If we are what we eat, some lake fish, it turns out, are
made of maple leaves. These fallen leaves play an integral
role in the food webs of lakes.
It has long been thought that aquatic plants form the base
of a lake's food web. The energy they contain supports
life, from invertebrates to the largest sport fish. Now,
a study funded by the National Science Foundation's (NSF) Biological Sciences Directorate
shows that aquatic plants are receiving a little help from
trees along the shoreline.
Scientists Michael Pace and Jonathan Cole of the Institute
for Ecosystem Studies in Millbrook, New York, found that
a significant part of the aquatic food chain is supported
by organic matter ("food") that originates on
A building block of life, organic carbon is essential to
aquatic food webs. In lakes, aquatic plants produce this
carbon by harnessing the sun's energy through photosynthesis. Some of the carbon supports the growth of fish and invertebrate
In Lakes Peter and Paul at the University of Notre Dame
Research Center, scientists conducted tests to determine
whether lake plant production was enough to support resident
The short answer: it's not. Test results
show that aquatic plants don't produce nearly enough
food to support lake animals. Therefore, to survive and thrive, the
lake animals are dependent on inputs from the surrounding
Leaves and other organic matter that enter lakes, it turns
out, are ultimately incorporated into aquatic animals. That
maple leaves may eventually become perch, and that the vegetation
around a lake can have profound impacts on the animal life
within that lake, blur the boundaries between aquatic and
As naturalist John Muir once wrote, tug on one strand of
nature, and you'll find it connects to all others.
So it is, biologists are discovering, with life itself.
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