In the Great Lakes region, the word “eDNA” is never far from “Asian carp.” And for good reason. The technology was originally applied by Notre Dame scientists in response to the federal government’s need to discover—and ultimately control—the spread of this voracious invader.
But in the six years since, environmental DNA has become a commonly used tool for detecting fish and other aquatic organisms. Biologists in the UK use it to locate crested newts, Kentucky scientists use eDNA to monitor salamanders, and a city in Washington state even plans to use the technology to track an invasive snail threatening salmon habitats. And scientists see even greater potential on the horizon.
Think of eDNA as forensic detective work. When a silver carp, salamander, or other aquatic animal shed skin cells, they leave behind traces of their DNA. Using the method developed at Notre Dame, scientists can run water samples through a fine-meshed filter, separate DNA from any other microscopic particles, and determine whether any of the genetic material matches the species they are looking for.
“The importance of the method lies in its ability to detect the presence of recluse species or ones with population levels that make catching them difficult,” said David Lodge, a Notre Dame biologist and director of the team that developed this forensic method.
Most of the testing done so far has focused on finding the genetic material of a single species. But Lodge, Notre Dame professor Michael Pfrender, and their team are working on an approach that would allow scientists to map the aquatic life of an entire habitat by sequencing all the genes in a water sample. Although it wouldn’t replace the more time-intensive field studies, this strategy could help natural resource managers know where to target conservation efforts. Lodge received funding to develop a metagenetics approach from the Department of Defense and the National Science Foundation after early results of IISG-funded research revealed ways to strengthen eDNA sampling.
Despite its growing use, eDNA testing is not without controversy, especially when it comes to Asian carp. And the approach does have its limits. eDNA doesn’t tell scientists how many fish there are or whether they are alive or dead. The genetic material found in the water could also come from other sources. There could be feces from birds that fed on Asian carp elsewhere. And boaters and anglers could unknowingly be transporting DNA from one waterway to another.
Still, supporters say the technology has huge potential.
“Nothing is as sure as holding the fish in your hand,” Lodge said, “but the repeated findings and patterns of Asian carp eDNA make the alternative explanations for how the material got there less plausible.”
Scientists at the University of Illinois at Chicago have unearthed a species of Lake Michigan bacteria that may become a powerful weapon in the fight against tuberculosis. Found in the sediment off the coast of Milwaukee, the microbe’s medicinal power lies in the small compounds it makes to defend itself.
UIC researcher Brian Murphy and colleagues at the College of Pharmacy are still trying to pin down how the molecules attack the M. tuberculosis bacterium, but they know that the compounds display drug-like potency against a range of antimicrobial-resistant strains that rivals existing clinical treatments.
This study is part of a larger effort by Murphy and others to determine the disease-fighting potential of aquatic actinomycete bacteria. Current treatments for many diseases are built around the chemical defenses used by land-based bacteria, but a growing number of pathogens are now resistant to standard drugs. Results like these in Lake Michigan suggest that freshwater bacteria may create molecules that dangerous pathogens have yet to evolve defenses against, making the Great Lakes a potentially untapped reservoir of treatments for some of the world’s deadliest diseases.
To understand the potential of the lakes, Murphy has collected more than 600 strains of freshwater actinomycete bacteria with support from an IISG Discovery Grant. The size and diversity of the library will help reveal both whether these bacteria are significantly different than their land-based cousins and if strains found in different lakes produce unique chemical defenses.
This analysis is still underway, but Murphy and his team have already discovered that the makeup of actinomycete communities in Lake Huron varies both by location and depth, a diversity that makes the lake a potentially important site in the hunt for new cures.
Much like a gardener hopes that their scattered seeds will eventually bloom into a lush garden, Illinois-Indiana Sea Grant awards seed grants to projects that address some of the biggest concerns in the Great Lakes in the hopes that the initiatives will grow into something larger. These Discovery Grant projects—totaling over 40 since 2009—cover a broad range of topics, and their results help natural resource managers and policy makers preserve Lake Michigan and strengthen nearby communities.
So, what are these projects exactly? We’re glad you asked. Discovery Grant Projects II shines a light on unexpected and emerging contaminants in stream water. Other featured projects examine the market for domestic seafood and give Hoosiers real-time access to fish consumption advisories. And another still paints a clearer picture of how Asian carp are changing the food web in the Illinois River.
Download the first edition, Discovery Grant Projects, to learn about past research on water quality, aquaculture, biodiversity, and more. And visit our Research page to read more about past projects and get a peek at ongoing research.