Unsung Heroes of Water Quality

The term ‘hero’ is way overused. Chevy recently called NFL players “unsung heroes”. Really Chevy? Heroes? For what? And I think a couple million dollar contract is pretty well sung. But when it comes to water quality, especially estuarine and specifically Chesapeake Bay water quality, one key player in that goes unmentioned. We hear time and again how if we could restore the Chesapeake’s oyster population, we could restore water quality. And that’s true. Oysters are amazing filters, and restoring the Chesapeake’s oysters would go a long way in restoring water quality. But the Bays problems start way up watershed, and so too do the solutions to the problem, partly in the form of, well an unsung hero of water quality.
I drift out from the bank into big open water of the Susquehanna. Conowingo dam isn’t running right now, so the water is low and its easy for me to drift away from the shore without getting swept downstream. There is supposed to be an incredible mussel bed in this area somewhere. I instantly see thousands of Asian clam shells, an invasive imported to North America when Chinese Immigrants come to build our railroads. The clams have marched across this, and every other temperate continent, and some call this animal the most invasive freshwater organism on the planet. A few more feet out and I start to see dead mussel shell, patina green on white with mother of pearl spots where the adductor mussels attached when the animal was alive. I was hoping to find some live ones. While eastern elliptio mussles aren’t endangered, there aren’t many young entering the population in the Susquehanna River, especially upstream of the Conowingo dam. We haven’t seen a population decline yet we think because elliptios are very long lived…possibly 100 years, so the death of the old timers hasn’t quite caught up with the lack of young to affect the number of mussels. I hope to see some small ones.
Mussles do a great job of blending in so most people don’t know they are there, and most people, including estuarine scientists, don’t realize their water filtering abilities. Bill Lellis from the USGS researched the filtering capacity of the elliptio population in the Delaware River and found that they filter between 2 and 6 billion gallons of water per day. I have a hard time conceptualizing 2-6 billion so just as a point of reference, Baltimore City “only” uses about 50 million gallons per day. Freshwater mussels can do the heavy lifting of water filtration and therefore water quality improvement.
Finally I see the frills and open slit of an incurrent syphon. Then another and another. I am finally on the bed, and just relax, drift and enjoy watching these unsung heroes of water quality do their thing: filter water headed to the Chesapeake. We devote a lot of time and attention to restoring oysters to the Chesapeake, in the name of water quality. Maybe we should do the same for the unsung filtering heroes, the fresh water mussels of our up watershed rivers and streams.