Friday, September 13, 2019

Wombat “hunting” across Australia and a wild ride

Picking up wombat poo--better than sitting behind a computer all day

         In 2007, I set out on a trip with Seth Newsome, husband Chris, and son Evan to study the geo-ecology of the Southern Hairy Nosed Wombat (Lasiorhinus latifrons). In a recent paper (Miller et al., 2005), we had compared the carbon isotope values of fossil emu and Genyornis eggshell with those of the wombat, an herbivorous grazer. The Southern Hairy Nosed Wombat is still extant in South Australia, so it seemed logical to study this modern organism in order to interpret a sizable collection of fossil specimens. I contacted Rod Wells at the University of Adelaide, who is the world expert on the Southern Hairy Nosed Wombat, and set up a field trip to his wombat preserve.

         Wombats live in burrows they excavate into the red, hard-pan soil. They aren’t strictly colonial, but you often find their burrows within 100 meters of one another. I’d read that wombats were slow - traveling at a top speed of 100 meters per hour  - and they foraged during the early morning and late afternoon. I also learned that if a predator (e.g., dingo) tried to enter their burrow, the wombat wedged its substantial rump in the burrow essentially blocking access.
Evan Swarth inside of wombat burrow, South Australia

         One evening, we went “wombat hunting” to observe them foraging on a local ranching station. Several wombats were grazing far from their visible burrows like gazelles grazing on the Serengeti Plain in Africa. Seth and my son Evan wanted to see how close they could get to them, so they started slowly walking then sprinting towards them. Within seconds, the wombats raised their heads, saw the impending danger, and ran towards their burrows. Quickly the pace increased until the wombats were running at full tilt, easily outrunning the humans. As they neared their burrows, the wombats took a dive and disappeared neatly underground. Definitely faster than 100m/hour!
Southern Hairy Nosed Wombat out for a stroll

         We were able to collect many wombat skulls, teeth, and bones because of their interesting, fastidious, and unique behavior. When a wombat is nearing death, it goes into its burrow to die. Later its younger relatives push the deceased animal just outside of the burrow leaving the skeleton conveniently available for sampling. We collected hair, teeth, skeletons, feces, and dietary plants from their range south of Adelaide all the way across the Nullabar Plain.

            Wombats have continuously growing teeth, so the teeth can be sub-sampled and analyzed to determine the variation in diet and drinking water across several seasons. We were interested in using carbon and oxygen isotope values in their teeth to examine seasonality in this region of Australia. Fossil wombat teeth collected in the Murray-Darling basin showed distinct seasonal trends providing us with a record of how influential the Intertropical Convergence Zone (ITCZ) has been in fueling the summer monsoon in this region over time.

Marilyn, Evan, and Seth Nullabar Plain 2007
            Unfortunately, we were unable to accurately date our fossil wombat teeth using radiocarbon methods, because apatite is contaminated during processing with modern carbon. When teeth are compared with eggshell material from the same location, we could use carbon isotopes as a record of whether grasses were C3 or C4, a parameter than remains important in interpreting the isotopic composition of eggshells and inferring the strength of the summer monsoon, and by extension ecosystem structure. Analyses of wombat teeth from specimens older than the megafaunal extinction >45,000 years ago had 60% C4 plants in their diet.  After the major extinction event, carbon isotope results from teeth showed only a 20% contribution from C4 plants, similar to the shifts we measured in the carbon isotopes of emu eggshells.

            At the end of our “wombat” expedition in 2007, we headed our 4WD vehicle towards Alice Springs from the Nullabar Plain. Seth and Chris were the drivers. Evan and I were passengers. There wasn’t a major road connecting the very southern part of the continent with central Australia. We’d need to detour about 400 km out of the way if we drove on paved highways. This was my 7th trip to the Outback, and all of us were accustomed to traveling on dirt tracks. A look at our atlas map showed a nice short cut called Googs Track, which seemed like an easy 2-3 hour short hop saving us a lot of time. We always traveled with plenty of water, extra fuel, spare tires, and food.
Googs Track memorial for Dinger

            We started heading north on the track around 10 am, thinking we’d be on the main road, Stuart Highway, going to Alice by about 2 pm, if we took our time and stopped for lunch. The track began easily. Chris started as the driver with me in the front passenger seat, Evan and Seth in the back. Our first high dunes brought shouts of yippee! I insisted that Chris toot the horn in case a vehicle was coming from the other direction. Fortunately, we hadn’t seen any vehicles coming south. After the 50th serious dune crossing, we stopped for a rest. It had taken us a couple of hours to go about 50 km of the 200 km track.

            The wilderness views were stunning. We climbed dune after dune each one a challenge to climb with a wild winding ride on the downsides. We were happy to be privileged to see such a beautiful landscape. After another hour we reached a small memorial to Goog and his son Dinger, who plowed the track with their bulldozers and tractors. It was just 1:30 pm when we pulled off the main track to see one of the salt lakes a few km off the track. Seth was now driving with Evan sitting shotgun next to him. We were going fast—then rounded a curve and saw another vehicle coming straight for us—also traveling fast. Seth slammed on the brakes, the vehicle fishtailed in the sand, and we stopped mere inches from the other vehicle.
Salt lake off of Googs Track, 2007
 Everyone jumped out of the vehicles. I was shaking. The guys in the other vehicle were what I’d call “hoons”, Australian rednecks. They thought this was funny. I did not. If we’d collided with them, we’d be stuck with no support likely for days.  Chris took over driving. Evan was banished to the back seat. If we had been lax about seat belts on dirt roads before, I was now strict that they were on for all at all times.     
            Chris wrote in his field notes:

“ The dunes became more frequent and they were high. Soon we were flying up one side of the dune to the crest at which point we lurched suddenly over the top and plummeted down the other side. On some descents our stomachs dropped out as we flew over the crest. The driver had the least uncomfortable seat because he could hang onto the steering wheel when the car began jostling and rocking. Our roller coaster ride over the dunes was a lot like being in a small boat going over big swells in the open ocean.”

            Three hours later at 4 pm, on our 250th huge sand dune, we were exhausted. Chris and Seth traded off, and fortunately we had not met any more vehicles head on.  We reached the end of Googs track in the village of Malbooma around 5:30 pm as the light was fading, shaking our heads on how this could have been thought of as a “short cut” in any sense of the word.
We made it to the end--safely!

            This journey was before cell phones gave you instant information on road conditions. We learned later that people took 2-3 days to traverse the 350 dunes on Googs track. Luckily for us, traffic usually always goes south to north, which saved us from further possibility of a head on collision. I’d take that road again any day, but this time, I’d want to enjoy its beauty and solitude for 2-3 days.
Watch out for wombats--you never know where you'll see one!

Tuesday, September 10, 2019

The old Geophysical Laboratory on Upton Street

Geophysical Laboratory early 1900s

            Built in the early 1900s, the Geophysical Laboratory, two blocks off of busy Connecticut Ave. in Washington, DC, was designed specially for sensitive temperature measurements important for determining how the interior of the Earth was structured. The Laboratory’s interior walls were 18 inches thick (about 40 cm) and the exterior walls, at least two feet thick. Perched on top of the 2nd highest hill in Washington (the National Cathedral is the highest), the Lab commanded a view of much of downtown D.C. through the filter of tall trees that graced the grounds. I first saw the Lab in July 1977, a couple of days before starting my postdoc. It was the 4th of July weekend, so I was to start work immediately after the holiday. My friend Nancy “Nat” Peters drove me by. We stared in awe of the august building. I was humbled.

            When I arrived for work a day or so later, entering into the double doors of the main entrance, the 1st Floor hallway was eerily silent. Wooden museum cabinets flanked the walls containing mineral specimens that had been given names in honor of the famous scientists who had worked at the Geophysical Lab. I reported first to Tom Hoering in his office and lab suite on the 1st Floor. Hoering’s office centered on his old oak desk and was flanked on either side by lab benches holding a balance for weighing, a small refrigerator, and two gas chromatographs. He loved being among the hum of instruments, even in his office. The main lab held three mass spectrometers—an old homemade instrument, a new Nuclide mass spectrometer to measure hydrogen isotopes, and a 3rd mass spectrometer for measuring the chemical structures of unknown compounds from sediments, oils, and rocks. Lab benches by the front windows were covered with custom made glass vacuum lines with columns of liquid mercury, pumps, and furnaces. A smaller interior lab included two ancient, soapstone hoods that barely worked, a bromine-pentafluoride vacuum line, and the laboratory bench that became my “home” for doing research for the next several years.
Tom Hoering with his mass spectrometer, circa 1977

            After a brief meeting, I was taken to the 2nd Floor where the Director had a suite of offices and the secretarial staff was located. In those days, people used telephones and letters to communicate, rather than email or text messages. Secretaries answered most phone calls, then used a complex series of bells to summon us to answer the phone. My call sign was 5-1: ding ding ding ding ding pause ding. Hoering’s was 5-2. When we heard five rings, we both listened up. The secretaries also typed all of our manuscripts and correspondence. They were sources of important information on how things really worked.

            I was assigned a desk space at the other end of the hall from Tom’s lab, just outside of Larry Finger’s crystallography laboratory on the 1st Floor. With tousled curly brown hair and a matching beard of a similar unruly nature, Finger had designed an automated laboratory with two or three sophisticated X-ray instruments specially designed to measure the crystal structure of very small pieces of common and rare minerals. He was an early computer whizz. His inner office, stacked with paper computer codes, punch cards, and various computer parts, was the typical scientific mess. Larry was assigned the job of computer support for the Lab, which took up a considerable amount of his valuable time. Often he was seen as a grumpy tyrant, but in reality, he was very generous with his time and knowledge.

            Over the next few years, my Lab “real estate” expanded from the Basement all the way to the Attic floor. To sterilize the media for my microbial cultures, I used an autoclave—a large, hot, pressurized cylinder that was installed in the basement room where the maintenance staff ate their lunches and changed their clothes. When I was coming down the spiral staircase into this room—the support staff lair--I whistled so that I wouldn’t literally catch them with their pants down. One floor lower was where the Boiler Room and Electrical Vault lay. The Lab’s only shower, peppered with mold and grime from years of neglect, was located on this level. The few women at the Lab rarely, if ever, used it. The Electrical Vault doubled as a Barber Shop, run by our mail clerk, Harvey Lutz. Budget conscious staff scientists had their hair trimmed there on a regular basis.
L. B. Patrick "Pat", Dave Ratliff, and Pedro Roa, Janitorial staff, circa 1985

            The Attic was a similarly unusual place that served many purposes. It housed a storeroom of used glassware and chemicals, a dark room for processing photographs and slides, an archive of old papers, a museum-like office with former staff member Frank Scheirer’s pipe, desk, and papers, and a small room that I used for transferring microbial cultures. When any postdoc needed a few beakers for an experiment, she/he was sent by Dave Singer, the Assistant to the Director, to the Attic to see if some could be found in the jumbled storeroom. The storeroom held a treasure trove of old historic junk, including all of the radioactive samples analyzed over the Lab’s history.

            In order to maintain sterile conditions, I needed to shine ultraviolet lights on the bench tops for 8 hours prior to working. Here was my routine: 1) make the culture media in my lab on the 1st Floor; 2) carry it and the glassware for growing the microbes into the Basement where it was sterilized; 3) bring it up to the Attic for inoculating with microbes; 4) carry down the cultures to my lab on the 1st Floor. Hardly convenient, especially since the Laboratory had no elevator!

            Tucked underneath the stairs on the Ground Floor, Doug Rumble’s small lab housed the Nuclide isotope ratio mass spectrometer we shared. I would prepare samples in my 1st Floor lab, then shuttle them downstairs for final analyses. Our gas tanks came into the Ground Floor from an adjacent parking lot. When we needed one upstairs, our janitorial staff used an old-fashioned dumbwaiter to physically haul it up. The instrument shop took up much of the real estate on the Ground Floor. Employing three to four machinists at any one time, the Shop could make any complex metal structure you could imagine. Having this facility on site made the difference for most of the Lab’s scientists, who designed their own specialized equipment. The men’s only restroom was on the Ground Floor and was the only restroom in the building when it was built, meaning there was no ladies restroom! Sometime in the 1930s, a Ladies room was built on the 2nd Floor.
The Shop and Electronics Staff, circa 1983

            The rear of the Laboratory held three external, separate buildings—the Dog Sheds, low “temporary” laboratories built for research during World War II; the Electronics Shack, housing our electron microprobe; and a metal shed holding years of old, often-leaking chemicals. Rus Hemley managed to build a nice lab in the Dog Sheds that overlooked the volleyball court, that was outside the Dog Sheds and actively used for games at lunchtime. We also used the court for disposing waste bromine pentafluoride, a nasty explosive chemical reacted safely with the water vapor in DC’s humid air.

            The exterior of the Lab was tan stucco, with a very distinct patch on the side that was replaced after a serious fire. Two tall holly trees dwarfed the front flanks of the building. Rambling roses covered the front entrance giving the appearance of a modern day Sleeping Beauty castle. Azaleas imported from Japan by visiting scientists rimmed the front lawns. We held picnics and barbecues there, as well as the Friday afternoon beer sessions. A curving driveway swept up from Upton Street in a loop. It was not that unusual for someone’s car to roll off the driveway into the lawn because their parking brakes weren’t set.
Front of 2801 Upton Street, circa 1987

            In photos of the Lab when it was first built, all of the trees were small saplings. A large weeping willow, planted by staff member Joe Boyd to hide the electrical lines, frequently took out our power at the first sign of wind or a thunderstorm, something that happened almost weekly in the summer. The saplings grew into massive oaks, maples, and walnut trees. In one of the massive storms that swept through the area, postdoc Zach Sharp and I watched from the front doors as tall trees were completely uprooted, flying like tooth picks under the influence of the violent winds. The grounds were nearly destroyed; electric lines were downed. A large, uprooted walnut tree at the rear of the Lab was recycled one weekend by my husband Chris and postdoc Susse Wright’s husband Tom. Tom Wright, an NSF program director, grew up on a tree farm in Alabama and had a chain saw. He and Chris sawed off the limbs, loaded the heavy trunk onto the back of Chris’s Jug Bay Wetlands Sanctuary work truck and took it to a small sawmill in southern Maryland. We have a picnic table built with the lumber and shared some of it with others at the Lab. I cherish it as a memory of that day and of the old Upton St. Laboratory.

            Without question the old Geophysical Laboratory building had history, class, and a unique character. We all loved it, but eventually it began to limit our scientific research. The electrical system was a rat’s nest. My laboratory had power lines coming in from three sources, one of which ran through the Instrument Shop. When they turned on a certain milling machine, one of my mass spectrometers would catastrophically shut down. We didn’t have enough space for new equipment; if we did, it often got stuck on the stairways bringing it in. NSF refused to fund a new mass spectrometer we desperately needed until we moved to the new lab. The fume hoods could no longer handle the chemicals we were using. The DC Environmental Protection agency was appalled at our old chemical storage shed. In summer time, the room air conditioners were insufficient to cool labs. In winter, the old boiler often broke down for days at a time. The Lab was contaminated with radioactive carbon, so our work on dating bones needed to move to the National Bureau of Standards. It was time for a change.
Bottom row: Charlie Prewitt, Joe Boyd, Doug Rumble, Ed Hare, Tom Hoering; Back row: John Frantz, Dave Mao, Dave Virgo, Bob Hazen, Larry Finger, Rus Hemley, Bjorn Mysen, Marilyn, 1990 prior to moving

            In 1990, we moved to 5251 Broad Branch Rd., N.W. campus amid a flurry of activity. Ed Hare claimed he wouldn’t move and refused to pack up his lab when the moving trucks came. The Laboratory photo that year showed us all in our work clothes, informally posing on the front steps. Tom Hoering worked so hard, he took naps on cardboard spread out on his old lab benches, now vacated. The move took over two weeks. When it was over, we came back to see the bones of our beloved building. Even today, when I dream about the Geophysical Lab, which I do often, it’s always the Old Lab that I dream about. Memories of the old Lab are dear to many.
Moving Day, 1990

Rounding Third Base and Heading Home

Cards from Franny and Flowers the Rumbles   My daughter Dana is marrying George Goryan on June 25 at our home in Mariposa...