As I was leaving my job with the Chesapeake Bay Program, I explained to my colleagues that by giving up my daily and interminable 100-mile commute, I would gain almost 535 hours a year. I made a pledge to them, and myself, to spend at least 100 of those hours seriously looking at the extraordinary natural world I live in and at least 100 hours a year writing about what I saw. My logbook, in part, records:
“Received word today of a memorial service for Don Heinle who died at 63 … in Washington (State). Honoring my own bargain, I spent some time watching the creek today and must now write about it.”
Donald R. Heinle is a name not widely known among today’s Chesapeake pundits, but he was a respected and courageous scientist during his more than a decade of work on the Bay. I had reason to ponder his work this chilly, but sunny morning.
Ice had formed overnight, just a thin layer, but it covered a couple of square miles and was enough that diving ducks could not feed. As it began to break up, loose flocks of about 500 ruddy ducks (Oxyura jamaicensis) moved silently up the creek and began eagerly diving for the shoots and rhizomes of horned pondweed (Zannichellia palustris), one of the Bay’s submerged aquatic grasses which had been slowly growing since autumn.
Our creek is turbid in summer, being fed nitrogen from the Patuxent’s upstream sources far in excess of its biological needs. But with winter’s clearer water, enough light reaches the bottom, even at about an 11 foot-depth that millions of shoots — perhaps 200 million plants in this creek — begin to sprout in late autumn. They grow slowly in the cold, by February rising 1–3 inches, but when the creek warms, they can reach a meter above the bottom along the shallow creek margins.
Turbidity and nutrient-fed plankton rob the deeper areas of light in spring but the grasses still survive until June down to 8 feet or so and are marvelous habitat for fish larvae and young crabs
Looking back to the Bay of the 1960s, when my colleague Don Heinle came to work at Solomons, other SAV species, wigeon grass (Ruppia maritima) and eelgrass (Zostera marina) took over to populate the Bay’s shallows through autumn, but eutrophication largely brought an end to that succession in the Middle Bay.
Chesapeake Biological Laboratory professor Joe Mihursky said that when he came to Solomons about 1962, he and Andy McErlean (now at EPA) were early Chesapeake scuba divers and recalled 10–15-foot visibility in warm weather. “Gradually” Joe said, “little by little it got murkier and in a few years we had to do our diving in winter. One afternoon in 1970, Don (Heinle) came up to the lab and said: “‘C’mon, you guys have to see this’ and took eight or 10 of us out the CBL pier to look at a deep red ‘mahogany tide,’ which was still unusual at the time.”
Mahogany tides, turbid blooms formed by billions — even trillions — of microscopic dinoflagellate plankton cells are fed by excess nitrogen and are now an annual feature of Chesapeake tributaries, where they drastically cut light penetration. In 2000, their widespread occurrence made most regional newspapers and the failure of many submerged grass beds was attributed to their theft of the necessary sunlight.
This winter morning in 2001, it was just 34 degrees as I launched my kayak to inspect the thin sheet of ice. As I paddled through the shallows, I could see the shoots of SAV beneath me, about 8–15 per square yard — except where mute swans (Cygnus olor) could reach down with their long necks to root them up, and leave in their place shallow, dark pits about 10 inches across. The ruddy ducks were working in much deeper water, staying down an average of 30 seconds and only resting and preening on the surface about 14 seconds between dives.
The ice reflected light from the early morning sun in all manner of patterns, but as I nosed into this razor thin sheet, there were hundreds of almost perfect equilateral triangles 1–3 inches on a side, sometimes consolidating into rhomboidal shapes a full foot long.
I picked up some near the edge, finding they were only a few hundredths of an inch thick and themselves made up of a beautiful crystalline network branching out at an angle close to 110 degrees.
In the clear water, I could see the small slightly pinkish forms of juvenile comb jellies, or sea walnuts, (Mnemiopsis leidyi) members of the taxonomic group Ctenophora. It never fails to surprise me that these delicate wraiths can prosper in cold clear water, though their relatives do so in Arctic waters.
Ctenophores feed by capturing zooplankton on adhesive organs called colloblasts and sweeping their prey along pathways lined with undulating hairlike cilia, down the body and into their mouths. These rows of cilia are also the animal’s means of locomotion and are called ctenes. They appear and grow longer as the critters leave their larval stage. (These are truly “ctene-age” jellyfish!)
At any one time, I could look down and count eight or so, each with sunlight flickering a rainbow of colors from them as the ctenes beat in rhythm. They are voracious feeders on zooplankton crustaceans called copepods, which also feed on the explosion of phytoplankton as excess nutrients pour into the Bay with the spring freshet.
By summer, they will grow from fingertip-size to the dimension of plum tomatoes, and in the process they can strip the water column of larger zooplankton forms at the same time that larval and juvenile fishes are competing for the identical food supply.
Back on my beach, I walked along the shore with just a foot of sandy bottom exposed by the falling tide. There — like sunlit globs of glass — were nearly a hundred more comb jellies, stranded as the water level dropped. By late spring, their surviving companions would number in the millions.
This has probably happened each spring in the Chesapeake since it was formed at the end of the Pleistocene Epoch. The ctenophores are harmless to human swimmers, indeed with their brilliant phosphorescence at night, they are fascinating to bathe among, or to watch as your boat passes through swarms of them, leaving a trail with bursts of bright blue luminance in the wake.
Comb jellies themselves become food for the Bay’s hated sea nettles (Chrysaora quinquecirrha) which in early summer will plague those of us seeking to cool off as hot weather descends. As the ctenophores disappear, one pretty much knows that nettles are on the rise.
Meanwhile, both are prey for sea turtles entering from the Atlantic as the Chesapeake Bay warms each spring, especially the omnivorous loggerheads (Caretta c. caretta).
Don Heinle encountered this cycle of gelatinous plankton species back in the mid-1960s when Drs. L. Eugene Cronin and Joe Mihursky hired him to work at the CBL, then part of Maryland’s Natural Resources Institute. He was fresh out of graduate school in College Park and his job was to study zooplankton, especially the fertile copepods which were believed to support the entire base of the estuarine fishery food chain.
“Joe,” he told Mihursky one day, “there are too many damn jellyfish out there, I just can’t get a clean sample in my plankton nets.” A net towed behind one of the CBL’s research vessels might, in a 10-minute haul through rich zooplankton, come up with a small cup of dense, pinkish copepod “paste” concentrated by the net’s fine mesh filtering many cubic meters of water. But, when “blooms” of jellyfish throng the waters feeding on zooplankton, the net would quickly — sometimes immediately — clog with thousands of bulky jellyfish, pounds, sometimes tens of pounds of them, from which the intermingled tiny copepods could never be counted or identified. It was a mess, and when formaldehyde (the usual preservative) was added, all that remained was an amorphous gelatinous mass.
Heinle could not do his job under those conditions, so he invented what Mihursky described as a “cow catcher,” a network of coarse mesh formed as an inverted cone over the mouth of the conical plankton net as it was drawn through the water. This did a pretty good job of tumbling off the larger jellyfish and excluding them from the sample.
Heinle’s subsequent work formed some of the best basic research done on zooplankton in the Chesapeake Bay and its subestuaries from the late ’60s until 1980. He was an early user of bomb calorimetry to look at the food value of copepods and was among the first to attempt to work out a food budget for the Patuxent Estuary. He found that phytoplankton production appeared insufficient to support the number of copepods he found, and he was an innovator in postulating that detritus (organic debris) and bacteria were significant energy sources.
Heinle was also innately fun-loving and curious. At an Ocean City conference one night, he and biologist Chuck Gibson took the door off their motel room and went “surf-dooring” in the Atlantic. The door was restored to its rightful place by morning and no one was the wiser.
One day, Heinle was rummaging in the attic at the CBL, where boxes of materials had been squirreled away since Reginald Van Trump Truitt started started work in Solomons around 1919. Among the Niskin bottles and reversing thermometers he found early papers by R.P. Cowles, who sampled the Bay 1915-21, and Carroll Blue Nash, the first biologist to look in detail at the Patuxent in the 1930s. Amazed by their content, he trotted these down and pushed them under his colleagues’ noses. “Look,” he said, “There are dramatic differences from what we get today. The Secchi disk visibilities have decreased and the deep water oxygens are lower. This river’s in trouble.”
The fun-loving Heinle also played slow-pitch softball on Mihursky’s team in Prince Frederick. They called themselves the “Drive-ins” because their field was the site of Bunky Hipple’s abandoned drive-in movie theater.
A lanky young local who owned the laundromat joined their games. His boat livery business had gone down along with water quality in the Patuxent. He’d also just been elected county commissioner, on a campaign budget of $164, all out of his own pocket, because he thought outside donations would make him beholden. His name was Bernie Fowler.
After the games, Fowler would talk to the biologists about the river to try to figure what had happened. He heard about the old manuscripts and together, they decided that development upstream and massive increases in sewage discharge were killing the estuary.
Fowler galvanized the Tri-County Council for Southern Maryland, composed of Calvert, Charles and St. Mary’s, all with strong and struggling watermen’s communities. They resolved to sue the upstream counties for the damage they were doing.
To some extent, Mihursky said, the damage, given the state of knowledge at the time, was inadvertent. The upstream counties had been advised by Johns Hopkins University, where expert sanitary engineers such as Abel Wolman and John Geyer had done a study estimating that the mixing coefficients in the Piedmont Patuxent should be sufficient to metabolize and purge the river during its long flow downstream. This was a new science at the time, though, and their mixing coefficients were too low for the placid, Coastal Plain section of the Patuxent.
USGS researcher Bob Cory’s continuous recordings from dissolved oxygen meters on the Benedict Bridge showed deep sags in oxygen, enough to jeopardize aquatic life in the river.
Scientists signed on to contribute their knowledge to the fray, and Don Heinle found himself in many ways the point man. He gave a deposition, testimony in which he brought out the old studies and contrasted them with the new data. The resulting judicial decision has been called the first in America to recognize the external economics of environmental impact, and to recognize upstream responsibility for downstream damages. The effect was electrifying.
Very quickly, Heinle was under extraordinary pressure from very highly placed economic and sometimes anonymous interests. There were phone calls at 2 a.m. to University of Maryland officials. (The University runs the CBL.) One source reported words to the effect of “curb your dog or euthanize him.”
There were also threats to close the Laboratory; it was no longer relevant now that land had been donated over at Horn Point on the Eastern Shore’s Choptank River.
Heinle had a wife and baby daughter; the pressure was tremendous, but he stood by his convictions and upon the principal of academic freedom. He was up for promotion and tenure, name of the game for university scientists. He got tenure (his job was no longer threatened) but he was denied the promotion, and thus recognition of his stature as a scientist.
Discouraged and disheartened by 1980, he returned to the West Coast, where he’d worked in the salmon fishery during his student days, and entered the private sector, becoming senior biologist at the firm of Ch-2M Hill and eventually a respected and well-compensated mentor to his colleagues.
He was contemplating retirement to the 60 acres of coastal land he owned when that fatal heart attack intervened.
During the ’60s and most of the ’70s the EPA was resistant to any claims that nitrogen from upstream sources would damage the estuary. It was only years later that the CBL and Academy of Natural Sciences biologists Chris D’Elia and Jim Sanders would conclusively link mesohaline eutrophication with nitrogen from upstream sewage and nonpoint sources. Most of today’s Chesapeake restoration effort is founded on that one conclusion.
Our society will continue to pay billions of dollars for the lack of attention paid to nitrogen for decades, while its loads poured off the land and out of wastewater plants.
We can thank Don Heinle for the intelligence and fortitude he showed during the time it took us to learn that lesson. Godspeed, and peace, old friend. I will never see those glistening ctenophores in the late winter Chesapeake without remembering your contributions.