Blue Crabs and the Bay

By Dr. Lynton Land

We are being told that Chesapeake Bay blue crab harvests have declined to the point that watermen need Federal disaster relief to survive. But what about next year? How will bailing out watermen this year improve crab harvests in future years?

Some Virginians are proposing more meetings to study the problem. Yet we know with absolute certainty the cause of the Bay's major problem - abysmal water quality and dead zones. And we know the solution. Hopefully, the crabs will also have meetings and decide to breed more. We don't need more meetings - we need significant action, without which there can be no improvement in water quality in the Chesapeake Bay. We must reduce the nutrients, nitrogen (mostly nitrate and ammonia), and phosphate that are being discharged into the water.

To use an analogy, Chesapeake Bay is like a leaky boat, the leaks corresponding to the sources of nutrients that are the cause of the problem. The biggest leak is the inefficiency of agricultural fertilization. This is known with certainty. Only between about 2/3 and 3/4 of the chemical fertilizer applied to a typical field is removed from the field as the crop is harvested. The remainder is released to the environment. In an effort to maximize crop yield, and farm profits, fertilization rates are “pushed” to the limits suggested by agronomists, who focus solely on farm economics and ignore the societal cost of pollution. A second, smaller but still major leak, is the point-source discharge of nutrients from wastewater treatment plants. And then there are lots of little leaks, like acid rain (nitric acid), storm water runoff, septic systems, etc.

How can the leaky boat be fixed? Some people advocate a bigger bilge pump, meaning more filter-feeding organisms like oysters and menhaden. Just as a bigger bilge pump is not the solution to a leaky boat (bilge pumps fail and leaks never get smaller), more filter-feeding organisms, desirable as they are, cannot solve the Bay’s problems. These kinds of organisms merely filter out the algae that have grown in the water because of all the nutrients, use a very small amount of the nitrogen and phosphorus to grow, and “defecate” the rest. The particles sink to the bottom, where bacteria consume them and release the nutrients right back into the water. Filter-feeding organisms like oysters help make the water clearer so that sea grass (Submerged Aquatic Vegetation) can survive, but the nutrients are not removed from the Bay ecosystem.

The only solution is to fix the leaks, the biggest one first. Agricultural fertilization efficiency can be significantly improved by taking three steps:

1. Ban the least efficient fertilizers, municipal sewage sludge and poultry litter, that release about half the applied nitrogen and more than half the applied phosphorus to the environment, to no benefit of the crop. Crops that normally receive 120 pounds of chemical nitrogen fertilizer per acre receive 400 pounds of nitrogen per acre in the form of sewage sludge, to grow exactly the same crop. Where do you suppose all that extra nitrogen goes? These materials are better used as biofuels.
2. Require split fertilizer application, known to increase the amounts of nitrogen and phosphorus taken up by crops and to decrease the amounts lost to the environment. Development of timed-release fertilizers is also a goal that needs to be achieved, and agronomists would better serve society to develop more efficient fertilization practices rather than promote the use of poultry litter and sewage sludge, the latter called “biosolids” to shield its real origin from the public.
3. Mandate riparian buffers at least 100 feet wide, (ultimately) consisting of mature trees with a ground cover at the edge of every stream, river and estuary. Citizens who desire a view of the water can prune the lower limbs of the trees. Riparian buffers are known to be effective and cheap. They should be mandated everywhere, irrespective of the land use, so as to ensure that every waterfront property owner bears some of the “pain” from their establishment, and stiff penalties should be enforced for noncompliance.

To fix the other large leak, wastewater treatment plants should all be upgraded to, or approach, the “Limit of Technology” so the discharge of nitrogen and phosphate is reduced as much as possible. The money required can be derived from the same sources used to build the plants in the first place – federal and state funds, usage fees and municipal bonds. At the same time, mandatory septic system inspection, and tank pump-out if necessary, should be imposed throughout the watershed so that every citizen bears some of the “pain” no matter how they dispose of their septage. The Bay has continued to deteriorate because we do everything as cheaply as possible. Unless we recognize the worth of the Bay and that society must cost-account that worth into economic decisions, no progress is possible. Improving water quality in the Bay will incur real costs, and if we choose to pay those costs, which we have not done to date, the best we can do is to spread the financial “pain” as widely and fairly as possible.

Nothing stated above is new. We have known the reasons for the Bay’s problem since the Army Corps of Engineers study in 1965-1973, which cost nearly $100 million in today’s dollars. That study was repeated by EPA the next decade, and another nearly $100 million spent, reaching the same conclusions. Albeit better quantified, the conclusions of these early studies have been confirmed over and over by more recent documents, such as the “Virginia Tributary Strategies.” The science is cast in stone. No meetings or task forces will change anything. Disaster relief for watermen this year will not change anything. If the leaks are not significantly reduced, the biggest first, only the kinds of mandated actions outlined above will result in measurable improvement in Chesapeake Bay water quality.