Perilous Times and Climate Change
Millions of aquatic animals in land-locked Bolivia's river systems have
died in unusually cold weather during the ongoing winter.
by Staff Writers
Santa Cruz De La Sierra, Bolivia (UPI) Aug 31, 2010
Millions of aquatic animals in land-locked Bolivia's river systems have
perished in unusually cold weather during the ongoing winter.
The casualties include at least 6 million fish, thousands of
alligators, turtles and river dolphins, scientific reports cited by
Nature News said.
Losses of penguins were reported in Brazil and cattle deaths, affected
by a cold snap from the Antarctic, hit farmers in Paraguay.
The scientists' version of how the aquatic animals were decimated was
hotly contested by visitors to Nature News Web site, while official
Bolivian reports on the aquatic deaths were still awaited.
Bolivia is no stranger to extreme weather conditions as its geography
interacts with humid tropical conditions but the aquatic deaths took
scientists by surprise.
Tens of thousands of Bolivians who depend on the river resources face a
bleak future as officials try to work out how to deal with a developing
ecological crisis and its impact on the communities and national
economy.
The deaths came to light after a sudden cold spell during the Southern
Hemisphere's winter, which begins in late June and lasts to the third
week of September.
The region around the city of Santa Cruz de la Sierra, in the eastern
part of Bolivia, usually experiences warm subtropical climate.
Temperatures average 74 degrees Fahrenheit with 68 percent humidity.
Scientists who visited the affected rivers said Bolivia could be facing
its worst ecological disaster in recent history. They reported river
waters dotted with tens of thousands of dead fish, denying nearby
communities access to safe drinking water.
The trouble began after cold Antarctic air settled over the southern
cone of South America for most of July.
Water temperature in Bolivian rivers, normally about 59 degrees
Fahrenheit, dropped to about 39 degrees Fahrenheit and was matched by
the air temperature -- coldest since 36.5 degrees recorded in 1955.
Other experts cited by Nature News said shock caused by extreme cold
could cause the mass deaths among fish. "When fish die, it's usually
not a single stressor, but multiple stressors interacting," said Steven
Cooke, an aquatic ecologist at Carleton University in Ottawa. "So, if
cold shock or cooler temperatures are being implicated in mortality,
there's probably something else going on as well."
Other experts said pollution from the large-scale burning of of
farmland around Santa Cruz could also be responsible for aquatic deaths.
Officials said funding was awaited to conduct detailed research into
the aquatic deaths. Meanwhile, Bolivians in the affected areas are
hoping for government help with the cleaning of the river waters before
disease sets in.