Photo Gallery: Threatened Freshwater Environments

waste water at a treatment plant in China's Hebei Province

California's Salton Sea,Dead Tilapia

CHINA,Fen River Pollution.

Washington D.C, Night Heron, Anacostia River

Before New York

When Henry Hudson first looked on Manhattan in 1609, what did he see?

By Peter Miller

Computer Generated Image (top) by Markley Boyer, Photograph by Robert Clark

Of all the visitors to New York City in recent years, one of the most surprising was a beaver named José. No one knows exactly where he came from. Speculation is he swam down the Bronx River from suburban Westchester County to the north. He just showed up one wintry morning in 2007 on a riverbank in the Bronx Zoo, where he gnawed down a few willow trees and built a lodge.

"If you'd asked me at the time what the chances were that there was a beaver in the Bronx, I'd have said zero," said Eric Sanderson, an ecologist at the Wildlife Conservation Society (WCS), headquartered at the Bronx Zoo. "There hasn't been a beaver in New York City in more than 200 years."

During the early 17th century, when the city was the Dutch village of New Amsterdam, beavers were widely hunted for their pelts, then fashionable in Europe. The fur trade grew into such a lucrative business that a pair of beavers earned a place on the city's official seal, where they remain today. The real animals vanished.

That's why Sanderson was skeptical when Stephen Sautner, a fellow employee at WCS, told him he'd seen evidence of a beaver during a walk along the river. It's probably just a muskrat, Sanderson thought. Muskrats are more tolerant of stressful city life. But when Sautner and he climbed around a chain-link fence separating the river from one of the zoo's parking lots, they found José's lodge right where Sautner had said it was. When they returned a couple of weeks later, they ran into José himself.

"It was just getting dark," Sanderson said. "We were standing on the riverbank shooting the breeze, when all of a sudden we saw the beaver. He swam right up to us, then he started doing circles in the river. We backed up a little, and he did that beaver alarm call with his tail, slap, slap against the water. So we decided we'd better take off."

The beaver's return to the Big Apple was hailed as a victory by conservationists and volunteers who'd spent more than three decades restoring the health of the Bronx River, once a dumping ground for abandoned cars and trash. José was named in honor of José E. Serrano, the congressman from the Bronx who'd pushed through more than $15 million in federal funds over the years to support the river cleanup.

For Sanderson, José's story meant something more. For almost a decade he has led a project at WCS to envision as precisely as possible what the island of Manhattan might have looked like before the city took root. The Mannahatta Project, as it's called (after the Lenape people's name for "island of many hills"), is an effort to turn back the clock to the afternoon of September 12, 1609, just before Henry Hudson and his crew sailed into New York Harbor and spotted the island. If people today could picture what a natural wonder Hudson had looked upon, Sanderson figured, maybe they'd fight harder to preserve other wild places. "I wanted people to fall in love with New York's original landscape," he said. "I wanted to show how great nature can be when it's working, with all its parts, in a place that people normally don't think of as having any nature at all."

Cities Trap More Carbon Than Rain Forests, Study Says

There may be something more to the phrase "urban jungle." Compared with tropical rain forests—the densest natural ecosystems—cities store more carbon, acre for acre, in their trees, buildings, and dirt, a "surprising" new study says.

With Earth's temperature rising due to increased emissions of greenhouse gases, such as carbon dioxide, scientists are taking a closer look at all the places that naturally store carbon—and how to lock up more.

"Everyone thinks about the tropical forests, but I don't think people consider cities as a way to store carbon," said study leader Galina Churkina of the Leibniz Centre for Agricultural Landscape Research in Germany.

Although a lot of studies have focused on carbon in forests, grasslands, and other natural ecosystems, looking at cities—which now house half of the world's population—is relatively new, Churkina said. Intentionally storing carbon in cities could be one approach to counter global warming, she said.

Carbon Cities

Churkina and colleagues pulled together previous evidence looking at various stores of organic carbon—carbon that comes from living things, as well as from such as plants and animals, wood, dirt, and even garbage.

Cities—including both dense metropolises and sprawling suburbs—store about a tenth of all the carbon in U.S. ecosystems, the study estimated.

In total, U.S. cities contain about 20 billion tons of organic carbon, mostly in dirt, according to the new study to be published in an upcoming issue of the journal Global Change Biology.

Some of this carbon-rich topsoil is in parks and under lawns, but it's also sealed underneath buildings and roads—a remnant of grasslands or forests that were there before development.

Of all this urban carbon, about three billion tons are locked up in human-made materials—two-thirds of it in garbage dumps, and the rest in building materials such as wood.

Tree Power

Many cities have already launched ambitious plans for turning gray to green, such as Los Angeles' Million Trees LA project, which aims to plant a million trees in the Californian city over several years.

Trees take up CO2 and turn it into carbon in their trunks, branches, and leaves, so planting more trees helps counter some of the excess CO2 in the air.

Likewise trees also cool cities and reduce the need for air-conditioning, according to urban forest expert David Nowak of the U.S. Forest Service in Syracuse, New York.

By planting trees around buildings, he added, "you avoid about four times more CO2 emissions than the trees sequester."

Study leader Churkina added that "people could [also] try to store more carbon in gardens by smart management of the land. The carbon storage in lawns is quite amazing."

Tricky Balance

However, figuring out whether more lawns or trees in cities would actually fight global warming "can be tricky," said earth scientist Diane Pataki of the University of California, in Irvine.

"Managing urban soils to store more carbon can use energy, and those fossil fuel emissions have to be taken into account," said Pataki, who was not involved in the research.

For example, the process of making fertilizer typically burns a lot of natural gas. Later, when the fertilizer breaks down in the soils, it releases nitrous oxide—also known as N2O, or laughing gas.

(Related: "Laughing Gas Biggest Threat to Ozone Layer, Study Says.")

Since N2O is a much more powerful greenhouse gas than CO2, fertilizer can offset some or all of the carbon gain, Pataki added.

Study leader Churkina agreed. "You have to follow the whole life cycle of things, and cannot just think of carbon storage."

Waste to Energy

Building wood houses instead of using concrete could also help, said Leif Gustavsson, an expert on sustainable technologies at the Mid Sweden University in Õstersund.

However, the main benefit comes from better use of building waste, not the carbon stored in the structures, said Gustavsson, who was not involved in the new research.

Of the wood used in building homes in Sweden, his research found, only about 20 percent goes into the building, and 80 percent is waste.

"We should use all of that waste to replace fossil fuels," he said, burning it instead of coal, oil, or natural gas to generate electricity or heat.

Wood-frame houses typically need less energy for heating and cooling than concrete buildings, avoiding more fossil fuel use, Gustavsson added.

Bricks and concrete also require a lot of energy to create, whereas harvesting sustainably grown wood uses much less energy—another carbon savings.

(Related: "Hot New High-Tech Energy Source Is ... Wood?")

Overall "it's a good thing if you can increase the carbon stored in society," he said.

"Everything makes a small difference."

Alternatives for PLASTICS?

All-natural fibers: Canvas, jute, hemp, etc. are strong, long-lasting, and come from renewable sources.
Brown paper bags: These cost more up-front than plastic bags, but have none of the after-costs.
Paper bags come from renewable sources, are biodegradable, re-useable, and recyclable. They contain no toxic chemicals.
Using our heads, and our hands: Our first tools – our hands – are the most renewable resource ever invented for carrying things.
Boxes: Stores have a constant influx of cardboard packing boxes. We save our grocers’ time and effort when we take purchases home in these boxes.
Waxed paper, parchment paper, paper bags, cloth napkins: These materials can be used to wrap our snacks and lunches without destroying birds, animals, and sea life.
Truly bio-degradable synthetics: Today, cellophane, corn starch-based compounds, and other benign products are being developed used, but they still often contain plastic. Please use the above alternatives instead!

why no PLASTIC?

Not bio-degradable: Plastic is food for no one. It never completely breaks down.
Litter: Even when thrown into the way these bags are unsightly, distracting on highways, and clog storm sewer systems.
Can’t recycle: Plastic can only “down-cycle” – making at most one stop on the way to landfill or litter.
Toxic: Plastic particles get into our food and air. Certain types of plastic have been associated with increased incidence of asthma, cancer, or other disorders.
Kills wildlife: Sea turtles and marine mammals ingest plastic bags thinking they’re food.
Choking the ocean: Plastic debris has spread all over our beaches and into the ocean. In a recent surface trawl of the Pacific, six pounds of plastic were found for every pound of zooplankton.