Featured Professional: Sally E. Walker

Editor’s note: This issue we feature Sally E. Walker, a Paleobiologist/Taphonomist in the Department of Geology at the University of Georgia in Athens. Eleanor Gardner, who completed her M.S. in Geology under Sally’s guidance, crafted the interview questions.

Sally Walker in Antarctica
Sally Walker in Antarctica

How did you become interested in taphonomy and paleoecology?  Were you drawn to fossils as a child?

The question for me is: When did you think you were going to be a scientist? When I was a child (~6 years old), I really liked to draw. I would draw on the walls in my bedroom. That led me to try to figure out how to remove the crayon from the walls, and therefore my first experiment! I mixed vegetable cooking oil and my mother’s very expensive Chanel No. 5 perfume that she saved for many years to buy, and viola – it worked, no crayon markings. I’ll spare you what my mother thought of this idea. So no, I was not interested in fossils as a young child, but instead very interested in forensics and criminology. This is probably because I read Nancy Drew, the Hardy Boys, and Tom Swift books as a kid. My favorite was Tom Swift because he was a scientist who not only went into space, but he also explored the ocean in a submersible. I wasn’t allowed to watch much TV, but I did get to see nature and underwater programs (Jacques Cousteau) on TV. By the time I was nine, I wanted to be a marine biologist and go to the Galápagos and do research on tortoises. My family, however, had other desires for me like being a secretary and homemaker. I cannot tell you how many Betty Crocker cooking sets I got as a kid at Christmas, all the while staring enviously at the nature books that my brother received. One Christmas stands out as the turning point: When I was 12, my grandfather gave me a microscope and I cried with joy for a very long time after opening the package. Everyone stopped – they had no idea that a microscope would mean so much to me. I have tears now just thinking about that day. I immediately took it home and started looking at my water turtle’s skin under the scope, and I found a whole new world of organisms (protists)! Ever since then, I have not been without a microscope and I have remained true to my interests that I developed at a young age: combining forensics (taphonomy) and historical marine biology (paleobiology).

I know that hermit crabs (and their traces) interest you.  How did you come to be fascinated by hermit crabs and their ichnological record?

While a graduate student, I was curating fossils for my Professor at UC Berkeley, Dr. Carole Hickman, and I didn’t want to remove the creatures that encrusted the shell (all curators usually remove this material to have a beautiful shell). She let me leave the encrusters on and suggested that I look into hermit crabs; she was familiar with Dr. Jim Carlton’s work on hermit crabs. I had no idea what she was talking about, but I soon figured it out. Independently, I read a paper by Dr. Anna Kay Behrensmeyer on her forensic experiments that determined how long vertebrate bones last in a particular terrestrial environment, and the light bulb went off in my head: I designed field experiments like hers to test how long snail (gastropod) shells lasted in various marine environments, and along the way, examined what effect hermit crabs had on those shells. My first field experiments were destroyed by nefarious crabs, which led me to examine not only hermit crabs but mistaken predation on empty gastropod shells, and how the fossil record of gastropod shells is possibly biased by biological entities as much as by physical and chemical factors.

Where are some of your favorite places to travel, paleontologically-speaking?

The Galápagos Islands and Antarctica are my two most favorite places for research, although I also really enjoy Bermuda and the Bahamas as well.

What research question currently excites you the most?

What are the physical, chemical, and biological factors that affect shell carbonate preservation in Antarctica and how do those factors bias the marine invertebrate/protist fossil record of Antarctica? This question further involves the following questions: how much carbonate do these organisms produce, how much is preserved, and what is their importance to the polar carbon cycle?

What is involved in preparing for and conducting a taphonomy research project in Antarctica?

One of the most amazing things about Antarctica is that it is currently protected by a multinational treaty. Antarctica is a very important part of our Earth system, meliorating our climate. It takes a lot of preparation to work there, and the National Science Foundation (for the USA) does an incredible job facilitating research there and protecting the Antarctic ecosystem.

We recently found that a single-celled creature (a foram) that lives on Antarctic scallops makes as much shell carbonate in a year as tropical lagoonal forams. That is pretty impressive considering that it is supposed to be very difficult to make carbonate shells in the coldest waters on Earth (- 2 oC). This suggests that polar organisms may contribute a lot to the Earth’s carbon cycle (which affects climate), but are rarely considered. Read more about this discovery in a paper by Hancock et al. (2015).

What is a typical work day like for you? What are some of your favorite parts of your job? Your least favorite?

A typical day is about 10 to 12 hours on average, including weekends, and can be composed of the following: I read new scientific papers and incorporate them into my lectures or labs; I write and set up my labs; I mentor undergraduate and graduate students (and they mentor me!) in research and scientific writing. I also answer queries about identifying fossils or what it is like being a paleontologist, write letters of recommendation for students for jobs and graduate school, evaluate young professors for tenure or full professor and write letters of support. I typically also evaluate and review grants and review scientific papers; I collect and analyze data, do the illustrations and photographs, and write scientific papers; I have committee work for the department, college and university level; I have professional service work for the Paleontological Society. In short, my day is not typical, and that is what I like (and I really like my students and research)!  I least like being the token female on committees to make it more “diverse” and having to deal with gender bias.

Given that the goal of FOSSIL is to link amateur groups with professionals, what are your thoughts about the role of amateurs in the science?

Frankly, we are all amateurs before the beauty of science. I don’t make a distinction between amateur and professional: regardless of what degree we have (if a degree is what “amateur” is based on), if we are trying to make science better, using the principles of science, and keeping the STEM fields alive (for instance, not denying that climate change occurs despite overwhelming evidence from the past and today), then we are all working toward the same STEM goals. We are on the same team! I know many “amateurs” that know far more than me about particular fossils. Therefore, I don’t consider them amateurs, I consider them valued colleagues. Therefore, their role in science and society is just as valuable as my role.

Many of our fossil clubs and societies are very committed to education and work hard to engage youth. As a university professor who often does public outreach/education, do you have any advice to share about effective ways to get children and teens interested in paleontology?

Yes – take them on field trips, get them involved in a research project, and museums. Hands-on activities are the best.

Sally at the Burgess Shale
Sally at the Burgess Shale

Do you see on the horizon any new directions or opportunities in paleontology emerging as the result of technological advances or new discoveries?

Yes, many cool new topics. First, the technological revolution: the digitization of museum fossils and the gigapan images of fossils that are being produced are revolutionizing our science. This new technology allows not only scientists to use the fossils for research, but also K-12 and university students as well. The new technology that allows paleontologists to non-destructively examine samples and image them in 3-D is also amazing. We can then print 3-D copies of these fossils to use for outreach and class projects. The use of drones is changing how we do geology and paleontology (we can overview an outcrop and zoom in on the fossils, even though they could be hundreds of feet up a steep rock wall face). There are new sampling techniques for analyzing stable isotopes and chemical elements from fossils that are very exciting.   Second, from a conceptional point of view, I love the Earth System Science approach to studying paleobiology: Conservation paleobiology and how the past can be used to examine how modern ecosystems have changed under the influence of humans; paleo-macroecology, or how body size and body plans have changed over time, as well as how ecosystems are structured. I also like that parasitism and mutualism are now being studied, in addition to predation and competition. And lastly, I think that paleogenomics and biomarker studies are giving us a more complete window of organism relationships, their history in deep time, and the biological aspects that we can’t necessarily see from the shape (morphology) of fossils.

Do you have a favorite fossil discovery?

Yes. I really enjoyed working with my former Ph.D. student, Dr. Lisa Gardiner and my dear colleague, Dr. Steven Holland, when we discovered the first hermit crab walking trace known in the fossil record. We were scouring the sea cliffs (fossilized dunes from the Pleistocene Epoch) on San Salvador Island in the Bahamas for hurricane damage when we discovered this trace fossil. After measuring the details of the track way and casting it, Lisa and I then tried to figure out if a land hermit crab (of the genus Coenobita) made the walking trace. We found a land hermit, whom we named “Tulip,” and had her walk on wet vs. dry sand, on flat surfaces, and on sloping surfaces. We measured her tracks and trackways on these surfaces and compared it to the fossil we’d found, and they were essentially identical. We then named the trace after Lisa’s wonderful undergraduate mentor, Dr. Al Curran, who is an expert on the trace fossils of the Bahamas. That trace fossil is Coenobichnus currani, and thinking about it brings back many happy memories. Read more about this fossil in Walker et al. (2003).

To learn more:

Learn more about what a research expedition in the Antarctic entails at “Postcards from the Poles.”

Read about the science behind the Antarctic project in this article from The Antarctic Sun.

Sally’s Antarctica research is profiled in this AAAS Spotlight.

Listen to an interview with Sally on the NSF Kids’ Science Challenge.

References Cited:

Hancock, L., Walker, S.E., Perez-Huerta, A., and Bowser, S.S. (2015). Population dynamics and parasite load of a foraminifer on its Antarctic scallop host with their carbonate biomass contributions. PLoS ONE 10(7): e0132534 doi:10.1371/journal.pone.0132534.

Walker, S.E., Holland, S.M., and Gardiner, L. (2003). Coenobichnus new ichnogenus, a walking trace from a land hermit crab, early Holocene, San Salvador Island, Bahamas. Journal of Paleontology 77: 576-582. DOI: https://doi.org/10.1017/S0022336000044255


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