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By Rob Brumbaugh
True or false: What gets poured down the drain in Ohio affects the health of fish in the Gulf of Mexico?
It's true, even if the reason may not seem obvious.
One of the biggest problems facing our coastal bays and estuaries is nutrient pollution — nitrogen in particular. These nutrients can come from a diversity of sources, but the biggest two culprits are agriculture and city and town wastewater, which is discharged into streams that eventually lead to the ocean.
Of course, nutrients are important for fertilizing crops that support us all. But when released into the environment, excess nutrients have the devastating impact of OVER-fertilizing coastal seas.
As a result, outbreaks of toxic algae and dead zones (areas of depleted oxygen) spread unseen beneath the waves, suffocating fish, crabs and other marine life in their path.
So how can we protect our waterways? Enter the humble bivalve…
Putting Shellfish to Work
Bivalve shellfish — oysters, clams and mussels — are prodigious feeders on algae and other microscopic food found in coastal bays and estuaries. When bivalves feed on these particles, they provide a valuable service by filtering and cleaning coastal waters, which benefits underwater plants and other marine life, as well as people.
Bivalves also tend to enrich the sediments around them with organic waste and material — called "pseudofeces" — that they filter out of the water but don't digest. Bacteria in the sediments then break down this organic material, digesting it and reducing it to its most basic components.
One by-product is — you guessed it — nitrogen, in a form that is released harmlessly into the atmosphere where it comprises 78 percent of the air we breathe. This process is a service that oysters and other bivalves historically provided for free.
But today, shellfish populations in most places are just a small fraction of their former abundance and we are no longer receiving the full benefit of what shellfish naturally do for us.
More Than a Meal: What's a Shellfish Worth?
Scientists and economists alike are beginning to recognize that this "ecosystem service" that shellfish provide has real economic value.
We increasingly are paying for removing nitrogen from our wastewater through our utility bills and other fees used to maintain or upgrade sewage treatment facilities. We also pay for polluted waters in the form of fewer fish and, ultimately, fewer jobs and a lower quality of life in coastal communities.
So, what if we were to invest in more shellfish restoration that would provide MORE of this service? And is there a market — similar to a carbon market — that might provide an incentive for this restoration?
Could a market for shellfish restoration help us improve and protect our coastal waters more rapidly?
Coastal communities are increasingly turning to "nutrient trading" as a regulatory approach to reducing nutrient pollution, and in some cases voluntary mechanisms are being developed reduce pollution from various sources.
For example, The Chesapeake Fund was recently established by a coalition of non-profit organizations to enable voluntary payments for offsetting nutrient pollution in the Chesapeake Bay. Habitat restoration projects such as wetlands and riparian buffers funded through this program are designed to efficiently and effectively reduce nitrogen reaching Chesapeake Bay.
Perhaps shellfish farmers and oyster restoration projects should be included in the 'menu' of potential projects that could be supported, helping to offset inputs from wastewater-treatment plants or even individual households that wish to reduce their "nitrogen footprint."
(March 2009)
Fast-Forward to the Future of Conservation!
- A Dow Jones Average for the Environment
- Get Kids Back to Nature
- Conservationists — Can We Talk?
- A New Market for Shellfish
- The Turbine Beneath Our Feet
- Taking a Census of Nature
- Get Urbanites Interested in Conservation
- Sea Change for Ocean Management
- Bringing Business to the Parks
- Small Island Nations: Green Leaders?
- Truly Sustainable Hydropower
- Measuring Conservation Success
Photo credits (top to bottom, left to right): © Danny White/TNC (Bucket of oysters); © Lisa Drake (Rob Brumbaugh)
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