National Geographic Society

By Sandra Postel, National Geographic Freshwater Fellow

We don't see or hear them, but every day they quietly go about their work--filtering and cleansing our rivers and streams. And if we don't act soon, they'll disappear from the workforce just when we need them most.

I'm talking about shiny pigtoes, monkeyface, pink heelsplitter, and purple wartyback--freshwater mussels with funny names that belie the seriousness of their labors. They suck water in, filter out bits of algae, bacteria and other tiny particles, and then release it back to the river cleaner than before.

One mussel alone can cleanse as much as a gallon of water per hour. Add up the work of a whole mussel community, and you get a virtual water treatment plant.

According to Ethan Nedeau, an expert on the freshwater mussels of New England, even half the population of mussels at work in a one-half mile segment of New Hampshire's Ashuelot River can help cleanse more than 11.2 million gallons of water a day--roughly the quantity of household water used by 112,000 people.

The United States ranks first in the world in the number of known species of freshwater mussels--292, compared with just 10 in all of Europe. But we're losing these "living filters" all too fast.

Today 69 percent of U.S. freshwater mussel species are to some degree at risk of extinction or already extinct. The most diverse assemblage of freshwater mussels ever known was located in the middle stretch of the Tennessee River in northern Alabama. Before the damming of the river in the early 1900s, 69 mussel species had been spotted in this reach; 32 of them have apparently disappeared, with no recording sightings in nearly a century.

My favorite freshwater mussel is the orange-nacre mucket (Lampsilis perovalis), found only in the rivers and streams of Alabama's Mobile River basin. Like many freshwater mussels, the orange-nacre mucket has a fascinating life cycle and exhibits some of the most sophisticated mimicry in the animal kingdom.

The females essentially use their offspring to lure fish into helping them colonize new stream bottoms. They package their larvae at the end of jelly--like tubes that can extend eight feet out into the water. To fish swimming by, the larvae dancing in the riffles of the river current looks like a tasty minnow. When the fish bites, the tube breaks, releasing the larvae into the stream. A few of the offspring attach to the fish's gills and hitchhike around with their finned host for a week or two, absorbing nutrients and growing along the way. Finally, the young mussels drop off, float to the river bottom, and colonize new territory--and before long begin their vital task of water purification.

Along with 16 other threatened or endanged mussel species in the Mobile watershed, the orange-nacre mucket is at risk of extinction---in large part due to excessive pollution and dams that have diminished the river habitat they need to survive.

To me, the loss of such industrious, fascinating creatures diminishes more than our water quality--it diminishes our natural heritage and our world.

Only habitat improvements, in some cases combined with mussel breeding and release efforts, can save these and the other 200 freshwater mussel species at risk nationwide.

So as we celebrate World Water Day, I hope we also celebrate the freshwater mussels that help keep our waters clean and healthy--and commit to efforts to conserve them.

Because I bet we'll miss these little creatures with the whimsical names when they're gone.

Sandra Postel directs the independent Global Water Policy Project and lectures, writes, and consults on international water issues. She is also Freshwater Fellow of the National Geographic Society, and serves as lead water expert for the Society's freshwater initiative. Postel is the author of several acclaimed books, including Last Oasis, which appears in eight languages and was the basis for a 1997 PBS documentary, and is co-author, with Brian Richter, of Rivers for Life. Her essay "Troubled Waters" was selected for Best American Science and Nature Writing. From 2000 to 2008, Postel served as visiting senior lecturer at Mount Holyoke College, and later in that term as director of the college's Center for the Environment. Postel is a 1995 Pew Scholar in Conservation and the Environment, and in 2002 was named one of the "Scientific American 50" for her contributions to water policy.

If you're looking for ways to invest your money in 2010, you'll get a return on companies building wastewater treatment plants, according to United Nations (UN) experts speaking to journalists gathered today at UN offices in Nairobi, Kenya.

Satinder Bindra, director of communications for the UN Environment Program (UNEP), said his financial advisor told him this week that "one of the best investments this year is water quality improvement."

The theme of the 17th annual World Water Day, on Monday, is "Water Quality" with an emphasis on water pollution caused by human sewage, often dumped directly into rivers, lakes, and the ocean in the developing world, where treatment plants can be few and far between.

According to the UN Environment Program (UNEP), more people die every year from exposure to polluted water than in all wars and conflicts around the globe. And most of that pollution is in the form of pathogens from human and animal waste.

As populations and economic development climb, and water resource are spread even more thin, we are reaching a tipping point at which wastewater issues can no longer be ignored, according to the experts. One of the results: wastewater-treatment and sanitation projects becomes a entry point for larger-scale, and often well-funded, development projects. Engineering, and water treatment and supply companies that will be contracted for these projects stand to make profit.

While the corporate world and investors capitalize on cleaning water, taxpayers and governments could also find financial reward. For every dollar invested in wastewater treatment, it is estimated that society gets a $3-34 return when you consider medical and environmental costs, according to Nancy Ross, communications director at the California-based Pacific Institute, which specializes in global water issues.

The Value of Water, Wetlands, and Forests

If you're personally not looking for insider trading tips, there is another angle on water economics that may be of interest--the value of green infrastructure, including wetlands that provide natural filtration, fisheries support, and flood control, and forests that protect water quality.

Wetlands alone are valued at $400 billion globally, according to the Pacific Institute.

A paper issued yesterday by the Convention on Biological Diversity, cites an analysis of Chinese forests that puts a $1-tillion pricetag on the water storage and filtration functions of these trees. Soil and vegetation store, and to some degree keep clean, nearly 60 percent of the world's renewable freshwater. That water, when returned to the atmosphere through evapotranspiration, or water vapor, eventually falls back to the ground through precipitation, providing a generally reliable water source for drinking, agriculture, and business.

Intact forests also help reduce the amount of sediment--considered a pollutant--that ends up in the water supply through erosion, a common result of deforestation. The Convention on Biological Diversity values the water storage capacity of the trees in China at nearly three times what they are worth as lumber.

On the other side of the world, the Amazon rain forest, according to Pavan Sukdev of UNEP, is a similar water pump that sends nearly 20 billion tons of water daily into the atmosphere and generates rain for a nearly $1-trillion, primarily agricultural-based economy in the region.

Yet, deforestation continues.

In an attempt to curb the cutting and protect freshwater sources, the World Bank and environmental nonprofits are funding forest protection projects in Costa Rica, Nicaraqua, South Africa, and elsewhere. But the challenge remains putting a pricetag on some of these ecosystem services in a market where they have traditionally been unaccounted for, according to the Convention report.

Business Constraints

Companies, especially beverage companies, are feeling the immediate effects of water pollution. According to UNEP's Sukdev, bottled water producers Evian and Vittel are now paying upstream farmers $280 a hectare (2.5 acres) to protect forests, reduce sediment loads to the river, as well as the use of chemical herbicides and gross amounts of nitrogen-rich fertilizers--in essence to keep the water cleaner.

Scarcity sounds alarm bells too, for business. A 2009 Citigroup report said that unsustainable water usage has caused water scarcity to become a limiting factor in the growth of China, India, Indonesia, Australia, and the western U.S. A sister survey of Fortune 1000 companies found that 40 percent said water shortages would have a severe, if not catastrophic, impact on their business.

Citi concluded that we are on the verge of water bankruptcy.

For more on clean water and water conservation, visit National Geographic's freshwater website.

--Tasha Eichenseher

Photograph by UNICEF/Giacomo Pirozzi

Sandra Postel
National Geographic Freshwater Fellow

Welcome to the world of water. As National Geographic's freshwater fellow, I'll be sharing with you ideas and stories about water in all its facets--from the big global challenges of water scarcity and intensifying droughts and floods to how we as individuals and communities can take part in solving water problems in our own backyards and across the globe.

For more than 25 years now, I've never strayed too far from one simple question: Can we human beings use and manage water in ways that not only meet our needs but that allow the rest of life on this planet to thrive too?

I believe we can. But today, things don't look good. A lot of life is at risk. More than a billion people don't have access to safe drinking water, and several million die each year as a result. Many species of fish, frogs, insects, and mussels may blink out in our lifetimes. Here in North America, 40 percent of freshwater fish species are at risk of extinction. The fraying of the web of life means our own social fabric is at risk, too. It's all connected, even if we can't always see the threads.

On the heels of National Geographic magazine's special issue on water, the National Geographic Society is embarking on a large effort to motivate more of us to care about and conserve freshwater. The average American lifestyle takes 1,800 gallons (6,814 liters) of water a day to support--twice the global average.

Fortunately, there are many ways to live well while using less water. We will be offering stories, photos, online tools, lessons from the field, and more to highlight the problems and solutions--and inspire action.

We also plan to work with partner organizations and scientists to help foster preservation of freshwater species by restoring the natural patterns of flow that life within rivers needs to survive.

In National Geographic's recently released book, Written in Water, I wrote about my search for honest hope that enough water can be provided for all people and living things to thrive. Here's an excerpt:

As the plane lowered its landing gear, I strained my neck to watch the edge of Lake Mead recede. A few seconds later, a lush green golf course came into view. With late afternoon temperatures pushing 107 degrees, there was scarcely a golfer in sight. Downtown, on the strip, the dice-rolling gamblers had no idea how high the stakes were becoming.... Read the essay.

Water is life. Water is finite. All the water that's here now is all there ever was--and ever will be. It's all about sharing it--with nature and each other.

We're on a critical mission--and we hope you'll join us.

Sandra Postel directs the independent Global Water Policy Project and lectures, writes, and consults on international water issues. She is also Freshwater Fellow of the National Geographic Society, and serves as lead water expert for the Society's freshwater initiative. Postel is the author of several acclaimed books, including Last Oasis, which appears in eight languages and was the basis for a 1997 PBS documentary, and is co-author, with Brian Richter, of Rivers for Life. Her essay "Troubled Waters" was selected for Best American Science and Nature Writing. From 2000 to 2008, Postel served as visiting senior lecturer at Mount Holyoke College, and later in that term as director of the college's Center for the Environment. Postel is a 1995 Pew Scholar in Conservation and the Environment, and in 2002 was named one of the "Scientific American 50" for her contributions to water policy.