Caitlyn R. Witkowski

University of Bristol | UB · School of Earth Sciences

Past changes in the atmospheric concentration of carbon dioxide (PCO 2) have had a major impact on earth system dynamics; yet, reconstructing secular trends of past PCO 2 remains a prevalent challenge in paleoclimate studies. The current long-term PCO 2 reconstructions rely largely on the compilation of many different proxies, often with discrepanc...

The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than those of the present day. As such, the study of early Eocene climate provides insight into how a super-warm Earth system behaves and o...

Sedimentary deposits yielding extraordinarily-preserved fossils (known as Lagerstätten) may provide significant insights into the physiology and environments of ancient plants, particularly when the fossils represent their original characteristics with limited diagenetic modifications. To better understand molecular, isotopic, and morphological cha...

The Earth has been around for a long time. Earth’s climate history is called its paleoclimate, where “paleo” means old or ancient. In this article, we explain how studying paleoclimate helps us understand how and why the Earth (and the life on it) evolved over time. Scientists can study the fossils, chemicals, and minerals preserved in ice or ancie...

During the late Eocene to the early Oligocene, marine records document a globally congruent record of declining carbon dioxide concentrations, Antarctic icesheet growth, and associated reorganisation of the global climate system. In contrast, the few existing terrestrial records demonstrate high heterogeneity of environmental change and are difficu...

Quantifying how land surface height, such as that of the Tibetan region, has changed with time is crucial for understanding a range of Earth processes, including atmospheric dynamics, biotic evolution and tectonics. Elevation reconstructions are highly uncertain and controversial, in part because of assumptions used in their calculation. The larges...

Soil bacteria rank among the most diverse groups of organisms on Earth and actively impact global processes of carbon cycling, especially in the emission of greenhouse gases like methane, CO2 and higher gaseous hydrocarbons. An abundant group of soil bacteria are the mycobacteria, which colonize various terrestrial, marine and anthropogenic environ...

Records of carbon dioxide concentrations (partial pressure expressed as pCO 2) over Earth's history provide trends that are critical to understand our changing world. To better constrain pCO2 estimations, here we test organic pCO2 proxies against the direct measurements of pCO2 recorded in ice cores. Based on the concept of stable carbon isotopic f...

Soil bacteria rank among the most diverse groups of organisms on Earth and actively impact global processes of carbon cycling, especially in the emission of greenhouse gases like methane, CO2 and higher gaseous hydrocarbons. An abundant group of soil bacteria are the mycobacteria, which colonize various habitats due to their impermeable cell envelo...

The early Oligocene represents the beginning of the modern icehouse world. To better understand how vegetation and climate changed during this period, we reconstruct quantitively the early Oligocene vegetation and climate by analyzing fossil spore and pollen assemblages from Lühe basin, Yunnan Province, in southwestern China. The reconstructed pale...

Understanding long-term trends in atmospheric concentrations of carbon dioxide (pCO2) has become increasingly relevant as modern concentrations surpass recent historic trends. One method for estimating past pCO2, the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) has shown promise over the past several decades, in particul...

Carbon dioxide concentrations in the atmosphere play an integral role in many Earth system dynamics, including its influence on global temperature. The past can provide insights into these dynamics, but unfortunately reconstructing long-term trends of atmospheric carbon dioxide (expressed in partial pressure; pCO2) remains a challenge in paleoclima...

Carbon dioxide concentrations in the atmosphere play an integral role in many earth system dynamics, including 10 its influence on global temperature. Long-term trends can provide insights into these dynamics though reconstructing long-term trends of atmospheric carbon dioxide (expressed in partial pressure; PCO 2) remains a challenge in paleoclima...

The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than present day. As such, study of early Eocene climate provides insight into how a super-warm Earth system behaves and offers an opportun...

Mathematical models of epidemic dynamics offer significant insight into predicting and controlling infectious diseases. The dynamics of a disease model generally follow a susceptible, infected, and recovered (SIR) model, with some standard modifications. In this paper, we extend the work of Munz et.al (2009) on the application of disease dynamics t...

The molecular preservation of exceptionally preserved conifer needles from middle Miocene and Pliocene deposits on Banks Island, Canada, was investigated using pyrolysis-gas chromatography–mass spectrometry (Py-GC-MS). Solvent-extracted residues from Miocene Larix, Glyptostrobus, and Pinus, Pliocene Picea, and their associated bulk material, yielde...

Fossil materials record ancient life and their adapted environment. Arctic plant fossils are critical for our understanding of the Earth’s paleoenvironment when high latitudes were under ice-free conditions. All Arctic plant fossils in this research are conifers, plants conducive for morphological and molecular study because of their incredible gen...

In US history, much human rights policy developed in four waves during the twentieth century. These waves were triggered by similar circumstances, but all proved short-lived as structural constraints such as limited US power over other countries’ domestic actions, competing US policy priorities, a US hesitance to join multilateral institutions, and...