February 2016 AIS Spotlight
Letter from the Director
Dear friends –
Just like phosphorus or nitrogen, aquatic invasive species are pollutants that affect the quality of our lakes, rivers, and wetlands. They negatively impact our ability to enjoy our state’s natural resources as well as the ecosystems and wildlife that these waters support. In some places, they are even interfering with our ability to ensure clean drinking water for residents.
That’s precisely why we at MAISRC are pleased to see AIS included as a top-priority issue at the Governor’s Water Summit later this week, and why I was happy to accept the invitation to help plan the event. It will bring together a wide variety of stakeholders, including water quality experts, farmers, legislators, and interested members of the public, and will help guide the administration’s water agenda for the coming years.
Our collective efforts in the fight against AIS have been gaining momentum, but it’s still not enough to get the job done right. It’s important to let the Governor know that as a state, we need to be smarter about our work to prevent and manage AIS; a task we cannot do without increased and sustained funding of our efforts. Specifically:
- Prevention efforts need to be effectively and efficiently targeted toward the highest risk species and toward areas with the greatest risk of being infested. Research is needed to help determine these risks and to inform government decision-making so that the right policies are created and enforced.
- Networks of citizen scientists, such as AIS Detectors, are needed to ensure that new infestations of AIS are detected as quickly as possible. This needs to be paired with truly rapid control responses at all levels. MAISRC is working to improve early detection tools, and with its science-driven partnership with University of Minnesota Extension, is working with partners around the state to empower this kind of action.
- AIS control tools are needed where they don’t currently exist, and we need to improve existing controls to ensure they’re fulfilling their potential. Research into use of herbicides, for example, can ensure we’re not inadvertently poisoning our waters or spending our limited resources on efforts that do more harm than good.
The building blocks for all of this work are in place. Agencies are engaged, lakeshore associations are empowered, and we now have an institution dedicated specifically to research AIS solutions for Minnesota. For us to do our job, however, an investment in dedicated and ongoing financial support is needed. Can we count on you to let the Governor know?
We are committed to advancing the knowledge and building the capacity that Minnesota needs to reduce the impacts of aquatic invasive species on our cherished lakes, rivers, and wetlands to ensure that these waters, which belong to all Minnesotans, are protected for now and for future generations.
Dr. Susan Galatowitsch
Director, Minnesota Aquatic Invasive Species Research Center
Predicting the spread of starry stonewort in Minnesota
When starry stonewort – an invasive alga that can grow tall and dense while displacing native plants and interfering with recreation – was found on Minnesota’s Lake Koronis this summer, many feared that the effects would be monumental. Starry stonewort has yet to appear elsewhere in Minnesota, and MAISRC researchers wasted little time to better understand the threat posed by this nuisance species.
In order to determine which lakes are most at risk of invasion, MAISRC researchers Luis E. Escobar, Daniel Larkin, and Nicholas Phelps teamed up with Dr. Huijie Qiao, an expert in invasion ecology and biogeography at the Chinese Academy of Sciences in Beijing, to perform species distribution and ecological niche modeling of starry stonewort.
Researchers evaluated occurrences of starry stonewort in its native range of Europe and Asia as well as its introduced range of New York, Michigan, Indiana, Wisconsin, and Minnesota. They focused on examining the relationship between where starry stonewort is successfully invading and broad climate variables such as annual mean temperature, minimum temperature of coldest month, annual precipitation, and precipitation seasonality.
By characterizing what constitutes ideal environmental conditions for starry stonewort across the landscape, researchers were able to predict areas of suitable habitat in North America where it could potentially invade and persist if introduced.
“One of the most notable things we discovered through this modeling is that in the United States, starry stonewort is persisting in novel habitats – meaning that it is occurring in areas here that are climatically distinct from its native range,” said Dr. Larkin. “This could explain why it’s typically rare and sometimes even endangered in much of its native range but can act very aggressively here. It seems that conditions in portions of the upper Midwest and other regions in the U.S. are ideal for its growth and spread.”
The next step in this research is to focus in more specifically on Minnesota, taking into account more localized landscape and climatic variables. Researchers will look at the invasion risk for specific lakes, and will also investigate how climate change could impact the susceptibility of lakes in the future.
“Identifying areas of risk is crucial to inform prevention and early detection efforts when spring and boating season return,” added Dr. Phelps. “You can’t manage and prevent these invasive species on a hunch. We have to really know which areas are most at risk and stay one step ahead.”
The maps and accompanying numerical tables with estimated physiological tolerances will be completed this month. They will not only serve as a baseline for future research on this species in its invasion and native range, but will also be provided to the Minnesota Department of Natural Resources to inform prevention and early detection.
Major milestone reached in effort to sequence the draft zebra mussel genome
The Minnesota Aquatic Invasive Species Research Center is partnering with the U’s Genomics Center to do something that’s never been done before: sequence the zebra mussel genome.
This work, which kicked off in the fall, recently reached an important milestone: the Genomics Center completed the first step of generating sequences from billions of short fragments of the DNA, which were originally extracted from a single, 4-centimeter long zebra mussel.
This process, done using a technology called “Illumina paired-end sequencing,” generated roughly 1.5 billion high-quality chunks of data – or “reads” as they are called – an excellent outcome, according to project lead Dr. Michael McCartney. On the downside, however, was the finding that zebra mussels appear to have DNA sequences that are repeated over and over in their genomes. This was the case when another bivalve mollusk, the Pacific oyster, was sequenced, and it presents a challenge when it comes to assembling the reads into a complete genome.
To overcome the problems that repetitive DNA pose, researchers at the Genomics Center are also using a technology that generates sequences from fewer, but longer, fragments of DNA. The information learned from this work will be analyzed by bioinformatics experts at the Supercomputing Institute, thanks to recently received funding from the U’s Informatics Institute. Together, this diverse group of researchers hopes to generate a full-length draft of the genome within several months.
By genetically “typing” hundreds of mussels according to thousands of DNA markers, and by mapping these markers in reference to the draft genome, researchers Michael McCartney and Sophie Mallez will be able to determine the origin of the mussels in prominent lakes that are already infested, such as Mille Lacs and Minnetonka. They also hope to identify important routes of spread that can be targeted for prevention. In the future, with additional funding and partnerships, this research could also reveal genetic weaknesses in the species that could be targeted or manipulated for control efforts.
New eDNA degradation results suggest high potential for false negative detections of Asian carp, other species
With the publication of a new paper this month, MAISRC researchers announced new discoveries about the decay rates of environmental DNA (eDNA) and what it means for the detection of aquatic invasive species.
eDNA – genetic material that is released by an organism into its environment – can be used to detect a species without physically capturing it, making it popular for researchers who are studying rare or hard-to-find species. In Minnesota, the process has been used as scientists work to establish the presence of Asian carp in the Mississippi River watershed.
Using common carp as a surrogate for Asian carp in the lab, MAISRC researchers discovered that eDNA degrades very quickly in lake water: approximately 90% of it was undetectable after 24 hours under most conditions. This finding means that the chances of a false negative eDNA result — failure to detect a species when it is present — are perhaps greater than previously thought.
The researchers also found that temperature and water chemistry, specifically the concentration of dissolved organic carbon, affected the persistence of eDNA. Using previously published data on eDNA distribution in lakes, these results indicate that eDNA would be expected to persist for almost two weeks in winter as opposed to a few days in summer.
“This discovery doesn’t change the fact that eDNA is still a good method for detecting AIS,” said Eichmiller. “But it does impact how we interpret the readings.”
To learn more about this research, read the full paper “Effects of Temperature and Trophic State on Degradation of Environmental DNA in Lake Water,” here.
In lakes and rivers across the state, fish kills – localized die-offs of fish and other aquatic species – are an unfortunate reality. These events can be caused by oxygen depletion, overpopulation, or infectious diseases, which is what piqued the interest of MAISRC and fish health researcher Dr. Nicholas Phelps.
If infectious diseases can cause die-offs in native fish, might they cause die-offs for invaders as well? In fact, could we even use this approach to control invasive fish like Asian and common carp?
To further assess this approach, the Phelps lab has been working to characterize the virome of silver, bighead, and common carp. The virome – essentially a snapshot of all the viruses in a fish, whether problematic or not – is giving researchers, for the first time ever, a baseline understanding of what viruses exist in carp. Phelps is collecting samples from randomized sites in Minnesota, as well as from known fish kills across the country.
Samples of carp were gathered from lakes in Minnesota as well as the Chicago, Fox, and Illinois Rivers, where silver carp have become prolific. These samples are processed in the lab for virus isolation, followed by realtime PCR and next generation sequencing.
“Basically, we are conducting molecular tests that will give us a full list of viruses in each species of fish, with the hope of discovering a brand new virus that is only found in carp and which could be used as a very species-specific biocontrol,” Phelps said.
So far, approximately a year and a half into the project, two novel viruses have been identified from common carp and grass carp mortality events: novel picornavirus and novel paramyxovirus. The previously known grass carp reovirus (GCRV) was also confirmed, which was the first report of GCRV associated with fish mortality in the United States.
“Further down the road if we discovered a species-specific pathogen, we could theoretically grow the virus in a lab and release it to a lake or river where the carp are congregated to infect them,” Phelps added. “The virus can replicate itself and spread quickly – it would be like a kid with a cold at daycare.”
In addition to providing opportunities for biocontrol, understanding the virome of invasive species will serve as a potential early indicator for the movement and distribution of pathogens that may threaten native species.
Upcoming invasive carp forum featuring MAISRC researchers
MAISRC researchers Dr. Peter Sorensen and Dr. Adam Kokotovich will both be presenting at an upcoming forum on invasive carp. The forum, which brings together stakeholders from the University, the Minnesota DNR, nonprofit organizations, and the public, will be held on March 10.
Dr. Sorensen will be providing the group with an update about using deterrents such as sound barriers and water velocity at locks and dams, and Dr. Kokotovich will discuss an invasive carp risk assessment that will include a gathering of nationwide Asian carp experts earlier that week. Stay tuned for future updates on this risk assessment.
Join MAISRC for a ribbon-cutting ceremony
Please join University President Eric Kaler, Dean Brian Buhr, and MAISRC Director Susan Galatowitsch on March 2 to celebrate the opening of the newly renovated Minnesota Aquatic Invasive Species Research Center laboratory, a project made possible through funding from the 2014 Minnesota Legislature, the Environment and Natural Resources Trust Fund, and the Clean Water Fund. Read more details here.
Get an inside peek at the new lab, which will be home to cutting-edge research on zebra mussels, curly-leaf pondweed, heterosporis, Asian carp, and more.
Heavy appetizers will be served; please RSVP here or call (612) 626-1412 by Monday, February 29, 2016.
Parking is available in the Gortner Ramp (the MAISRC lab is directly southwest of the ramp).
Save the date for the 2016 Minnesota Aquatic Invasive Species Research and Management Showcase
Mark your calendars for Thursday, September 22 and plan to join MAISRC on campus for our third annual Research and Management Showcase! Watch our e-newsletter and our website for more information, including how to register and breakout session topics.
We did it! MAISRC reached its goal of raising $4,400 to purchase important new equipment in time for the 2016 field season.
Thank you to the Ada Lake Association, Association of Cass County Lakes, Big Marine Lake Association, Green Lake Property Owners Association, PLM Lake and Land Management Corp., Whitefish Area Property Owners Association, and the ten individuals who donated anonymously!
With this support, we will be able to buy a new car-top jon boat and a new boat motor to replace a failing one. This will help MAISRC researchers continue their research on Eurasian watermilfoil, emerging fish diseases like heterosporis, zebra mussels, carp, and more.
If you missed out on this fundraiser, you can always support MAISRC online. Researchers at MAISRC are working tirelessly to protect Minnesota’s precious lakes and rivers from aquatic invaders, and we’re so grateful you’re by our side. Thank you!