Back in the days
of classical biology, just about every grad student could select a puddle of
some sort and go forth and do a census.
That allowed one to punch one’s ticket as a professional. This will be way easier and it will allow us
to test thousands of lakes in particular.
It also sets the
stage for conducting complete census of waterways at least and acting on it if
justified. More important we are
entering a new regime for biology of resurrection biology for lost biomes and
lost species. This tool becomes critical
to step in and quickly detect invasives that need to be removed from freshly restored
refugia.
Generally this
is great news and figuring out how to do the same on land is a challenge.
Thousands of
fish ID'd from glass of water
Friday, 17 January 2014Jennifer Viegas
A glass full of
water is all fish detectives needed to identify approximately 13,000 fish
living in the larger body of water from which the sample was taken, report
researchers.
The secret is in DNA that water-dwelling organisms
regularly release into their environment.
"It might be unpleasant to think about when
going for a swim in the ocean, but the water is a soup of cells shed by what
lives there," says study lead author Ryan Kelly of theUniversity of Washington.
He explains that fish shed cells from their skin.
They and other organisms also release unneeded things, such as damaged tissues
and bodily waste.
"Every one of those cells has DNA and, if you
have the right tools, you can tell what species the cell came from," says
Kelly. "Now we're working to find the relative abundance of each species
present."
He and his colleagues tested the technique out at
the Monterey Bay Aquarium's 450,000 litre Open Sea tank, which is among the 10
largest aquarium exhibits in the world.
This tank was suggested because the inhabitants are
known and could be compared to what the new technique revealed was present,
giving the authors a way to judge the method's accuracy.
The approach successfully identified the eight
species of bony fishes in the tank and determined that tuna and sardines made
up the greatest amount of biomass in the tank.
The technique turned out to be so finely tuned that
it also picked up DNA from long-dead menhaden from the Atlantic Ocean, fish
that had been processed, transported and added to the tank as food.
It was a surprise when an Atlantic species turned
up, until the researchers realised where the DNA was coming from, and then they
made calculations to take that into account.
Out in the open water
The researchers next hope to try the technique out
in a natural setting: San Francisco Bay. It could be used in any number of
locations, however. The goal is to have an easier, more accurate marine life
census tool.
Once obtained, the resulting census info could then
be used to help scientists better monitor and manage aquatic habitats.
It could, for example, reveal the arrival of
invasive species before they become a major problem, or provide new ways to
look at marine food chains and other basic ecosystem
features.
The study is published in the online journal PLOS ONE.
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