Printer Friendly

Fish fry.


Fishermen wouldn't have much trouble catching their fill in this Brazilian lake. The only problem is, all of these fish are dead.

What has caused Rey Lake to become jam-packed with belly-up fish? In the Amazon region, where Brazil is situated, the sun shines a lot. This causes the water in lakes and rivers to evaporate, or change from liquid to a gaseous water vapor. Usually, lots of water evaporates each day, but at the same time, there is plenty of rain to replace it, so the lakes stay full. In recent years, however, the Amazon region has been experiencing severe drought conditions, says James Eisner, a geography professor at Florida State University. With less-than-normal rainfall, there is not enough precipitation to replace the evaporating water. Result: Rey Lake is drying up. After a while, what little water remains becomes too muddy for the fish to get the oxygen they need to survive. The dead fish die and float to the lake's surface.

According to Elsner, the lack of rain may be due to a shifting of wind patterns caused by the warming of waters in the northern Atlantic Ocean. Normally, north-blowing winds and south-blowing winds meet in an area called the intertropical convergence zone, or ITCZ. Where these winds join, they produce rain and create thunderstorms. This zone used to be located above Brazil. Now, the ITCZ has moved northward to the Caribbean Sea.

Global warming, or the increase in Earth's average temperature, may be to blame for the warmer waters, says Elsner. If that's the case, more droughts are likely in the future. But there could be other explanations too, he says. For instance, warmer waters could be a normal part of the thermohaline circulation cycle, or a period of 20 to 30 years in which the Atlantic Ocean naturally warms and cools. If that's the case, residents of the Amazon simply need to wait for the balance of rain and evaporation to be restored.

With two or three good rainy seasons, the fish could be swimming in Rey Lake again, says Eisner.
COPYRIGHT 2008 Scholastic, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2008, Gale Group. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:GROSS OUT
Author:Moser, Jennifer
Publication:Science World
Date:Jan 14, 2008
Previous Article:Scorpions: friend or foe? Do scorpions deserve their bad reputation? One scientist finds out.
Next Article:Explain this!

Related Articles
Japan: frozen food consumption slips, as production and imports both dip: it's the worst it's ever been, with volume declining even though prices are...
Tough year for Japanese market again as both imports and consumption slide: domestic production gains, but just barely, and value of domestic output...

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters