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Context:  Invasive species Zebra mussels larvae found in Colorado River, the most important river in the American Southwest.

Details

The News

• Voracious zebra mussels appear to be spreading into the Colorado River near Grand Junction.
• The waters are now called “suspect” for zebra mussel presence, and will be moved into the “positive” category if more widespread testing continues to turn up the larvae.
• Adult mussels have not yet been found, with the larvae visible only under a microscope.

Zebra mussels

• Zebra mussels are small shellfish marked by alternating light and dark bands.
• Size: They are typically two inches or less.

• Life Span: Four to eight years.
• Reproductive rate: Extremely high reproductive rate of 30,000-1,000,000 new mussels per year and are able to reproduce at one year of age.
• Native: Native to the drainage basins of the Black, Caspian and Aral Seas of Eastern Europe.
• Habitat: A freshwater species, can adapt to and inhabit brackish waters. Can tolerate wide ranges of environmental conditions.

Problems caused by Zebra Mussels

• Affect the food web: Filter small particles such as phytoplankton, small zooplankton, and detritus  from water and capable of filtering up to 1 liter of water within a 24-hour period, and, over time, can severely affect the food web.
• Biofouling: They are the only freshwater mussel that can secrete durable elastic strands, called byssal fibers, by which they can securely attach to nearly any surface (stone, wood, concrete, iron, steel, aluminum, plastic, fiberglass, PVC, and even crayfish), forming barnacle-like crusts several feet

Concern in North America

• The first North American zebra mussel discovery was in Lake St. Clair, Michigan, in 1988.
• Raw water intakes, such as those at drinking water, electric generation, and industrial facilities, can become infested with zebra mussels.
• Hinder boating and navigation: Organisms attached to hulls increase drag and reduce speed, thus increasing fuel consumption.
• Docks can be destabilized or sunk by mussel colonization.
• An invasive species capable of wiping out entire aquatic ecosystems and causing millions of dollars in damage to infrastructure has been found for the first time in the Colorado River.

Invasive Alien Species(IAS) IAS are species introduced into places outside their natural range that have negative impacts on native biodiversity. IAS have major impacts on human health, livelihoods and food security, and undermine progress towards achieving many of the UN Sustainable Development Goals. The rate of new introductions is increasing, and the impacts from IAS can be compounded by climate change. IAS are not only an environmental problem, and a cross-sectoral approach must be taken to address them. Preventative measures, such as biosecurity, are the most cost-effective ways to tackle IAS. Examples

Colorado River

• Origin and Fall : From Rocky Mountains of Colorado and pouring out into the Gulf of California in Mexico.

The Flow:

• The main channel of the Colorado River runs for approximately 278 miles through Marble Canyon and the Grand Canyon.
• The Grand Canyon’s rock sequences is built with layers of limestone, sandstone, shale, granite, and schist.
• After the formation of these rocks, the Colorado River began to carve its way, and with the erosions by tributary streams, the canyon widened.
• Age of the River: Scientists have studied rock deposits, and through these, it was determined that the Colorado River must be 5-6 million years.
• Length: 2,330km, the river is the sixth largest in the United States.
• Depth: Its average depth is around 20 feet, and its deepest point is 85 feet.
• River basin: Spans about 647,000sq km (250,000sq miles), or approximately 8 percent of the continental US.
• Upper basin – Wyoming, Utah, New Mexico, and Colorado – and a lower basin, Arizona, California, and Nevada.
• Significance: The river is used to generate hydroelectric power, as well as for recreation activities. But its primary use is in the agricultural sector, which accounts for nearly 70 percent of the supply.
• Threat to the river: Voted most endangered US river in 2022. Climate change is expected to reduce the river’s flow by between 10 and 30 percent by 2050.
• Drought has impacted large portions of the Colorado River Basin for years – shrinking snowpack, hotter temperatures and increasing evaporation have led to widespread aridification that endangers water supplies and river health.
• The excessive agricultural use of the river jeopardizes the water quality of the river.

Sources:

Indian Express, IUCN.

PRACTICE QUESTION Q. An invasive alien species is an agent of change and threatens native biological diversity and the consequences can be catastrophic. Examine 150 words.