Thure E. Cerling
Encyclopedia
Thure E. Cerling is a Distinguished Professor of Geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 and Geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...

 and a Distinguished Professor of Biology at the University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

.
"A single hair can determine a person's location during the past weeks or even years" – Thure E. Cerling


Cerling’s research interests are primarily focused on the geochemistry
Geochemistry
The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks, water, and soils, and the cycles of matter and energy that transport the Earth's chemical components in time and space, and...

 processes occurring near the Earth's surface and on the geological record of ecological change. Particularly, working on conservation biology
Conservation biology
Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...

, he understood the modern animal diet and physiology by using stable isotopes as natural tracers as well as studying dietary changes of different mammalian lineages extending over millions of years.

Focusing on lakes, modern soils and ecosystems, Cerling has been able to understand the evolution of ecosystems, monsoons, and the atmosphere over geological time scales by applying isotope systematic. Furthermore, his research group is studying how to re-build the evolution of the landscapes over the last one million years by exploiting the isotopes produced by cosmic rays on rocks in situ.

Besides teaching, his current works focus on the development of landforms in semi-arid regions, on the geology of Old World paleo-anthropologic sites and on contaminant migration in the water, including the use of tritium and helium as hydrological tracers.
Nowadays Cerling lives in Salt Lake City, Utah.

Early life

Thure E. Cerling received his Bachelor of Science
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...

 degree in geology and chemistry from Iowa State University
Iowa State University
Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...

, in Ames, Iowa
Ames, Iowa
Ames is a city located in the central part of the U.S. state of Iowa in Story County, and approximately north of Des Moines. The U.S. Census Bureau designates that Ames, Iowa metropolitan statistical area as encompassing all of Story County, and which, when combined with the Boone, Iowa...

, in 1972. In 1973, Professor Cerling received his Master of Science
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...

 degree in geology from Iowa State University. Then, in 1977, he was awarded a Ph.D. in geology by the University of California at Berkeley. The following years, from 1977 to 1979, he worked as a research scientist at Oak Ridge National Laboratory and, since 1979, he is a member of the University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

’s faculty.

Global ecological changes

With the publication of “Expansion of C4 ecosystems as an indicator of global ecological change in the late Miocene” in 1993, Dr Cerling, helped by Yang Wang and Jay Quade, made relevant studies relatively to carbon isotopes. Thanks to a deep analysis of palaeovegetation from palaeosols and palaeodiet measured in fossil tooth enamel, was demonstrated a global increase in the biomass of plants using C4 photosynthesis between 7 and 5 million years ago. The decrease of atmospheric CO2 concentrations over the history below a threshold that favored the C3-photosynthesizing plants was considered as a valid reason for the global expansion of C4 biomass.
The publication “Global vegetation change through the Miocene/Pliocene boundary” in 1997 confirmed these results, demonstrating even how at lower latitudes the change appeared to occur earlier because of the threshold for C3 photosynthesis is higher at warmer temperatures.

Give me a hair and I’ll tell you where you have been.

Thure Cerling and James Ehleringer, a biology professor at the University of Utah, founded Isoforensics in 2003, a company with the aim of interpreting the stable isotope composition of various biological and synthetic materials. This was the first step for the discovery they made which was first published on February 25, 2008, by the “Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences
The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences...

” with the title “Hydrogen and oxygen isotope ratios in human hair are related to geography”.
To know where people have been and where they lived for a while are information that became available by analyzing the stable isotope composition of their scalp hair. Cerling discovered that a strand of hair could provide valuable clues about a person's travels by studying the variation of hydrogen-2 (δ2H) and oxygen-18 (δ18O) isotopes and comparing them to the ones in the drinking water. The extent of the information that can be deduced depends on the length of the hair: the longer is the hair, the greater is the extraction of information. The variation with geography of isotope concentrations is linked with precipitations, cloud temperatures and with the amount of water that evaporates from soil and plants. When clouds move off the ocean towards inland the ratios of oxygen-18 to oxygen-16 and hydrogen-2 to hydrogen-1 tend to decrease because of the rain water with oxygen-18 and hydrogen-2, being heavier, tends to fall first.
Samples of tap water were collected from more than 600 cities across the United States as well as hair samples from the barbershops in 65 cities in 20 states. The comparison showed that both hair and drinking water samples had the same isotopic variations. In order to display these information, the scientists produced color-coded maps based on the correlation of the isotopes in hair to those in drinking water. This maps show how ratios of hydrogen and oxygen isotopes in scalp hair vary in different areas of the United States. It was so proved that the water drank by a human being leaves in the hair an evidence which contain oxygen and hydrogen isotopes equal to the ones in the tap water.
This technique would have been a new tool for policemen, anthropologists, archaeologists and doctors.

The elephant tail hair: how many things they can say!

Professor Cerling, helped by James Ehleringer and Christopher Remien (two University of Utah colleagues), George Wittemyer of Colorado State University and member of “Save the Elephants” in Nairobi, and Iain Douglas-Hamilton
Iain Douglas-Hamilton
Iain Douglas-Hamilton, OBE, is a zoologist known for his study of elephants.He earned both a B.Sc. and a D.Phil. in zoology from Oriel College, Oxford, and he is the recipient of the 2010 Indianapolis Prize for his work on elephant conservation.His chief research interest is to understand elephant...

, who founded the association “Save the Elephants”, conducted a research around the Samburu
Samburu National Reserve
The Samburu National Reserve is located on the banks of the Ewaso Ng'iro river in Kenya; on the other side of the river is the Buffalo Springs National Reserve in Northern Kenya. It is 165 km² in size and 350 kilometers from Nairobi and ranges in altitude from 800 to 1230m above sea level...

 and Buffalo Springs
Buffalo Springs National Reserve
Buffalo Springs National Reserve is a protected area in the Isiolo District of Eastern Province, in northern Kenya.-Organization:The reserve was established in 1948 as part of the Samburu - Isiolo Game Reserve, and the present boundaries were established in 1985...

national reserves in northern Kenya analyzing carbon and other stable isotopes in elephant tail hair to discover where and what Victoria, Anastasia and Cleopatra, three daughters of a mother elephant named Queen Elizabeth, usually eat over a six-years period (2000–2006). In order to monitor their life, the elephants were equipped with a Global Positioning System that recorded their positions every hour for the whole research period. For getting the sample of tail hair, elephants were immobilized with drug-filled dart guns when necessary. Considering that the hair grows about an inch per month, a single hair contained isotopic information to diet during an 18-month period.

Wet and dry seasons: different responses

The analysis of ratios of carbon-13 to carbon-12 along the length of a single elephant hair led Cerling and his crew to understand the elephants' diet. During the wet season, after the grass had grown long enough for elephants to grab with their trunks, their tail hair showed the presence of different form of carbon, indicating a high amount of high-protein grass. On the other hand, during the dry season, the results obtained by the analysis of the hair pointed out how elephants had switched over to shrubs and trees.

Birth and Cattle

For what concern the Samburu-Buffalo Springs, five weeks after the rainy season had started, the grass became rich in nutrients and the females were most likely to conceive, giving birth 22 months later, just in time for another rainy season to provide nutrients to the grass they would have eaten: the cycle could restart.
The research also pointed out how developed is the competition between elephants and cattle: during the typical wet season diet of elephants, the overgrazing by cattle caused the grass to be very short, resulting in a limited access to it for elephants, out-competing them. This situation could have influenced the elephants' ability to bulk up for pregnancy.

Behavior

All these analyses pointed out even that there are some elephant families friendlier than others and showed how there are dominant families that settle down in the best places, where there is plenty of food and water.

Publications by Cerling

  • Thure Cerling; Iain Douglas-Hamilton; Lee Siegel: ”Elephant Tracks” University of Utah News Release, January 2, 2006.

External links

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