Dead lakes, too?
Dead zones are also found in the Great Lakes. A dead zone in Lake
Erie now happens every year in the lake’s shallow central area off
Cleveland. Factors contributing to Lake Erie’s hypoxic zone are low
water levels and fertilizer runoff from large farms. The lake’s
dead zone has expanded for the past seven years and now consumes the
oxygen in the deepest waters of the lake, the lowest 7.6 meters of
the 23-meter-deep lake. Scientists fear that it is affecting the
dynamics of the lake’s food web, including fish stock abundance and
production. Increased nutrient input to the lake, perhaps from forest
disturbance to clear fields for corn and other crops, caused
bottom-water anoxia and altered the lake’s diatom community
structure. According to a study done by Lisa Osterman in 2005,
seasonal dead zones in the northern Gulf of Mexico are not rare.
These existed since the 1800's, but have developed to an astounding
rate in modern days. This not only surprised Osterman, but also lead
to a launching of a large study in order to compare previous and
recent dead zones. The astonishing rate at which dead zones are being
created has become a problem for countless underwater creatures, who
have been displaced by the problems. The low-oxygen levels in the
deep has killed numerous life forms, such as catfish, skate, and
flounder. Iroquois settlement in the region died out in the 15th
century. But the ghostly remains of a dead zone still lurk in
Crawford Lake, waiting to surface should excess nutrients again be
added to its waters. States Ekdahl, “The eutrophic diatom
assemblage from the time of the Iroquois occupation remains in place,
primed for further nutrient input despite the hundreds of years that
have passed.” Will that be the fate of the Great Lakes, the Gulf of
Mexico, the Baltic Sea, and the Black Sea, hundreds of years after
we’re gone? Or will we use the insights we’ve gained to change
the future? Through the combustion of contemporary scientific
information, and willingness to accommodate life forms, individuals
may be able to adapt to a new life that will in turn save the lakes
from damage by dead zones.
By: Shaza Karam
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