News / Science & Technology

Species Loss Compromises Earth’s Vital Systems

Water quality improves in a more diverse ecosystem

Bradley Cardinale built 50 mock streams in his laboratory for the three-year experiment.
Bradley Cardinale built 50 mock streams in his laboratory for the three-year experiment.

Multimedia

Audio
Rosanne Skirble

Scientists have long thought that diverse ecosystems like forests, lakes and streams are especially good at removing pollutants that human activities put into the environment.

A new study in the journal Nature, confirms that theory.  

University of Michigan ecologist Bradley Cardinale demonstrates how water quality improves in a more diverse ecosystem.

In his laboratory Cardinale built 150 meter-long cases that enclosed mock streams. He cultured between one and eight common algae species in each waterway. The tiny micro-organisms are important actors in removing pollution from the water. He then exposed the streams to nitrate, a common pollutant from agricultural run-off and auto emissions.

University of Michigan graduate students monitor a water quality experiment.
University of Michigan graduate students monitor a water quality experiment.

It took Cardinale three years to set up the experiment, run it and process the data. On average streams with eight species were cleaned four-and-one-half times faster than water with just one species. Cardinale says specific algae species adapt to specific stream habitat.

"As you added more and more species to the stream what happened is that all of these different habitats got filled up and the stream as a whole became a much better bio-filter for this particular nutrient pollutant."

Cardinale says scientists as far back as Charles Darwin in the 1860s proposed that every species plays a specific role in the ecosystem and compliments each other.

"Basically a diverse world always comes down to having unique niches that allow species somehow to exist with each other. So any system where niche partitioning is a key biological phenomenon, the results of the study I’ve shown here and it’s implication for water quality should probably apply."

This sample mock stream contains algae growth after six months and represents between 12 to 15 generations and millions of algae cells.
This sample mock stream contains algae growth after six months and represents between 12 to 15 generations and millions of algae cells.

While Cardinale’s study showed that water quality improved in the streams with greater biodiversity, the ecologist notes it did not address how many species would be needed to completely remove the pollutant from soil and water.

"We previously expected that somewhere between three and five species was enough to clean nitrate out of soil and water. And my study extends those results to at least to eight species where we didn’t even begin to see a plateau."

Cardinale says he expects the number is more than eight, but far less than the several hundred found in a stream. The University of Michigan ecologist hopes future studies will determine that tipping point.

You May Like

Is Air Travel Safe?

Aviation expert says despite tragic losses of Malaysian Airlines flights 370 and 17, industry experienced lowest fatality rate in recorded history last year More

Multimedia 100 Days Later, Nigerian Girls Still Held

Activists holding rallies in Nigeria and several other countries to mark 100th day of captivity for more than 200 schoolgirls being held by Boko Haram More

Chocolate Too Bitter? Swap Sugar for Mushrooms

US food technology company develops fermentation process using mushrooms to reduce bitterness in cocoa beans, believes it will cut sugar content in candy More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Carriers Suspend Travel to Israeli
X
Carolyn Presutti
July 23, 2014 1:21 AM
The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video US Carriers Suspend Travel to Israel

The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video NASA Focuses on Earth-Like Planets

For decades, looking for life elsewhere in the universe meant listening for signals that could be from distant civilizations. But recent breakthroughs in space technology refocused some of that effort toward finding planets that may harbor life, even in its primitive form. VOA’s George Putic reports on a recent panel discussion at NASA’s headquarters, in Washington.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.
Video

Video Nature of Space Exploration Enters New Age

Forty-five years ago this month, the first humans walked on the moon. It was during an era of the space race between the United States and the Soviet Union. World politics have changed since then and -- as Elizabeth Lee reports -- so has the nature of space exploration.

AppleAndroid