computer science. Everyone had a different role, and we worked really well together. We did a lot of background research to see what kinds of problems pediatric students might be going through, what resources are available, and how our potential solution would be helpful. During the event, they had mentors circulating among the teams – clinicians, business people – and they gave us great advice on how to shape our idea.

The team intends to develop their idea. In the brief time since the hackathon, the team has already reached out to potential industry and academic partners including Rensselaer’s Center for Biotechnology and Interdisciplinary Studies and Institute of Data Exploration and Application, and is discussing how they can take their idea from design to reality, Su said.

There’s a lot of potential. It’s crazy seeing it go from a problem and idea to a product. What’s we’ve designed thus far is a prototype, and we want to work on refining it and keeping that momentum going. If we’re able to do it, it would be great to partner with hospitals to use this app, so it could impact the children who need it.

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Regardless of the outcome, Su says the event was a win.

This is an experience that I can carry into my career. For one thing, working on a team going toward a common goal is what I imagine it will be like in the workplace. Also, having autonomy to be in charge to work on this. Even the technical skills like learning about different technologies that are out there. We used IBM Watson software to automate some of the process and learned how to implement that. And it was a networking opportunity, meeting people in the hospital, in business, and other students. All of that is relevant to career goals.

Rensselaer students Joseph Osei-Kusi, Obeng Buo, Snehansh Pabba, Wan Na Chun, Gabrielle (Alex) Ford, Carissa DelGaudio, Kathryn Hollowood, and Smriti Moorjani also participated in the event.

[The Jefferson Project at Lake George is conducting ongoing research into how human activities may be affecting the lake and surrounding wetlands. This guest blog by Aaron Stoler, a post-doctoral research associate in the lab of Jefferson Project Director Rick Relyea, summarizes recent research published in the journal Environmental Pollution. The Jefferson Project is a collaboration between Rensselaer, IBM Research, and The FUND for Lake George, founded to develop a new model for technologically enabled environmental monitoring and prediction to understand and protect the Lake George ecosystem and freshwater ecosystems around the world.]

What did you want to know?

Chemical contamination is common in nature. For example, pesticides are frequently applied to homes, gardens, farms, and forests to control native and non-native pest species. However, pesticides can move into aquatic ecosystems, such as wetlands, and have unexpected effects. At the same time, changing species composition in our forests can also affect wetlands as they drop their leaves into the water. These leaves serve as food for many organisms and different leaf species contain different suites of chemicals. Our goal was to understand how these two factors might interact.

How did you go about it?

We conducted a large, outdoor experiment using 48 tanks that each contained 130 gallons of water. To each tank, we added black oak, elm, or red maple leaves. To create a food web that is representative of wetlands found throughout the Lake George watershed, we added bacteria, fungi, algae, two tadpole species (gray treefrogs and green frogs), amphipods, and zooplankton. We then applied the commonly used insecticide carbaryl (commercially name: Sevin®) at environmentally relevant concentrations and frequencies (no carbaryl added, weekly additions of 10 micrograms per liter (µg / L), a single early-season addition of 50 µg / L, and a single late-season addition of 50 µg / L). We followed the growth and development of all organisms for 1.5 months.

What did you learn?

We discovered that the tree leaves and the insecticide both affected the wetland food web. Red maple and elm leaves, which decompose rapidly, caused greater growth of algae, tadpoles, and amphipods than oak leaves, which decompose slowly. Regardless of leaf species, carbaryl induced a sharp decline in the abundance of amphipods and some zooplankton species, and this led to an increase in floating algae. For the tadpoles, leaf species and carbaryl showed interactive effects. For gray treefrog tadpoles, carbaryl caused 8–13% lower survival when elm or maple leaves were present, but not when oak leaves were present. For green frog tadpoles, carbaryl caused lower growth when oak or maple leaves were present, but not when elm leaves were present. Collectively, these results underscore the fact that commonly used pesticides can have interactive effects with the leaf inputs from changing forests. More generally, it demonstrates that different human impacts commonly have interactive effects on aquatic ecosystems.

The research, titled Effects of a common insecticide on wetland communities with varying quality of leaf litter inputs,” can be found at:  doi/10.1016/j.envpol.2017.04.019

 

[The Jefferson Project at Lake George is conducting ongoing research into how human activities may be affecting the lake and surrounding wetlands. This guest blog by Aaron Stoler, a postdoctoral research associate in the lab of Jefferson Project Director Rick Relyea, summarizes recent research published as a featured article in the journal Freshwater Science. The Jefferson Project is a collaboration between Rensselaer, IBM Research, and The FUND for Lake George, founded to develop a new model for technologically enabled environmental monitoring and prediction to understand and protect the Lake George ecosystem and freshwater ecosystems around the world.]

What did you want to know?

Stressors on an ecosystem rarely act alone. For example, the spread of chemical contaminants like salt is generally associated with land-use changes. Increased use of road salt for deicing has elevated the salinity of many freshwater ecosystems and this contamination often occurs in areas where humans have caused changes in forest tree composition due to logging and fire suppression. For wetland ecosystems, changes in the diversity and abundance of trees can have dramatic effects. Leaf litter is food for many freshwater organisms, and different species of leaves provide unique resources (think about the chemicals that come from different tea leaves) and can alter the chemistry of wetlands. For example, red maple leaf litter contains high levels of soluble carbon that can darken the water. We wanted to know how the stress of salt contamination and changing leaf litter resources interact.

How did you go about it?

We conducted a large-scale, outdoor experiment using 48 tanks that each contained 130 gallons of non-chlorinated well-water. To each tank, we added either black oak leaves, red maple leaves, or no leaves (as a control) with or without road salt. We added sodium chloride road salt at four different concentrations (no salt added, 100, 200, and 800 milligrams of choloride per liter  or “mg/L”). After adding salt and the leaves, we introduced bacteria, fungi, and algae to all tanks. We also added animals that commonly live in wetlands surrounding Lake George, including two species of tadpoles (American toads and wood frogs), snails, and zooplankton. We followed the growth and development of all organisms for 1.5 months.

What did you learn?

In experimental tanks without salt, the presence of red maple leaves reduced the survival, mass, and development of American toads compared to tanks with oak leaves or no leaves. In contrast, both oak and red maple leaves increased the mass of developing wood frogs. By itself, salt had no effects on the amphibians. When we examined other species in the food web, we found that high concentrations of salt combined with red maple leaves caused a sharp decline in the abundance of some zooplankton species, which led to a subsequent increase in the algae that the zooplankton normally consume. Our results indicate that, by itself, road salt contamination only harms the wetlands when it is present at very high concentrations (i.e., above 200 mg/L, which is more than 10 times higher than Lake George but within the concentrations observed in many streams and wetlands). Importantly, however, these effects depend on which species of trees surround and drop their leaves into the wetlands each fall. The species of trees that are present, of course, often depends on human activities including logging, fire suppression, and the introduction of invasive pests that can kill particular species of native trees.

The research, titled Leaf litter mediates the negative effect of road salt on forested wetland communities,” can be found with the DOI: doi/10.1086/692139

 

[We hope you enjoy this letter of appreciation and advice which graduating Rensselaer senior Christina Akirtava wrote to her “RPI Family.”]

My father always told me “Don’t be ordinary, be extraordinary.” With these words in mind, I tried to make every day at Rensselaer Polytechnic Institute count. Of course there were days I enjoyed with friends, or spent outside instead of doing work; however, all of my actions led to a well-balanced undergraduate experience that makes me the confident person I am today.

Being a first-generation child raised in the United States left me in the dark about a lot of things. Scrambling to understand the undergraduate application process was rather daunting. Yet, four years ago, I was lucky enough to have been accepted to Rensselaer to study bioinformatics and molecular biology.  At first, I wasn’t thrilled about going to school only 90 minutes away from home, and it rained on Accepted Students Day, which was not encouraging. But I grew to love being close to home and now cherish the Troy-Albany area. I learned a lot throughout my time here, and feel obligated to give my advice.

There are three major points I would like share: set goals; form connections with professors; and make supportive friends.

1. Set goals.

It is important to stay ambitious and have high standards. Going into Rensselaer, without any computational background, I knew the Institute’s unique bioinformatics program would be a challenge. As a result, I took extra steps to excel in my studies and registered for classes during summer and winter breaks. This allowed me to stay on top of my work and fit classes into my schedule that I would not have taken otherwise. By junior year, I had three required classes left for my major and completed minors in electronic arts and psychology. I also discovered a new passion as I earned a minor in astrobiology, which is one of the only five astrobiology programs offered in undergraduate schools in the country. Balancing different courses kept me sane and made me a more attractive candidate for other programs.

2. Form connections with professors.

The most valuable thing I learned from RPI is that connecting with your professors opens door you never knew existed. I realized this a bit late, but having support is essential. A famous quote I used to form my graduate essay was: ‘If I have ever seen further, it is by standing on the shoulders of giants.’ – Issac Newton. I was lucky enough to have Prof. Chris Bystroff as my undergraduate advisor, and professors Rick Relyea, George Makhatadze, and Donna Crone as mentors. My first research position was under Prof. Relyea. I worked alongside his team for the Jefferson Project of Lake George. Experiencing undergraduate research opened avenues I never thought possible. With the support of Prof. Makhatadze and Prof. Bystroff, I set up a one in a life time opportunity by landing a position under Dr. Winter at the Technical University of Dortmund, Germany Biophysics Lab. Taking a semester off to dive into pure research not only taught me endless biotechnical skills, but broadened my understanding of different cultures. I loved research so much, that coming back as a senior, I decided to apply for doctoral programs. Having grown close to several professors, I found unlimited support that I missed when applying as a high schooler. By the time interviews rolled around in January, I practiced enough mock interviews at the career center that I worried more about my interview outfits than the actual interview questions. Now with less than a month left to graduation, I am saddened to leave RPI, but excited to start the next chapter in my life. Pursuing my PhD at Carnegie Mellon in computational biology will be tough, but with endless experiences under my belt, I know I am well prepared. Looking back, my daily actions and connections with professors have kept my internal drive strong.

3. Make supportive friends.

As a last piece of advice, I want to stress the importance of surrounding yourself with supportive people. Having friends that will build you up and help you overcome stressful times is a must. So thank you to everyone who has been my friend, mentor, or advisor during my undergraduate career. Without your endless support, I would not have reached the heights I am at today.

P.S. Sleep whenever possible.

Sincerely, Christina Akirtava

[The Jefferson Project at Lake George is conducting ongoing research into how human activities may be affecting the lake. This guest blog by Bill Hintz, a post-doctoral research associate in the lab of Jefferson Project Director Rick Relyea, summarizes recent research published in the journal Ecological Applications. The Jefferson Project is a collaboration between Rensselaer, IBM Research, and The FUND for Lake George, founded to develop a new model for technologically enabled environmental monitoring and prediction to understand and protect the Lake George ecosystem and freshwater ecosystems around the world.]

What did you want to know?

We wanted to know how the most commonly used road salt, sodium chloride, affects organisms found in lake food webs, which contribute to important ecosystems services including water clarity, water quality, recreation, and fishing. Because species in a food web are all interconnected, an impact on one species can have a domino effect on other species in the food web. For example, if road salt affects a species in one part of the food chain (e.g., fish or zooplankton), this may initiate a chain of events that indirectly affects many other species. Scientists call this a “trophic cascade.” In our study, we wanted to know if road salt at different concentrations can trigger such a chain of events in lake food webs.

How did you go about it?

We conducted a large-scale, outdoor experiment using 40 tanks that each contained 275 gallons of Lake George water. To each tank, we added 200 pounds of sand and a layer of leaves to mimic the bottom of a lake. We added common species that live in Lake George including different species of algae, zooplankton, fingernail clams, snails, crustaceans, and fish. We then exposed the tanks to one of five concentrations of road salt: 15, 100, 250, 500, and 1000 milligrams of chloride per liter. Each salt concentration was replicated four times and the experiment ran for 83 days.

What did you find out?

We discovered that high salt concentrations in the presence of fish caused dramatic changes in the food web including a large reduction in the abundance of zooplankton, triggering a trophic cascade. Given that zooplankton eat algae, the decline in zooplankton due to salt caused an increase in algae, which reduced water clarity. Moderate to high salt concentrations also reduced the abundance of filamentous algae, which can be important habitat for many lake organisms. At the highest salt concentration, we observed a 92 percent reduction in the abundance of one crustacean species (i.e., amphipods), which are an important food source for many fish. High salt concentrations also increased the mortality of fingernail clams and a non-native snail species, but had positive effects on a native snail species. The two highest salt concentrations had positive effects on the growth of the fish. In summary, road salt caused widespread impacts throughout the food web, but these effects only occurred at concentrations of salt that were more than 10 times higher than the salt concentrations currently found in Lake George.

The research, titled Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length,” can be found with the DOI: doi/10.1002/eap.1487/

 


[The Jefferson Project at Lake George is conducting ongoing research into how human activities may be affecting the lake. This guest blog by Bill Hintz, a post-doctoral research associate in the lab of Jefferson Project Director Rick Relyea, summarizes recent research published in the journal Environmental Pollution. The Jefferson Project is a collaboration between Rensselaer, IBM Research, and The FUND for Lake George, founded to develop a new model for technologically enabled environmental monitoring and prediction to understand and protect the Lake George ecosystem and freshwater ecosystems around the world.]

What did you want to know?
We wanted to know how common road salts affect young trout found in streams, and which salts are the most toxic. Three of the most common road deicing salts are sodium chloride, magnesium chloride, and calcium chloride. Snow melt and stormwater runoff carries these salts off roads and eventually into streams. The contamination of stream ecosystems by road salts can negatively affect organisms in the streams. Given that young trout and salmon are hatching and growing in streams in the spring, it is important to know how road salts affect the growth of newly hatched trout.

How did you go about it?
We acquired newly hatched rainbow trout from a local hatchery and exposed them to five environmentally relevant concentrations of sodium chloride, magnesium chloride, and calcium chloride. These concentrations can be observed in streams of the Lake George basin and in streams around the world where road salts are applied. We exposed trout to road salts for 25 days as they grew and developed, and then weighed and measured them.

What did you find out?
Road salts had distinct effects on trout growth, but none of the salts affected trout development or resulted in death. Magnesium chloride did not affect trout growth at any concentration, which was interesting because it is thought to be the most toxic deicing salt to fish. The most common deicing salt, sodium chloride, did not affect trout growth at the lowest three concentrations, but reduced trout length by 9 percent and mass by 27 percent at the highest concentration, which is a concentration observed in highly contaminated streams. We found that calcium chloride had the greatest impacts on trout growth. At modest concentrations, it reduced trout length by 5 percent and mass by 16 percent. At the highest concentration, calcium chloride reduced trout length by 11 percent and mass by 31 percent. Our findings indicate that sustained high levels of road salt in streams could lead to smaller young trout, which may have implications for the health of recreational trout fisheries.

The research, titled “Impacts of road deicing salts on the early-life growth and development of a stream salmonid: Salt type matters,” can be found with the DOI: 10.1016/j.envpol.2017.01.040

Cell Graphs

by Mary Martialay on February 2, 2017

Could the same approach that mapped the Internet be used to identify tumor cells? Bulent Yener, who has devoted more than a decade of research to the idea, recently reviewed how his work and that of other researchers contributed to biomedical research in “Cell-Graphs: Image-Driven Modeling of Structure-Function Relationships,” published in the January edition of Communications of the Association of Computing Machinery. The above video, which accompanies the article, explains how Yener and other researchers used an unorthodox analysis of the interactions between cells to determine their function.

In the video, Yener, a Rensselaer professor of computer science and director of the Data Science Research Center, explains how he transferred the techniques he applied in working on a map of the Internet produced by Bell Labs in 1999 to systems biology:

I asked myself, what would grow like the Internet, in a selfish, decentralized, chaotic way? Maybe cancer has similar behavior. Can I build the map of a tumor, the graph of a tumor, can I show that graph is different than a tissue without a tumor. And that’s how it started.

Yener’s work, funded by the National Institutes of Health, begins with images of cells taken from a sample of tissue or an organ. By applying a variety of image processing techniques, researchers are able to obtain information about multiple aspects of the structural organization of the cells. Then, the cell graph technique uses graphing theory to determine the structure-function relationship of the cells by modeling the structural organization of that tissue/organ sample. Here’s how Yener describes the approach in the CACM article:

Its main hypothesis is that cells in a tissue/organ organize to perform a specific function. For example, the spatial distribution and interaction of cells in a salivary gland tissue is different than that of brain tissue since they perform very different functions. Thus, if one can understand tissue organization then one can successfully predict the corresponding function. The cell-graph technique deploys image processing, feature extraction and selection, and machine learning algorithms to establish a quantitative relationship between structure and function.

In a cell-graph, nodes represent the cell nuclei and pairs of nodes are connected by a link based on the spatial, chemical, or biological relationship between them. From this information, Yener creates a matrix, or graph, that represents the links between the nodes. In his vernacular, nodes are also called “vertices,” and links are also called “edges.”

Once I have this matrix, in this form, then I can do magic using math. From this matrix I can calculate more than 120 properties, or as we call them ‘features’ that are encoded in the table about the spatial relationships of these nodes or vertices. That’s where the power of graph theory comes from.

The properties Yener calculates denote the structural organization of the cells in the tissue or organ, and by applying various machine learning techniques to that information, he can classify, predict, or diagnose the functional state of the tissue based on that organization.

It’s a tool that makes it possible for people to discover existing relationships that are hidden to us.

Graph theory could be used to map any kind of complex relationship with multiple players. In his own work, Yener is enabling a shift from a reductionist approach – that dissects the system and then tries to put each piece together – to one based in computation.

 

 

(In this guest post, Devin Jones, a graduate student in the lab of Rensselaer biologist and Jefferson Project at Lake George Director Rick Relyea, discusses research results recently published in the journal Environmental Pollution. The research tests the effects of road salt and road salt alternatives alone and in combination with natural stressors on vernal pond communities. This research is part of the Jefferson Project – a collaboration between Rensselaer, IBM Research, and The FUND for Lake George – founded to develop a new model for technologically enabled environmental monitoring and prediction to better understand and protect the Lake George ecosystem and freshwater ecosystems around the world.)

Vernal pools­­—seasonal water bodies formed by the collection of water in small depressions of the terrestrial landscape—are vital habitats for wildlife and are an important energy source for the ecosystem. For example, the amphibians and invertebrates that use vernal pools as breeding habitats transfer energy from the aquatic environment to the terrestrial environment following metamorphosis. Also, vernal pools contain many species that interact through predator-prey and competitive interactions to form complex food webs.

Like other ecosystems, vernal pools are affected by human activities, and researchers working with the Jefferson Project at Lake George are interested in how they may be affected by de-icing road salts. More than 50 percent of all de-icing materials used on roads are made of sodium chloride (NaCl), and salt overspray and runoff into adjacent natural systems can change the physical and chemical environment. While the Jefferson Project is focused on the influence of increased salinity in Lake George, wetlands, streams, ponds, and vernal pools in the surrounding watershed have links to the Lake George food web.

Runoff carrying road salts from adjacent roads increases chloride concentrations in vernal pools. Much of our knowledge about the direct sublethal and lethal effects of chloride contamination comes from single-species toxicity tests conducted under laboratory conditions. Yet, we don’t fully understand how the increased salinity in vernal pools will interact with natural stressors (e.g., predator-prey and competitive interactions) of aquatic communities under natural conditions.

To investigate those effects, researchers turn to mesocosms – large tanks of water that can be used to simulate natural freshwater systems – at the Rensselaer Aquatic Facility. The collaborative effort explored how various concentrations of NaCl or a road salt alternative influenced vernal pool communities under different stressors.

To create semi-natural vernal pool communities in our outdoor mesocosms, we filled the tanks with water, and then added leaf litter to simulate the forest floor and algae and zooplankton collected from local ponds. Once the communities were established, we added wood frog and American toad tadpoles at constant densities.

Once we established the vernal pool communities, we altered two-thirds of them to create “stressor treatments.”

In the “competitive environment,” we doubled the density of tadpoles for each species. Amphibian egg masses contain anywhere from 600 to 1,200 embryos, and wood frogs may deposit over 50 egg masses in a single vernal pool. By doubling the density of wood frog and American toad tadpoles, we mimicked these high-density environments to simulate increased competition for food resources among tadpoles.

In the “predator environment,” we added caged dragonfly larvae. Dragonfly larvae are voracious predators of aquatic organisms and release kairomones — chemical signals released by predators following the digestion of prey— that permeate throughout the aquatic community. Caging the dragonfly larvae allows kairomones to saturate the mesocosm while preventing the dragonfly larvae from eating the tadpoles.

The remaining third set of mesocosms was a “no-stressor environment” and was not altered.

We then contaminated our vernal pool communities with three realistic concentrations of either NaCl or a road salt alternative made of NaCl, magnesium chloride (MgCl2), and potassium chloride (KCl). We compared the effects of these six road salt treatments to the outcomes of communities in mesocosms that received no salt additions.

If you’re doing the math, this experimental design included seven salt treatments crossed with three stressor treatments. These 21 treatment combinations were replicated four times for a total of 84 outdoor mesocosms.

Our experiments ran for 49 days, and during that time we discovered that NaCl and the salt alternative reduced the pH of our communities as salt concentration increased. At the highest concentration of the salt alternative and the two highest concentrations of NaCl, we observed lethal effects on the zooplankton of our communities. In communities exposed to the highest concentration of NaCl, the lower abundances of zooplankton led to an increase in the abundance of floating algae (their food source). Though we did not find a full trophic cascade in our systems, previous research has shown increased floating algae decreases the availability of light to the attached algae below, thus decreasing the abundance of important resources for grazers like tadpoles and snails. The below image shows a high salt pool on the left (with an increase in floating algae) and a no salt pool on the right.

We also observed reduced American toad tadpole activity in communities exposed to the highest NaCl concentration, a sublethal effect. Decreased activity may negatively impact resource consumption, slow time to metamorphosis, or even have long-term fitness consequences that appear following metamorphosis.

Although we found main effects of salt concentration and natural stressor within our communities, we found no evidence of road salts interacting with the stress of predation or competition.

This research was published as the “Investigation of Road Salts and Biotic Stressors on Freshwater Wetland Communities in the February 2017 issue of Environmental Pollution.

Freshwater ecosystems are commonly contaminated with multiple chemicals and pollutants. Understanding how the toxicity of contaminants changes with the presence of natural stressors allows researchers to predict how communities will be impacted under realistic conditions. By investigating the effects of road salts on vernal pool communities, members of the Jefferson Project are gaining a further understanding of how contaminants can impact freshwater ecosystems beyond single species, laboratory toxicity tests. Understanding what happens in the vernal pools may improve future predictions for the dynamics of the watershed, and how human activities will affect other freshwater communities worldwide.

 

(In this guest post, Aaron Stoler, a postdoctoral researcher in the lab of Rensselaer biologist and Jefferson Project at Lake George Director Rick Relyea, discusses how the Relyea lab investigates the impact of stressors on stream communities. This research is part of the Jefferson Project – a collaboration between Rensselaer, IBM Research, and The FUND for Lake George – founded to develop a new model for technologically enabled environmental monitoring and prediction to better understand and protect the Lake George ecosystem and freshwater ecosystems around the world.)

As use of de-icing salts on roads throughout North America increases, salt concentrations on land and in the water have dramatically increased. Snow melt carries salt away from the roads where it was deposited, and into streams that ultimately feed into lakes. As part of their research into the effects of road salt pollution on lake ecosystems, researchers from the Jefferson Project at Lake George have started chasing the problem upstream to the headwaters where aquatic contamination first occurs. In these small streams, salt levels can reach levels that are two orders of magnitude higher than in lakes. This is not life as normal for communities of organisms that are used to pure freshwater.

To understand the effects of road salt contamination in headwater streams, researchers are using artificial streams housed at the Cary Institute of Ecosystem Studies in Milbrook, New York. There, fellow Rensselaer postdoctoral researcher Bill Hintz and myself have partnered with senior scientist Emma Rosi-Marshall to explore how pristine stream communities change when exposed to increased concentrations of road salt.

If road salt contamination damages stream ecosystems, it could be very problematic for downstream lake ecosystems. Streams are not just the source of water for most lakes; they are also the source of many nutrients and food for fish and other species that live in the lakes. Streams collect organic material from the surrounding landscape, such as leaf litter, sticks, and the soil that erodes after a rainfall. Bacteria, fungi, and algae consume and degrade this material. In turn, bacteria, fungi, and algae serve as food for aquatic insects, which serve as food for small fish. This means that every fish that you catch in a lake is made up mostly of nutrients that were once on land.

The artificial streams we use to explore the impacts of stressors like salt on streams are simple but innovative: an oval-shaped trough (called a “raceway”) holds up to 60 liters of water, while a paddlewheel moves the water through the trough at a continuous speed. Only a few facilities in the world have such artificial streams, and the Jefferson Project is excited to make use of this rare resource.

To start the experiment, we seeded each trough with leaf litter, rocks, and insects collected from a natural stream at the beginning of autumn. We then contaminated the artificial streams with road salt. One month after contaminating streams, we measured activity levels of bacteria, fungi, and algae, and have also measured how multiple species of stream insects responded to the salt.

We have just completed our first experiment to assess the effects of road salt on stream ecosystems. Although we are still processing the samples, we’ve already seen some pretty stunning results. Within days after salt contamination, streams with high levels of salt were stained brown. We think this is a result of faster leaf litter decomposition in salt-contaminated streams. Faster litter decomposition means that more nutrients are available to microbes and insects. However, we found very few living insects in the high-salt streams, which suggests that high-salt levels are lethal to many freshwater insects.

Our team plans to replicate the study during the spring of 2017. In addition, we hope to continue the collaboration with the Cary Institute to further investigate how road salt contamination might interact with other stressful sources of pollution, such as pesticides, fertilizers, and pharmaceutical compounds. Combinations of contaminants are often found in natural systems and can have more harmful consequences on aquatic communities than contamination by individual contaminants. For example, our recently published research in the journal Environmental Toxicology and Chemistry showed some interactive and negative effects of combining a common insecticide with road salt in wetlands.

By examining the detailed effects of road salt in a variety of aquatic ecosystems, the Jefferson Project is uncovering how human activities affect both lakes and the larger surrounding landscape. In the future, this research will help to improve the management of human development in and around our natural ecosystems.