Long-term water quality trends in Midwestern lakes yield
good news in the form of little change in water clarity in the regions 3,000
lakes. But what makes this news unique is that the data to make this determination
was collected by non-scientists and local residents from the area’s towns and
villages.
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The data to support the study, which is published in the
journal PLOS ONE, has come directly from lakefront homeowners, boaters, anglers
and other interested members of the public with a vested interest in the water
quality of these aquatic resources.
Noah
Lottig, of University of Wisconsin-Madison’s Center for Limnologya and co-author of the paper, says ecologists are looking at
big-picture issues including land use changes and the effects of climate on various scales. This particular study has been conducted with the help of local residents.
“This
study highlights research opportunities using data collected by citizens making
important environmental measurements,” says Elizabeth Blood, program
director at the National Science Foundation (NSF) Directorate for Biological
Sciences.
“Their efforts provide scientists with data at space and time scales often
not available by other means.”
Tens of thousands of Secchi disk readings demonstrate water clarity
Non-scientists using a circular, plate-sized instrument called a Secchi disk took the water clarity measurements they sought. These water clarity measurements had been logged and documented on state agency records and online databased.
Secchi disks, used in the aquatic sciences since the mid-1800s, hang from a rope and
are lowered into the water until their distinct black-and-white pattern
disappears from view. This distance marks the “Secchi depth” for water clarity. Previous studies have shown that local residents’ Secchi readings are nearly as accurate as scientists’ measurements, says Lottig.
Lake
associations and other groups have used the disks for decades to document
conditions in their respective waters.
With
a dataset covering more than 3,000 lakes and stretching back to the late 1930s,
the team decided to ask questions about long-term change.
Before
and after the Clean Water Act
The
Clean Water Act provided a useful frame of reference. Signed into law in 1972,
the act set water quality goals for all U.S. waters. Thanks
to the data collected by residents, Lottig’s team had access to water clarity
measurements for decades before and after the act came into effect. Somewhere
in that data, the researchers reasoned, they might detect a landscape-scale
shift over time to clearer (often an indicator of cleaner) water.
Read
more at Research.gov.
Secchi Disk in use image via
Craftsbury Outdoor Center.