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Author: Patrick Anthony Rafter Publisher: ISBN: Category : Languages : en Pages : 117
Book Description
The tropical Pacific is a region where nutrient delivery, upper ocean dynamics, and global climate variability are tightly coupled. For example, the depth of the eastern equatorial Pacific (EEP) thermocline, for the most part, determines the delivery of the essential nutrient nitrate, but it is also a key aspect of an ocean-atmosphere feedback system responsible for global climate variability--the El Nino Southern Oscillation (ENSO). To provide a unique view of the upper ocean processes directly responsible for nutrient and climate dynamics in this region, I apply a single tracer--the ratio of 15N to 14N (hereafter "[delta]15N")--in modern seawater and sediment throughout the tropical Pacific. I find that the [delta]15N of nitrate is homogeneous throughout the tropical Pacific and is elevated by 2 / relative to the Southern and Atlantic Oceans by mixing with the denitrified waters of the eastern tropical Pacific. The results of this modern ocean survey are used to devise a new application of [delta]15N in eastern and western equatorial Pacific (WEP) sediments that provides a record of EEP nitrate consumption over the past 1,200,000 years. This record strongly suggests that the depth of the EEP thermocline--and therefore the upper ocean conditions driving the tropical climate system--has little to no response to high-latitude processes such as icesheet dynamics. Instead, as has been suggested by coupled ocean-atmosphere models, the east/west thermocline tilt responded primarily to changes in local seasonal insolation over thousands of years (a product of planetary axial precession). Some of the long-term changes in these deep-sea sediment [delta]15N records would seem to suggest an alteration of the original surface ocean signal, but additional [delta]15N measurements of sedimentary size fractions and components support the fidelity of bulk sedimentary [delta]15N as an archive of surface ocean nutrient cycling.
Author: Patrick Anthony Rafter Publisher: ISBN: Category : Languages : en Pages : 117
Book Description
The tropical Pacific is a region where nutrient delivery, upper ocean dynamics, and global climate variability are tightly coupled. For example, the depth of the eastern equatorial Pacific (EEP) thermocline, for the most part, determines the delivery of the essential nutrient nitrate, but it is also a key aspect of an ocean-atmosphere feedback system responsible for global climate variability--the El Nino Southern Oscillation (ENSO). To provide a unique view of the upper ocean processes directly responsible for nutrient and climate dynamics in this region, I apply a single tracer--the ratio of 15N to 14N (hereafter "[delta]15N")--in modern seawater and sediment throughout the tropical Pacific. I find that the [delta]15N of nitrate is homogeneous throughout the tropical Pacific and is elevated by 2 / relative to the Southern and Atlantic Oceans by mixing with the denitrified waters of the eastern tropical Pacific. The results of this modern ocean survey are used to devise a new application of [delta]15N in eastern and western equatorial Pacific (WEP) sediments that provides a record of EEP nitrate consumption over the past 1,200,000 years. This record strongly suggests that the depth of the EEP thermocline--and therefore the upper ocean conditions driving the tropical climate system--has little to no response to high-latitude processes such as icesheet dynamics. Instead, as has been suggested by coupled ocean-atmosphere models, the east/west thermocline tilt responded primarily to changes in local seasonal insolation over thousands of years (a product of planetary axial precession). Some of the long-term changes in these deep-sea sediment [delta]15N records would seem to suggest an alteration of the original surface ocean signal, but additional [delta]15N measurements of sedimentary size fractions and components support the fidelity of bulk sedimentary [delta]15N as an archive of surface ocean nutrient cycling.
Author: Jonathan Edward Lambert Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
I also identify a period between 100 and 60 ka during a potential reorganization of the upper water column in which variability in productivity occurs at a higher frequency than that of precession. Finally, while also related to ITCZ shifts, a nearby record closer to the equator is phase-lagged from Site U1486 - emphasizing the fine-scale regional differences in the drivers of primary productivity in the WPWP.
Author: Geological Society of London Publisher: Geological Society of London ISBN: 9781862391819 Category : Science Languages : en Pages : 342
Book Description
The Early-Middle Pleistocene transition (around 1.2 to 0.5 Ma) marks a profound shift in Earth's climate state. Low-amplitude 41 ka climate cycles, dominating the earlier part of the Pleistocene, gave way progressively to a 100 ka rhythm of increased amplitude that characterizes our present glacial-interglacial world. This volume assesses the biotic and physical response to this transition both on land and in the oceans: indeed it examines the very nature of Quaternary climate change. Milankovitch theory, palaeoceanography using isotopes and microfossils, marine organic geochemistry, tephrochronology, the record of loess and soil deposition, terrestrial vegetational change, and the migration and evolution of hominins as well as other large and small mammals, are all considered. These themes combine to explore the very origins of our present biota.
Author: Miriam Jones Publisher: Frontiers Media SA ISBN: 2889633373 Category : Languages : en Pages : 208
Book Description
The vast area of the North Pacific, spanning ~55˚ longitude, represents a challenge for documenting and understanding the geologic history of ocean, atmosphere, and terrestrial environmental change. Nevertheless, its importance for many issues, including our fundamental understanding of ocean and atmospheric circulation patterns and teleconnections with natural modes of climate variability through time, has led to a steady rise in the numbers of study sites and proxy types. By bringing together a wide range of proxies and timescales that examine the impacts of paleoclimate on ecosystems, water, carbon, and humans, and interactions between marine and terrestrial processes, this Research Topic contributes to an improved understanding of the region’s significance at global, hemispheric, and regional scales.
Author: Peter W. Glynn Publisher: Springer ISBN: 9401774994 Category : Science Languages : en Pages : 666
Book Description
This book documents and examines the state of health of coral reefs in the eastern tropical Pacific region. It touches on the occurrence of coral reefs in the waters of surrounding countries, and it explores their biogeography, biodiversity and condition relative to the El Niño southern oscillation and human impacts. Additionally contained within is a field that presents information on many of the species presented in the preceding chapters.
Author: Michael J.R. Fasham Publisher: Springer Science & Business Media ISBN: 3642558445 Category : Science Languages : en Pages : 324
Book Description
Oceans account for 50% of the anthropogenic CO2 released into the atmosphere. During the past 15 years an international programme, the Joint Global Ocean Flux Study (JGOFS), has been studying the ocean carbon cycle to quantify and model the biological and physical processes whereby CO2 is pumped from the ocean's surface to the depths of the ocean, where it can remain for hundreds of years. This project is one of the largest multi-disciplinary studies of the oceans ever carried out and this book synthesises the results. It covers all aspects of the topic ranging from air-sea exchange with CO2, the role of physical mixing, the uptake of CO2 by marine algae, the fluxes of carbon and nitrogen through the marine food chain to the subsequent export of carbon to the depths of the ocean. Special emphasis is laid on predicting future climatic change.
Author: Takeyoshi Nagai Publisher: John Wiley & Sons ISBN: 1119428319 Category : Science Languages : en Pages : 586
Book Description
An interdisciplinary study of the Kuroshio nutrient stream The surface water of the Kuroshio, a western boundary current in the North Pacific Ocean, is nutrient-depleted and has relatively low primary productivity, yet abundant fish populations are supported in the region. This is called the “Kuroshio Paradox”. Kuroshio Current: Physical, Biogeochemical and Ecosystem Dynamics presents research from a multidisciplinary team that conducted observational and modeling studies to investigate this contradiction. This timely and important contribution to the ocean sciences literature provides a comprehensive analysis of the Kuroshio. Volume highlights include: New insights into the role of the Kuroshio as a nutrient stream The first interdisciplinary examination of the Kuroshio Paradox Reflections on the influence of the Kuroshio on Japanese culture Research results on both the lower and higher trophic levels in the Kuroshio ecosystem Comparisons of nutrient dynamics in the Kuroshio and Gulf Stream Predictions of ecosystem responses to future climate variability
Author: Patrick Anthony Rafter
Author: Patrick Anthony Rafter
Author: Jonathan Edward Lambert
Author: Artur Piotr Palacz
Author: Rebecca Sprague Robinson
Author: Kristina Lynn Faul
Author: Geological Society of London
Author: Miriam Jones
Author: Peter W. Glynn
Author: Michael J.R. Fasham
Author: Takeyoshi Nagai