Wood frogs (Lithobates sylvaticus) freeze solid over winter and come back to life in spring
by Karen McDonald
Wood frog (Dave Huth)
Here in North America there are a wide variety of toads and frogs, but perhaps none are so unusual as the wood frog. These frogs are found in Eastern North America, Canada, and up into Alaska. On a warm spring night you might hear them singing(click here for sound clip) near bogs, vernal pools or upland forests, but something remarkable happens to them this time of year in the winter: They freeze solid. Now freezing solid isn’t remarkable by itself, but what is remarkable is that the frogs will literally come back to life in the spring, after having no heartbeat or brain activity (they don’t even breathe) for up to eight weeks! This baffles and amazes scientists, who are actively studying them even now.
Herve Memiaghe, front, in Gabon’s Rabi forest plot. The red line marks where they measure the tree’s diameter. (Smithsonian Institution)
Herve Memiaghe isn’t the average intern. Before coming to the Smithsonian Environmental Research Center, the 33-year-old Gabonese ecologist had already earned a master’s degree and spent four years working at IRET, the Institute for Research in Tropical Ecology in Gabon. Since 2012 he has also done field work in the Rabi plot as part of the Smithsonian’s global forest study.
The 25-hectare Rabi plot sits on the southwest coast of Gabon. Diversity spikes in the rainforests of Central Africa, where a single hectare can contain more than 400 different species. And that’s just the trees. The animals bring problems of their own. In Memiaghe’s experience, it’s not uncommon for hungry elephants to eat the tree tags along with the leaves.
“Sometimes we find the tag in the dung of elephants,” Memiaghe says. Usually the scientists can figure out where the tag came from, so it doesn’t throw off their research that much. “It just maybe can be a mess for the new people.”
by Monaca Noble, Kristen Larson, Linda McCann and Ian Davidson
Video: Biologists place pennies underwater to test how well volunteers can spot small invaders
What is the Bioblitz, and why would researcher Linda McCann cash in her dollar bills for hundreds of pennies in preparation for it?
Bioblitzers braved the rain to search for invasive species. (Deborah Mercy)
A Bioblitz is an intensive survey in which trained volunteers head out en masse to catalog species in a specific area. On September 28, volunteers in Ketchikan, Alaska, joined staff from the Smithsonian Environmental Research Center (SERC), San Francisco State and the University of Alaska to search for invasive marine species along Ketchikan’s waterfront. The Marine Invasive Species Bioblitz in Ketchikan had three goals: to engage and teach the public about invasive species, detect newly arriving species that threaten Alaskan coastal waters, and recruit these enthusiastic volunteers for future monitoring efforts.
7-year-old Cecilia Bowers collects frogs in the SERC forest. (SERC)
It’s 2 o’clock in the afternoon. In the forest beside SERC’s beaver pond, Dylan McDowell and Shelby Ortiz have just finished helping a dozen 7-to-9-year-old students search for frogs and toads. They’re headed to the stream when McDowell runs into a dilemma: Some of the children don’t want to release their frogs.
“It would be really hard to find frogs around where I live,” says Emma Guy, who doesn’t have any parks or forests near her home.
“Did you know a couple years ago, they found a brand new species of frog in New York City?” McDowell asks her. He’s referring to a new species of leopard frog confirmed in 2012, whose known range has Yankee Stadium almost dead center. Closer to home, SERC biologists discovered juvenile eastern spadefoot toads in one of its wetlands this summer—the toad’s first recorded appearance on the SERC landscape. McDowell’s point, at least for the afternoon lesson: Amphibians can appear almost anywhere if you know where to look.
As store aisles quickly fill up with back to school supplies, SERC’s summer education programs are coming to a close. SERC’s Education Team took a slightly different approach to summer programming this year. Instead of hosting summer camps, they sponsored three “activity weeks” throughout the summer. Each activity week had a specific theme, and was tailored to different age groups. The first of SERC’s activity weeks was “Changing Environments,” designed for students aged 13-15. The week focused on certain case studies that highlighted environmental changes. The students also visited SERC’s weather tower, and went on expeditions in the SERC forest to catch insects and frogs. “Kids Unplugged”, the next week, was made up of students aged 7 to 9. One of the more memorable lessons was when the kids made “scat” out of play-doh in order to better understand the types of birds and mammals that live in the SERC forest. The last activity week, “Junior SERC Scientists” introduced 10-12 years olds to problem solving and the scientific method. They used forensic clues to discover who “killed” a beaver. The kids put their sleuthing skills to the test and found that the murderer was none other than Education Intern Shelby Ortiz!
There is a certain art to the deployment of a crab tow. This brown metal and net contraption, about three feet long and a foot wide, scrapes over the bottom in search of juvenile blue crabs. Fitting three people, two coolers, a selection of buckets and bins and the tow in a 16-foot jon boat is something akin to a giant game of Tetris. Successfully launching and recovering the crab tow without smacking anyone in the face or knocking anything overboard requires practiced choreography and grace.
With a one-two-three, the metal tow hits the water with a splash. After 300 feet, lab tech Paige Roberts gracefully maneuvers the jon boat backwards and forwards to retrieve the tow. Paige captains the jon boat a bit like a fighter pilot—precision is required to coax the unwieldy boat around shoals, patches of sea grass and oblivious jetskiers. Click to continue »
Alyssa and Carey begin their search for key nutrients in a stream in the Choptank Watershed.
The nutrient lab is still plagued by the mystery of the missing nitrogen. More nitrogen enters the watershed than exits it, and the question remains: Why?
How much nitrogen makes it to the bay can have huge impacts on the water quality and bay health. The Choptank watershed, in a farm-heavy area, has much lower levels of nitrogen in stream water than expected. As farmers add fertilizer to their crops, some nitrogen gets taken up by the plants, and the rest washes away into the watershed , eventually reaching the Chesapeake Bay. Of the nitrogen that is added as fertilizer, only 20 to 30 percent of it is accounted for.
In a narrow, slow-moving stream in the Choptank watershed, fondly nicknamed “Pizza Branch” (due to its proximity to a lone pizza joint puzzlingly located in this predominantly farming area), researchers working under Tom Jordan, Principal investigator of the nutrient lab at SERC, are using different methods to help determine what’s happening to the nitrogen. The project is a joint effort between SERC and Tom Fisher’s lab at the Horn Point Laboratory of the University of Maryland.
Researchers brave high heat, humidity, and voracious mosquitoes to take water samples, a process that can take all day. While taking water from a stream may seem like a straightforward undertaking, the true complexity comes through in the lab, where analysis of microscopic dissolved compounds can reveal the secrets of a watershed.
“It’s a fun challenge to go all over a stream and take samples and bring them back to the lab, to discover things you can’t see with your eyes,” said Jordan. Click to continue »
If you take a stroll out along the green grated catwalk that lies several feet above the muddy marsh ground at SERC, the first thing you’ll notice is strange white structures dotting the lush landscape. No, the aliens haven’t landed. These white enclosures make up several experiments at SERC. The goal of each experiment is to determine how a changing climate will affect this valuable marsh habitat, which stores carbon, has high primary productivity, and provides homes for fish, crustaceans, insects,and more.
The SERC marsh. Under each capsule, conditions are set to mimic the CO2 concentration expected in 2100. ( Thomas Mozdzer)
Carbon and Nitrogen: Elements of Growth
Since 1987, SERC scientists have been pumping CO2 into these plastic chambers to simulate the marsh a century from now—a marsh in the grip of climate change. Inside these miniature time capsules, marsh plants grow with 350 parts per million more CO2 than is in the atmosphere today, levels scientists expect to see by the year 2100.As marsh plants grow, they take in CO2 from the air. This carbon can either end up sequestered in the soil or released back into the ecosystem through decomposition. The CO2 addition experiments conducted at SERC are the longest-running in the world.
Besides carbon, marshes also rely on nitrogen, an element necessary for the creation of proteins. Due to runoff from fertilizers, nitrogen levels are also increasing in estuaries like the Cheasapeake Bay. As the concentration of both CO2 and nitrogen increases, scientists at SERC are asking important questions about how the structure of the marsh will be affected, including how it will change the plant communities that will grow there.
European green crabs are eating and marching their way up the west coast.
One of nine marine invertebrates to make the list of the world’s 100 worst invasive species, they’ve had major economic impacts on shellfisheries in New England, including blue mussels, the Virginia oyster (Crassostrea virginica) and Bay scallops. Impacts are mounting on the west coast too, where losses to bivalve fisheries (Pacific littleneck, Japanese littleneck, softshell clams and blue mussels) are projected to reach $20,000-60,000 per year. Ecologically, their impact has been no less severe, as they prey on and compete with other crabs, bivalves, gastropods like snails and slugs, and many other invertebrates.
European Green Crab Carcinus maenas. Green crabs have visited every continent but Antarctica. They’ve colonized parts of the Americas from Alaska to the southern tip of Argentina. (Arthro)
Green crabs are exceptional world travelers, making it from their native region along the European Coast to six major regions of the world, including the Northwest Atlantic (Maryland to Newfoundland), the Northeast Pacific (California to British Columbia), Patagonia, South Africa, Japan and Australia. Their mode of transport may vary, but evidence suggests they’ve been transported with the live-bait trade and in ships’ ballast water.
Green crabs have been on the East Coast of the US for about 200 years, according the NEMESIS database. They made their first appearance near New Jersey in 1817. From there they moved north, reaching the Bay of Fundy, Nova Scotia in 1953, the Gulf of St. Lawrence by 1994, and finally, Placentia Bay, Newfoundland in 2007. Their southward expansion stopped at the Chesapeake Bay; possibly they couldn’t compete with the blue crab (Callinectes sapidus).
(Video: Woolly aphids dancing on a beech tree at the Smithsonian Environmental Research Center. Credit: Tyler Bell/SERC)
Any creature with the word “blight” in its name can hardly escape being labeled a pest. Beech blight aphids are no exception. Like mosquitoes of the tree world, aphids have a vampirical tendency to suck the sap out of trees they colonize, and–while they do not usually kill the entire tree–they can take out some of its smaller branches.
But like all names, pest is a matter of perspective. And aphids have evolved some redeeming qualities as well. Not least is their peculiar ability to dance in the face of danger.
This quirk has earned them a more endearing nickname: the boogie-woogie aphid. Whenever aphids feel threatened, they raise their rear ends and sway, sometimes hundreds or thousands at a time. Up close their abdomens resemble white feather dusters. It’s a defensive dance meant to ward off predators. But in a flip of the natural order, it’s generally the children–not the adults–who do the defending. If larger creatures like moth larvae get too close, young aphid nymphs spin around and sting the predators with the same stylet mouth pieces they use to drain the beech branches.
Honeydew: "aphid poo", excreted after aphids digest tree sap. (Susan Cook-Patton)
Sooty Mold: Fungi that colonize honeydew for its sugar, turning it black. (Kristen Minogue)
And while aphids mean death for small tree branches, for other creatures they give life. After drinking the tree’s sap, aphids excrete it as sweet-smelling honeydew. Ants and other insects flock to it for the nutritious sugar. So do fungi, which rapidly colonize the honeydew and turn it into black sooty mold. Unlike the aphids, the fungi do not penetrate the tree’s surface. Some researchers doubt whether beech blight aphids have any serious effect on the tree’s health, other than producing “vast amounts of aesthetically displeasing sooty mold.” Which would make the name beech blight aphid, though technically accurate, a bit unjust.
As one reader pointed out, “woolly aphid” and “beech blight aphid” do not mean the same thing. “Beech blight aphid” refers to the species Grylloprociphilus imbricator. “Woolly aphid” is a broader name that includes beech blight aphids and other aphids that secrete waxy threads to resemble wool. The video above shows woolly aphids that are probably beech blight aphids.