Category Archives: Travels

Birding at the Bardo

Some of the world’s best preserved Roman mosaics are housed at the Bardo Museum in Tunis, Tunisia, and the Archaeological Museum in El Jem, just a little south of Tunis. They date from the time of the “Roman African Province,” 146 BCE–435 CE, a time of great prosperity (for some). After the defeat of the Carthaginians, what is now Tunisia become a trading and agricultural hub in the Roman empire. The wealthy built many large, lavish houses, some of which were eventually buried under sands and rubble until the last century. Now, they stand in fabulous museums in Tunisia.

The mosaics are often huge, several meters in both dimensions. A few are comprised of geometric designs, but most show scenes from mythology and everyday life. The mosaic artists’ work is remarkable for its attention to the particularities of natural history: local birds, fish, and other species are represented with skill and often a touch of humor.

A painful beach scene:


Some ornithology: swallow, hoopoe (fairly common in rural areas, even today), crane, owl (standing as a symbol of defeat over envy, according to the signage), a peacock, moorhen, quail, what appear to be some thrushes ready to be made into pie, and, finally, a bird being made into pie.





















IMG2737Sadly, the museums are empty of visitors. We walked through hall after hall, alone save for museum employees. The same is true in much of Tunisia. A country whose coasts were thronging (and thonging) beach holiday resorts and whose cultural sites were popular destinations for history and archaeology buffs now receives few foreign visitors. Miles and miles of beach hotels stand completely empty, as if the Rapture had taken away all the lovers of blue seas, discos, and seafood. Historical sites — Roman, Carthaginian, Byzantine, French colonial — are visited by local schoolkids and few others. Two bombings by extremists succeeded in closing down a thriving tourist economy. The terrorists got exactly what they wanted: travel warnings from Western countries that stemmed the flow of foreign money to the only remaining Arab Spring democracy.

We tolerate all kinds of risks in life, but if a minuscule risk comes from a jihadist, our governments capitulate, promulgating the message of fear, enclosure, avoidance. Travel in the last years in the West Bank and Jerusalem, and now in Tunisia, all areas flagged as “dangerous” by State Department warnings, suggests to me that a more productive approach might be one of informed engagement.

To whet the appetite, the Roman amphitheater at El Jem. Seating for 35,000. Gladiator and animal rooms still intact. Walk right in…only a nesting kestrel in the high arches and some schoolkids for company:





Photo credits: David Haskell, Katie Lehman

Sebkhet Halk el Menjel

Underfoot: the crunch of thousands of shells. On the nose: a tang of salty algae. In the eyes: dust thrown here from the Tunisian deserts and over-plowed olive plantations to the south.

The lake was a surprise, a silver sheet interrupting a day’s drive through scrub and bare soil. As we approached, the sheet expanded, nearly thirty thousand acres of shallow water.


On the southern shore, shells were blown into drifts, a molluscan gravel onto which the wind also piled the discards of humanity.



Looking down into the lake, at first we saw only multicolored bivalve shells. Then, motion: turning, spinning, leaping. Tiny shrimp-like creatures, almost translucent.


These brine shrimp (Artemia, see a pair just to the right of the black pebble above) are among the few animals that can survive the hyper-saline waters of this lake. They feed by filtering specialized halophile bacteria and algae from the lake’s shallow waters.

Birds, including thousands of flamingos, are drawn by the abundance of shrimp. Like the shrimp themselves, flamingos filter the water for their food, pumping tongues through sieve-like beaks. Long experience with humans has taught the birds to stay away from the lake edges, but we approached close enough to hear the sluicing sound of shrimp-filled water squiring through lamellae in flamingo beaks.


This lake is one of many “Sebkhets,” salt lakes, in central Tunisia. The water seems to taunt the donkeys, camels, and goats that live around them: great expanses of liquid in a parched land, yet utterly undrinkable. To the north, more abundant Mediterranean rains turn the land green and hospitable. Further south, the taunting ends where the Sahara begins.


Photo credits: David Haskell, Katie Lehman

The dawn of the Age of Ideonella


Fellow humanoids, our task is nearly complete. We’re now annually making more than 50 million tons of polyethylene terephthalate or PET plastic. We’ve been at it a while: The land is garlanded, the oceans spiced. Thanks to us, the food supply for the Earth’s next overlord is almost ready.

Ideonella sakaiensis, a species of bacteria that seems to have evolved inside a PET recycling facility, is now ready to start eating. Shosuke Yoshida at Kyoto University and his colleagues report in Science that the species possess two enzymes that allow the bacteria to use PET plastic as their only source of carbon. The bacteria glue themselves to the plastic and secrete the first enzyme. They then draw the ooze that results from this digestive process into their cells where the second enzyme finishes the work. The whole process takes six weeks, an eternity in the bacterial world, but we can expect efficiencies to develop as the bacterium develops a better work ethic.

Only 14% of plastics worldwide are recycled, so Ideonella arrived into a world that any astute student of biotheology would surely recognize as designed specifically for the eventual evolution and triumph of the species.

In a commentary on the paper, Uwe Bornscheuer of the Department of Biotechnology and Enzyme Catalysis, Greifswald University, states that if the leftovers of the bacterial digestive process “could be isolated and reused, this could provide huge savings in the production of new polymer without the need for petrol-based starting materials”. In other words, we’ll be able to keep making PET plastic even when the oil runs out. Ideonella will no doubt be thankful.



Trail markers as whetstones?

Some interesting toothwork on trail markers in North Alabama: Almost every metal sign on the trails at the Land Trust of North Alabama’s Monte Sano Preserve is incised with dozens or hundreds of striations.

IMG1978 IMG1980 IMG1983

The artist? Gray or fox squirrels? We saw plenty of grays. Perhaps night-working flying squirrels? I’d welcome your thoughts!

Rodent incisors grow continually through their lives, a self-renewing mechanism necessitated by the walnut cases, seed husks, and other rock-like coatings with which plants so inconveniently wrap their progeny. These ever-growing teeth need continual shaping and sharpening. Might this be the reason for the rodents’ attention to the trail markers? I’ve seen similar markings on horn and bone. But these biological remnants are calcium-rich, unlike aluminum trail signs. It would be interesting to hang some files in the woods and watch the evolution of dentistry.


De rerum…corpus individuum? On the nature of the periodic table.

Through the caprices of classroom scheduling, I find myself teaching a writing class in a seminar room usually devoted to the study of the grammar of electrons and the narratives of covalent bonds. My colleagues in the Chemistry Department have posted a periodic table on the wall at the front of the classroom. This arrangement is typical. You’ve likely sat in such a room. Science classrooms, especially lecture halls, often have the Table lifted in front of and above the pews, in the same location as the stained glass window or crucifix above a church’s high altar.

There is a message here that extends beyond the practical utility of having a convenient chart of the elements at hand. Behold, congregation: This is the nature of our Universe. Order exists beyond the confusion of form. And indeed, this is the nature of things (thank you, Lucretius), if we restrict our gaze (as we must when we teach any class) to one particular scale of our world (about 0.3 nanometers, atom size). But the Table’s lofty and lonely position — it is seldom accompanied by any other words or symbols — is also misleading. The world is ranged in rows and columns only in one very particular way. For a biologist or a subatomic physicist, other images are more appropriate. Years ago, when I taught Introductory Biology to a large lecture-hall of first-year students, I would lower the projection screen to veil the Table, replacing it with images of ecological communities or individual living creatures. My purpose was not to deny the power or utility of the atomistic view, still less to claim that the study of chemistry is not relevant to biology, but to reclaim visual space within our science classrooms for the messy beauty of life: unpredictable, diverse, braided.

From Darwin, at the close of The Origin (I quote from the first edition):

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us…whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

Out of physical order, an unfolding process, one that cannot be contained within ruled lines.

In every classroom from whose walls the Table gazes, let us place an equally-sized artwork of the local community of life, humans included. A twin for what Whitman called “the figures…ranged in columns before me.” An entangled bank interpreted through art and science, the “endless forms most beautiful and most wonderful” of the human mind. That, or a classroom window.

Gannets, tough heads, and offshore oil drilling.

On a beach on the Isle of Palms, South Carolina:

gannet wing

…an immature Northern Gannet, washed ashore after a sea burial. Cause of death unknown. This bird’s brown plumage identifies it as a first-year bird, hatched this spring. Adults are white (seen here in my visit to a gannet colony in Scotland); second- and third-year birds are white splashed with brown.

North America hosts only six breeding colonies, all in Canada (three in the Gulf of St. Lawrence and three in coastal Newfoundland). Adults and youngsters alike head to southern waters for the winter, feeding offshore before returning to their rocky breeding sites in April. Overwinter survival for adults is often higher than 90%, but young birds have a harder time.

Gannets are plunge-divers, folding their wings and arrowing into the water, head-first. They use the momentum of the dive to swoop into schools of fish. If they miss on the first strike, they oar the water with their wings as they twist through the water after prey. Their bodies are well adapted to this punchy way of getting lunch. Air pockets and strong shoulder bones cushion the body. The conical head and chest offer little resistance to the flow of water or air. A study of Cape gannets found that they pierced the ocean’s skin like needles, barely decelerating as they hit. The beak has no nostrils, just a tiny slit that closes tight when water pushes against it. Gannet eyes are directed forward in a binocular gaze, protected by a movable transparent membrane. One tenth of a second after immersion, gannet eye lenses compensate for the changed refraction of light and snap into underwater mode.

North American gannets comprise about one quarter of the world population. The rest breed in Northern Europe and winter off the coast of Africa. After many decades of over-hunting and disturbance, American colonies have lately been growing. Aerial surveys of nesting sites indicate a annual increase of 4.4% from 1984 to 2009. After the Deepwater Horizon disaster, though, some breeding populations dipped. After the spill, gannets were the third most common bird species recovered (dead, sick, or oiled) by rescuers. Because the explosion and spill happened in late April, most adult gannets had left the Gulf. Immature birds lingered and were caught.

Now, the Atlantic waters off the southeastern coast are slated to be opened for drilling, despite opposition from the many human residents of the coast whose interests coincide with those of seabirds.

Photo and bird-finding credits: Katie Lehman and Eva Miller.

Beach stroll. “And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.”

Dune grasses, mist. Isle of Palms, South Carolina.


A ten minute walk north, wave-bitten condos:


The ground floor: collapsed. Condos in the back of the building: still occupied, it seems.


Can sand bags and plastic pipes muzzle the chewing maw of the Atlantic? Now taking bets.


IMG1777IMG1771Just north of the foundering land-ship, the sea plays a few rounds on the golfing green and takes home some souvenirs:


On the eroding sand escarpments, plants trained by hundreds of thousands of years of beach life grasp their opportunity, then set seed and move on to the next shifting wave of sand. Here is Oenothera drummondii, Beach evening-primrose. The plant is in full bloom in December, as are other species on the island. A crazy-warm winter; the sea feels it too.


Lit up

The Sewanee sky is often dark enough to see the silver smoke of the Milky Way drifting above the treetops. On other nights:

athletic field lights in cloudsClouds are ignited by light from dozens of pole-mounted bulbs around athletic fields. The pulse and swirl of light from the wind-driven clouds obscures all else. We vault the sky with our own glow.

Twenty percent of the world’s electricity is used for artificial lighting. In most countries, night lights are getting brighter and more abundant.

At the athletic field, no-one was on the turf. The pole-bulb clusters blazed on, regardless.

Come spring, robins will gather under the lights, singing their day-songs.

September 11th Survivor Tree

A memorial pool at the site of the Twin Towers in lower Manhattan. Water flows over the lip, down to the void. Names of the dead ring the pool, marking the footprint of the towers.

911 memorial“Freedom Tower,” the tallest skyscraper in the Americas, lances the clouds next to the pools.

freedom towerI visited in winter, on a sleet-slammed, windy day. In addition to paying my respects at the site of the attacks, I wanted to see and touch a special tree. People clearing the remains of the fallen towers found a Bradford pear under the dust and concrete. The tree had stood in a planter next to the towers. Most of the pear’s branches were shattered by the attacks, reducing the thirty-year-old tree to a stub.

Now, after years of care in the City’s Arthur Ross Nursery in the Bronx, the “survivor tree” is back at the site. Unlike the rod-spined white oaks that line the wide walkways at the memorial, the pear’s body is scarred and fragile. The tree stands within its own hooped railing, its placement and form jarring with the metronomic plantings of oaks (trees that form a living, green roof for the museum and train station below). Straps loop the pear’s branches and trunk, stabilizing wood that, although it is partly healed, has fractures — tree memories — that will forever remain within.

survivor pearsurvivor pear 2Despite these wounds, the tree’s body speaks of vitality. Twigs are bud-fat and arched skyward. Rows of sapsucker holes spoke of the time that the tree spent regaining its strength in the leafier and more woodpecker-friendly nursery.

survivor pear 3A human interpreter and guide stood with the tree and translated its story from wood-words to human language, explaining to new visitors why the tree stood where it did.

Some visitors slowed, listened, and rested their hands on the pear’s skin, leaning into the sturdy life.

Others raced around, laughing, snapping smiling selfies in the sleet: Me with the Tree, Me with the etched names of the dead, Me with a big tower. Survivor Tree commemorative trays, umbrellas, mugs, and ornaments are for sale in the Museum Shop.

Sadness upon sadness, “As if there was no death.”


Sand tracks

“In every outthrust headland, in every curving beach, in every grain of sand there is a story of the earth.” Rachel Carson, writing in Holiday magazine, 1958.

From the curving beach of St Catherines Island, another blog post in the grapheme series (parts I, II, and III). Sand scribblings. For the full coastal Georgia effect, view in a steam room with the heat turned up to one hundred degrees. Click on any image for the slideshow: