Ronald Amundson | |
---|---|
Nationality | American |
Alma mater | University of California, Riverside |
Scientific career | |
Fields | Isotope biogeochemistry, soil science |
Institutions | University of California, Berkeley |
Thesis | A chronosequential evaluation of the effects of reclamation on a saline-sodic soil (1984) |
Doctoral advisor | Lanny Lund |
Website | ourenvironment |
Ronald Amundson is an American environmental scientist [1] who is currently Professor at University of California, Berkeley. [2]
Amundson received his PhD from the University of California, Riverside in 1984. [3] For this work, he had analyzed the carbon and oxygen stable isotopic ratios of calcium carbonate within the soils in the San Joaquin Valley.
His interests are isotope biogeochemistry, environment history & ethics, ecosystems, pedology and soils. [4] His highest cited paper is "Rapid exchange between soil carbon and atmospheric carbon dioxide driven by temperature change" [5] at 759 times, according to Google Scholar. [6]
2019 - Elected Fellow of the American Geophysical Union [7]
The Eocene is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name Eocene comes from the Ancient Greek Ἠώς and καινός and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.
The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many rocks such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks.
Carbon-14, C-14, 14C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934.
Mass-independent isotope fractionation or Non-mass-dependent fractionation (NMD), refers to any chemical or physical process that acts to separate isotopes, where the amount of separation does not scale in proportion with the difference in the masses of the isotopes. Most isotopic fractionations are caused by the effects of the mass of an isotope on atomic or molecular velocities, diffusivities or bond strengths. Mass-independent fractionation processes are less common, occurring mainly in photochemical and spin-forbidden reactions. Observation of mass-independently fractionated materials can therefore be used to trace these types of reactions in nature and in laboratory experiments.
An isotopic signature is a ratio of non-radiogenic 'stable isotopes', stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic reference material. This process is called isotope analysis.
Ján Veizer is the Distinguished University Professor (emeritus) of Earth Sciences at the University of Ottawa and Institute for Geology, Mineralogy und Geophysics, of Bochum Ruhr University. He held the NSERC/Noranda/CIFAR Industrial Chair in Earth System Isotope and Environmental Geochemistry until 2004. He is an isotope geochemist; his research interests have included the use of chemical and isotopic techniques in determining Earth's climatic and environmental history.
The Mars ocean theory states that nearly a third of the surface of Mars was covered by an ocean of liquid water early in the planet's geologic history. This primordial ocean, dubbed Paleo-Ocean or Oceanus Borealis, would have filled the basin Vastitas Borealis in the northern hemisphere, a region that lies 4–5 km below the mean planetary elevation, at a time period of approximately 4.1–3.8 billion years ago. Evidence for this ocean includes geographic features resembling ancient shorelines, and the chemical properties of the Martian soil and atmosphere. Early Mars would have required a denser atmosphere and warmer climate to allow liquid water to remain at the surface.
The Cretaceous Thermal Maximum (CTM), also known as Cretaceous Thermal Optimum, was a period of climatic warming that reached its peak approximately 90 million years ago (90 Ma) during the Turonian age of the Late Cretaceous epoch. The CTM is notable for its dramatic increase in global temperatures characterized by high carbon dioxide levels.
Greenhouse gas emissions from wetlands of concern consist primarily of methane and nitrous oxide emissions. Wetlands are the largest natural source of atmospheric methane in the world, and are therefore a major area of concern with respect to climate change. Wetlands account for approximately 20–30% of atmospheric methane through emissions from soils and plants, and contribute an approximate average of 161 Tg of methane to the atmosphere per year.
The atmospheric carbon cycle accounts for the exchange of gaseous carbon compounds, primarily carbon dioxide, between Earth's atmosphere, the oceans, and the terrestrial biosphere. It is one of the faster components of the planet's overall carbon cycle, supporting the exchange of more than 200 billion tons of carbon in and out of the atmosphere throughout the course of each year. Atmospheric concentrations of CO2 remain stable over longer timescales only when there exists a balance between these two flows. Methane, Carbon monoxide (CO), and other human-made compounds are present in smaller concentrations and are also part of the atmospheric carbon cycle.
Susan E. Trumbore is an earth systems scientist focusing on the carbon cycle and its effects on climate. She is a director at the Max Planck Institute for Biogeochemistry and a Professor of Earth System Science at University of California, Irvine. She is a fellow of the American Geophysical Union and the American Association for the Advancement of Science, a Member of the National Academy of Sciences and recipient of the Benjamin Franklin Medal.
Asmeret Asefaw Berhe is a soil biogeochemist and political ecologist who served as Director of the Office of Science at the US Department of Energy from 2022 to 2024. She is a Professor of Soil Biogeochemistry and the Ted and Jan Falasco Chair in Earth Sciences and Geology in the Department of Life and Environmental Sciences; University of California, Merced. Her research group works to understand how soil helps regulate the Earth's climate.
Lisa Welp is a biogeochemist who utilizes stable isotopes to understand how water and carbon dioxide are exchanged between the land and atmosphere. She is a professor at Purdue University in the department of Earth, Atmosphere, and Planetary Sciences.
Caroline Masiello is a biogeochemist who develops tools to better understand the cycling and fate of globally relevant elemental cycles. She is a professor at Rice University in the Department of Earth, Environmental and Planetary Sciences and holds joint appointments in the Chemistry and Biochemistry Departments. Masiello was elected as a Fellow of the Geological Society of America in 2017. She currently leads an interdisciplinary team of scientists who are developing microbial sensors for earth system science.
The silica cycle is the biogeochemical cycle in which biogenic silica is transported between the Earth's systems. Silicon is considered a bioessential element and is one of the most abundant elements on Earth. The silica cycle has significant overlap with the carbon cycle and plays an important role in the sequestration of carbon through continental weathering, biogenic export and burial as oozes on geologic timescales.
Adina Paytan is a research professor at the Institute of Marine Sciences at the University of California, Santa Cruz. known for research into biogeochemical cycling in the present and the past. She has over 270 scientific publications in journals such as Science, Nature, Proceedings of the National Academy of Sciences, and Geophysical Research Letters.
Kristie Ann Boering is a Professor of Earth and Planetary Science and the Lieselotte and David Templeton Professor of Chemistry at University of California, Berkeley. She studies atmospheric chemistry and mass transport in the extraterrestrial atmosphere using kinetics and photochemistry. Boering was elected a member of the National Academy of Sciences in 2018.
Margaret Torn is an ecologist at Lawrence Berkeley National Laboratory known for her research on carbon cycling, especially with respect to the interactions between soils and the atmosphere.
Carol Kendall is a hydrologist known for her research tracking nutrients and contaminants in aquatic ecosystems using isotopic tracers.
Nina Buchmann is a German ecologist known for her research on the physiology of plants and the impact of plants on biogeochemical cycling. She is a member of the German National Academy of Sciences Leopoldina and an elected fellow of the American Geophysical Union.