Wednesday, December 2, 2020

Sue Ziegler--estuaries, isotopes, and working the system


Marilyn, Sue (overalls!), Ron Benner, Ellery Ingalls, Texas 1998

Both of my children were toddlers (1 and 4) in 1993 when Sue Ziegler ( came to southern Maryland to start an internship with my husband Chris at the Jug Bay Wetlands Sanctuary. Sue was a senior (4th year) at the University of Massachusetts and needed field experience. Jug Bay volunteers had been collecting water samples for more than 5 years to learn about water quality and nutrient cycling.


Sue was assigned a project to go deeper into nutrient cycling in sediments and waters as a function of time. In 1993, David Velinsky, a former postdoc then working at the Potomac River Commission, and I trained Sue how to do the chemical analyses and lent Jug Bay a portable spectrophotometer for her work.


Sue took to the muddy work like a duck to water.


By the end of summer, Sue had analyzed hundreds of samples and had roped David and me into the work. Included in her research plan were diurnal measurements—meaning samples had to be collected over a 24-hour period. At the time, my family spent every weekend at the Wetlands Sanctuary living in a log cabin reserved for my husband, the Sanctuary’s Director. It was easy to find people to sample from early morning to early evening, but what about the middle of the night?


My kids were still often waking up sometime in the night—I was a wimp of a mom who couldn’t do the “let them cry” method becoming popular then. So, when a 3 am sample was needed, I volunteered. I got up 20 minutes in advance, pulled a pair of sweat pants over my pajamas, then headed out into the dark night and drove the 1 mile down a dirt road way out to a freshwater tidal marsh. I walked along a boardwalk that extended 100 yards over towering marsh plants and thick mud to a duck blind.


There, Sue had all the bottles ready for sample collecting. I grabbed a set, went down a rickety set of wooden steps to a platform at water level, and bent down to sample the marsh water, followed by temperature and pH measurements.


Jug Bay Marshes

It was a magical time. I was wide awake and happy breathing decaying vegetation. The marsh had its own sounds—water lapping gently, wind in the wetland plants, and the faint chirping of katydids.


Sue returned during winter vacation to make the same measurements—but now it was cold as hell in the marsh. Those middle of the night samples were frigid, quick runs under a cold full moon. I was glad when the work was over.


Getting ready to graduate in June 1994, Sue was looking for her next step. She was an outstanding intern, so I recommended her to a good friend who was/is known as a leader in marine biogeochemistry—Ron Benner (Ron's Google Scholar Page), then a professor at the University of Texas Marine Science Institute, where I did my PhD research. Sue was hesitant at first to contact such an eminent scientist, but finally she did. He accepted her readily.


In comparison to my first trip to Port Aransas Texas where the UT Lab was located, the town was a bit more settled than it was back in mid-1970s (Blog on Texas Grad School). Nevertheless, Sue was yet another young, somewhat shy, Yankee female scientist headed to wild Texas. Sue thrived there studying ecosystem dynamics. Working with Ron’s technician, she spent days on a small boat in the Aransas bays sampling water and mud.


I served on Sue’s PhD dissertation committee, a real pleasure that allowed me to make frequent trips to Port Aransas for her exams. It was a big day to come down for her defense in 1998. And the party afterward! Sue and I shopped for the party loading pounds of ribs and chicken into the shopping cart, which was then piled high with 30-packs of Pearl and Lone Star beer cans. Sue passed with flying colors and the party was a real Texas wingding.


Sue's team working with nets to avoid black flies

Sue applied for a postdoc at the Carnegie’s Geophysical Lab and was easily a top candidate. She arrived in 1998 when we were just getting started with Astrobiology studies, and now had a new mass spectrometer with the elemental analyzer attached, as well as compound specific isotope instrumentation. I taught Sue new techniques in protein purification and immunology that I was learning. She began with a simple experiment—what happens to the stable isotopes as a single protein, Rubisco—the carbon fixing enzyme in plants—is degraded by bacteria. 

[Sue and I went to NASA Ames to the first Astrobiology Institute meeting, where she first met John Hayes--who bought her a beer!]


A sample’s amino acid fingerprint--the relative differences in the carbon isotopes among amino acids--could be altered during microbial decomposition either by the preferential breakdown of amino acids or addition of microbial proteins leading to a heterogeneous mixture.  Sue (Ziegler and Fogel, 2003) and I compared the carbon isotopes of amino acids of phytoplankton (e.g., diatoms) with particulate organic matter (POM) sample, bacteria, and dissolved organic matter in the Jug Bay estuary where Sue started her career back in 1993. The fingerprint for the POM fraction was very similar to the bacterial fraction on the basis of amino acid fingerprints. Interestingly, although bulk isotope compositions of POM were almost constant throughout the year, the carbon isotopes of some amino acids, varied by quite a bit. This particular study is important because it demonstrated the power of compound specific analyses for studying dynamic ecosystems with significant microbial inputs.


Not only was I getting into Astrobiology then, but I began a major initiative concentrating more on ecology. I was awarded two fellowships (Loeb and Mellon Fellow) by the Smithsonian Institution’s Environmental Research Center (SERC) in Maryland, which included unrestricted funds to develop collaborations with Smithsonian Institution scientists at SERC, as well as to provide access to my stable isotope lab at Carnegie since the Smithsonian did not have an IRMS facility at that time.


My first collaboration was with Anson Tuck Hines, Associate Director of SERC and a fish and crab biologist. Seining for estuarine fish and other field sampling took place weekly on the Rhode River, Hines’ lab study site on the Chesapeake Bay. We measured the carbon and nitrogen isotope compositions of over 800 samples of fish, invertebrates, zooplankton, phytoplankton, and seaweeds in the Chesapeake Bay. With plant ecologist Jess Parker, we rented a crane that took us to the tops of 30-40 meter trees to collect leaves in SERC’s temperate deciduous forest. How cool is that to be lifted high off the ground in a little bucket pointing out leaves you’d like to sample? We documented that leaves growing higher in the canopy have more positive carbon isotope values than those lower in the canopy.


Sue as postdoc, 1999

The Loeb fellowship opened up doors with Smithsonian colleagues, and it provided funding for me to hire laboratory technical support. With all of the samples to analyze, I needed to hire a lab assistant to help out. My first choice for the position was Mat Wooller, then finishing up his PhD at the University of Swansea in Wales. Mat had about a year left to finish up before he could move to the United States.  I was left with a quandary of what to do for the year gap. I ended up hiring Glenn Piercey, who had little to no direct experience with stable isotopes. Glenn’s girlfriend at the time—postdoc Sue Ziegler—was hoping that she and Glenn would have a chance to get to know each other further, if he had a job in the Washington DC area. Hiring Glenn seemed a good way to get the Loeb projects started. Within a few months, Sue and Glenn announced their engagement, were subsequently married, and have a full life and family. I’d say this was a most successful hire on many fronts.


Glenn and Marilyn, tree canopy sampling

In no time, Sue was snapped up by the University of Arkansas in 2000 to begin an Assistant Professorship in the Biology Department. Dave Evans was on the faculty at that time; with his expertise in plants, Sue’s interests in microbiology were a good fit and resulted in the start of good projects for her.


Her first teaching assignment was General Microbiology with a class of over 400 mostly pre-med students. Sue’s a slight woman, a couple inches taller than 5 feet, and has always been a casual dresser. In fact, I used to bug her as a postdoc to get a real purse, not just a backpack. She finally caved in and bought a small, around the shoulder pouch to carry her credit cards, nothing like a fancy leather bag that many women use.


Sue and son Noah, 2004

I pictured Sue with a t-shirt and khaki pants in front of the conservative Arkansas students. They pulled her chain for sure, but Sue’s tough and by the end of the semester, she wore a suit jacket to class and developed the very serious, almost stern, demeanor she has to this day. As was typical for her, she mastered teaching.


While Arkansas was decent enough, Sue learned—the hard way—that she was vastly underpaid relative to her male colleagues in the Biology Department. At Christmas time, when she was visiting her parents in nearby Virginia, she asked what I thought about that. With experience of my own in being paid 75 cents on the dollar, I advised her to ask directly for a raise. She did, but was low-balled, hardly making any headway towards financial parity.


When a Canada Chair position opened up in 2006 at Memorial University, Sue jumped at the chance to apply. She was successful once again! The family moved to the far-flung island of Newfoundland, which happens to be her husband Glenn’s home turf. Now a Full Professor, she is not even 50 years old!


She’s widened her scientific sphere to include soils, climate change, and fatty acids. Her lab includes not only isotope instrumentation, but chromatographic instruments of all kinds. I spent some time with Sue’s group in western Newfoundland one season. Although I am not allergic to anything in the lower 48 states, I was knocked down by an allergy to balsam fir. Sue recalled recently that when I managed to feel better I cooked a complete turkey dinner for her field crew.


Newfoundland wetland

Sue’s continued to fight the battle talented women continue to face in earth and physical sciences. She fought for air conditioning in her lab; decent grad students; to repair laboratories subjected to flooding; and fair assignment of teaching and service duties.


Her work is slowly being recognized (Sue's Google Scholar Page). Her publications are detailed, even introspective, and never simple. She’s taken advantage of carbon tracers to tease out microbial processes in soils. She’s trained students, added new colleagues—she’s there.


Ron Benner and Sue, 2017, The Sea Ranch, California

For the past 3 years, Sue has made the long trip from St. John’s Newfoundland to join Ron Benner and me in California. Since my diagnosis of ALS in 2016, she’s proven her commitment of friendship to me—something more valuable than publications or grant money.


That’s what matters after 27 years of working with people you like and admire in science.


  1. Thank you for writing this. It was a joy to read about one of my heroes from another of my heroes.
    Sue hired me as a technician at the Univ. of Arkansas and still took the time to teach me to appreciate science even though I was majoring in German at that time. Sue sets a standard, no pun intended, that few can match.

  2. I worked with Sue for the Fish and Wildlife Service over the Summer in '93 doing some on the ground wetlands verification work, and from time to time have wondered what became of her. This was a great way to find out. I wonder if she'll remember me...but even if not, when you see her again, say hi for me.


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