Hypoxia is a blight on the Bay

Published 8:34 pm Tuesday, August 4, 2015

By Susan and Biff Andrews

Last week, while boating on the James River near the James River Bridge, I noticed an oddity. It looked like there were scattered cloud shadows on the water, but there were no clouds in the sky.

They were algae blooms. Not truly a red tide, nor even a “mahogany tide.” But an algae bloom nonetheless.

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It stands to reason that we would have algae blooms now, with all the runoff from the early July rains and the water temperatures in the river now above 80 degrees. There were a fair number of stinging nettles floating by, as well.

There are three components of runoff that feed algae in the river: nitrogen (used in agricultural and lawn care operations); phosphorous, from the same two sources; and fecal coliform bacteria, from livestock and human wastewater treatment plants.

The warm water allows the algae to thrive, then they die and precipitate to the bottom, where bacteria consume them, using up the oxygen in the water. This is hypoxia, a low-oxygen zone. Fish and crabs die there.

Small clouds of algae moving at a good tidal clip will not cause hypoxia or any major fish kills. But not so with the Chesapeake Bay. The water in the Chesapeake moves north along the western shore, curls around, and heads south along the eastern shore. In the middle, the still water algae blooms die, sink and kill.

The Bay’s dead zone this year is 1.37 cubic miles in volume (I think I saw a stat saying that would fill 22 million Olympic-sized swimming pools). Everything in that zone dies.

Between January and June of 2015, 58 million pounds of nitrogen entered the Bay and its tributaries. (Believe it or not, that is 29 percent better than 2014).

All of this sounds pretty dire. And it is. But there are signs that the Bay’s health may be on the rise.

2014 was an excellent year for five or six types of bay grasses. These are necessary habitat for juvenile fish and crabs. They act as nurseries. This is a positive.

Oyster populations are on the rise. Man-made artificial reefs and the sowing of spats are great for water filtration. It’s impossible to overemphasize the filtering power of oysters. Google the videos sometime. They can turn a tank of cloudy water to crystal clear in minutes.

And, as noted in this column before, they taste great. Oysters are my friends.

The Chesapeake Bay’s dead zone is 10 percent smaller than last year. That’s good. More buffer zones along the Bay’s farmlands will help tremendously. (The Bay’s Eastern Shore farms dump twice as much nitrogen in the Bay as any other area along the Bay and its tributaries.)

The phosphate ban in detergents has been a boon. I haven’t noticed my clothes looking dingier.

Even wind direction — more southerly winds in recent years — seems to be conspiring to help control nitrogen in the dead zone.

Personally, I believe most of the problems of the Bay could be controlled by getting rid of lawn-care products. Those three numbers on the fertilizer bag or the weed-and-feed bag mean something. They should all read 6-6-6, the number of the Beast.

Think of the benefits to the ecology and wildlife habitat if yards were allowed to “return to nature.” A naturalist can only dream.

Climate change is real. Pollution of the James and the Bay is real. Algae blooms like I saw last week are real.

But there is hope.

Susan and Bradford “Biff” Andrews are retired teachers and master naturalists who have been outdoor people all their lives, exploring and enjoying the woods, swamps, rivers and beaches throughout the region for many years. Email them at b.andrews22@live.com.