On this Sunday past, Lily and I went to the National Aquarium, in downtown DC, in the basement of the Department of Commerce. Most people, when they hear "National Aquarium," think of the much bigger, much better facility in Baltimore's inner harbor. But Lily really wanted to see this one, so we went. I remembered from when I visited it as a kid that it was a pretty disappointing exhibit, and I can report from adulthood that... it still is.

Just the same, there were some cool creatures housed there in many tanks, and I hereby present the three best photos I took for your enjoyment:






(that last one is a snakehead fish - invasive in the Potomac River and its tributaries)

Labels: amphibians, dc, fish

As a high school student in Arlington County, Virginia, I used to take regular hikes down a path called Windy Run, and then walk along the south shore of the Potomac River, upstream. It was in the days before I knew anything about rocks, and I was mainly appreciating other aspects of nature, like the plant life, the birds, the bugs, the salamanders, and occasionally something really cool like a raccoon. But I was aware that the scene I observed and enjoyed was not the same scene that had always persisted.

I heard rumors from my uncle about patches of woods inside the DC Beltway that preserved virgin forest -- giant trees that gave a hint of the former majesty of this eastern hardwood forest. I read about an eastern herd of bison that would migrate north and south through the Piedmont and Coastal Plain, crossing the Potomac near Alexandria (before we killed them all). I noticed a gazillion deer, and had it explained to me that the lack of predators like cougars and wolves resulted in the herbivores' population explosion. We used to have elk here, but European colonists had extirpated them. The last of the bison were killed off by 1800, and the final elk met a bullet around 1850. This used to be a pretty wild place!

I observed trash nearly constantly, often mixed obscenely with natural debris, sheathed in mud, or woven into birds' nests. Every few minutes, a jet airplane on its approach to National Airport would thunder overhead. Those of us who lived in the flight path would learn to automatically put conversations on "pause" during the 30 seconds it took for the planes to pass. Visitors didn't know what to do about the noise; it was too pervasive to be ignored. But live here long enough, and you learned to ignore it. You adapted, like the birds adapted by putting aluminum foil and plastic bags into their nests.

And the river itself? It's gross. In the modern day, it's constantly muddy and silty, with a foul-smelling sewage/sediment biofilm all over the rocks and logs in the water. There's scummy flotsam and rumors that you'll get a rash if you swim in it. There's people fishing down by Teddy Roosevelt Island, and you have to wonder why... They're not going to eat the fish they catch out of this polluted stream, are they?

The theme of this month's Accretionary Wedge is "time warp." The Wedge is a geoblog 'carnival,' though it's been inactive for a while, this month sees its return to 'accreting.' For those of you who are new readers to NOVA Geoblog, it's probably a great opportunity to check out some of the dozens of other interesting geoblogs out there. So what does this have to do with my reflections on the local woods, and the Potomac River? This month's Wedge host is Lockwood from Outside the Interzone. He asked geobloggers, "Where and when would you most like to visit to witness and analyze an event in Earth's history?"

I'm going to use my time travel experience to go back in time right here, in Washington, DC. I want to go back to 1491*. I want to see what my home looked like before European settlers showed up and brought their particular brand of industrialization / civilization / land use changes / ecological perturbations to the Potomac River valley. It may surprise readers to learn that I'd opt for this -- a simple experience of pre-colonization North American nature -- over something tectonic and structural, but that's what calls to me on a deep, emotional level. I want to see a vibrant ecosystem with big trees. I want to see the water of the Potomac River look like water; I want to go swimming in it. I want to see what bird migration looked like before it dropped off so precipitously. I want to see a passenger pigeon, a carolina parakeet. I want to see for myself what a healthy amphibian population looks like. And bison fording the Potomac in Alexandria... perhaps emerging from the clear water with the autumn colors ablaze on the far side of the river? That would just be... awesome.

* Note that there's a good book by this same name, on this same theme, 1491. The book makes the case that there was already a lot of landscape/ecological modification playing out before Europeans arrived: that native Americans played a significant role in messing with natural systems and we shouldn't imagine an ecological paradise, just less of an ecological disaster.

Of course, going back to 1491 may have some negative aspects to it: there would be malaria endemic to DC at that time, and the native tribes might not take kindly to a time traveler popping in to ogle their forested homes. But I'll take those risks (they exist today in other places I've visited), since the pay-off would be such a profound deepening of perspective.

If I had the ability to go back in time, I'd use it to gain experience with pre-colonial North America. I'd check out the same river banks I would walk 500+ years later, and see what we've lost.

...And, once I've seen that former world, I can't guarantee that I'd come back.

Labels: amphibians, birdies, blogs, dc, environmental, geologic time, mammals, piedmont, rivers, virginia

Elizabeth Kolbert writes about topics I'm interested in reading. I dig her.

The latest is a piece she wrote in last week's New Yorker entitled "The Sixth Extinction?"

It's about the decline in biodiversity around the world, using frogs succumbing to a deadly fungus and white-nose syndrome in bats as case studies in extinction. It has a decent (though not perfect) geologic perspective -- worth reading. The online version is hidden behind a paywall, but maybe you can access it at your local library.

Labels: amphibians, evolution, geologic time, mammals

Audio (and video) to share the sound of springtime froggies calling, along the Berma Road trail in C&O Canal National Historical Park:

Labels: amphibians, maryland

It's rare for a terrestrial vertebrate to give up its lungs. But this fellow appears to have done just that. It's a newly-described species of frog from Indonesia. They get all their oxygen through diffusion over their skin surface, including skin flaps coming off the arms and legs. There are a few lungless species of salamanders and as well as caecilians, but this is the first frog: in dissections of eight specimens, nary a lung was found. CNN has more.

Labels: amphibians, evolution

This is an amphibian that you wouldn't want to meet in a dark alley: Beelzebufo, a monster fossil frog from Cretaceous sediments in Madagascar. It resembles the ceratophryine family of horned toads (sometimes dubbed "pac man frogs") that are now unique to South America, which the authors of a new study published in the Proceedings of the National Academy of Sciences.

Here, artist Luci Betti-Nash's whimiscal painting of Beelzebufo has it facing extant species Mantidactylus guttulatus, the largest frog in modern-day Madagascar.

The discovery of the big croaker suggests that South America and Madagascar were linked landmasses for much later than previously deduced from other lines of evidence. However, the newly-implied gap in time is substantial. Previously, it was inferred that the two landmasses separated 120 million years ago (Aptian), but the interpretation of this new fossil is that it must have been after 80 million years ago (Campanian). I'm not sure I buy that huge jump in separation dates based on a single genus of fossil frog: 40 million years is a substantial amount of time. On the other hand, sometimes "small" pieces of evidence like this lead to the development of new paradigms in scientific thinking. It has the potential to be the proverbial thread which unravels the sweater.

My caution: It's important to remember that fossils which resemble one another don't necessarily imply a continuous population: there's convergent evolution to consider, as well as the possibility of a highly conserved morphology over time. Both of these phenomena could maintain similar looking populations of "pac-man-esque" frogs on unconnected landmasses. And, I suppose, there's even the less-likely possibility of a "rafting" incident, where a few individuals ride a mass of vegetation across the ocean(s) from South America to Madagascar well after the two have separated. It happened to iguanas, after all: getting from South America to the Galapagos. Actually, with amphibians, their eggs can sometimes hitch a ride on bird feet too, colonizing distant new areas with ease. I'd like to know more about the presence or absence of relevant fossil frogs in Africa during the Cretaceous in order to better evaluate this new interpretation.

Read more about it in this New Scientist article. (I couldn't find the "cited" original article in PNAS, for some reason.)

Labels: amphibians, evolution, fossils, plate tectonics