|Mom, Florence Fogel, Marilyn (scowling like my brother) and Dad, Arthur Fogel, Graduation Penn State 1973|
Barghoorn noted that life had to conquer three different thresholds to evolve to where it is today. From the chemical soup of the early Earth, organisms needed to develop biosynthetic pathways such as photosynthesis. He presumed that the first organisms were heterotrophs, feeding on compounds in the chemical soup. Barghoorn argued that autotrophy—making biomass like plants do today-- was also needed to continue the supply of organic nutrients for heterotrophs. The second threshold was diversification, whereby single celled organisms needed to develop into more complex forms, including chains of cells or stromatolites, macro structures seen in sediments over the years.
The third threshold that organisms needed to transcend was the formation of cellular microstructures, notably the nucleus, in order to become multicellular organisms. Sedimentary deposits from three different continents, Africa, Australia, and North America confirmed to Barghoorn, Schopf and others that life was widespread on the earth during its first 2 billion years and had originated in similar fashion across the planet.
The conclusion that these were fossil microbes (Schopf and Barghoorn, 1967) started a four-decade debate about the biogenicity of these structures found in ancient rocks. The authors noted that although it is difficult, I would say impossible, to relate the potentially biological structures to intact cells, they concluded that the spheroids are “almost certainly of biological origin” representing cells, most likely algae. Electron microscopy of ancient sediments was a new technique at the time. Microscopic examination coupled with chemical and isotopic analyses seemed to prove the interpretation that these were fossil organisms. Their paper certainly caught my eye and my interests because it combined new chemical instrumentation to describe once-living organisms in a geological context. These three fields of science--biology, chemistry, and earth science--rolled into one sparked my career.
At Penn State, two experiences largely determined my interest in these fields: a 3-month Marine Science quarter at Wallops Island, Virginia, and a special class in Geochemistry. Both of these opportunities were sparked by my friend Nancy “Natasha” Peters. “Nat” and I met first quarter in summer 1970 when we lived on the third floor of Curtin Hall. We were both out of state students, thrust into the rural atmosphere of State College—she from the DC area, me the Philadelphia suburbs. That summer we were introduced to a group of renegade fraternity guys who inducted us into their frat with a ceremony complete with robes, candles, and the secret handshake. After that experience, we were partners in adventure for the next three years. Nat was a biochemistry major, aced all her exams, but wasn’t bitten by the same science bug that I was. She heard about the marine science program and wrangled us, just technically juniors, into a competitive list of students chosen to participate.
|Nancy Zeller at Wallops Island, 1972|
Wallops Island Station is a former Navy base on the coast of southern Virginia. It also served then and now as an outpost for NASA satellite tracking and small rocket launches. In March 1972, forty Penn State students led by Professor Albert Guber from the Earth Science Department moved into former Naval officer quarters on the outskirts of the base. There were only 4 women in the group---Nat, Nancy Zeller, and me, all long time friends, and one other. As students in the first class to start this program, we were pioneers. The quarter was broken into three segments in which we concentrated on subjects—Physical Oceanography, Marine Biology, and Geological Oceanography. It was heaven on earth for me as a student. Our studies consisted of evening lectures with day times spent in the field in the neighboring environments of Chincoteague and Assateague Islands and beaches. Weekly we went out on small boats in the bays and offshore collecting sediments, water samples, and marine organisms that we kept alive in tanks in our lab.
Nancy Zeller, Nat, and I pitched in our meager resources and with the help of Nancy’s dad purchased a small skiff with an outboard motor that we moored under a bridge on the road to Chincoteague. The inlet opened up to miles of pristine salt marsh with its green Spartina grasses, oyster beds, and tidal flats beckoning us to investigate their mysteries first hand. When we had a slow day, we got in that little boat in early morning, making temperature and salinity measurements, digging up clams that we cooked for dinner, and just plain immersing ourselves in the environment. Years later this experience influenced my choice of research projects. I was now thoroughly hooked and prepared to do whatever was necessary to make marine science a career.
|Nancy Zeller, Marilyn and sister Barbara, Penn State 1973|
We learned about petroleum and coal formation, how living organisms decayed and entered the fossil record, and about the origin of life on Earth. The research on Earth’s earliest life was all very exciting for me. Given revealed a set of fascinating papers to our small group of undergraduate and graduate students. I was immediately hooked! As a biology major, I wanted to know how to identify chert, the rock type where fossils were found. I wanted to use my fascination with biochemistry to find molecular fossils. Last but not least, ironically at the time, I was not at all interested in the carbon isotope papers published by Tom Hoering (1963; 1967) and others. Little did I realize then that carbon isotopes and the process of isotope patterning by blue-green algae (cyanobacteria) would come to occupy the majority of my research career.
Prof. Given’s class was a huge eye opener for me in many ways. I was able to use my knowledge and love of chemistry to begin to understand biological, environmental, and ecological processes. In the 1960s, scientists at the Carnegie Institution led by Philip Abelson, Tom Hoering, and P. Edgar Hare were discovering simple molecules like fatty acids in marine sediments and fossil shells (Abelson et al. 1956; Hare and Abelson, 1968). Then postdoctoral fellow Patrick Parker published a landmark paper (Parker, 1964) in which he not only described the molecular distributions of fatty acids in marine organisms, but isolated these molecules to measure their carbon isotope patterns. Parker and colleagues at the University of Texas Marine Science Institute (UTMSI) were publishing papers at a rate of one a year in the journal Science on new compounds found in sediments, marine ecosystems, and blue-green algae.
At the conclusion of my undergraduate years as a biology major, I was convinced that I wanted to combine biology, chemistry, and geology in an interdisciplinary career. Professor Given helped tremendously by suggesting two United States labs and one British group, that were engaged in the research I was most interested in. I chose to attend the University of Texas Marine Science Institute (UMTSI) in Port Aransas based on a welcoming phone call from Professor Patrick L. Parker. Pat Parker provided a positive response to my potential and offered me a position as a graduate student in an interdisciplinary course of study under the joint supervision of Parker (a marine organic geochemist), Chase Van Baalen (an algal physiologist and specialist in cyanobacteria), and Bill Behrens (a marine geologist). I accepted the position and in January 1974 I headed south to Port Aransas, Texas, on the coast of the Gulf of Mexico. In hindsight, my decision to study at UTMSI with Parker was without question, the right choice. Parker’s research on the relationship of modern organisms to the compounds found in Recent sediments, as well as his interest in carbon isotopes, set the path for my career in biogeochemistry.