ENVIRONMENT: Global Warming Threatens Marine Life
Rich Winkel
** Topic: ENVIRONMENT: Global Warming Threatens Marine Life//EMBARGOED// **
** Written 9:05 PM Jun 7, 1999 by newsdesk in cdp:ips.english **
Copyright 1999 InterPress Service, all rights reserved.
Worldwide distribution via the APC networks.
*** 07-Jun-99 ***
Title: ENVIRONMENT: Global Warming Threatens Marine Life//EMBARGOED//
/ATT EDITORS: The following item is EMBARGOED and must not be
printed, or otherwise reproduced before 1330GMT, Tues. June 8./
By Jim Lobe
WASHINGTON, Jun 8 (IPS) - As if overfishing and coastal pollution
were not destructive enough, global warming posed a potentially
lethal threat to many marine species, two major environmental
organisations reported Tuesday.
From tropical coral reefs to polar-ice edge communities, and
from tiny zooplankton to polar bears, scientists have documented
worrying declines in marine life which they believed could be at
attributed, at least partly, to the impact of global warming.
The new report, "Turning Up the Heat: How Global Warming
Threatens Life in the Sea" - compiled by the World Wildlife Fund
(WWF) and the Marine Conservation Biology Institute (MCBI) -
warned that whole species could be wiped out by warmer waters.
The report was based on an extensive review of studies and a
meeting earlier this year of some of the world's leading marine
researchers. It said that warmer surface air temperatures, which
most scientists blamed on the emission of greenhouse gases, also
were gradually warming the world's oceans.
Surface water temperature had risen by about one degree Celsius
over the past century and were expected to increase by up to
another three degrees in the next 100 years if emissions - caused
mainly by the burning of fossil fuels like oil and gas - continued
at current rates.
Marine life already was threatened by a number of human
activities, the report pointed out. Overfishing had resulted in
the collapse of major fisheries, and destructive fishing practices
like bottom trawling had devastated the habitat of the sea floor.
Coastal development and other activities that resulted in the
pollution of coastal waters had converted whole ares of the oceans
into so-called ''dead zones,'' while the invasion of alien
species, often carried in ships' ballast water to distant
habitats, has wiped out many native marine species around the
world.
''Global climate change is an additional stress on already
stressed species and ecosystems, and may be the 'straw that breaks
the camel's back' for many types of marine life,'' according to
the 47-page report.
The increasingly frequent appearance of the El Nino weather
phenomenon during the past 20 years provided a glimpse into the
impact that can be expected from long-term global warming, the
report said.
El Nino results from changes in atmospheric pressure in the
Pacific Ocean and is associated with higher sea surface
temperatures and sea levels, lower nutrients, and increased
intensity of storms and storm surges.
Recent El Ninos have proverd lethal to marine life, with the
death of up to 98 percent of coral reefs in some regions. El Nino
also has wreaked havoc in stocks of sardines and anchovies in
Perua, marine iguanas and kelp forests off California and some
species of seals, sea lions and seabirds.
Some scientists believe that global warming itself may be
increasing the frequency of El Nino.
It occurred in five of the first seven years of the 1990's, a
sharp increase from its pattern of the previous 7,000 years of
every two to 8.5 years. The 1997-98 El Nino was the strongest on
record.
Rising marine temperatures, according to the report, influence
all kinds of ocean conditions, including sea levels; upwelling,
which is critical to the survival of microscopic phytoplankton,
the base of the food web; and the circulation of the deep ocean
between the poles and the tropics.
Because polar regions will experience the greatest overall
temperature change from global warming, the biological impacts -
many of which have already been observed - will be greatest there.
Sea ice, which provides a platform for many marine mammals and
penguins, as well as a surface for algae that produce
phytoplankton, is diminishing in both the Arctic and the
Antarctic, according to the report.
''As this area diminishes, so does the food available to each
higher level on the web, from zooplankton to seabirds,'' the
report says. Penguins in Antarctica and Crabeater seals are
already declining in some areas as the ice recedes.
Reef fish and intertidal invertebrates , such as anemones, crabs
and snails in California provide evidence that fish and other
species are shifting toward the poles in response to ocean
warming, the report said.
In Europe, researchers also have observed a trend of species of
butterflies and birds to gradually move north to live out their
live cycle. A University of Leeds study found that
many bird species in Britain had moved an average of 12 miles to
the north over the past 20 years.
Coral reefs have proved to be particularly sensitive to
warming.
As surface temperatures have risen in recent years, many reefs
have bleached - meaning they expel the colorful algae that
produce the foods on which they rely - and, if temperatures remain
too high for too long and bleaching persists, the corals die.
That is happening around the world, according to the report. ''In
1998, the hottest year in at least six centuries, coral suffered
the most extensive and severe bleaching and subsequent mortality
in the modern record.''
New studies have found that Pacific salmon, especially sockeye,
are particularly vulnerable to temperature changes which affect
their metabolism. The warmer the water, the more food they need to
stay alive.
In 1997-1998, higher sea temperatures during the winter may
have led to the collapse of western Alaskan salmon populations,
according to the report which concluded that the Pacific sockeye
and other salmon species may soon be at risk of extinction.
Similarly, reductions in phytoplankton caused by warmer sea
temperatures have devastating effects on predators, such as
seabirds and marine mammals, at the top of the food web.
Scientists already have established a connection between warmer
water and declining reproduction and increased mortality among
different species of seabirds and seals and sea lions along the US
Pacific coast affected by the El Nino phenomenon.
(END/IPS/jl/mk/99)
Origin: ROMAWAS/ENVIRONMENT/
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