Crabs and other marine animals can become
contaminated with toxins from algal blooms.
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Rebecca Heisman is a science writer who lives
in Walla Walla, Wash. This is her first article in
Cropping algal blooms
in the bud
Local state governments, farmers, and scientists are working together to change things
for the better. Johnson hopes that if managers succeed in turning things around for
Lake Erie, the methods they develop can help
other water bodies affected by algal blooms.
In 2012, Canada and the United States
signed an agreement to set new phosphorus
limits for the Great Lakes, and the crisis in
Toledo in 2014 added new urgency to the
issue. The new phosphorus targets were
next step is to develop action plans to make
those targets a reality. Ohio, Michigan and
the Canadian province of Ontario are moving
faster than their respective national govern-
ments, setting accelerated timetables for
reducing phosphorus pollution.
Today, the U.S. Department of Agriculture
is providing farmers in the western Lake Erie
basin with financial incentives to help reduce
phosphorus runoff from agricultural fields.
Farmers can better manage the timing and
amount of fertilizer they apply to reduce the
amount of excess phosphorus. They can also
slow the flow of nutrient-laden runoff from
their fields by planting cover crops, or crops
planted primarily to reduce erosion, in the
off-season. Adding extra strips of vegetation
around the edges of fields also helps to hold
soil and water in place.
Algal blooms serve as a reminder of how
much people around the world rely on the
health of local aquatic and marine ecosystems, and what can happen when algae
bloom and damage these ecosystems. But
improved monitoring and more environmentally friendly farming practices could help
curb blooms in the future.
This was bad news for the people whose
livelihoods depended on the Dungeness
crab industry on the Pacific coast. Domoic
acid causes disruption in the brain and other
organs. High levels of the toxin can cause
short-term memory loss, seizures, and even
death. In response to the diatom bloom, offi-
cials had to close Dungeness crab fisheries
from Santa Barbara, Calif., to the Oregon
border, with dire economic impacts that are
still being felt today. S H U T
The 2014 Lake Erie
algal bloom lasted
for months, but it only
shut taps off for three
days. How did officials
clean up the water so
Toledo residents could
turn their faucets back
on? The local treatment
plant used activated
carbon to get rid of the
microcystins at the cost
of about $10,000 per day.
Activated carbon can
be made from a variety of
materials, including coconut shells, coal, and wood.
It is full of tiny pores that increase surface area and that allow water or
other liquids to flow through. Pollutants in the water, including microcystins,
cling to the surfaces of the carbon, or adsorb to it—not to be confused
with absorption, when one substance takes in another.
Researchers are also investigating how well potassium permanganate
(KMnO4) and biological filters work against the toxin.
Lake detox: Cleaning up