Living color makes bay's ills graphic


August 21, 1993|By TOM HORTON

This morning I will explain dissolved oxygen, salinity and algal blooms in Chesapeake Bay; also the importance of long-term watershed planning and mid-bay temperature/prey/predator connections.


They are important, but hard to make compelling in print.

So try this instead. Step into the computerized kiosk at the Chesapeake Bay exhibit that runs through Sept. 26 at National Geographic headquarters in Washington.

In vivid, rainbow graphics, you will see the bay in three dimensions; watch excess algae and the plagues of low oxygen it causes blossom and wither throughout the estuary with the passing seasons and years -- all in a few entertaining minutes.

A picture used to be valued at a thousand words. Now, a thousand words require less than a thousandth of a megabyte. The display at National Geographic takes about 50 megs on a hard disk.

The beauty of it is that 50 megs or more is what you get with all but the most basic of home computers nowadays. The whole display, in fact, can run with off-the-shelf software and hardware within the price range of schools or even home users.

As monitoring of the bay's waters grows more sophisticated, it is not far-fetched to envision "smart" buoys moored in channels, combined with remote sensing satellites, feeding rivers of data on an up-to-the-minute basis to computers that render graphically what is going on with water quality.

Think of the educational possibilities. A middle-school science class "runs" their local river through the last five summers in a few minutes, seeing a lovely green spread ever wider -- a comeback of submerged grass beds, following cleanup of the upstream sewage plant.

Or the kids watch daily as masses of brilliant red, signifying pollution, spread into a section of the bay; then check with crabbers there who say that, yes, they are starting to pull up lots of dead stuff in their pots.

Some of this is here now. The Environmental Protection Agency's Chesapeake Bay Program in Annapolis plans to begin distributing its annual State of the Bay report, showing changes in water quality since 1984, in color video form by 1995.

The ultimate would be to link water quality changes graphically to actual impacts on all the species of fish, crabs and shellfish in the bay, something that "is beyond our knowledge now," says Ed Stigall, chief of the Bay Program's technical section.

For a glimpse of the possibilities, however, look at what Stephen Brandt at the University of Maryland's Chesapeake Biological Laboratory in Solomons is doing.

Using underwater acoustics, hooked to a tape recorder and a computer, he can "see," as a hungry rockfish might see it, a slice of bay water, from surface to deep channel bottom, from western to eastern shores.

Brilliant patches, whorls and eddies of reds, yellows, greens and blues depict the distribution of plankton and the small fish like menhaden and bay anchovies that feed on it.

In May, this colors Brandt's slice of bay throughout much of its width and depth as good rockfish habitat. But by July the picture has shifted dramatically.

Warmer colors, reds and oranges and yellows, portray temperatures in the surface waters too high for rock fish to feed. Black, representing water with no oxygen, pushes up from the deeps.

The acoustic imaging shows as much rockfish food out there in July as in May; but now it is compressed into a narrow band between the dead deeps and the heated surface. And the colors representing rockfish habitat have shrunk from May's capacious pastures to July's inhospitable speck.

Now consider another area which has perhaps the most immediate potential for helping us literally see what is happening to the bay -- GIS, or Geographic Information Systems.

Land use in the watershed of the bay is linked to its water quality. Forest and wetlands, crucial pollution filters for runoff from farms and development, are diminishing annually.

Trying to mobilize people to losses like this that occur in bits across years and millions of acres recalls the proverbial frog -- put it in boiling water, and it will hop to safety; but warm its water gradually, and it will realize the danger too late.

But imagine if any citizen could pull up on a computer screen (or print out) a map of any area from his own area up to the six-state drainage of the Chesapeake.

Using information based on satellite overflights or aerial photography, you could highlight changes in the forest over time, losses of wetlands or prime agricultural soils.

With information derived from local zoning and population trends, you could project, in vivid hues, these trends into coming decades. All the statistics you might muster would not be nearly so effective in getting the "frogs" hopping mad about what is happening to our open spaces.

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