Can you provide a bit more information on what the students will actually be doing?
Briefly, students will screen for the presence of environmental DNA (eDNA) from invasive fish species by filtering water from carefully identified sites on local waterways. Passing the water through a small pore filter will concentrate any cellular material present on that filter. The filter contents will be placed in a buffer solution to protect the DNA and sent to Cornell for analysis by quantitative PCR (qPCR). The qPCR analysis will test for the presence of species-specific DNA from several invasive fish species.
The use of qPCR to analyze the eDNA samples has several advantages:
- It provides a quantitative measure of species abundance, allowing the copy number of the eDNA target to be related to the number of fish present.
- DNA sensitivity can be precisely measured to single copy levels.
- The assay is very specific with the probes we have developed, and is capable of detecting an invasive species fish within a background of 160 -200 other resident fish. Under ideal conditions detection sensitivity is calculated to be one grass carp in a 50-acre pond 10 feet deep.
Are the result scientifically valid?
Yes. The work is stringently monitored with built in controls to insure that the results are meaningful. All assays are run in duplicate, and additional tests are done whenever there is a questionable result.
Does the water filtration have to be done at the collection site?
Not necessarily. The half-life of fish eDNA is 4-6 hrs at 22° C, longer if the sample is kept chilled on ice. Testing has shown that carefully handled and chilled water will give positive results 18 – 24 hours after collection, depending on local water conditions like temperature, water quality, and the abundance of the DNA in the water. Generally, samples can be collected and processed later that day in the classroom.
What does a positive eDNA qPCR test mean?
The eDNA signal relates to presence and abundance of fish at a given location. For example, strong signal suggests (but does not prove) the possibility of an established population of invasive fish, while a very low eDNA signal could represent a low level population at the site or a few or even a single transitory non-resident invasive fish that passed through the test site. A later repeat of the eDNA test would help resolve this question. If the signal is no longer detected then the original may have been the result of a transitory fish. If the signal remains upon subsequent sampling, the invasive species is likely still at the location and the signal may indicate an established population. An increase in signal would suggest that the population is expanding.
Will you provide information to help students understand the project?
We will provide introductory materials for students that will provide background information regarding the nature and extent of the invasive fish problem in the US, as well as teacher and student protocols placing the research project in a real world context and describing in detail how to carry out the project, from selecting sites to collecting and filtering the water samples to analyzing the qPCR results.
Will you provide supplies to enable students do the collections?
We will supply all the materials needed to do the collection and provide shipping back to Cornell. The qPCR will be done at Cornell and the results sent back to the school with clear information on how to interpret them. There is an online form (similar to the ASSET kit request site for those of you familiar with that program) for teachers participating in the program to reserve collection kits for specific dates. Timing is on a first come, first serve basis but we have enough kits so that date selection is generally not a problem.
Does the program pay for related travel, field trip expenses etc?
No. The program does not have the funds at this point to support field trips.
How long will the program continue?
We are currently funded by the USDA NIFA HATCH program until 2020.
Can students in grades 5 – 8 participate?
Yes. Elementary students have participated in the program with great enthusiasm and excellent results. Collection is easy and elementary students can understand the basic ecological concepts associated with the program. Individual teachers can tailor the use the educational materials and interpretation of results to meet the needs of specific grade levels.