Oceans more vulnerable to agricultural runoff than previously thought, s...( Researchers have long suspected that fe...)

Researchers have long suspected that fertilizer runoff from big farms can trigger sudden explosions of marine algae capable of disrupting ocean ecosystems and even producing "dead zones" in the sea. Now a new study by Stanford University scientists presents the first direct evidence linking large-scale coastal farming to massive algal blooms in the sea.

Writing in the March 10 issue of the journal Nature, the authors conclude that some highly productive regions of the ocean are much more vulnerable to agricultural runoff than was previously assumed.

The study is based on satellite imagery of Mexico's Gulf of California, also known as the Sea of Cortez-a narrow, 700-mile-long stretch of the Pacific Ocean that separates the Mexican mainland from the Baja California Peninsula. The area is a hotspot of marine biodiversity and one of Mexico's most important commercial fishing centers.

"Biological productivity in most of the world's oceans is controlled by the supply of nutrients to the surface water," wrote the authors, who are all affiliated with Stanford's School of Earth Sciences. "The Gulf of California contains some of the highest nutrient concentrations in the oceans and sustains highly elevated rates of biological productivity."

In the gulf, wind-driven upwellings regularly bring nitrogen and other nutrients from the seafloor to the surface, stimulating the rapid reproduction and growth of microscopic algae called phytoplankton. These algal blooms are natural events that benefit life in the gulf by generating tons of phytoplankton-a major source of food for larger organisms.

But some phytoplankton species produce harmful blooms, known as red or brown tides, which release toxins in the water that can poison mollusks and fish. Excessively large blooms can also overwhelm a marine ecosystem by depleting oxygen in the water. Scientists suspect that many harmful blooms are artificially fueled by fertilizer runoff from farm
'"/>

Contact: Mark Shwartz
mshwartz@stanford.edu
650-723-9296
Stanford University
9-Mar-2005

Page: 1 2 3 4
Related biology news :

1. AAAS Oceans Panel examines advances in science and technology to boost fishery sustainability
2. Living Oceans Foundation leads Red Sea expedition
3. The Oceans Project: Galatee Films announces a new film
4. MIT: Oceans are a major gene swap-meet for plankton
5. Oceans are 70 percent shark free
6. Oceans may soon be more corrosive than when the dinosaurs died
7. Oceans turning to acid from rise in CO2
8. Forecasting system provides flood warnings to vulnerable residents of Bangladesh
9. Rural America more prepared for disaster -- also more vulnerable
10. Treatments for urinary infections leave bacteria bald, happy and vulnerable
11. Urgent call to action issued to protect worlds most vulnerable populations from influenza pandemic