Letter: Submerged grasses don’t filter bay waters
The article by Celeste Dudley ("YOU can help save the bay!" Gardening Corner) in last week’s Gazette-Journal misinforms the public and provides false hope that submerged grasses can "filter pollutants" from bay waters.
Seasonally, submerged grasses die back, break off and rot, consuming oxygen. Nutrients absorbed in the growing are recycled back into the water, so nothing is either removed or filtered out. Any working schlep should be able to see that, but ask VIMS’ PhDs and you’ll have to smell his breath for a half hour and still not know a heck of a lot more.
In the bay, that narrow band of shallow bottom next to the land is covered by water, which is naturally saturated by oxygen. "Saturated" means just that; the water can’t hold more oxygen—grass or no grass. So? The oxygen produced by the leaves is excess, accumulates as bubbles you can see, rises to the surface and pops off into the air—the oxygen cycle. Check out the drama as it plays out: A narrow band of SAV (grass) oxygenizes a gasping, miles-wide bay, while the grass wizards of Oz pull the strings to finagle more grant money. Ain’t we lucky? If you want to bring back submerged grass, re-establish the environment it needs to flourish. Then, do your restoration planting and hope for the best.
George B. DeMarco