Doug Rumble--isotope geochemist and restaurant critic

(L-R): Garret Huntress, Marilyn, and Doug Rumble, fancy dress party 2006

“Do you like good sushi?” he would ask. Who doesn’t like good sushi? Washington DC abounds with great places to sample sushi from small, packed classic places to Avant-garde restaurants with the latest trends in fine Japanese dining. Doug Rumble knew them all. It became his trademark—the restaurant critic--at the Geophysical Lab for over 45 years.

He and I worked together for 35.5 years sharing laboratory space that entire time. It wasn’t always easy sharing lab space with someone that had almost completely different sensibilities about what constitutes an efficient lab space—but we made it work—most likely because at a very basic human level we worked to understand each other. Douglas Rumble III and I recently chatted over Zoom comparing our lives now on the other side of the continent.

Marilyn's lab in foreground; Doug's in background, 2008

Doug retired at the end of 2019, as the Geophysical Laboratory merged with DTM, which happened quietly and slowly as fall progressed. It was time. Doug’s 10 years older than I am, and I’m at the age where I plan to retire in a few short months. We’ve always talked about this time and what we’d do once it arrived. Yesterday, in his new home surrounded by Ponderosa pines and sitting next to his wife, Doug waxed poetic about the geology of Northern Arizona. They’d just completed a hike that took them to a deserted outcrop impacted by recent volcanic activity. If they’d been in Washington, DC, they’d have been stuck in their house with nowhere to go.

             

When I arrived at the Geophysical Laboratory in 1977, I came from relatively humble beginnings. Nowadays, Penn State and the University of Texas are powerhouse public schools. Then, both schools were very popular locally with big football teams and loyal alumni. Neither belonged to the Ivy League. The majority of staff members at the Lab were graduates of Harvard, Yale, Caltech, University of Chicago, or Johns Hopkins. Doug was a graduate of Columbia and Harvard, sporting the Harvard flag on the inside of his office door. Ve-ri-tas or Latin for “Truth” was emblazoned on its center.

Although it was often intimidating for me to join the ranks of my colleagues then, I learned to pay attention to my own work and what I knew rather than worry about how others viewed me. Doug and I shared the back laboratory in Tom Hoering’s suite of old chemistry labs when I was a starting postdoc. I worked silently inside my white, plywood transfer “hood” which allowed me to grow sterile cultures of microorganisms alongside of Doug’s handmade glass and metal vacuum line. He was a relatively new staff member, a permanent position given to promising young scientists and had yet to get his own lab. At that time, Doug was primarily a field geologist with a talent in geochemistry, but was learning the stable isotope trade. Although he had a few years experience on me, we were both under the mentorship of Tom Hoering at that time.

Shuhei Ono, Marilyn, Doug--new Sulfur mass spec

I’ve already written about many of the hare-brained things I did when I first started as a stable isotope biogeochemist. Here’s one of my favorite stories about Doug. He decided he needed to change the oil in the vacuum pump that was the workhorse for making sure his oxygen isotope analyses of rocks worked without issue. The pump on his ‘line’ was one of the larger ones, attached to a tenuous glass tube with a stout rubber hose. Doug had wrestled the hose off the pump and dragged it to the center of the lab. He lifted it onto one of the Carnegie’s ancient wooden stools, found a 1-liter beaker, and started to remove the oil cap and drain the dirty oil.

“Darn!” he said, as I heard the clunk of the cap hit the bottom of the beaker. The slimy cap had slipped from his fingers landing in the sludgy oil. I watched as the oil poured out quickly, rapidly reaching the top of the beaker.

Ed Young and Doug, laser vacuum line, circa1995

“What am I going to do?” he exclaimed, as the oil starting spilling onto the linoleum floor. I grabbed the lab’s trashcan, rushed it over under the oil spout, and saved the day. The old trashcan was a mess, but not nearly the mess that would have happened should that extra liter and a half of oil poured out on the floor. Hoering would have never let him forget it.

“Thanks for that,” said a relieved Doug. I felt good. Even though this is a trivial action, I’d thought fast and helped my colleague. We began to develop a professional relationship.  I knew nothing about metamorphic rocks; he knew nothing about enzymes and photosynthesis. It didn’t take long for us to talk over problems we were having with mass spectrometers and share our analytical isotope triumphs when we had them. When I was appointed as a staff member two years later, Doug was as happy and proud of me as any.

Together we wrote a proposal to the National Science Foundation for a new mass spectrometer that was to be built by the Nuclide Corp. in State College, PA. It was the first of its kind with a metal inlet system, isotope collectors that could be individually adjusted, and an upgraded vacuum system. The proposal was funded and we shared in the maintenance, financing, and operation of this instrument for almost 15 years from 1982 to 1996. I spent time in his laboratory analyzing oxygen isotopes of manganese oxides. We shared the mentoring of many postdocs. Mutual respect and friendship followed.

While Doug was an extremely driven, focused scientist, he had other interests. Over the years, he obsessed over ocean kayaking, Paris, Japan, restaurants, cooking, Dartmouth, bird watching, fine wines, China, opera, and river sculling.  His family was front and center in his life, and his bulletin board outside his office was covered with their pictures. Every summer Doug and his wife Karen would head up to Lyme, New Hampshire, where they rented a cabin on a lake populated by loons. Those of us remaining in sweltering DC dealing with electrical outages were often jealous of his peaceful serene summers.

Brendan O'Connor, high school intern mixing Doug a drink, Karen in background, 2008

Scientifically, his research themes expanded from metamorphic rocks and fluid flow to graphite to meteorites to sulfur isotopes to methane isotopes. His last work was pioneering the development and use of the large format mass spectrometer known as Panorama. Doug is an exacting writer and a gifted speaker, who turns on his Southern accent when he gets excited about a topic.

When either of us experienced personal challenges, the other was there offering a chicken casserole, an understanding ear, and some sage advice. While I pick up on social cues with emotional intelligence, Doug has a broader philosophical approach to life. We had discussed years ago that when the time had come for either of us to retire, we’d let each other know.

Ken Rumble, son, roasting Doug at 70th birthday party

Before coming west to the University of California, our joint lab space was essentially split in half. My side included instruments that were fully automated, high throughput machines that operated 24/7/365. I had high school kids making measurements. We played loud music, swore, and carried out pranks. Doug’s half was aging, complicated, and often on standby after two decades of producing the best quality isotope data of its kind in the world. After I left for a new life in California, he missed me. Fortunately for me, we’ve kept in close touch.

Together we’ve shared five isotope ratio mass spectrometers and remain good friends to this day. To those who aren’t familiar with these instruments, it’s quite a fete to work together—and remain friends--keeping equipment in top shape.

Tom Hoering, who passed away in 1995, had trained us well.

“Show it who’s boss,” he’d taught us. And we did.

Weird and wacky isotopes

Marilyn sampling polar bear poop, Svalbard

“Did you get the stones?” she asked, without even saying hello or how did the operation go. I was in Holy Cross Hospital recovering from gall bladder surgery earlier in the day. The surgery was a no-brainer compared to the disappointment I felt in failing to get the gallstones—my very own gallstones—to make the perfect isotope standard.

“They refused!” I had labeled a 50-milliliter plastic sample tube all ready to go, but recent laws prevented patients from obtaining their own body parts removed by surgery because they might be “infectious”. Come on—gallstones aren’t going to infect anyone.

The caller was none other than my friend and colleague Noreen Tuross. Noreen and I have proudly held up a bunch of samples we thought qualified as the weirdest or wackiest for years. In 1988, Noreen came to the same hospital armed with a Styrofoam bucket packed with dry ice to collect my placenta after I gave birth to my daughter. She was given it, without any fuss or bother. We were embarking on the nursing mother isotope study with me and my daughter as first subjects. It made sense to get the tissue interface. The doctor knew I was a scientist, so she wasn’t surprised by the request. In 1991, when my son was born, Noreen was there again. We have an n=2 (meaning two separate specimens) of my placentas.

Noreen and Marilyn, we shared an instrument and often had playful moments, circa 2005

For years we told the story over the dinner table. Dana and Evan were initially appalled, then were kind of proud their placentas were in the Smithsonian, now in a -80°C freezer at Harvard. It's a family joke. Noreen and I swore when we were running out of ideas, nearing retirement, we’d analyze them. I’m heading rapidly towards retirement, but we both still have good ideas to work on. No analyses there yet.

Back then, it was much more difficult to analyze the isotope composition of a sample. The analyses were not automatic in any sense of the imagination. So when we analyzed a sample it had to be somewhat important.

One of my favorite stories with Noreen is the time she tried to turn herself into a “paleo Indian” [an American Indian before corn was introduced in North America] with an isotope signature signifying a complete lack of corn in her diet. In the United States, corn, either in animal’s diets or from high-fructose corn syrup, influences most of our meat supply, our dairy supply, and our sugary products. Therefore, when you analyze human tissues, like fingernails for example, they are always labeled with a good portion of carbon originating from corn.

Noreen’s diet included rice, lamb from New Zealand, vegetables, and baked goods without sugar. The lamb was expensive, so she didn’t eat much of that. She didn’t lose any weight, but after six months, she had more colds than normal.

“Do you think it's the weird diet you’re on?” I asked.

“Marilyn, I have a PhD in Medicine. I know what I’m doing,” she answered.

At 3 months, 4 months, and 6 months, she sampled her fingernails hoping to see the influence of corn diminishing, turning her isotope signature into a “paleo Indian”. At the old Geophysical Lab, the nitrogen isotope mass spectrometer was right next to my desk. The vacuum line for prepping samples was in the adjacent lab. Noreen worked the line; I ran the mass spec. In those days, we had a special computer code for analyzing the data that was written by our electronics guys, Dave George and Chris Hadidiacos. The data came out printed on a dot-matrix printer, chugging line by line.

The 3-month sample was analyzed first. It takes roughly three months for fingernails to grow from cuticle to fingertip. We didn’t expect big changes and we were mainly looking for changes in carbon isotopes, not nitrogen. When the data came out, I looked. Noreen’s original nitrogen isotope signature was +10 parts per thousand (‰). It was slightly elevated: +11.5 parts per thousand.

The 4-month sample came next. Whoa—now it was +14 parts per thousand, quite a change. All of the biogeochemistry folks gathered around the mass spec, speculating on what this meant.

“Run it again,” Noreen suggested, which I did. The same value came up again.

The 6-month sample was next. By this time, we were laying bets on what the value would be. The analysis took about 15 minutes—and we watched as the printer spit out a value of +16 parts per thousand.

I ran it again to make sure. Chemistry and physics did not lie.

What does this mean? It had been hypothesized that when an animal was in negative nitrogen balance, they metabolized their own tissues to get enough protein to keep them alive. When this happened, the lighter isotope of nitrogen (nitrogen-14) was excreted, while the heavier isotope (nitrogen-15) remained. Noreen’s increased value going from +10 to +16 meant that she’d been surviving on her body’s protein reserves, not taking in enough from her diet, something you want to avoid.

“Don’t tell my husband!” she said. I didn’t, until nearly 25 years later after I’d told the story a million times to other people. He merely shook his head, knowing his brilliant, but feisty, wife was capable of almost anything.

The diet ended that day. Noreen’s carbon isotope pattern never reached that of a paleo Indian. It takes a lot to turnover the tissues in a human body.

I’ve written previously about analyzing Tom Hoering’s urine and blood. My list of weird things includes polar bear poop, goop from a friend’s ceiling, ants from the National Institute of Health, and King Midas’s tomb. After some of this stuff, I complained to my colleagues that I’d never be elected to the National Academy of Sciences if I kept up this type of disorganized, nutty work. Fortunately, that turned out not to be the case.

Son Evan and Seth Newsome with wombat poop, 2008

This week, I queried my colleagues about the weirdest, funniest samples they’d analyzed. The answers poured in. Here are some of them. Many of these had to do with bodily fluids, tissues or breath.

-Devil’s blood—a metabolic study on Tasmanian devils with facial tumor disease using doubly labeled water.

-Elvis Presley’s hair. A grandmother of a student of Mike Engel’s was at Elvis' induction into the army. Elvis gave her a lock of his hair and she was kind enough to give me a strand. That guy loved his corn mash whiskey!!

-Stable Isotope Lab Director urine. This was part of a hair study (never published), where I shifted the isotope signature of body water by drinking Trinity bottled water (Pleistocene from Idaho) and high altitude beer. It took about 25 days to shift this body’s water.  

-Cat poop from feral Galapagos cats (looking into their consumption of rare Galapagos penguins), Ring and Harbour Seal blubber and blood (for a polar bear study), bat guano from southern Arizona (to define the onset of the North American Monsoon).

-Remains of the sacrificial victims of the Aztecs, which is definitely high on the weird/creepy scale!  I learned about their diets and places of residence during the last years of their life.

-Eel mucus

-CO₂ from breath of python snakes

-Whale poop and dinosaur poop that we obtained from Central India below the Deccan Basalts (65 Ma) believed to have been discharged by Titanosaurs.

-Dinosaur coprolites (i. e, poop) from the Late Cretaceous Lameta Formation of India.

- Spider legs, rat urine or Pacific lamprey eye lenses

-House fly breath.  Some entomologists were doing labeled feeding trials and kept feeding and then killing their house flies and having us burn them.  They were interested in turn over rate.  I suggested that we might be able to save their flies by measuring their breath. I put one fly in a 12ml test tube, capped it, and stuck two needles through the septa. Waited 30 or 45 minutes for the fly to respire.  Stuck the tube with fly inside into an automatic instrument (Gasbench) and  measured CO₂. Afterward they opened the vial and returned the fly to its cage.

- To teach the students about how stable isotopes can be used in ecosystem studies, we analyze their hair.  But, of course, at the same time, we also collect hair from our colleagues and anyone else that might be walking by!  Over the years, this has produced a nice data set of new mothers and their breastfeeding babies.  We call the latter, "Momivores".  So far, the Momivores have always been a trophic level above their Moms!

-Whale poop.  Right whales and Humpback whales.  Not sure if the researchers ever did anything with the isotopes, but I think they used the %N to determine how much N was released to the ecosystem and to suggest that marine mammals play an important role in the delivery of recycled nitrogen to surface waters. 

-Creepy red honey– the bees were harvesting maraschino cherry syrup!

-Mouse milk

-Bird snot to figure out if parasitic fly larvae of Darwin‘s finches were feeding on their blood ! 

-Mouse breath

-My wife’s breast milk and my daughter’s fingernails ala Fogel 1989...

-Deep sea "slurp" of a bacterial mat in a methane cold seep. Beggiatoa bacterial mats have a lot of "fluff" to them so it's not easy to grab with a manipulator arm. What's easier and part of an array of fun tools to do deep sea sampling is a vacuum nozzle. We just slurped that whole thing up!

-Animal breath. You take a 60ml syringe with a hose and suck in air in front of the animal. You take multiple samples and if you have different mixtures of air and breath, with a Keeling Plot you can determine the isotopic composition of the end-member breath.

-Freeze-dried bee guts and bee vomit lately in order to understand the metabolic influence of the nosema parasite on honey bees.

-Doubly labeled gull blood and of course chimp poo. Although I did analyze some ²H-depleted water samples that had been distilled in the basement of some dude in the suburbs... he thought it was gonna cure cancer, but apparently it was not depleted enough.

Sometimes samples came in weird boxes

-Snot

-Dolphin blow hole exhaust

-Grasshopper spermatophores

-Mosquito larva head capsule (now that's just too geeky)

-When I was an undergrad, one of the organic chemistry profs was studying mosquitoes, and it was the job of his graduate students to feed the bugs. Actually, not so much "feed", as "provide for". So, into the screened enclosure go the grad students stripped down to shorts, and the bugs take what they need. I suspect this would not be acceptable practice 40 years later.

-Tree vomit- While sampling tree rings in Kashmir valley by a corer I accidentally punctured the xylem sap conducting cells. The tree started gushing out water that smelled like vomit. We had to quickly take out the corer and seal the hole with wood pieces so that the discharge stops and the tree heals its wound.

-Cut up Hyrax hyraceum [a type of African “rabbit”] for analysis. It’s rock hard crystallized urine that develops because they use the same spot as a latrine for generations. It made the whole hall smell like old goats, and the saw was never quite the same.

-A variety of banana in the Cook Islands thought extirpated, the royal banana. The tree 'bleeds' purple and the fruit is a goldeny-orange. Best banana I ever tasted, but that's probably because it ended up roasted in an earth oven with freshly-grated coconut.

-Bird gizzard. Though there have been plenty of times I've added stuff at the end of a proper run, just to satisfy curiosity: blu-tac, dandruff etc

-Poo from baby turtles was a fun analysis. Well for me anyway, all I saw was dried, encapsulated samples.  The student had to put nappies on each of the baby turtles to collect the stuff. After pics appeared in the uni news he copped a lot of ribbing.

-Vampire breath

-Mosquitos full of blood from myself and of another test person, who pretended to be a vegetarian.....

-Animal breath (elephant, camel, sloth, rhino, koala, tapir, Hipopopotamus and many more)

-Lark's vomit? Possum urine? Spit

-Bird regurgitation

-Sheep fed with nitrate, then stuck the sheep in a box and waited for the resulting emissions. Half liters jars of sheep box atmosphere were brought into the lab. You know how they sell cans of pristine air? Well, this may qualify as canned country air! The student who pursued this was a determined worker!

-Crab faecal matter

-Sauna sweat

-Jellyfish, water treatment filter fiber bacteria scum... There is a plan to run this "organic" turkey heart in our freezer...

-“I have a great one from about a decade back when I was starting as an assistant manager to Ben Harlow at WSU. It was often my job to deal with unboxing, sorting, storing etc of bulk analysis samples that we received in all stages. Some already wrapped, some unwrapped but powdered, some just raw materials to be fully processed, etc etc, you know the drill. Best/most fascinating delivery I ever got was prefaced by an angry message from the campus delivery man’s manager, informing me the poor guy had had a horrible experience just dropping this one off. He’d gotten soaked and now smelled like a rotten lake...No surprise after I found the package in the mailroom! A grad student, bless his heart, had gathered all his precious samples and mailed to us to do all the processing. What were they? A huge variety of stream food web samples from some remote corner of somewhere, accessible only via backpacking - probably took him a week to get to and trek back out. And how had he mailed them?? Each sample OF LIVE FISH, CRAWDADS, AND OTHER THEORETICALLY LIVE STUFF!! was enclosed in a standard ziplock baggie, the baggies layered to ~half fill a styrofoam cooler, the cooler duct taped shut and labeled, and the whole microcosm mailed to us standard shipping, as simple as that. What did we receive??? I’m sure you can imagine! A leaking, reeking pond of tepid water, some horrific “trophic interactions,” and ~40-50 limp and open ziplock bags.”

-Archeological popcorn from the Atacama Desert. It comes from a burial dating to 1500 years ago. The popcorn is so well preserved that when you see it, you wouldn't believe it is that old. One of our colleagues tried one, ugh! He didn't get sick, fortunately.

-Sodium fluoroacetate-laced milk powder. “This mixture had been delivered with a threatening letter to primary producer companies. The govt forensic lab rang to ask if I could do fluorine isotopes on 1080 poison (fluoroacetate). I immediately pictured myself masterfully delivering the blow that F is monoisotopic and hanging up the phone. But no, you lose your title of masochist and you’re no longer in stable isotopes. So I offered to do the 3 other isotope systems, O, H and C. The sample arrived and it proved to be possible to fairly easily pick 1080 crystals with fine tweezers from the milk powder under a polarized light field microscope.

New Zealand uses a lot of 1080 for pest control – banned in many countries – but with relatively little public resistance to its use here because we have a very unusual ecosystem with no native mammals. None. Opponents do exist though, and they have been known to take direct action, so everyone’s thoughts were that they might be responsible…The culprit was unmasked fairly quickly. I gotta say that fingerprint DNA actually nailed him, but our isotope results gave great backup and was a good advertisment for stable isotopes. And the culprit was… the guy who sold the rival type of poison, cyanide based, for pest control. He got 8 ½ years jail.”

-Black smoker chimney. The combination of organic matter and fine-grained sulfides in the chimney burst into flame instantly, the entire sample enveloped in a fluorine fire with copious pale green FeF3 “smoke”! And watching it all through a binoc microscope  protected only by a 5mm thick BaF2 window (crystal with perfect cleavage).

-Diamonds and Champagne bubbles…don’t ask what we did with the non-analysed samples…

-Fibers from mummy shrouds

-Nitrate from WWI bombs

-Château Margaux 1904!

-Detrital zircon grains...found inside an inner cranial cavity of an eel-like fish in the waters of coastal Florida. The 'fish head zircons' were discovered by a local biologist studying behavior of the species.