Tuesday, April 28, 2020

Any creative scientist worth her salt

Slow down for Wombats!

Any creative scientist worth her salt has almost as many unproductive ideas that lead nowhere as she does ideas that produce publishable results. [The same goes for men as well…] The goal is to let your thoughts soar to places that force them to go where they normally don’t reside. Taking a scientific risk in the course of one’s career keeps things fresh, pushes the boundaries, and opens new doors and collaborations.

We all make “mistakes” doing things that we wouldn’t have done if we’d thought more about it or knew more. That’s not I’m writing about here. I called those “isomistakes”.

Below are more of my “brilliant” ideas that didn’t pan out. I had many successes developing and implementing robust methods for isotope measurements. I wrote earlier about my first major failure with oxygen isotopes in organic matter. Not only did the methods fail, but the impetus for the science didn’t pan out either.

After trying to coax hydrogen gas out of iron tubes, Hoering and I had the idea that we’d confirm our deuterium measurements by measuring tritium isotope fractionation. We calculated what we would expect for tritium, 3H, (mass 3) versus deuterium 2H (mass 2). Our colleagues at DTM had some leftover tritium from the biophysics group and an old scintillation counter to measure radioactivity. I grew phytoplankton cultures in tritiated water, took precautions to keep the radioactivity contained, then prepared the samples for the radioactive counter. Anyone who’s measured tritium or 32P knows that these measurements aren’t as precise as measuring with mass spectrometers. We didn’t spend much time on this and moved on.
We thought we had a clever way to catch large fish, Wooller, Quinn Roberts, and Marilyn

In the field, I’ve already written about the failed experiments using labeled uric acid to trace chicken waste.
In the lab, I had the idea that liposomes—essentially microscopic bags made from synthetic lipids--could encapsulate proteins and protect them from degradation. I had an intern from Yale for the summer trying to carry out these experiments. By the end of the summer, I’d driven him to chain smoking and years later he told me the frustration drove him into a life of economics and policy. He’s now a senior advisor in finance! https://www.janushenderson.com/en-us/advisor/bio/george-maglares/

Negative results can be extremely disappointing and deflating. Postdoc Robin Sutka worked with her postdoc advisor Dave Emerson at the American Type Culture Collection trying to prove that iron-oxidizing bacteria used the enzyme Rubisco to fix carbon dioxide as autotrophs. These bacteria have the Rubisco gene. People assumed they used the enzyme to take up carbon. Robin cultured the microbes with 13C labeled bicarbonate for at least 12 weeks in a row. We expected to see a whopping isotope signal, but week after week, the results showed that maybe—maybe—only 5% of their carbon came from the bicarbonate. This is not enough to yell Success! We never quite figured out what was going on. It seemed time for all of us to move on to other things. Robin turned her career to the business sector and is now a senior chromatography sales rep for Thermo-Fisher.

In the mid-1980s, I worked with Geophysical Lab colleague Ed Hare on isotope methods for extracting collagen from fossil bones.  Noreen Tuross was in residence about this time and she served as the go-between us after awhile. I worked on this subject on and off for the next 20 years. We tried modern biochemical methods to try to retrieve useable collagen from heavily degraded Australian megafauna fossils. The results were always disappointing. Fortunately, I worked for as many years with eggshells from ostriches and emus, which preserve isotopic and elemental compositions for hundreds of thousands of years. 
Fossil Wombats

Teeth hold onto their stable isotope signals for even longer, but forget trying to readily date them with 14C in the mineral apatite. Seth Newsome and I tried and failed with an extensive collection of wombat teeth. We have great excursions of isotopes within a seasonal cycle. Without a secure date, though we had to lump our data into “before” and “after” extinction rather than get a better picture of ecosystem change. The wombat adventure was a good ecological experience, and I probably have the world’s largest permitted collection of Southern Hairy-Nosed Wombat skeletal materials.

In 1998, I had a “better” idea. Colleague John Magee from the Australian National University had been given three samples of termite “pavements” that were found in archeological contexts. These sedimentary termite samples were fossilized termite mounds that native people had used to build hearths for their cooking fires.

Termites consume plants. If termite hearths had some organic matter remaining in them, they could provide a good representative sample of vegetation that was associated with human activities. We were not allowed to touch human remains, but our work relies on human alterations of the ecosystem to influence Australia’s continental climate. Analyses of the three fossil termite hearths showed they had ample carbon in them for bulk isotope analysis. I thought they might prove to be the perfect samples to link human activity to climate change.
Marilyn and termite mound, Western Australia, 2010

Termites are the grazers of Australian deserts. They are ubiquitous. My next great idea was to collect modern termite mounds from southern Australia all the way to the Top End, near Darwin. In 1998, we started in Perth, traveling north collecting about 75 samples along the way.  When I brought the samples back to the United States through Customs, I declared my plants. The custom forms asked if I had any insects. Technically, I did not. It was 1998; Bill Clinton had just testified that he did “not have sex with that woman.” I only had termite remains.

I anticipated that I’d find a gradient in carbon isotope values in the termite mounds that corresponded with the percentage of C3 and C4 plants on the land that vary as a function of latitude. I pictured the Money Figure, as we call them, the figure that gets a publication in Science or Nature.

Next, I planned to implement compound specific isotope analyses of lignin monomers—fragments of a plant’s structural material—to determine plant types as well as species specific isotope patterns. Rose Filley, Tim Filley’s wife, was my lab assistant at that time. Tim was a postdoc working mostly with George Cody. He had a new method for analyzing lignin. Never mind the full chemical name. TMAH was a magic reagent that could do the reaction to chemically release and modify the lignin monomers in one easy step at a moderate temperature.
Y2K Party: Evan is on George Cody's lap; Tim Filley front, next to Dave and Suz George; Rose in back right with child, 2000

But if your samples were not sealed up right, the glass tubes exploded. And TMAH stinks! This of course happened with one batch of samples. We learned to be more careful.

Turns out that the termite mounds I collected showed that those termites ate only grasses—and only C4 grasses at that. My Money Figure was a bust showing no relationship between latitude and carbon isotopes. Furthermore, we never found any more fossilized termite hearths, no matter how hard we looked. To make matters worse, the compound specific work was work! There was little to no reward.

Another brilliant idea shot down. Rose went on to become a managing director for Purdue’s Climate Change Research Center shifting away from her geochemical roots.
It was her brother from Yale who shifted to finance after another brilliant idea bombed. 

I suppose this leaves me as a stubborn individual going from one idea to the next—reflecting along the way. I kept marching forward. Sometimes failure provides a person with a way to realize that something isn’t right for them. In that case, it’s not really a failure. It’s a Learning Experience.

1 comment:

  1. I thoroughly concur and have raised my kids to know that you can often learn more from failure than success. As far as your isotalk is concerned, you lost me at “hello”. XXX


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