LISTSERV mailing list manager LISTSERV 16.5

Help for SCIENCE-FOR-THE-PEOPLE Archives


SCIENCE-FOR-THE-PEOPLE Archives

SCIENCE-FOR-THE-PEOPLE Archives


SCIENCE-FOR-THE-PEOPLE@LIST.UVM.EDU


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

SCIENCE-FOR-THE-PEOPLE Home

SCIENCE-FOR-THE-PEOPLE Home

SCIENCE-FOR-THE-PEOPLE  June 2004

SCIENCE-FOR-THE-PEOPLE June 2004

Subject:

Dead Zones Increasing in World's Coastal Waters

From:

Wren Osborn <[log in to unmask]>

Reply-To:

Science for the People Discussion List <[log in to unmask]>

Date:

Thu, 17 Jun 2004 11:35:34 -0700

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (208 lines)

At least some are acting to reverse this trend.

Another reason to cut fossil fuel usage, increase sustainable organic
farming, vegetarianism, and encourage lower population growth.

I really have trouble understanding people who don't know the meaning
of finite.

An idea--suburban dwellers should have enough chickens to supply their
own eggs and a vegetable garden instead of a lawn.  The chickens can be
fed on kitchen scraps, which now are being ground up in the garbage
disposal for the ocean to deal with adding to the pollution of the
ocean, and produce (and pests) grown in the garden.  Think of the
benefits from eating their own eggs and food from the garden.  More
healthful, fresher vegetables, and probably cheaper.  The environment
would benefit from less transportation resulting in  less pollution and
less large scale fertilization (the suburbian can use the chicken
manure and compost anything the chickens don't eat).

Wren Osborn


http://www.earth-policy.org/Updates/Update41.htm

June 16, 2004-10

Copyright  2004 Earth Policy Institute

Dead Zones Increasing in World's Coastal Waters

Janet Larsen

As summer comes to the Gulf of Mexico, it brings with it each year a
giant
"dead zone" devoid of fish and other aquatic life. Expanding over the
past
several decades, this area now can span up to 21,000 square kilometers,
which is larger than the state of New Jersey. A similar situation is
found
on a smaller scale in the Chesapeake Bay, where since the 1970s a large
lifeless zone has become a yearly phenomenon, sometimes shrouding 40
percent of the bay.

Worldwide, there are some 146 dead zones-areas of water that are too
low in
dissolved oxygen to sustain life. Since the 1960s, the number of dead
zones
has doubled each decade. Many are seasonal, but some of the low-oxygen
areas persist year-round.

What is killing fish and other living systems in these coastal areas? A
complex chain of events is to blame, but it often starts with farmers
trying to grow more food for the world's growing population. Fertilizers
provide nutrients for crops to grow, but when they are flushed into
rivers
and seas they fertilize microscopic plant life as well. In the presence
of
excessive concentrations of nitrogen and phosphorus, phytoplankton and
algae can proliferate into massive blooms. When the phytoplankton die,
they
fall to the seafloor and are digested by microorganisms. This process
removes oxygen from the bottom water and creates low-oxygen, or hypoxic,
zones.

Most sea life cannot survive in low-oxygen conditions. Fish and other
creatures that can swim away abandon dead zones. But they are still not
entirely safe-by relocating they may become vulnerable to predators and
face other stresses. Other aquatic life, like shellfish, that cannot
migrate in time suffocate in low-oxygen waters.

Dead zones range in size from small sections of coastal bays and
estuaries
to large seabeds spanning some 70,000 square kilometers. Most occur in
temperate waters, concentrated off the east coast of the United States
and
in the seas of Europe. Others have appeared off the coasts of China,
Japan,
Brazil, Australia, and New Zealand.

Coastal Dead Zones Around the World

[SEE WEPAGE]

Source: UNEP, GEO Yearbook 2003 (Nairobi: 2004), compiled from Boesch
2002,
Caddy 2000, Diaz et al. (in press), Green and Short 2003, Rabalais 2002.

The world's largest dead zone is found in the Baltic Sea, where a
combination of agricultural runoff, deposition of nitrogen from burning
fossil fuels, and human waste discharge has overfertilized the sea.
Similar
problems have created hypoxic areas in the northern Adriatic Sea, the
Yellow Sea, and the Gulf of Thailand. Offshore fish farming is another
growing source of nutrient buildup in some coastal waters.

Forty-three of the world's known dead zones occur in U.S. coastal
waters.
The one in the Gulf of Mexico, now the world's second largest, disrupts
a
highly productive fishery that provides some 18 percent of the U.S.
annual
catch. Gulf shrimpers and fishers have had to move outside of the
hypoxic
area to find fish and shrimp. Landings of brown shrimp, the most
economically important seafood product from the Gulf, have fallen from
the
record high in 1990, with the annual lows corresponding to the highly
hypoxic years.

Excess nutrients from fertilizer runoff transported by the Mississippi
River are thought to be the primary cause of the Gulf of Mexico's dead
zone. Each year some 1.6 million tons of nitrogen now enter the Gulf
from
the Mississippi basin, more than triple the average flux measured
between
1955 and 1970. The Mississippi River drains 41 percent of the U.S.
landmass, yet most of the nitrogen originates in fertilizer used in the
productive Corn Belt.

Worldwide, annual fertilizer use has climbed to 145 million tons, a
tenfold
rise over the last half-century. (See data.) This coincides with the
increase in the number of dead zones around the globe. And not only has
more usable nitrogen been added to the environment each year, but
nature's
capacity to filter nutrients has been reduced as wetlands are drained
and
as areas along riverbanks are developed. Over the last century, the
world
has lost half its wetlands.

In the United States, some of the key farming states like Ohio, Indiana,
Illinois, and Iowa have drained 80 percent of their wetlands. Louisiana,
Mississippi, Arkansas, and Tennessee have lost over half of theirs. This
lets even more of the excess fertilizer farmers apply flow down the
Mississippi River to the gulf.

There is no one way to cure hypoxia, as the mix of contributing factors
varies among locations. But the keys are to reduce nutrient pollution
and
to restore ecosystem functions. Fortunately, there are a few successes
to
point to. The Kattegat straight between Denmark and Sweden had been
plagued
with hypoxic conditions, plankton blooms, and fish kills since the
1970s.
In 1986, the Norway lobster fishery collapsed, leading the Danish
government to draw up an action plan. Since then, phosphorus levels in
the
water have been reduced by 80 percent, primarily by cutting emissions
from
wastewater treatment plants and industry. Combined with the
reestablishment
of coastal wetlands and reductions of fertilizer use by farmers, this
has
limited plankton growth and raised dissolved oxygen levels.

The dead zone on the northwestern shelf of the Black Sea peaked at
20,000
square kilometers in the 1980s. Largely because of the collapse of
centralized economies in the region, phosphorus applications were cut
by 60
percent and nitrogen use was halved in the Danube River watershed and
fell
similarly in other Black Sea river basins. As a result, the dead zone
shrank. In 1996 it was absent for the first time in 23 years. Although
farmers sharply reduced fertilizer use, crop yields did not suffer
proportionately, suggesting they had been using too much fertilizer
before.


While phosphorus appears to have been the main culprit in the Black Sea,
nitrogen from atmospheric sources-namely, emissions from fossil fuel
burning-seems to be the primary cause of the dead zones in the North and
Baltic seas. Curbing fuel use through efficiency improvements,
conservation, and a move toward renewable energy can diminish this
cause of
the problem.

For the Gulf of Mexico, curbing nitrogen runoff from farms can shrink
the
dead zone. Applying fertilizer to match crop needs more precisely would
allow more nutrients to be taken up by plants instead of being washed
out
to sea. Preventing erosion through conservation tillage and changing
crop
rotations, along with wetland restoration and preservation, can also
play a
part.

Innovative programs such as the American Farmland Trust's Nutrient Best
Management Practices Endorsement can reduce the common practice of using
too much fertilizer. Farmers who follow recommendations for fertilizer
application and cut their use are guaranteed financial coverage for
potential shortfalls in crop yields. They save money on fertilizer
purchases and are insured against losses. Under test programs in the
United
States, fertilizer use has dropped by a quarter.
With carefully set goals and management, it is possible for some dead
zones
to shrink in as little as a year. For other hypoxic areas (especially in
the Baltic, a largely enclosed sea with slower nutrient turnover),
improvement may take longer, pointing to the need for early action. For
while dead zones shrink or grow depending on nutrient input and climatic
conditions, the resulting fish dieoffs are not so easily reversed.

Copyright  2004 Earth Policy Institute

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
May 2001
March 2001
February 2001
January 2001
December 2000
November 2000
October 2000
September 2000
August 2000
July 2000
May 2000
April 2000
March 2000
February 2000
January 2000
December 1999
November 1999
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
September 1998
August 1998
July 1998
June 1998
May 1998

ATOM RSS1 RSS2



LIST.UVM.EDU

CataList Email List Search Powered by the LISTSERV Email List Manager