|
|
|
Of course, zebra
mussel filtering can improve water clarity, making the water nicer to look
at. But as I said, filtering can also change plant and animal communities.
Each adult zebra mussel can filter about one liter of water per day but
based on zebra mussel densities in the western basin of Lake Erie, experts
calculate that zebra mussels filter all of the water in the basin once every
three days.
|
|
In some ways
that can be good. For example, in lakes Erie and St. Clair, rooted aquatic
plants have become established in areas where they have been absent for a
long time. In other areas, aquatic
plants are more dense than normal, and have extended into deeper waters
because the decrease in turbidity allows increased light penetration. But
increased clarity also open the door for invasive aquatic species, resulting
in lakes that look like the one in this photo.
|
|
Zebra mussels
have contributed to the increase in Lake Eries water clarity, which began
with the initiation of the phosphorus abatement programs in the 1970s.
According to Dr. Ruth Holland Beeton, who conducted research near Stone
Laboratory on Lake Erie in the 1970s before phosporus abatement programs,
water clarity was approximately 3 feet, improved to 6 to 10 feet in the 1980s
after a decade of reduced phosphorus inputs, and improved again to 10 to 17
feet in the early 1990s, after zebra mussels colonized the area.
|
|
|
|
|
