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N: bacteria; and now amphibians?

November 6, 2011

Yesterday I attended my first DC Science Writers’ Association, DCSWA, event – the Smithsonian’s National Zoo Autumn Conservation Festival, which takes place every year at the Smithsonian’s Conservation Biology Institute. Normally, this annual event is held at the Smithsonian’s Front Royal (VA) location, but since it’s under construction, the event occurred this year at the National Zoo itself. This was my first visit to the zoo, whose beautiful setting reminded me of Taronga Zoo in Sydney (Autralia). [HUC 02070010, Middle Potomac-Anacostia-Occoquan]

Since Nanowrimo book was going to center around a lab technician as one of my main characters, I was especially interested in getting a tour of the genetics lab. Before I got there, though, I stopped at the tents to talk to other scientists about their work with and for the Smithsonian. Which is how I found myself learning about the Chytrid fungus, the cause of the skin disease, chytridiomycosis, often fatal to amphibians; as well as about bacteria that live on the skin of some amphibians, which apparently protect them from the disease. Researchers are scrambling to find out if these bacteria can be persuaded to move from salamanders’ skin to frogs’ skin.

Amphibians everywhere are facing extinction for several reasons, including shrinking habitat, but also exposure to diseases they aren’t immune to, both of which are negatively impacted by climate change.

Our very own Appalachian region salamander populations are in trouble – which I find especially alarming, because this region contains the most salamander diversity in the world. I’ve been fascinated by amphibians all my life, but frogs and toads were who I saw the most, back in Illinois and Indiana. Then Spouse introduced me to the Great Smoky Mountains National Park, in Tennessee and North Carolina, a place he’d grown up visiting with his parents. The GSMNP is uniquely situated so that it is as far south as some northern species get, as far north as some southern species get, and the same for east and west. So there is an astonishing array of biodiversity in this one place. And it was here that I first encountered, then fell in love with, salamanders. We’d cross a slippery stream during a hike, and I’d scour the water and rocks for movement, because that’s an easy way to spot critters. And that’s how I found my first salamander! I have three photos (non-digital) of two different kinds of salamanders that I saw on a trip in late May 2001: the dark brown one is climbing upon and then sitting on a mossy rock in the water; the black one with a reddish-brown spot on hir cheek is sitting on a wet granite rock. On a trip in late September 2003, I found and photographed (also non-digital) part of a light brown salamander amongst green foliage near a rock slick with moisture. Now whenever I’m near streams, I’m always looking for salamanders. I haven’t yet seen any in Maryland, but maybe I need to broaden my search. When I spoke to Kimberly Terrell yesterday, she told me salamanders are “hugely prevalent” in forests. That all you need to do is turn over rocks, which is something I haven’t tried, but I’m going to start doing immediately!

Reid Harris and graduate students at his lab at James Madison University in Harrisonburg (VA) are researching protective bacterial communities that grow on the skin of some salamanders.

This work is of vital interest to scientists studying other amphibians also facing chytridiomycosis, like Brian Gratwicke, who works with frogs in Panama. Panama is another hotspot of diversity, especially for tropical frogs. Dr. Gratwicke is part of an ambitious project that seeks to save breeding populations of endangered frogs before they disappear entirely. They hope to one day release captive frog back into the wild, but before that could be possible, they need to find a way to counteract chytridiomycosis.

I asked Dr. (Kimberly) Terrell where this fungal disease was coming from, and how had it become such a problem? Scientists now think that amphibian chytrid fungus came from southern Africa. And it turns out that African frogs were imported in large numbers all over the world to become lab animals and pets, and to be used somehow in pregnancy tests. These frogs are apparently carriers of chytridiomycosis, which escaped into North and Central America, where it has become an exotic invasive species, now wreaking havoc on amphibians all over.

So now I need to figure out how I can accommodate amphibians and their mutualistic bacteria into my storyline. Which also means a lot more reading about amphibians. Yay, science!

[Check out this absorbing video about Appalachian salamanders, and the threats they are facing today that affect humans just as much: climate change, mountaintop removal, degraded water quality from pollution, habitat loss.]

Entrance to National Zoo in DC, west side, 11.5.11

labs and tents of scientists at SCBI's Autumn Conservation Festival, 11.5.11

Nancy Rotzel, Genetics Lab Mgr, conducts tour of her facility, 11.5.11

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