Science to Achieve Results (STAR)

Organs-on-a-Chip: The Future of Chemical Toxicity Testing

By Tom Knudsen, Ph.D.

Illustration of a human brain on a computer chipLast week, my colleague Jim Johnson shared a blog post (Exciting Times for Toxicology: Creating New Predictive Models) about EPA’s leadership role to advance chemical toxicity research, including news that the Agency’s Science to Achieve Results (STAR) grant program will provide research institutions with up to $6 million each to further develop organotypic culture models (OCMs)—“organ-on-a-chip” microsystems. The grants support innovative research that will eventually model complex functions of the human system like metabolism, multicellular communication within a tissue or target organ, and how these multiscale systems change over time.

Today, I am excited to share the three institutions that will receive EPA support to advance this innovative work. The institutions and their work are highlighted below.

  • University of Wisconsin, Madison – Human Model Analysis of Pathways Center:
    The Center will research innovative cellular modeling methods to develop a broadly applicable set of tools for toxicity screening. Researchers will develop OCMs for functions within the liver, central nervous system and mammary gland with invasive carcinoma.
  • Vanderbilt University Resource for Organotypic Models for Predictive Toxicology:
    The Center will advance alternative methods of chemical toxicity testing using 3D cultures of tissues to reduce uncertainties regarding specific chemical exposures. The models will simulate a more accurate response in the liver, mammary gland, limb/joint formation, and placental tissues under different conditions and stressors.
  • University of Washington – Predictive Toxicology Center for Organotypic Cultures and Assessment of AOPs for Engineered Nanomaterials:
    The Center will develop innovative OCMs to evaluate potential toxicity in cells and organs following exposure to metal-based engineered nanomaterials within an adverse outcome pathway (AOP) model. The research will target airway tissues, kidney, liver, and testis. Models will also factor in lifestage and genetic background.

We believe that the “organ-on-a-chip” microsystems and models the centers develop will provide vital information to predict toxicity and chemical exposure within the human body and at different lifestages and provide data that further minimizes the lengthy testing involved with animal studies. Organotypic culture models have the potential to improve, evaluate, and extend computational models that are currently under development by our own scientists.

Research data will not only help explain how organs and tissues respond to various chemicals, but these models will ultimately be used to validate other predictive models such as EPA’s virtual embryo models which will advance our understanding of the potential links between chemical exposure and development, disease, or other responses.

For more information on OCM Research and our STAR grants, please see our fact sheet.

About the Author: Tom Knudsen, Ph.D. is a developmental systems biologist at EPA’s Center for Computational Toxicology. His research focuses on predictive models of developmental toxicity—building and testing sophisticated computer models. In addition to his research at EPA, Dr. Knudsen is an Adjunct Professor at the University of Louisville, Editor-in-Chief of the scientific journal Reproductive Toxicology, and Past-President of the Teratology Society. Read more about him and his work.

 

 

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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The Road to “Genius:” It All Started with Science

By Sherri Hunt

Sherri Hunt and Tami Bond for web (1)

MacArthur Fellow Tami Bond (left) and EPA Scientist Sherri Hunt

When I started at EPA back in 2003, my mentor, Darrell Winner and I, began working with a recently funded grantee of the Agency’s Science to Achieve Results (STAR) program, Tami Bond. She was my first insight into the projects EPA typically funds and we were extremely excited to follow her career as she investigated the effects of black carbon. Darrell and I would soon come to know Tami as a visionary and talented researcher that is changing the world with her ground-breaking research.

Over the past decade, EPA has supported Tami’s work through several grants issued to the University of Illinois where she has led projects investigating the complex relationship between black carbon and climate change. ​ A few months ago, she was awarded a 2014 MacArthur Fellowship. Also known as “genius grants,” these prestigious awards are given to individuals who have shown extraordinary originality and dedication in their creative pursuits. Her scientific curiosity and resourcefulness have helped her become a leading name in black carbon research.

When I think back on my past 11 years working with the EPA, Tami stands out in my mind as a great role model for innovative and visionary scientists all over the world. She is a dedicated scientist that isn’t afraid to tackle big problems, yet still brings an attention to detail unlike anything Darrell and I have ever seen.

Tami’s global approach to black carbon research is a prime example of her ability to conduct meticulous research to investigate the world’s global problems.

Black carbon, a particle created through the incomplete combustion of fossil fuels, biofuels, and biomass directly absorbs sunlight and reduces the reflectivity of snow and ice, accelerating ice and snow melt. It also contributes to the adverse impacts on human health associated with ambient fine particles, including cardiovascular and respiratory effects. Although there is still some uncertainty about black carbon, it is clear the reduction of black carbon emissions will bring both climate and public health benefits.

Early on, Tami had the forethought to look at the detailed analytical problem that exists between the scientific knowledge base surrounding black carbon and taking action on climate change. Thanks in large part to her work, we now know that black carbon offers a promising mitigation opportunity for addressing some near-term climate effects.

The MacArthur Foundation applauds Tami for her creative “beyond the laboratory” work combining engineering and public policy to provide “the most comprehensive synthesis of the impact of black carbon on climate to date.” Her research indicates that global black carbon emissions contribute to anthropogenic climate change much more than we previously thought.

Although solving this puzzle is a daunting one, I’m confident a dauntless scientist like Tami holds the key to understanding the specific climate impacts of black carbon and helping millions of people breathe cleaner air.

About the Author: Sherri Hunt, Ph.D., is the Assistant Center Director and Matrix Interface for the EPA’s Air, Climate, and Energy research program. She enjoys reading, running and connecting scientific experts to develop the next generation of work that will enable more people to breathe cleaner air.

 

Image courtesy of John D. & Catherine T. MacArthur Foundation.

Image courtesy of John D. & Catherine T. MacArthur Foundation.

EPA STAR Grantee and MacArthur Fellow Tami Bond, Ph.D. recently stopped by EPA’s Headquarters in Washington, DC and answered a few questions for us.

When did you first know you wanted to be a scientist?

I still don’t know if I want to be a scientist but I know I want to solve problems.

I grew up in Southern California which was very polluted at the time and it never occurred to me that that was weird. That there were days that you just couldn’t play outside and that was just the normal. After I had moved away, I was coming back to visit my parents. In Southern California there is a bowl of mountains and all of the Los Angeles pollution washes up against the mountains where my parents lived. As the plane was diving down into this cauldron of brown soot I just went “I have to do something about this.” That was my ‘a-ha’ moment.

I’m not sure I would consider myself a scientist really. I’m an engineer and I use scientific tools to solve problems.

Was there a moment when you knew you wanted to be an engineer?

I went to college for a year and then I left. I worked in an auto shop and I just wanted to learn a lot about cars because I thought they were cool. The environment in the auto shop was a little bit chauvinistic. So one day, I woke up and I decided I want to go to engineering school and then it just clicked. I figured I’m not going to work on cars – I’m going to design cars.

What do you like most about your research?

The ability to put things together. I enjoy the hard science and the discovery but we are still at a rewarding phase of scientific development. A lot of disciplines haven’t merged and people don’t know how to merge them. The notion that you can solve something using two or three different tools is fun.

What has the EPA STAR program meant to your work?

A lot. There are agencies that fund basic science but EPA is the one that really focuses on the use of basic science to tackle applied problems. And that’s what I’m attracted to — things that make a difference to people. I think I would be really frustrated if EPA or the STAR program didn’t exist.

What advice would you give to students who are interested in a career in science or engineering?

Learn the basics really well. Don’t worry about if it relates to what you want to do because everything will eventually relate to what you want to do.

What do you think our biggest scientific challenge is in the next 20/50/100 years?

This is probably not what you are expecting to hear but the ability to synthesize all the information that is flowing from the scientific community. We are generating knowledge at an amazing rate. A single person’s brain is not getting any more connections in it and yet the amount of information is growing exponentially. We need the ability to capitalize on the wealth of knowledge that we have already developed.

I can think of societal challenges like climate change or energy consumption that we’re going to have to tackle but I think that the challenge for scientists is in the way we do business so that we are able to tackle these challenges.

If you could have one super power, what would it be?

I would like to be able to become really small so I wouldn’t need to use instruments to look at particles.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Exposing the Missing Link: Advancing Exposure Science to Rapidly Evaluate Chemicals

By Tina Bahadori, Sc.D.

Compilation of images showing close up of hands cleaning, family preparing food, and children brushing teeth

 

Acknowledging that exposure is vital to understanding and preventing human and environmental risks, the National Academies of Science in its 2012 report, “Exposure Science in the 21st Century: A Vision and A Strategy,” called for characterizing exposures quickly and cost-effectively at multiple levels of integration—including time, space, and biologic scales—and for multiple and cumulative stressors. The report further emphasized the importance of scaling up methods and techniques to detect exposure in large human and ecologic populations of concern.

To realize this vision, our EPA researchers are leading the forefront of exposure science, developing and testing new paradigms to efficiently generate and collect exposure information. In one area, for example, we are rapidly estimating levels of exposure and developing models to evaluate chemical exposures across consumer products and chemical life cycle.

Just last year, our scientists published several scientific peer-reviewed journal articles about these pivotal efforts and publicly released their exposure estimation tools for anyone to use and to evaluate their utility. Put together as a suite of exposure science tools, the following three examples showcase how advances in our research have transformed exposure science in a very short time.

  • ExpoCast is a tool that implements a collection of models and data to provide high-throughput exposure estimations for thousands of chemicals. Evaluating both farfield and nearfield exposure routes, our tool has been used to develop exposure estimates for approximately 1,900 chemicals; these estimates can be used to prioritize chemicals with the greatest likelihood for exposure.
  • Stochastic Human Exposure and Dose Simulation High-throughput model (SHEDS-HT) produces estimates for thousands of chemicals in a more rapid and cost-effective manner. SHEDS-HT accounts for multiple routes, scenarios, and pathways of exposure to understand the total exposure to these chemicals while retaining population and life stage information.
  • Chemical Product Categories Database (CPCat) catalogs the use of over 40,000 chemicals used in different consumer products. The database compiles chemical use information from multiple sources while product information is gathered from retail stores’ public Material Safety Data Sheets (MSDS).

To further advance the vision for exposure science in the 21st century, EPA invited the academic research community through the Science to Achieve Results (STAR) program to develop and apply new methods and technologies to efficiently collect data that will support a more comprehensive understanding of the science. Recently, we awarded grants—totaling $4.5 million—to five universities to conduct innovative research to advance methods for characterizing real-world human exposures to chemicals associated with consumer products in indoor environments. I am greatly looking forward to the work produced by these ambitious research teams because the data collected and research results will provide much needed and otherwise absent exposure information, and will help advance the relevance and applicability of current models.

Since innovation and transformation occur most rapidly in collaborative environments, on February 3-4, 2015, we will be hosting an EPA Exposure Science in the 21st Century Grants Kickoff meeting to publicly announce the grant recipients and to germinate and facilitate collaborations among EPA exposure scientists and the grant recipients.

The grant recipients include these transdisciplinary teams:

  • University of California, San Francisco—Principle Investigator: Tracey Woodruff Ph.D.
  • Duke University—Principle Investigator: Heather M. Stapleton Ph.D.
  • University of California, Davis—Principle Investigator: Deborah H. Bennett Ph.D.
  • Virginia Tech—Principle investigator: John Little Ph.D.
  • University of Michigan—Principle Investigator: Xudong Fan Ph.D.

To quantify, manage, and prevent risk, we need both exposure and toxicity information. To this end, EPA’s Toxicity Forecaster (ToxCast) which screens thousands of chemicals for potential health effects has proven to be an invaluable resource. Combined with our advances in high-throughput exposure estimations, we are beginning to have a better understanding of the landscape of chemical exposures and how to prioritize them for potential environmental and human health risks.

Our research is still evolving—we hope to maintain this accelerated pace and continue to advance the leading edge of the science. But to ground our research in pragmatic and health protective solutions, we recently requested a new study by the National Academy of Science to provide guidance on how best to integrate these advances into risk-based evaluations.

I believe the time is ripe scientifically—with advances in biotechnology, computational biology and chemistry, informatics, and allied fields—to change the face of chemical risk assessments for existing chemicals, for selection of safer alternatives, and for innovating and designing modern materials and products. I am confident that our research in exposure science will provide the missing link that has long hindered these advances.

About the Author: Tina Bahadori, Sc.D. is the National Program Director for EPA’s Chemical Safety for Sustainability research program. Learn more about her on EPA’s Science Matters: Meet our Scientists web page.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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This Week in EPA Science

By Kacey FitzpatrickResearch Recap Graphic Identifier: Thanksgiving Edition

I come from a big family so on holidays – Thanksgiving in particular – the kitchen can get pretty hectic. This inevitably ends with someone breaking, spilling, or burning something.

While a burnt turkey would be a major disappointment to some of us, it’s the least of kitchen worries for nearly half of the people in the world, who rely on the use of open fires and traditional cookstoves and fuels to cook their food. Cookstove smoke is a major contributor to dangerous indoor air quality, affecting the health of millions.

EPA is an international leader in clean cookstove research and we’ve highlighted some of those efforts this week.

  • Clean Cookstoves Research: An Opportunity to Benefit Billions
    Bryan Bloomer, Ph.D. joined EPA Administrator Gina McCarthy and other prominent leaders this week at the first ever ministerial- and CEO-level Cookstoves Future Summit, “Fueling Markets, Catalyzing Action, Changing Lives,” in New York City.
    Read more.
  • EPA Clean Cookstove Research
    EPA provides independent scientific data on cookstove emissions and energy efficiency to support the development of cleaner sustainable cooking technologies. EPA also conducts studies to understand the health effects from exposure to emissions from cookstoves.
    Read more.

And here’s some more research that has been highlighted this week.

  • Highlighting the Health-protective Properties of Alaskan Berries (your Elders already knew)
    Regions of the Alaskan arctic tundra are considered to be on the ‘front lines’ of climate change. The climate exerts a decisive impact on terrestrial plants, including the wild indigenous berries that thrive even above the tree line, the most hostile environments throughout the state.
    Read more.
  • UMass Amherst Receives $4.1 million EPA grant for Drinking Water Research
    EPA award a grant of $4.1 million to the University of Massachuessets, Amherst to establish the Water Innovation Network for Sustainable Small Systems (WINSS), which will develop and test advanced, low-cost methods to reduce, control and eliminate various groups of water contaminants in small water treatment systems.
    Read more.

If you have any comments or questions about what I share or about the week’s events, please submit them below in the comments section!

 

About the Author: Student contractor Kacey Fitzpatrick is thankful for her new job writing about EPA research for the Agency’s Office of Research and Development.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Children’s Health: An Investment in Our Future

By Dr. James H. Johnson Jr.

Group of children at school

Children’s health is our best investment.

Although children make up 30 percent of the population, they are 100 percent of our future. As a former college professor, I’ve had the distinct honor of serving as an educator and mentor to many, many young people, and there is no greater personal or professional pleasure than watching that kind of investment grow.

Children's Health MonthToday marks the beginning of Children’s Health Action Week at EPA, and I’m thrilled to kick off a number of blog posts we will be sharing about what is without a doubt one of the greatest investments we make in our nation’s future: children’s environmental health research.

In 1998, EPA, together with our partner at the National Institute of Environmental Health Sciences (NIEHS), established the EPA/NIEHS Children’s Environmental Health and Disease Prevention Research Program (Children’s Centers), one of the most successful public health research programs in the world. The program funds multi-disciplinary, community- and university-based research centers that together serve as a network of top experts and practitioners in children’s environmental health.

The Children’s Centers program fosters collaborative research that connects scientists, social scientists, pediatricians, public health professionals and community organizations all focused on a single overarching goal: to improve the health and environments of children. Together, their work has led to groundbreaking research results. Examples include:

The Centers are explicitly designed to match researchers with public health experts and caregivers so that the results of their work quickly and effectively reach those who can put it into practice and protect children wherever they live, learn and play.

For the past 16 years, EPA has invested over $130 million (matched by NIEHS) to fund more than 30 Children’s Centers.

This week, EPA is not only celebrating the great strides we have made in children’s health research, but we are also recommitting ourselves to our overall mission of ensuring safe and healthy lives for all children. The Children’s Centers are providing the research that will help parents and mentors achieve that. It is a rewarding investment.

Please join me in celebrating children’s health week and 16 years of scientific achievement by learning about how EPA and its partners are providing a better world for our children, today.

About the Author: Dr. James H, Johnson Jr. is the Director of EPA’s National Center for Environmental Research, which runs the Agency’s Science to Achieve Results (STAR) program as well as other grant, fellowship, and awards programs that support high quality research by many of our nation’s leading scientists and engineers.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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This Week in EPA Science

By Kacey Fitzpatrick

Research recap graphic identifier, a microscope with the words "research recap" around it in a circleFor most of the U.S., access to clean drinking water is as easy as turning on the faucet. In fact, a lot of hard work has gone into making sure our waterways are healthy and the water we drink is safe. Forty years ago, Congress passed Safe Drinking Water Act and since then EPA has contributed an incredibly vast amount of research to protecting human health by safeguarding the nation’s public drinking water supply—you might say it’s an ocean’s worth.

We and others highlighted a lot of water-related EPA research this past week. And an EPA-grantee was named a recipient of a MacArthur Foundation “Genius” awardee! Below is this week’s “EPA research recap.”

  • Prescription for Trouble? Studying Pharmaceuticals in Wastewater.
    Due to human excretion and people flushing unused pills, pharmaceuticals can end up in the wastewater stream, presenting a challenge to the nation’s wastewater treatment plants. EPA researchers are studying pharmaceuticals in wastewater to help protect the nation’s waterways. Researchers designed a model to estimate potential concentrations of active pharmaceuticals in treated wastewater. Read more.
  • Tri, Tri, Tri Again for Clean Water
    Recently, the Washington DC area experienced storms and heavy rainfall that caused a combined sewer overflow and sent a mixture of sewage and stormwater into the Potomac River. This caused the swim portion of the Nation’s Triathlon to be canceled due to unsafe water quality. EPA works to promote green infrastructure practices to help minimize and prevent stormwater events that can threaten public health, all while protecting the quality of rivers, streams, and lakes. Read more.
  • EPA engineer led effort to reduce wastewater pollution along the Arizona-Mexican border
    Raw and partially treated sewage has flowed persistently for years across the border from Nogales, Mexico into neighboring Nogales, Arizona. Through a decade of hard work, Thomas Konner, an EPA engineer, was instrumental in leading the U.S. effort to upgrade the wastewater infrastructure along the border and greatly improve the water quality and the environment. Read more.
  • Green Island and the Hyporheic Zone: Why Restoration matters
    Large river floodplains present diverse benefits to communities, yet management strategies often fail to consider the broad suite of ecosystem services provided by these systems. EPA is evaluating the benefits associated with restoring large river floodplains, specifically levee setback and revetment removal. This effort will provide scientific support for community-based environmental decision making and support restoration efforts. Read more.
  • Detection of Silver Nanoparticles in Vadose Zone Environments
    Use of nanoparticles is quickly increasing within the global marketplace as a result of their beneficial use in science, medicine, engineering and technology.However, very little is known about the effects that the increased and widespread use could have on the environment. EPA and Oklahoma State University have partnered to research and determine the effects. Read more.
  • EPA Grantee Tami Bond Named 2014 MacArthur Fellow
    The University of Illinois professor did a comprehensive study of how human-produced soot (black carbon) is affecting the atmosphere, illuminating how it is one of the leading contributors to climate change and standardizing how researchers measure and describe it. Bond received her first EPA “Science to Achieve Results” (STAR) grant in 2003, and currently has two other projects supported by the program. Read more.

Looking forward, next week is “Climate Action Week” and we’ll be featuring how EPA researchers are working to support taking action on climate change.

If you have any comments or questions about what I share or about the week’s events, please submit them below in the comments section!

About the Author: Writer Kacey Fitzpatrick is a member of the science communication team in EPA’s Office of Research and Development as a student contractor.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Nutrient Management: Always on My Mind

By James R. Mihelcic, PhD, BCEEM

EPA-grantee and guest blogger James R. Mihelcic

EPA-grantee and guest blogger James R. Mihelcic

I am inspired to solve the complex problem of nutrient (nitrogen and phosphorus) management every day.  I think about solving this problem when I tend my winter garden of lettuce and peppers, around my neighborhood as I watch stormwater race from lawns to the Hillsborough River, in the classroom, and when I spend time outdoors enjoying our nation’s waters.

And I am in good company with my thoughts. You see, the National Academy of Engineering has identified managing the nitrogen cycle as one of their Grand Challenges.

I even started my New Year by canoeing in the Chassahowitzka National Wildlife Refuge and got to thinking about nutrients.  This was because some of the springs that feed the refuge have developed the tell-tale signs of nutrient pollution (green, slimy-looking plant growth) from on-site wastewater generation and lawn runoff from surrounding homes.  On that day we were also welcomed into the winter home of a group of manatees.  Manatees depend on sea grass for survival, and excessive nutrients cloud coastal waters, preventing sea grass growth. 

With support from an EPA Science to Achieve Results (STAR) grant, we established our Center for Reinventing Aging Infrastructure for Nutrient Management, which is transforming my daily thinking to everyday reality.  We are reimagining aging coastal urban infrastructure systems to consider nutrient recovery and management that contribute to sustainable and healthy communities.

Manatee at a U.S. Wildlife Refuge, Florida. Image courtesy of U.S. Fish and Wildlife Service.

Manatee at a U.S. Wildlife Refuge, Florida. Image courtesy of U.S. Fish and Wildlife Service.

I have great expectations for our Center research and demonstrations.  Our goals are to develop the science behind new technology and management innovations, and to develop a deep understanding of integrated systems.  We will demonstrate and assess innovations to provide new knowledge for students, community members, practitioners, and other stakeholders.

We are even transforming how we educate new engineers. For example, our new textbook, Environmental Engineering: Fundamentals, Sustainability, Design integrates sustainability and nutrient concepts into every chapter, and has the potential to reach over 10,000 undergraduate engineers every year.

Our research will benefit the public because poor water quality lowers the economic, social, and environmental value of our nation’s waters for current and future generations. 

In Florida, our springs, rivers, estuaries, coastal waters, and the Everglades all suffer because of nutrient pollution.  We have already come up with some ways to help manage nutrient pollution while also meeting the agricultural needs to provide national and global food security. For example, we have shown that 22% of the global demand for phosphorus could be met if we just recovered this valuable resource from domestic wastewater. We’ve also shown how wastewater infrastructure that serves a rapidly urbanizing world can be integrated with recovery of valuable water and nutrients to improve food security.

You can see why nutrients are always on my mind.  I hope they are now on yours.

About the author: EPA-grantee and guest blogger James R. Mihelcic is a Professor of Civil & Environmental Engineering and State of Florida 21st Century World Class Scholar at the University of South Florida (Tampa), where he directs the Center for Reinventing Aging Infrastructure for Nutrient Management

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Braving the Weather to Promote Green Infrastructure in Philadelphia

Reposted from “EPA Connect, the official blog of EPA’s leadership

 

CEQ Chair and EPA Deputy Administrator brave the snow.

Council on Environmental Quality Chair Nancy Sutley and EPA Deputy Administrator Bob Perciasepe brave the snow in Philadelphia.

 

By Bob Perciasepe 

Yesterday, I was up in Philadelphia joined by CEQ Chair Nancy Sutley and Mayor Nutter to announce nearly $5 million in EPA grants made possible through the Science to Achieve Results (STAR) program. These investments are going to five universities, and aim to fill gaps in research evaluating the costs and benefits of certain green infrastructure practices.

The projects to be invested in, led by Temple University, Villanova University, Swarthmore College, University of Pennsylvania and University of New Hampshire, will explore the financial and social costs and benefits associated with green infrastructure as a stormwater and wet weather pollution management tool.

read more…

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Studying Plant and Insect Response to Environmental Change: A Love Story

By Jessica Dawn Pratt

EPA Fellow Jessica Pratt examines sagebrush.

EPA STAR Fellow Jessica Dawn Pratt

As a native Midwesterner, I was not impressed with the brown and shrubby coastal sage scrub ecosystem that covered hillsides around my new home when I moved to southern California in September of 2005. It was drab, short and prickly compared to the northern hardwood forests to which I was accustomed.

But, as an ecologist, I was excited to live in a “biodiversity hotspot,” a place that rivals the species diversity of many tropical forests and is home to numerous endemic and endangered plant and animal species.

I quickly learned that September was the end of the summertime drought that characterizes California’s Mediterranean climate. As I watched the brown and shrubby hillsides come to life with the winter rains, I fell in love with the coastal sage scrub ecosystem.

In addition to being incredibly diverse and unique, the coastal sage scrub ecosystem also faces many threats, including development, habitat fragmentation, pollution, climate change, invasive species, and wildfire. So, in 2008 when I began the Ph.D. program in Ecology & Evolutionary Biology at the University of California, Irvine, I was determined to work on questions related to its conservation and restoration. A Science to Achieve Results (STAR) Fellowship from EPA allowed me to do just that.

My graduate research examines how California sagebrush (Artemisia californica), an icon of the coastal sage scrub ecosystem, is responding to environmental changes like climate change and nitrogen pollution, and how the response of this important plant species affects the animals that depend on it.

It is my hope that understanding how important species respond to environmental change – and how those responses “scale up” throughout the ecosystem to affect other species – will help us predict and mitigate the impacts.

The first part of this work, published online in Global Change Biology and summarized on UC Irvine’s web site, shows that sagebrush in the southern part of its range will adjust better to climate change than sagebrush in the north.

To determine this, plants collected from a 400-mile stretch of coastal California were grown in experimental plots in Orange County where we tested their response to altered precipitation. Populations from southern sites, where year-to-year rainfall amounts have historically been rather variable, were more flexible to altered precipitation than populations from the north, where precipitation has been more predictable. The findings indicate that a species’ response to climate change won’t always be equal across its range.

Moreover, we saw that year-to-year variability in rainfall at weather stations across the species range is increasing more rapidly in the north, in the very regions where plants may be the least able to tolerate this effect of climate change. As such, including southern sagebrush in northern restoration plantings may be one way to ensure that we give this species an opportunity to adapt to our changing climate.

As we move forward with habitat conservation and restoration in this era of change, it may be prudent to consider the flexibility of the plants that we use in such endeavors so that the greening up of California’s shrubby hillsides each fall may continue long into the future.

About the Author: Jessica Pratt is a Ph.D. Candidate in Ecology & Evolutionary Biology at the University of California, Irvine. Her research examining plant and insect community responses to environmental change in Southern California is funded through the EPA’s STAR Fellowship Program.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Discovering Silica Cycling

By Joanna Carey

Rivers draining more forested watersheds contain significantly less silica than those draining more developed watersheds.

I am standing, engrossed in quiet, on a wooden bridge in Northern Massachusetts, with a perfect view of the Ipswich River.  I can see it meander once before it eventually opens up to form a babbling riffle. This river is alive, performing complicated metabolic processes as the water moves downstream.

Thanks to my EPA Science To Achieve Results (STAR) Graduate Research Fellowship, I went to this bridge (among others) weekly for a year, sampling the river for nutrients. While filtering my water samples here, people walking by would often ask, ‘how is the river doing?’

Before answering, I would hesitate; it turns out this is a complicated question!

From a human health perspective, most of the rivers I studied were in fine shape (thanks to the Clean Water Act and EPA), meaning that people could swim in the river without getting sick. However, other aspects of the river condition could use improvement.

Human activities, such as wastewater discharge, use of fertilizers, and fossil fuel combustion, are increasing the amount of nutrients flowing into rivers, which can spark excess algal growth and other negative repercussions on the entire ecosystem.

As an EPA STAR Fellow, I had the opportunity to be one of the first in the world to examine how watershed land use impacts the amount of silica in the rivers. Silica, or SiO2, is a required nutrient for diatoms, a common type of phytoplankton (tiny photosynthetic organisms) in temperate waters.

Why is the amount of silica in the rivers important?

Well, it all goes back to the fact that rivers supply over 80% of the silica that’s found in marine waters. And the amount of silica directly controls the amount and type of phytoplankton that grow in the ocean. Because phytoplankton makes up the base of the marine food chain, their type and abundance directly impacts organisms higher up on the food chain, such as commercial fisheries.

My research resulted in the discovery that land use type is indeed an important driver of the amount of silica in rivers.

I found that rivers draining more forested watersheds contain significantly less silica than those draining more developed watershed, which may be because of the large amount of silica taken up by land plants. It appears that lack of vegetation in urbanized landscapes results in more silica entering river systems. While more silica in rivers is not a bad thing, the research highlights a previously unrecognized way in which human actions are altering the environment.

For the last three years, I have been honored to be an EPA STAR Fellow. The award not only allowed me to perform the research of my dreams, but highlighted for me the importance of these fellowships for training the next generation of scientists. Thanks to the EPA, I can now count myself among the experts in aquatic biogeochemistry!

About the Author: Joanna Carey, a former STAR Fellow, is currently an ORISE post-doctoral fellow with the EPA Atlantic Ecology Division in Narragansett, RI studying the impact of oysters on nitrogen cycling in Southern New England.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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