This is a a problem that will go away once we make a full conversion
to biochar based soil management. It obviously cannot happen too
soon.
The biochar sequesters the nutrients until called upon and prevents
losses into the groundwater.
In the meantime we have no national will to do much because no one
appears to be getting hurt except the local sea life. Any comment of
mine is superfluous except to point out that it keeps getting worse as one would expect.
Biggest Dead Zone
Ever Forecast in Gulf of Mexico
Oxygen-deprived area
may be size of New Jersey, scientists say.
Christine Dell'Amore
National Geographic
Published June 24,
2013
A possibly
record-breaking, New Jersey-size dead zone may put a chokehold
on the Gulf of Mexico (map) this summer, according to a
forecast released this week.
Unusually robust
spring floods in the U.S. Midwest are flushing agricultural
runoff—namely, nitrogen and phosphorus—into the Gulf and spurring
giant algal blooms, which lead to dead zones, or areas devoid of
oxygen that occur in the summer.
The forecast,
developed by the University of Michigan and Louisiana State
University with support from the U.S. National Oceanic and
Atmospheric Administration, estimates a Gulf dead zone of between
7,286 and 8,561 square miles (18,870 and 22,172 square kilometers).
The largest ever reported in the Gulf, 8,481 square miles (21,965
square kilometers), occurred in 2002.
On the flip side,
the Chesapeake Bay—the country's biggest estuary—will likely
experience a smaller-than-average dead zone this summer.
The forecasts are made
using computer models, which are based on U.S. Geological Survey data
of nutrient runoff in U.S. rivers and streams.
National Geographic
talked to forecast contributor Donald Scavia, an aquatic
ecologist at the University of Michigan, about dead zones—and why
we should care about them.
What's a dead zone?
A dead zone, which
occurs in the oceans and Great Lakes, is an area usually in the
bottom waters where there's not enough oxygen to sustain life. It's
generally caused by algae stimulated by lots of agricultural
nutrients in surface waters. When nutrients enter the water, [they]
create an algal bloom. [When] the algae sink, bacteria start
decomposing them, which uses up the [available] oxygen. (Also
see "World's Largest Dead Zone Suffocating Sea [2010].")
During summer, what
you have is a stratified water column that inhibits oxygen from the
atmosphere getting down to the deep water. As the bacteria use up
oxygen, it's not being replenished, so oxygen concentrations decrease
until you get to two milligrams of oxygen per liter of water, which
is bad for fish. Below that, fish that can will leave that area.
Other organisms that can't [leave] die.
What are examples of
organisms that would die?
Animals that live on
the bottom. Worms, clams, the kind of things that fish like to eat.
Some fish may have trouble.
Why do we track and
study dead zones?
It's important because
most often those areas that become uninhabitable byfish, are
preferred habitat for fish. To draw on an analogy that's ironic, it
would be like taking thousands of square miles of land in the Midwest
out of production. People wouldn't like it.
So dead zones are an
invisible issue.
Yes. They're deep in
the bottom waters, and you can't see oxygen.
What was your reaction
to your finding that the Gulf of Mexico may have a record-breaking
dead zone?
To be honest, I was
expecting that, mostly because of reports of massive flooding in the
Midwest. The nitrogen and phosphorus in the floodwaters drive the
problem.
What's causing the
spring floods?
In recent history, the
number of larger and more intense storms has been increasing—most
climate models suggest storm intensity is going to continue.
(See "Global Warming to Create 'Permanent' Ocean Dead
Zones?")
Is the news that the
Chesapeake Bay's dead zone is small promising?
It's not really,
because people in the area are not doing enough nutrient
management—it was a dry spring. The amount of nutrients going into
systems is really dependent on rainfall. The more water you get, the
more nutrients you get going in there. The real management
issue—regardless of whether it's a wet or a dry year—is you've
got to keep the nitrogen and phosphorus on the land and not in the
rivers.
Is that mostly done by
state regulations?
It's actually mostly
controlled by the Farm Bill, the main funding mechanism for
conservation in agriculture. The problem with the Farm Bill is
there's far more money for supporting commodities and subsidies and
not enough into conservation. I'm not blaming farmers—farmers do
what the Farm Bill pays them to do—but we need a Farm Bill that's
smarter and supports more conservation programs. (The most recent
Farm Bill, which is updated every five years, was rejected by
the House of Representatives on Thursday.)
Do dead zones have
lasting effects on the environment?
There's a sense in the
Chesapeake, Lake Erie, and the Gulf of Mexico that repeated dead
zones are somehow making systems more sensitive to nutrients. For
instance, the same amount of nutrient load now is producing larger
dead zones than a decade ago. (See "Female Fish Develop
'Testes' in Gulf Dead Zone.")
We think it has
something to do with residual organic matter that's carried over from
one year to the next, or from the changing types of organisms living
in the ecosystem. (Also see video: "Did Gulf Spill Boost
'Dead Zone'?")
What should the public
know about dead zones?
The key thing is they
really have the potential to devastate the fishing industry—for
instance, shrimp in the Gulf, walleye in the Great Lakes, and striped
bass in the Chesapeake Bay. The solution is really to be more
aggressive in dealing with pollution coming from agriculture.
This Q&A has been
edited for length and content.
2 comments:
Yeah, it's amazing how fast things can get to FUBAR, when you blow -up an oil well and nuclear plant at Fukishima Diachi... ;)
Fantastic!
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