Evaluating Carbonate Saturation Effects on Magnesium Calcium Core Top Calibration in Benthic Foraminifera PDF Download
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Author: Publisher: ISBN: Category : Benthic animals Languages : en Pages : 128
Book Description
Magnesium calcium paleothermometry in benthic foraminifera is intended to provide a salinity-independent reconstruction of bottom water temperature. The temperature calibration is however, rather uncertain, due to evidence of additional carbonate saturation effects on Mg incorporation into benthic tests. The overarching goal of this thesis is to directly determine the magnitude of the carbonate saturation effect and the threshold at which this effect significantly alters temperature estimates based on the Mg/Ca content of benthic foraminiferal tests. My research has focused on using homothermal homohaline depth transects from the Norwegian Sea and Gulf of Mexico in the context of a global core top calibration. This thesis consists of 45 core tops from four cruises. In these transects, the relationship between carbonate saturation and Mg/Ca is not strongly pronounced, possibly due to the large variability in the data. As is, it does support the hypothesis that in saturated waters, temperature exerts the primary control on benthic foraminiferal Mg/Ca. A two-part global calibration equation has been constructed for under-(delta[CO3-2] 3 mu mol/kg) and over-saturated (delta[CO3-2] 3 mu mol/kg) waters. However, these equations produce unrealistic bottom water temperature reconstruction when applied to a downcore record in the eastern basin of the tropical Atlantic Ocean (1° 21'S 11° 58'W; 3912 m). These results suggest that further work is needed to improve the reliability of the Mg/Ca-T-delta[CO3-2] equation and to accurately determine the threshold at which delta[CO3-2] effects become pronounced. Likewise, future studies should look into using multi proxy approaches for correcting Mg/Ca-T estimates for saturation effects, such as the use of B/Ca measurements as a proxy for delta[CO3-2].
Author: Publisher: ISBN: Category : Benthic animals Languages : en Pages : 128
Book Description
Magnesium calcium paleothermometry in benthic foraminifera is intended to provide a salinity-independent reconstruction of bottom water temperature. The temperature calibration is however, rather uncertain, due to evidence of additional carbonate saturation effects on Mg incorporation into benthic tests. The overarching goal of this thesis is to directly determine the magnitude of the carbonate saturation effect and the threshold at which this effect significantly alters temperature estimates based on the Mg/Ca content of benthic foraminiferal tests. My research has focused on using homothermal homohaline depth transects from the Norwegian Sea and Gulf of Mexico in the context of a global core top calibration. This thesis consists of 45 core tops from four cruises. In these transects, the relationship between carbonate saturation and Mg/Ca is not strongly pronounced, possibly due to the large variability in the data. As is, it does support the hypothesis that in saturated waters, temperature exerts the primary control on benthic foraminiferal Mg/Ca. A two-part global calibration equation has been constructed for under-(delta[CO3-2] 3 mu mol/kg) and over-saturated (delta[CO3-2] 3 mu mol/kg) waters. However, these equations produce unrealistic bottom water temperature reconstruction when applied to a downcore record in the eastern basin of the tropical Atlantic Ocean (1° 21'S 11° 58'W; 3912 m). These results suggest that further work is needed to improve the reliability of the Mg/Ca-T-delta[CO3-2] equation and to accurately determine the threshold at which delta[CO3-2] effects become pronounced. Likewise, future studies should look into using multi proxy approaches for correcting Mg/Ca-T estimates for saturation effects, such as the use of B/Ca measurements as a proxy for delta[CO3-2].
Author: Cary Mock Publisher: Newnes ISBN: 0444536426 Category : Science Languages : en Pages : 3883
Book Description
The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next
Author: Peter Lemke Publisher: Springer Science & Business Media ISBN: 9400720270 Category : Science Languages : en Pages : 473
Book Description
The Arctic is now experiencing some of the most rapid and severe climate change on earth. Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, many of which have already begun. Changes in arctic climate will also affect the rest of the world through increased global warming and rising sea levels. The volume addresses the following major topics: - Research results in observing aspects of the Arctic climate system and its processes across a range of time and space scales - Representation of cryospheric, atmospheric, and oceanic processes in models, including simulation of their interaction with coupled models - Our understanding of the role of the Arctic in the global climate system, its response to large-scale climate variations, and the processes involved.
Author: National Research Council Publisher: National Academies Press ISBN: 030916155X Category : Science Languages : en Pages : 200
Book Description
The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.
Author: National Research Council Publisher: National Academies Press ISBN: 0309209196 Category : Science Languages : en Pages : 153
Book Description
There is little dispute within the scientific community that humans are changing Earth's climate on a decadal to century time-scale. By the end of this century, without a reduction in emissions, atmospheric CO2 is projected to increase to levels that Earth has not experienced for more than 30 million years. As greenhouse gas emissions propel Earth toward a warmer climate state, an improved understanding of climate dynamics in warm environments is needed to inform public policy decisions. In Understanding Earth's Deep Past, the National Research Council reports that rocks and sediments that are millions of years old hold clues to how the Earth's future climate would respond in an environment with high levels of atmospheric greenhouse gases. Understanding Earth's Deep Past provides an assessment of both the demonstrated and underdeveloped potential of the deep-time geologic record to inform us about the dynamics of the global climate system. The report describes past climate changes, and discusses potential impacts of high levels of atmospheric greenhouse gases on regional climates, water resources, marine and terrestrial ecosystems, and the cycling of life-sustaining elements. While revealing gaps in scientific knowledge of past climate states, the report highlights a range of high priority research issues with potential for major advances in the scientific understanding of climate processes. This proposed integrated, deep-time climate research program would study how climate responded over Earth's different climate states, examine how climate responds to increased atmospheric carbon dioxide and other greenhouse gases, and clarify the processes that lead to anomalously warm polar and tropical regions and the impact on marine and terrestrial life. In addition to outlining a research agenda, Understanding Earth's Deep Past proposes an implementation strategy that will be an invaluable resource to decision-makers in the field, as well as the research community, advocacy organizations, government agencies, and college professors and students.
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Author: Rachel Elizabeth Brown
Author: Jessica K. Blanks
Author: Cary Mock
Author: Petra Dekens
Author: Peter Lemke
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Author: E. Boltovskoy
Author: National Research Council
Author: National Research Council