Category: Science

Is the Potomac back?

“So, what’s new?”

I ask the question each spring on my first visit to the Potomac. Maybe a massive silver maple has fallen after many years of leaning farther and farther over the water. Or perhaps the head of an island disappeared, replaced by mountain of logs and smashed docks. Or the river might reveal to me some new plant or creature.

Change means life, and the Potomac is a living river, always coming up with surprises, always something new.

That’s the way it’s been in the past. But how about this year? I wondered because the year before it seemed that the river was struggling to survive, as if it were a covid-19 patient on a ventilator. Hardly any fish, birds, insect life, just the sparkle of the sun dancing on the waves, pretty, but deceiving.

The reason for the downturn, I had concluded, was the back-to-back floods of 2018 that had scoured everything in their paths, like armies on a scorched earth campaign. (I later learned there was more to it than that.)

First impressions. Emerging from the creek I turned onto the river and headed upstream. The current ran strong, so I hugged the shore where logs and fallen trees created pockets of slack water where I could make progress. I looked for any clue that the river was healing.

Nooks and crannies on the river bottom
give cover to a well-camouflaged fish.

The first thing I checked out was the river bottom. Last year it was covered with a layer of silt deposited by the floods, as lifeless as the outwash from a construction site. But now, although the water was a little discolored, I was able to see the familiar mosaic of stones and shells, the river equivalent of the nooks and crannies of an English muffin, creating micro-refuges for fish and many other creatures. I felt encouraged.

I was also happy to see tough, sturdy plants poking up out of the river bank, holding the promise of a mini forest of blue and yellow blooms. In contrast, all last year the shores lay bare and covered with foul mud, as if they had been bulldozed.

Birds called in the branches above me and I saw flashes of movement. A cuckoo briefly emerged, its sleekly pointed wings and long tail giving it the agility of a stunt plane as it pursued a luckless insect. Back out of sight it called with a throaty kao-kao-kao followed by a series of staccato ka-ka-kas.

I started keeping mental notes. Great blue herons flew off of snags at my approach. Gangs of shaggy cormorants perched on half-submerged logs out in the mainstream. An immature bald eagle flew past me, and far over head a mixed flock of black and turkey vultures rode the thermals.

It did seem like the river had come back to life. But so soon? The experts I had consulted in my last article—an ancient Greek poet, Dr. Antonio Fauci, a legendary microbiologist, a roomful of government biologists, and a shifty trickster named Potowmack—agreed that nature will decide what ultimately happens to the river, and when. That sounded ominous, not surprising since that same nature also has bestowed us with what cognitive psychologists call a negativity bias: We fixate more on bad things than on good things. Biogeographer Jared Diamond calls this “constructive paranoia,” the idea that it makes more survival sense to prepare for the worst than to lie back whistling Happy Days Are Here Again.

Butt-bobbing birds. But maybe the happy days had in fact returned. Continuing up the shoreline I was seeing an unusual number of stilty-legged birds probing the mud for worms and other invertebrates. They would take to the air when I got near, fly a hundred yards up the river, and in a few minutes we’d do it all over again.

These are solitary sandpipers, one of my avian favorites. For one thing, despite their nondescript plumage, they’re easy to identify from their idiosyncratic butt bobbing. The other thing is their migrations. With just a couple of ounces of bone and muscle and a brain the size of a pea, they somehow get from the Amazon Basin, up through the US, to finally breed along the lakes and streams of Canada and Alaska.

Also impressive in their own lumbering way were the turtles. They formed lines on nearly every log. The big ones cannon-balled into the water when I got too close, followed by the plops of the little ones. A muskrat swam toward me and then disappeared in a tangle of exposed tree roots.

Were the soft rushes always here,
or are they new this year?

I was about to leave the shore to head for a string of little gravel bars on the Virginia side when I noticed something new, at least to me. It was a patch of stiletto-tipped rushes that looked familiar from my years of slogging through salt marshes. But those were dark and rigid, while these, called  soft rushes, were lighter green and not as stiff.

Maybe the rushes had always grown along this stretch of the river, and I just never noticed them. Or perhaps the flooding produced some change that gave them a foothold. In any event, the soft rush is a very common plant, though far from ordinary. Like houseflies, humans and killer whales, it is a cosmopolitan species, native to every continent except Australia.

An uncertain sign. At the gravel bar I pulled my canoe onto a mat of yellow-green roots and got out my fishing rod. I cast a few times down one eddy line, then down the other, and was not surprised at the non-results.

Then I dropped my lure directly downstream from the bar, and immediately felt the pulsating energy of a fish at the end of the line. It was a smallmouth bass, and it was determined to do the opposite of whatever I wanted it to do. I guess that pretty much defines the allure of fishing.

I knelt to pick up the fish, admiring its golden brown coloration and the vertical bands down its flanks. It was plump and healthy, with no sores or tumors that have raised alarms about the health of fish in the Potomac. I took a picture of the two of us and slipped out the hook. The fish paused for a moment at the water’s edge, and then vanished.

Handsome and healthy: icon of the
Potomac (referring to the fish).

Was the fish a sign that the river was back? Or was it just a fish? I turned to Patowmack the Trickster for an answer. He replied with a riff on Aristotle: “One bass does not a fishing season make.” As if for emphasis, a wild turkey let loose a mocking gobble from the nearby woods, and continued gobbling as I began my downstream paddle.

Ancient ritual. Now the sun was descending over the rapids and I began to see pale yellow insects, their bodies arched and their translucent wings erect as they lay on the surface, then rising into the air like spirits. There were thousands of them.

I was witnessing one of nature’s great rituals, a celebration of life and its perpetuation.  These were mayflies, an insect that spends most of its existence as armor-bodied nymphs, scuttling about on the underside of rocks on the river bottom. Now, responding simultaneously to some signal, they were transforming themselves into airborne creatures to search for a mate, reproduce, and then die.

I wasn’t the only one to take notice. Up and down the river I could hear the splashes and slurps of the fish as they feasted. Swallows joined in, swooping down to scoop up the tiny morsels and leaving behind little splashes that sparkled in the last light of the day.

Mayflies are part of what biologist E. O. Wilson calls the “little things that run the world.” If the mayflies are OK, there’s hope for everything else.

To which Patowmack the Trickster would reply, “Well, we’ll just have to wait and see.”

Fishing in the age of pandemics

During all of last year, I caught maybe four fish on the Potomac River. I would launch my boat in the creek at Pennyfield Lock and paddle through a stone-lined tunnel that runs under the C&O Canal. Nearing the creek’s mouth I would pull myself through the branches of a recently fallen tree, and choose: upstream or downstream.

It didn’t really matter. Upstream I’d probe likely bass hangouts at the foot of the rapids. Nothing doing. Then I’d drift down to a series of deep holes, where I would bump my crayfish imitation along the bottom, ready for that tell-tale twitch. The twitch never came.

If I chose downstream I would cast towards shore along the rock wall that buttressed the old canal, but nothing grabbed my lure. Then I would try a series of rock ledges where I had previously caught fish, good ones. Results the same.

I tried different places on the river: Dargan’s Bend, Harpers Ferry, and spots along the Monocacy and the Shenandoah tributaries. I talked with other fishermen. “Doin’ any good?” The answer was always the same.

This was serious. It was not like, “Well, the fish aren’t biting, so I’ll just go play golf.” For me, fishing in the Potomac is not a hobby, a pleasant pastime, but rather a critical link to my world.

Looking for answers. I wanted to know what happened to my river and what I could expect this season. So I went to the person I most trusted for answers to life’s critical questions: Dr. Antonio Fauci.

Fauci: Keep it simple and
keep it straight.

I could have gone to local fish biologists and even my own Patowmack the Trickster, who undoubtedly knows more about the Potomac than America’s epidemiologist-in-chief. And we will get to them later.

But in this moment in history, Fauci is the expert of first resort. He knows the Big Thing; he is the hedgehog of the ancient Greek poet Archilochus. He knows that, whether it’s the Potomac or a pandemic, nature ultimately holds the cards. The certainty with which Fauci knows this gives him the authority we crave in a perilous time.

When Fauci’s boss, Donald Trump, insisted that the country would be “opened up and just raring to go by Easter,” Fauci smiled and replied, “You don’t make the timeline; the virus makes the timeline.”

Unusual among public figures, Fauci is also Archilochus’s fox, who knows many things. He is a careful observer of the complexities of the natural and human reality. He is comfortable with nuance and doesn’t shy from contradictions. He is not only an authority, like the hedgehog, but also knows what he’s talking about.

As a bonus, it even turns out that Fauci knows something about fishing in the Potomac, and we’ll learn about that later as well.

The river rages over Great Falls.

River on a rant. I’ll first sketch a kind of brief clinical history about what’s happened on the river over the past couple of years.

The troubles began in 2018 when back-to-back storms and flooding hammered the river. I was dismayed to see the familiar riverscape of rocky islands and ledges disappear under a swirling, seething torrent of brown water carrying logs, whole trees, plastic water bottles, and every other manner of trash that defines the human presence in the river basin.

The shoreline disappeared, and with it the spots where I launch my kayak or canoe. All gone. And the fishing? I scarcely even tried.

I spent the winter thinking about the next season, when I’d be back in my boat, and the river would be back to normal.

Where were the fish?  The following spring I felt a little apprehensive as I slipped my boat into the water. It was as if I was visiting an old friend who hadn’t been well for a while.

The river sparkled under the cloudless sky. My paddle felt alive in my hand as it sent me gliding past the battered roots of massive sycamores and silver maples.

But even before I picked up my fishing rod, I could see that my friend was not the same. The river was strangely still, like those covid-19 videos of Times Square empty of people.

Swept clean and cracked in the sun,
the silt-covered shore would
need time to revegetate.

The shoreline was bare, as if it had been bulldozed. Gone was the green carpet of newly sprouted plants that would later turn into masses of yellow and blue wildflowers, some taller than me. No gangly blue herons flew from their riverside perches, croaking their annoyance at being disturbed.

Not only could I not catch a fish. I couldn’t even see any. I stood up my canoe and poled through the shallows, scanning the water for shadowy forms fleeing to their hiding spots. But nothing moved.

Creatures great and small—gone. The rich underwater garden of stargrass and wild celery, home to fish, turtles, and so many other creatures, had disappeared. The river bottom, formerly covered with rocks and shells that pulsed with living creatures, was now replaced by silt.

As dusk approached, no deer emerged from the forest to browse along the shore. Gone too were the foxes that would trot out of the shadows into the patches of sunlight, and then vanish again.

At dusk, mayfly nymphs shuck
their aquatic armor, take to the air,
mate, and die.

The mayflies had nearly disappeared as well. In years past, vast hatches would emerge at dusk to shed their tough body armor and emerge as fluttering, fairy-like creatures of pure white. The fish would be ready for them, and from up and down the river I could hear their slurps and splashes. The sky would also come alive with flights of swallows that would swoop down to pick the tiny creatures off the water’s surface, leaving series of splashes that caught the reflection of the setting sun. But now the river was silent and the sky was empty.

All was still except for the except for the distant slap of a beaver’s tail.

It looked down at me, a little curious,
but mostly annoyed.

Message from above. Back in the creek, a barred owl suddenly landed on an overhanging snag just ahead of me. Was it that master of shapeshifting, Potowmack the Trickster?

The bird swiveled its head to look down at me as I admired its elegant tweed plumage and its demeanor of self-assured wisdom, reminding me of Fauci behind the White House briefing microphone. Then the owl squatted down and a white stream hit the water.

That was all the proof I needed. Although the Trickster’s wisdom cannot be ignored, he is no Fauci when it comes to dignity and decorum. This boorish fellow, more clever than wise, makes his points with practical jokes and crude pranks.

Here’s an example. One afternoon I was struggling through a floating island of stargrass. My shoulders strained with each paddle stroke. I looked straight ahead, never glancing towards the shore, where the topmost branches had begun to whip about, nor behind me, where I would have seen a great cloud building. Then everything went dark. Blasts of wind grabbed my paddle and pelted my eyes with icy rain. My body flinched with each crash of thunder and flash of lightening. It was very scary.

The storm passed with a final rumbling of thunder. “You must never focus on just one thing,” I heard. “Be alert to every detail, all around you, all of the time.”

The experts weigh in. Good advice, as usual. But every time I tried to broaden my thinking about the river’s sudden decline, my mind snapped back to that dominant image of brown, surging waters and their sinister, muffled roar. The memories were still so fresh, so readily available to my search for answers.

But as time went on, my fixation on the 2018 flooding began to weaken. Maybe the flooding wasn’t the whole story. I remembered an acronym used by the legendary microbiologist Rene Dubois: OGOD. The initials stood for “one germ, one disease,” shorthand for the perils of ascribing one cause to a disease when there might be many causes, both direct and indirect. Similarly, Dr. Fauci and his colleagues speak of “comorbidities” that exacerbate the severity of covid-19’s effects on a patient.

Of course, Fauci, the Trickster, and Dubois were correct, as confirmed by a group of state and federal biologists who met last August in Harpers Ferry, West Virginia, to carry out a Mid-Atlantic Smallmouth Bass Health Assessment.

Flooding a factor. According to the biologists, the problem wasn’t just the flooding of 2018, but an increase in extreme flow events over a period of many years. Brandon Keplinger, West Virginia fisheries biologist, noted that six of the top flow years over the past century have occurred just in the past decade. Even worse, four of these top flows took place in May and June, when the smallmouth and sunfish build their nests and spawn. The fast currents destroy nests and wash the eggs and newly hatched fry downstream.

Keplinger said that fish populations could recover so long as flooding during spawning seasons occurs less than four to six years in a row. But according  to him and other experts, climate change could make such regimes of heavy flows the new norm.

Adult smallmouth bass presently in the river seem to be holding their ground and increasing in size, according to Maryland state biologist Michael Kashiwagi. However, surveys are turning up many fewer minnows than normal, which would reduce food available to the bass, and particularly the juvenile population.

Flathead catfish are the latest
addition to the Potomac menagerie.

Minnows and monsters. Fishing guides at the meeting also noted the drop in bait fish numbers and voiced concern that they might be falling victim to a program of spraying Bacillus thuringiensis insecticide by the State of Maryland to help control black flies.

Biologist Kashiwagi also noted the threat posed by increasing numbers of flathead catfish. Native to the Mississippi basin, where they grow to more than 100 pounds, the flatheads were introduced into the Chesapeake region by the State of Virginia in the late 1960s to give fisherman another target species. It turned out that the flatheads themselves target nearly anything that they can get their mouths around, including bass.

The biologists went on to cite the increased prevalence of algae blooms resulting from nutrients washing into the river from farms and municipal waste treatment plants. When the algae dies, their decomposition depletes oxygen needed not only by the fish themselves, but also by the macrointertebrates on which the fish depend for food.

With a mix of concern and
revulsion, I release the diseased
fish back to the river.

Stealth pollutants. The industrial pollution that once stained the river nightmarish hues and made it stink are largely gone. Nevertheless, I sometimes catch bass marked with red sores and lesions.  The culprit is so-called emerging contaminants, invisible and odorless, yet likely causing far-reaching impacts on the river and its fish.

Familiar household products
create a toxic brew in the river.

Vicki Blazer, United States Geological Service biologist who has pioneered in the study of these emerging contaminants, told the Harpers Ferry group that even minute amounts of herbicide residues, pharmaceuticals, and personal care products, create a toxic cocktail that not only causes visible damage, but also the now-famous intersex fish, where immature eggs develop in the testes of male bass.

A plague of kayakers. Added to the list of woes is me and my kayak, according to West Virginia biologist Keplinger. One great thing about kayaks is that they’re cheap. I used to think that is a good thing: The more people who get to know the river, the greater its constituency when it needs defenders. Kayaks also can go anywhere, no matter how rocky or shallow. I thought that was a good thing too.

I was wrong. While I despise sightseer helicopters that disturb wildlife and leaf blowers that addle my brain, I never considered how flotillas of kayaks send fish fleeing in fright when they should be feeding and tending their nests and young.

Go-anywhere kayaks subject fish
to one more stress.

A final irony. Now we’re at the start of another season. Will I find my old river as it was before? Or will it have changed, maybe forever?

So far, I don’t know. I haven’t put my canoe in the water yet because my home state of Maryland placed a moratorium on most fishing and boating.

It’ was a moratorium that could only have been invented by the Trickster. The governor’s order stated that kayaking and paddle boarding were OK, but not canoeing, which is my choice for the early season. The order also prohibited recreational fishing, but allowed something it called “sustenance” fishing.

It was too much to contemplate—the flooding, the flathead catfish, the emergent pollutants, the plastic kayaks, and now, a group of state officials sitting around a laminate-topped conference table hammering out the closure order. “I’ve always hated canoes,” said one, “ever since summer camp.”  Added another, “Where I come from, we catch it, we eat it.”

The Trickster would think this was pretty funny. For his part, Fauci might be sympathetic, since it turns out that he knows something about fishing and canoes, and even the Trickster.

Back in 2007, at an awards ceremony, the former director of the National Institutes of Health Clinical Center, John I. Gallin, recounted an incident when he and his Fauci were fishing on the Potomac.

Fauci got a bite, recalled Gallin, and “he got so excited. . . that he flipped over our canoe. . . I don’t believe he caught that fish.”

Now the the closures finally have been lifted. My canoe is on top of my car and my gear is stuffed in the back. By Thursday the river will have dropped below flood stage and, to paraphrase Trump, I’m raring to go.

Hopefully, the Trickster will be someplace far away, social distancing.

You will know them by their signs

A well-placed cork is just the thing to
stop hot air and reduce global warming.

Potowmack the Trickster would have enjoyed last Saturday’s March for Science on Washington, D.C.’s National Mall. He would have particularly liked the signs, with their crude jokes and sly displays of erudition.

He also would have liked the marchers. Although self-professed seekers of truth, they were no zealots, tight-lipped and scowling. Despite the cold and the rain, they laughed and joked even as they chanted.

The Trickster would surely have appreciated the ironies as well. Here were thousands of people with PhDs and published papers happily doing what people have done since ancient times, when truth and facts were indistinguishable from superstition and myth.

The science marchers were not merely celebrating science. If that were the case, they would have carried posters with the image of Bill Nye the Science Guy. Instead, many of their posters bore photos and cartoons of Donald Trump, the very personification of arrogance and willful ignorance.

It’s a time-tested strategy: Cast the other group as irredeemable villains—deplorables, even—and by this means strengthen your own cohesion and capacity for collective action. So it has been with the highland tribe against the lowland tribe, the Romans against the Gauls, the Cowboys vs. the Redskins. And now the champions of science here on the Mall mobilizing to battle the science deniers.

The Trickster would have loved all of this. In fact, I’ll bet he was there, perhaps in the poster of Trump with a cork in his mouth.

He even found time to infiltrate the “DNC War Room” in the form of a (probably) young and well-meaning Democratic staffer. While the marchers were brandishing their signs, the staffer was sending out a fund-raising appeal with the tag line, “Add your name if you believe in science.” She might have had a vague feeling that maybe using the word “believe” would give the scientific enterprise the factual equivalency of homeopathic medicine and tooth fairies. But in the end she hit the send button.

Sensible shoes. I felt my first rush of collective solidarity when I boarded the metro in the Maryland suburbs to head downtown. Instead of the usual tourists from the nation’s heartland, with their sports jerseys and supersize drinks, the seats were occupied by people like me, dressed in earth-colored clothing and shoes that could withstand the cold and the rain and mud down on the Mall. They spoke quietly among themselves.

Arriving at Metro Center the trickle of marchers emerging from the escalator joined the stream heading down the sidewalk toward the Mall. As we crossed Pennsylvania Avenue we were joined by many more like ourselves, and our stream became a river that emptied into a sea of marchers gathered by the Washington Monument. In one hand they held umbrellas, in the other they held signs.

A bounty of signs. These weren’t the kind of signs passed out by union organizers in the morning and collected again in the afternoon. Each sign was a personal expression. Some were original, often using scientific archanery to make their points. Others merely repeated current slogans. “There is no planet B” was one of the favorites. Original or not, the sentiments were authentic. For a sampling of my favorites go to “Scientists with Sharpies.”

Some of the signs were the product of an evening hunched over a poster board with a box of sharpies. Others were just a scrawl on a piece of paper. Elaborate or humble, the rain fell equally on all and made them glisten.

I’m sure there is some (fact-based) study out there that analyzes why people post their feelings on signboards, or car bumpers, or on buttons they wear on their shirt or blouse, rather than as an anonymous tweet. I’d guess that the sign carrier wants to personally and physically identify with the idea, not merely promote it.

The marchers were proud of their signs. When I pointed a camera their way they would snap to a pose. “Can you also take a picture of the back side?” the man asked as he pivoted himself and his sign.

Galileo: no fan of alternative facts.

‘Eppur si. . . what? I admit it—I didn’t carry a sign. But I did have an idea for one whose cleverness and erudition made me flush with pride. It almost certainly would have been unique. Or so I thought.

My sign would have read, “Eppur si muove [It moves nevertheless],” which was the phrase Galileo was supposed to have uttered after being forced to retract his claim that the earth moves around the sun, and not the other way around as was maintained by 18th century astronomy deniers.

But I never made my sign. I wanted my hands free to take pictures. I’ve always been the picture taker.

It was just as well. As I was leaving I spotted the words “Eppur si. . .” on a piece of cardboard stuck under a man’s arm. He shrugged as he showed me his sign. “I didn’t think anyone here would know what it meant,” he said.