Episode 15
Copyright © John Page Williams Jr. All rights reserved.
This is John Page Williams with another reading from Chesapeake Almanac. This sketch is called "Eelgrass: Carpet of Life."
We felt as if we were floating on air as this gift carried us over the shallow flats in the northwest corner of Pocomoke Sound. The water was crystal clear, and the bottom was a green carpet much of the way from Broad Creek to the Chesapeake Bay Foundation's lodge on Great Fox Island. Since it was the end of April, the water temperature was in the midfifties and we knew that the green grass was all eelgrass. It was the thickest stand around Fox Island in years and we cheered when we saw it. Eelgrass is a very valuable resource.
To understand that statement, it is helpful to know a little bit about the plant. Eelgrass lives in a harsh environment. It is one of only a handful of flowering plants that can live submerged full-time in salt water. Salt causes severe water balance problems that kill most higher plants, but eelgrass has developed the capability to excrete it. So, for that matter, can plants like saltmarsh cordgrass that live on the banks around the eelgrass beds; but eelgrass can also live fully submerged, which the cordgrass cannot. Eelgrass has also developed the capability to take oxygen out of solution in the water and transport it throughout leaves, stems, and roots.
Finally, the plant has developed the ability to disperse pollen without the aids of insect or wind, which most other flowering plants rely on for that task. Instead, it uses water currents to broadcast its threadlike pollen grains. When a grain washes up next to the female stigma of another plant, it winds around the stigma so that the two can fuse and form a seed, which will also be dispersed by currents. These adaptations permit eelgrass to grow in areas where it has only minimal competition from other species.
Eelgrass thrives in a broad range of water temperatures, so it is widely distributed around the world. In North America, it's found from northern Florida all the way up to the Arctic Circle, including parts of Hudson Bay. On the Pacific Coast, it grows from Southern California to southwestern Alaska, including Prince William Sound, and even in the sloughs up on Kodiak Island.
The ability to grow in cool temperatures gives it an important advantage in the Chesapeake, because it can begin in early spring while the water is clear and have its seeds made by the time phytoplankton growth reduces light penetration in June. Remember that a submerged flowering plant needs a great deal of sunlight energy to reproduce. The heavy plankton growth that most of the Bay now experiences in summer--as a result of excessive nitrogen and phosphorus--reduces underwater light to below the level that most submerged flowering plants need to reproduce. The early start benefits more than the eelgrass alone. We were about to have a firsthand look at the ecological value of a lush eelgrass bed in early spring.
As preparation for the trip, we had all read the chapter "Summer and Scraping" from William W. Warner's classic book Beautiful Swimmers, in which Warner describes spending a day with an expert Smith Island soft-crabber, pulling a specialized toothless dredge called a scrape through the eelgrass beds in the area. Now we stowed our gear in the Fox Island lodge and put a scrape in the skiff and went to see for ourselves.
Liz McKnight on her first trip to Fox was "flabbergasted at the amount and variety of life in the grass." We all watched with great pleasure as her children, Philip (then aged nine) and Anna (then six), pawed through the bales of grass that the scrape brought up. Hidden inside were grass shrimp and sand shrimp, oyster toads, juvenile sea trout, baby spot and croakers, young flounder, little hogchokers, tiny shrimp-like amphipods, long green pipefish, mud crabs, and, of course, lots of blue crabs of all sizes, from tiny juveniles to big, mature jimmies.
For Anna, sorting through the grass was like a treasure hunt with all kinds of new creatures to discover. Philip, a little older, could understand for the first time "how everything is connected to everything," about how functional a patch of submerged grass can be. Suddenly he understood why his father, Turney McKnight, likes to hang around the edges of eelgrass beds, casting bucktails and plugs to the speckled trout (and in the fall, rockfish) that cruise those edges looking for small fish that stray out of them. Turney grinned when he saw the light go on in his son's eyes.
He also smiled as he watched Liz figure out the critical role that eelgrass plays in the lives of the crabs and the crabbers of Pocomoke and Tangier sounds. She had seen a couple of the low slung "Jenkins Creekers," or scraping boats, being readied for the season in Crisfield. Now she realized that the water was almost warm enough for the crabs to slough, or shed their shells, for the first time in the year.
A few crabs had already done so, and the first of the scrapers had been out making exploratory "licks" to see what was happening. The main run would begin some 10 days later, on the strong tides of the new moon, but the crabs were already in the grass, getting ready to hide from predators during this very vulnerable stage in their lives. The fact that eelgrass begins growing early in the season is of tremendous value to these crabs.
Our object lesson with eelgrass was a spring one, but if we had been at Fox in summer, we would have seen even more life in the beds; and in the late fall, we would have seen waterfowl feeding on it. All the Chesapeake's submerged grasses are valuable to the system, but eelgrass is one of the best. It suffered from a disease early in the 20th century, which caused much concern around Tangier and Smith islands. Then it came back strongly, only to be affected like the other Bay grasses by the excessive algae growth that is plagued our Cesapeake for the past five decades. Planktonic algae drifting in the water block light from the plants below, and other species of algae attach themselves to the leaves of the grass, fouling them like a boat bottom and blocking out even more light.
Now eelgrass is returning in parts of the Bay, from the Potomac at Smith Island south. The best places are broad, shallow flats that are protected from high wave energy, like the upper end of Pocomoke Sound, the Virginia Eastern Shore creeks, Mobjack Bay, and the Pocoson River.
Even so, eelgrass is growing in only about 20 percent of the areas where it used to be abundant. It suffers especially around slow-flushing creeks and coves where algae growth is high because of heavy runoff and discharges from towns and cities.
Eelgrass is a good indicator of our success in cleaning up the Bay. We should cheer anytime we see a thick stand like the one that so fascinated Philip and Anna, but we do well not to pat ourselves on the back until widespread distribution signals major progress.
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For more on topics touched upon in this episode, see
For more happenings around the Bay in June see our other Chesapeake Almanac podcasts and read our blog post "Worms in Love in June."
