Ocean dead zones have nearly quadrupled since 1994
Coastal ecosystems threatened worldwide by nutrient-rich runoff
Jeremy Hance, mongabay.com
April 3, 2008
Coastal areas worldwide are suffering from over-enrichment of their waters by nitrogen and phosphorus, finds a new
study from the World Resources Institute (WRI). This over-enrichment, known as eutrophication, causes numerous
environmental problems, eventually devastating coastal environments. In overly nutrient-rich waters phytoplankton,
micro- and macroalgae grow to excessive portions; these 'algal blooms' diminish subaquatic vegetation, damage coral
reefs, and deplete populations of fish, shellfish, marine mammals, and sea birds. In the worst case scenarios the
massive algal blooms form hypoxic or dead zones due to loss of oxygen in the water, essentially condemning the
ecosystem.
Eutrophication is human-caused. The culprits are agricultural fertilizer, domesticated animal manure, industrial and
urban runoff, sewage, and atmospheric nitrogen. These waste products have caused nitrogen and phosphorus to triple
in coastal areas in the last fifty years alone. In Europe and the U.S. fertilizer and manure are the main sources,
because much of their sewage is treated before entering the water system. In regions like Africa, Latin America, and
Asia where sewage and industrial waste are rarely treated, these wastes provide larger sources of nitrogen and
phosphorus.
The study found 415 sites
globally that are suffering
from eutrophication. In
Europe 65 percent of its
Atlantic coast suffers from
eutrophication in some
degree or another. The news
is worse for the United States:
78 percent of the assessed
areas showed eutrophication.
"A significant portion of the
world's population - nearly
half of which lives within 40
miles of a coast - is
vulnerable to harmfully overenriched ecosystems," said
Mindy Selman, lead author of
the study. As well as marine
animals, the problem greatly
This map identifies 415 eutrophic and hypoxic coastal systems worldwide. Of these, 169 are documented
affects human communities,
hypoxic areas, 233 are areas of concern and 13 are systems in recovery. The map is based on research
which rely on the coast and its
conducted by WRI’s NutrientNet program and Dr. Bob Diaz at the Virginia Marine Institute.
resources for their livelihoods.
Agriculture, growing industry, fossil fuel combustion, and population growth are together causing significant
For example, according to the
growth in areas receiving nitrogen and phosphorous end flows. Over the past 50 years, nitrogen flux has
study a massive algae bloom
doubled and phosphorus has tripled, according to the Millennium Ecosystem Assessment. These cumulative
in 1998 cost Hong Kong $40
changes are, quite literally, choking coastal waters around the world.
million USD as it wiped out
almost the entirety of Hong Kong's fish farms.
Hypoxic regions have risen rapidly in less than two decades. The last count showed 44 dead zones in 1994. The WRI
study found 169. Two infamous hypoxic regions are the Gulf of Mexico, fed by the overly-enriched Mississippi, and the
Black Sea, which is currently recovering from a spike in fertilizer-use during the Soviet area.
Even these numbers: 415 areas globally effected by nutrient-rich runoff, 169 of which can be classified as hypoxic, are
under-estimations. The WRI was only able to take into account areas that possessed reliable data on their water. "The
number of degraded coastal areas around the world is sure to be a much greater problem than even our study of 415
areas suggests," Selman said. The report states that Africa, Latin America, the Caribbean, and Asia do not monitor
their coastal water-quality closely.
The study recommends the first step in confronting this problem is increasing research on eutrophication, including
studies in areas that lack information. The study also urges global society to become more aware and involved.
"Eutrophication is an issue that requires greater attention by governments and society in general. Left untouched, it
may have dire consequences for many ecosystems, the food webs that they support, and the livelihoods of the
populations that depend on them."
Cuyahoga River Fire
www.ohiohistorycentral.org
On June 22, 1969, industrial pollutants on the Cuyahoga River caught fire in Cleveland, Ohio, drawing national
attention to environmental problems in Ohio and elsewhere in the United States. The Cuyahoga River Fire lasted just
thirty minutes, but it did approximately fifty thousand dollars in damage -- principally to some railroad bridges spanning
the river. It is unclear what caused the fire, but most people believe sparks from a passing train ignited an oil slick in
the Cuyahoga River. This was not the first time that the river had caught on fire. Fires occurred on the Cuyahoga River
in 1868, 1883, 1887, 1912, 1922, 1936, 1941, 1948, and in 1952. The 1952 fire caused over 1.5 million dollars in
damage.
On August 1, 1969, Time magazine reported on the fire and on the condition of the Cuyahoga River. The magazine
stated,
Some River! Chocolate-brown, oily, bubbling with subsurface gases, it oozes rather than
flows. "Anyone who falls into the Cuyahoga does not drown," Cleveland's citizens joke
grimly. "He decays". . . The Federal Water Pollution Control Administration dryly notes:
"The lower Cuyahoga has no visible signs of life, not even low forms such as leeches and
sludge worms that usually thrive on wastes." It is also -- literally -- a fire hazard.
As a result of this fire, Cleveland businesses became infamous for their pollution, a legacy of the city's booming
manufacturing days during the late 1800s and the early 1900s, when limited government controls existed to protect the
environment. Cleveland and its residents also became the butt of jokes across the United States, despite the fact that
city officials had authorized 100 million dollars to improve the Cuyahoga River's water before the fire occurred. The fire
also brought attention to other environmental problems across the country and helped lead to the passage of the Clean
Water Act in 1972.