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Articles 211 - 240 of 663

Full-Text Articles in Earth Sciences

Estimating Carbon Flux From Optically Recording Total Particle Volume At Depths Below The Primary Pycnocline, Alexander B. Bochdansky, Robert B. Dunbar, Dennis A. Hansell, Gerhard J. Herndl Dec 2019

Estimating Carbon Flux From Optically Recording Total Particle Volume At Depths Below The Primary Pycnocline, Alexander B. Bochdansky, Robert B. Dunbar, Dennis A. Hansell, Gerhard J. Herndl

OES Faculty Publications

Optical instruments can rapidly determine numbers and characteristics of water column particles with high sensitivity. Here we show the usefulness of optically assessed total particle volume below the main pycnocline to estimate carbon export in two systems: the open subarctic North Atlantic and the Ross Sea, Antarctica. Both regions exhibit seasonally high phytoplankton production and efficient export (i.e., a strong biological pump). Total particle volumes in the mesopelagic (200-300 m) were significantly correlated with those in the overlying surface mixed layer (50-60 m), indicating that most particles at depth reflect export from the surface. This connectivity, however, is modulated by …

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Growth Phase Proteomics Of The Heterotrophic Marine Bacterium Ruegeria Pomeroyi, Dasha Krayushkina, Emma Timmins-Schiffman, Jessica Faux, Damon H. May, Michael Riffle, H. Rodger Harvey, Brook L. Nunn Dec 2019

Growth Phase Proteomics Of The Heterotrophic Marine Bacterium Ruegeria Pomeroyi, Dasha Krayushkina, Emma Timmins-Schiffman, Jessica Faux, Damon H. May, Michael Riffle, H. Rodger Harvey, Brook L. Nunn

OES Faculty Publications

The heterotrophic marine bacterium, Ruegeria pomeroyi, was experimentally cultured under environmentally realistic carbon conditions and with a tracer-level addition of 13C-labeled leucine to track bacterial protein biosynthesis through growth phases. A combination of methods allowed observation of real-time bacterial protein production to understand metabolic priorities through the different growth phases. Over 2000 proteins were identified in each experimental culture from exponential and stationary growth phases. Within two hours of the 13C-labeled leucine addition, R. pomeroyi significantly assimilated the newly encountered substrate into new proteins. This dataset provides a fundamental baseline for understanding growth phase differences in molecular …

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Temporal And Spatial Scales Of Correlation In Marine Phytoplankton Communities, A. M. Kuhn, S. Dutkiewicz, O. Jahn, Sophie Clayton, T. A. Rynearson, M. R. Mazloff, A. D. Barton Dec 2019

Temporal And Spatial Scales Of Correlation In Marine Phytoplankton Communities, A. M. Kuhn, S. Dutkiewicz, O. Jahn, Sophie Clayton, T. A. Rynearson, M. R. Mazloff, A. D. Barton

OES Faculty Publications

Ocean circulation shapes marine phytoplankton communities by setting environmental conditions and dispersing organisms. In addition, processes acting on the water column (e.g., heat fluxes and mixing) affect the community structure by modulating environmental variables that determine in situ growth and loss rates. Understanding the scales over which phytoplankton communities vary in time and space is key to elucidate the relative contributions of local processes and ocean circulation on phytoplankton distributions. Using a global ocean ecosystem model, we quantify temporal and spatial correlation scales for phytoplankton phenotypes with diverse functional traits and cell sizes. Through this analysis, we address these questions: …

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Closing The Oxygen Mass Balance In Shallow Coastal Ecosystems, Matthew H. Long, Jennie E. Rheuban, Daniel C. Mccorkle, David J. Burdige, Richard C. Zimmerman Nov 2019

Closing The Oxygen Mass Balance In Shallow Coastal Ecosystems, Matthew H. Long, Jennie E. Rheuban, Daniel C. Mccorkle, David J. Burdige, Richard C. Zimmerman

OES Faculty Publications

The oxygen concentration in marine ecosystems is influenced by production and consumption in the water column and fluxes across both the atmosphere-water and benthic-water boundaries. Each of these fluxes has the potential to be significant in shallow ecosystems due to high fluxes and low water volumes. This study evaluated the contributions of these three fluxes to the oxygen budget in two contrasting ecosystems, a Zostera marina (eelgrass) meadow in Virginia, U.S.A., and a coral reef in Bermuda. Benthic oxygen fluxes were evaluated by eddy covariance. Water column oxygen production and consumption were measured using an automated water incubation system. Atmosphere-water …

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Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Elizabeth L. Chamberlain, Steven L. Goodbred, Richard Hale, Michael S. Steckler, Jakob Willinga, Carol Wilson Nov 2019

Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Elizabeth L. Chamberlain, Steven L. Goodbred, Richard Hale, Michael S. Steckler, Jakob Willinga, Carol Wilson

OES Faculty Publications

Constraining time is of critical importance to evaluating the rates and relative contributions of processes driving landscape change in sedimentary basins. The geomorphic character of the field setting guides the application of geochronologic or instrumental tools to this problem, because the viability of methods can be highly influenced by geomorphic attributes. For example, sediment yield and the linked potential for organic preservation may govern the usefulness of radiocarbon dating. Similarly, the rate of sediment transport from source to sink may determine the maturity and/or light exposure of mineral grains arriving in the delta and thus the feasibility of luminescence dating. …

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Pacts 1.0: A Crowdsourced Reporting Standard For Paleoclimate Data, D. Khider, J. Emile-Geay, N. P. Mckay, Y. Gil, D. Garijo, V. Ratnakar, M. Alonso-Garcia, S. Bertrand, O. Bothe, P. Brewer, A. Bunn, M. Chevalier, L. Comas-Bru, J. Hertzberg, Y. Zhou Oct 2019

Pacts 1.0: A Crowdsourced Reporting Standard For Paleoclimate Data, D. Khider, J. Emile-Geay, N. P. Mckay, Y. Gil, D. Garijo, V. Ratnakar, M. Alonso-Garcia, S. Bertrand, O. Bothe, P. Brewer, A. Bunn, M. Chevalier, L. Comas-Bru, J. Hertzberg, Y. Zhou

OES Faculty Publications

The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of …

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Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill Oct 2019

Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill

OES Theses and Dissertations

After years of efforts to restore the Chesapeake Bay, bacterial levels are down and species diversity has increased, however, algal blooms (primarily dinoflagellates) persist, occurring nearly every summer. Dinoflagellates produce resting cysts that accumulate in the bottom sediments and are thought to provide seed populations for future algal blooms when they are resuspended. When estuarine sediments are advected from a bed, other materials, such as pollutants, nutrients, and organic matter are also released into the water column. Thus, resuspended sediments can contribute to the degradation of water quality, habitat, and aquatic life, and impart negative impacts on local ecosystems and …

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Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers Oct 2019

Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers

OES Theses and Dissertations

To improve understanding of geographic mineral distribution from the circum-Arctic Ocean, samples from the Arctic periphery were collected and analyzed for (semi-) quantitative mineral composition. Most samples were collected from the North American region of the Arctic Ocean, a region which has had limited mineral investigation. In addition, more than 1000 published clay mineral data points were gathered to provide the most comprehensive clay mineral distribution map to date. The identification of a smectite source within the Canadian Arctic may reduce the usefulness of this mineral as a unique provenance signal for the Eurasian region. Smectite speciation may be useful …

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Biogeochemical Controls Of Surface Ocean Phosphate, Adam C. Martiny, Michael W. Lomas, Weiwei Fu, Philip W. Boyd, Yuh-Ling L. Chen, Gregory A. Cutter, Michael J. Ellwood, Ken Furuya, Fuminori Hasshihama, Jota Kanda, David M. Karl, Taketoshi Kodama, Qian P. Li, Jian Ma, Thierry Moutin, E. Malcolm S. Woodward, J. Keith Moore Aug 2019

Biogeochemical Controls Of Surface Ocean Phosphate, Adam C. Martiny, Michael W. Lomas, Weiwei Fu, Philip W. Boyd, Yuh-Ling L. Chen, Gregory A. Cutter, Michael J. Ellwood, Ken Furuya, Fuminori Hasshihama, Jota Kanda, David M. Karl, Taketoshi Kodama, Qian P. Li, Jian Ma, Thierry Moutin, E. Malcolm S. Woodward, J. Keith Moore

OES Faculty Publications

Surface ocean phosphate is commonly below the standard analytical detection limits, leading to an incomplete picture of the global variation and biogeochemical role of phosphate. A global compilation of phosphate measured using high-sensitivity methods revealed several previously unrecognized low-phosphate areas and clear regional differences. Both observational climatologies and Earth system models (ESMs) systematically overestimated surface phosphate. Furthermore, ESMs misrepresented the relationships between phosphate, phytoplankton biomass, and primary productivity. Atmospheric iron input and nitrogen fixation are known important controls on surface phosphate, but model simulations showed that differences in the iron-to-macronutrient ratio in the vertical nutrient supply and surface lateral transport …

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Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown Jul 2019

Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown

OES Theses and Dissertations

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in the world, covering more than 100,000 km2. The GBM River system transports over one billion tons of sediment annually and delivers ~750 million tons to the Bay of Bengal, ~25% of which is advected by tides into the fluvially abandoned western delta plain. The Sundarbans National Forest (SNF) is located within the GBM Delta and, covering more than 10,000 km2, is the world’s largest continuous mangrove stand. The present rate of sediment delivery allows the SNF platform elevation to keep pace with regional sea level …

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Lipid Biomarkers Of Bering And Chukchi Sea Euphausiids And Their Application To Diet History, Rachel L. Pleuthner Jul 2019

Lipid Biomarkers Of Bering And Chukchi Sea Euphausiids And Their Application To Diet History, Rachel L. Pleuthner

OES Theses and Dissertations

In the eastern Bering Sea, Thysanoessa raschii are the most abundant krill species and a keystone trophic member that serve as both an important grazer and link to upper level consumers. In this system krill experience large annual variation in food resources, especially during ice advance and retreat; multiple lipid classes are used to temper the effects of those fluctuations, as well as to fuel reproduction and growth. Two shipboard feeding experiments that occurred during late spring and early summer of 2010, respectively, monitored the lipid retention in adult T. raschii and examined the fluctuation of specific lipid biomarkers under …

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The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke Jul 2019

The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke

OES Theses and Dissertations

The El Niño – Southern Oscillation (ENSO) is the largest interannual component of Earth’s climate system, capable of exerting significant influence over global climate patterns that affect communities around the globe. Nevertheless, a comprehensive understanding of the ENSO system and its relationship to tropical Pacific climate dynamics remains unclear. Although new paleoceanographic proxies have shown promise in in their ability to constrain past ENSO change, little is known about how ENSO varied in response to millennial-scale climate events over the last 25,000 years. Here, I present new records of tropical Pacific mean state and ENSO variability over the last 25,000 …

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Next-Generation Rainfall Idf Curves For The Virginian Drainage Area Of Chesapeake Bay, Xixi Wang, Xiaomin Yang, Zhaoyi Cai Jun 2019

Next-Generation Rainfall Idf Curves For The Virginian Drainage Area Of Chesapeake Bay, Xixi Wang, Xiaomin Yang, Zhaoyi Cai

Civil & Environmental Engineering Faculty Publications

Probability-based intensity-duration-frequency IDF curves are needed but currently lacking for Department of Defense DoD to construct and manage its infrastructure in changing climate. The objectives of this project were to 1 develop an innovative approach for considering rainfall non-stationarity in developing such IDF curves and 2 apply this approach to the state of Virginia. In this regard, the observed data on 15-min rainfall at 57 gauges and the precipitations projected by twelve pairs of Regional Climate Model RCM and Global Circulation Model GCM were used. For a given gauge or watershed, in terms of fitting the empirical exceedance probabilities, a …

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Rates Of Relative Sea Level Rise Along The United States East Coast, Jesse N. Beckman, Joseph E. Garcia Apr 2019

Rates Of Relative Sea Level Rise Along The United States East Coast, Jesse N. Beckman, Joseph E. Garcia

Virginia Journal of Science

Recent studies have indicated that some coastal areas, including the East Coast of the United States, are experiencing higher rates of sea level rise than the global average. Rates of relative sea level rise are affected by changes in ocean dynamics, as well as by surface elevation fluctuations due to local land subsidence or uplift. In this study, we derived long-term trends in annual mean relative sea level using tide gauge data obtained from the Permanent Service for Mean Sea Level for stations along the United States East Coast. Stations were grouped by location into the Northeast, Mid-Atlantic, and Southeast …

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Submarine Groundwater Discharge In The Southern Chesapeake Bay: Constraints From Numerical Models, Charles Louis Carlson Apr 2019

Submarine Groundwater Discharge In The Southern Chesapeake Bay: Constraints From Numerical Models, Charles Louis Carlson

OES Theses and Dissertations

Terrestrial and oceanic forces drive fluid flow within the coastal zone to produce submarine groundwater discharge (SGD). Groundwater flowing from the seabed serves as a significant pathway for contaminants and nutrients, producing an active biogeochemical reaction zone. In order to quantify the importance of SGD in geochemical and hydrologic budgets for the lower Chesapeake Bay, three coastal Virginia transects (southern Eastern Shore, Lafayette River, and Ocean View beach) with different topographic gradients were modeled using similar boundary conditions and consistent treatment of hydrogeologic layers. A sensitivity study was performed on the variables of recharge rate, seawater density, and hydraulic permeability. …

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Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean, Molly P. Mikan Apr 2019

Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean, Molly P. Mikan

OES Theses and Dissertations

Understanding how the functionality of marine microbial communities change over time and space, and which taxonomic groups dominate distinct metabolic pathways, are essential to understanding the ecology of these microbiomes and the factors contributing to their regulation of elemental cycles in the oceans. The primary goal of this dissertation was to investigate the community metabolic and taxonomic responses and the degradation potential of two compositionally distinct marine microbiomes within the shallow shelf ecosystem of the Chukchi Sea after rapid fluctuations in algal organic matter availability. Novel bioinformatics tools were collaboratively developed and used together with community proteomics (metaproteomics) to characterize …

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The Effect Of Evapotranspiration On The Groundwater Dome And Past Drought Conditions At Cape Henry, Virginia, Bryce Omar Shoup Apr 2019

The Effect Of Evapotranspiration On The Groundwater Dome And Past Drought Conditions At Cape Henry, Virginia, Bryce Omar Shoup

OES Theses and Dissertations

First Landing State Park, located in Virginia Beach, is a cuspate foreland developed from a succession of erosional and progradational events forming a series of dunes and interdunal swales. Low-lying swales dominate the southern portion of the park forming many wetlands, but the northern portion of the park has fewer wetlands. An asymmetric groundwater dome has been observed on Cape Henry, cresting north of the geographic center of the cuspate foreland. The purpose of this study was to determine if the wetlands that dominate the southern portion of the park are the major driver of the asymmetric groundwater dome and …

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Formation Of Water-Soluble Organic Matter Through Fungal Degradation Of Lignin, Seyyedhadi Khatami, Ying Deng, Ming Tien, Patrick G. Hatcher Jan 2019

Formation Of Water-Soluble Organic Matter Through Fungal Degradation Of Lignin, Seyyedhadi Khatami, Ying Deng, Ming Tien, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Lignin is a major component of decaying terrestrial vegetation in soils and has been reported to contribute substantially to the formation of soil carbon humus and associated water extracts of soil. To better understand this process of humification, lignin from brown-rot degraded wood is subjected to a white-rot fungus (Phanerochaete chrysosporium)whose enzymes are particularly effective in lignin degradation. This enzymatic attack was monitored by ultrahigh resolution mass spectrometry of water soluble extracts of the fungal cultures. The ensuing molecular level characterizations showed that the P. chrysosporium fungi induced aromatic ring oxidations followed by ring opening as expected. However, …

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Impacts Of Basin-Scale Climate Modes On Coastal Sea Level: A Review, Weiqing Han, Detlef Stammer, Philip Thompson, Tal Ezer, Hindu Palanisamy, Xuebin Zhang, Catia M. Domingues, Lei Zhang, Dongliang Yuan Jan 2019

Impacts Of Basin-Scale Climate Modes On Coastal Sea Level: A Review, Weiqing Han, Detlef Stammer, Philip Thompson, Tal Ezer, Hindu Palanisamy, Xuebin Zhang, Catia M. Domingues, Lei Zhang, Dongliang Yuan

CCPO Publications

Global sea level rise (SLR) associated with a warming climate exerts significant stress on coastal societies and low-lying island regions. The rates of coastal SLR observed in the past few decades, however, have large spatial and temporal differences from the global mean, which to a large part have been attributed to basin-scale climate modes. In this paper, we review our current state of knowledge about climate modes’ impacts on coastal sea level variability from interannual-to-multidecadal timescales. Relevant climate modes, their impacts and associated driving mechanisms through both remote and local processes are elaborated separately for the Pacific, Indian and Atlantic …

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Hurricane Model Development At Gfdl: A Collaborative Success Story From A Historical Perspective, Morris A. Bender, Timothy Marchok, Robert E. Tuleya, Isaac Ginis, Vijay Tallapragada, Stephen J. Lord Jan 2019

Hurricane Model Development At Gfdl: A Collaborative Success Story From A Historical Perspective, Morris A. Bender, Timothy Marchok, Robert E. Tuleya, Isaac Ginis, Vijay Tallapragada, Stephen J. Lord

CCPO Publications

The hurricane project at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL) was established in 1970. By the mid-1970s pioneering research had led to the development of a new hurricane model. As the reputation of the model grew, GFDL was approached in 1986 by the director of the National Meteorological Center about establishing a collaboration between the two federal organizations to transition the model into an operational modeling system. After a multiyear effort by GFDL scientists to develop a system that could support rigorous requirements of operations, and multiyear testing had demonstrated its superior performance compared …

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Compositions And Structures Of Particulate And Colloidal Organic Matter In Aquatic Environment By Advanced Analytical Techniques, Yong Ran, Dainan Zhang, Shujie Hu, Yu Yang, Jingdong Mao Jan 2019

Compositions And Structures Of Particulate And Colloidal Organic Matter In Aquatic Environment By Advanced Analytical Techniques, Yong Ran, Dainan Zhang, Shujie Hu, Yu Yang, Jingdong Mao

Chemistry & Biochemistry Faculty Publications

Dissolved, colloidal and particulate organic matter (DOM, COM and POM) is important in the global carbon cycle and knowledge of their sources and structures can be critical to understanding their roles in biogeochemical cycles. This study explored the sources and chemical structures of COM and POM samples from the Pearl River Basin, China by elemental, chlorophyll a (Chl a), radiocarbon and stable carbon isotopic analyses, NMR techniques, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. The chemical and nano-sclae structures of two ultrafiltered dissolved organic matter (UDOM) samples from surface seawater of the Pacific and Atlantic Ocean …

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Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath Jan 2019

Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Abstract: Phosgene in the atmosphere is produced via the degradation of carbon tetrachloride, methyl chloroform, and a number of chlorine‐containing very short lived substances (VSLS). These VSLS are not regulated by the Montreal Protocol even though they contribute to stratospheric ozone depletion. While observations of VSLS can quantify direct stratospheric source gas injection, observations of phosgene in the upper troposphere/lower stratosphere can be used as a marker of product gas injection of chlorine‐containing VSLS. In this work we report upper troposphere/lower stratosphere measurements of phosgene made by the ACE‐FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument and compare with results …

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Delivering Sustained, Coordinated, And Integrated Observations Of The Southern Ocean For Global Impact, Louise Newman, Petra Heil, Rowan Tebilco, Katsuro Katsumata, Andrew Constable, Esmee Van Wijk, Karen Assmann, Joana Beja, Phillippa Bricher, Richard Coleman, Daniel Costa, Steve Diggs, Riccardo Farneti, Sarah Fawcett, Sarah T. Gille, Katharine R. Hendry, Sian Henly, Eileen Hofmann, Ted Maksym, Matthew Mazloff, Andrew Meijers, Michael M. Meredith, Sebastien Moreau, Burcu Ozsoy, Robin Robertson, Irene Schloss, Oscar Schofield, Jiuxin Shi, Elisabeth Sikes, Inga J. Smith, Sebastiaan Swart, Anna Wahlin, Guy Williams, Michael J. M. Williams, Laura Herraiz-Borreguero, Stefan Kern, Jan Lieser, Robert A. Massom, Jessica Melbourne-Thomas, Patricia Miloslavich, Gunnar Spreen Jan 2019

Delivering Sustained, Coordinated, And Integrated Observations Of The Southern Ocean For Global Impact, Louise Newman, Petra Heil, Rowan Tebilco, Katsuro Katsumata, Andrew Constable, Esmee Van Wijk, Karen Assmann, Joana Beja, Phillippa Bricher, Richard Coleman, Daniel Costa, Steve Diggs, Riccardo Farneti, Sarah Fawcett, Sarah T. Gille, Katharine R. Hendry, Sian Henly, Eileen Hofmann, Ted Maksym, Matthew Mazloff, Andrew Meijers, Michael M. Meredith, Sebastien Moreau, Burcu Ozsoy, Robin Robertson, Irene Schloss, Oscar Schofield, Jiuxin Shi, Elisabeth Sikes, Inga J. Smith, Sebastiaan Swart, Anna Wahlin, Guy Williams, Michael J. M. Williams, Laura Herraiz-Borreguero, Stefan Kern, Jan Lieser, Robert A. Massom, Jessica Melbourne-Thomas, Patricia Miloslavich, Gunnar Spreen

CCPO Publications

The Southern Ocean is disproportionately important in its effect on the Earth system, impacting climatic, biogeochemical, and ecological systems, which makes recent observed changes to this system cause for global concern. The enhanced understanding and improvements in predictive skill needed for understanding and projecting future states of the Southern Ocean require sustained observations. Over the last decade, the Southern Ocean Observing System (SOOS) has established networks for enhancing regional coordination and research community groups to advance development of observing system capabilities. These networks support delivery of the SOOS 20-year vision, which is to develop a circumpolar system that ensures time …

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Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu Jan 2019

Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu

Civil & Environmental Engineering Faculty Publications

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High-resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km2 and a conservative volume of ~1,035 km3. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of …

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Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon Jan 2019

Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon

OES Faculty Publications

The observation system has been developed to investigate the rip currents at Haeundae beach using Xband marine radar. X-band radar system can observe shape, size, and velocity of rip currents, which is difficult to obtain through field observation by conventional device. Algorithms which automatically detect locations, shapes, and magnitudes of rip currents were developed using time averaged X-band radar sea clutter images. X-band sea clutter images are transformed through 3D FFT into 2D wave number spectrum and frequency spectrum. Rip current velocities were estimated using differences in wave-number spectra and wave frequency spectra due to Doppler shift. The algorithm was …

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A Deep Eastern Equatorial Pacific Thermocline During The Last Glacial Maximum, H. L. Ford, C. L. Mcchesney, J. E. Hertzberg, J. F. Mcmanus Nov 2018

A Deep Eastern Equatorial Pacific Thermocline During The Last Glacial Maximum, H. L. Ford, C. L. Mcchesney, J. E. Hertzberg, J. F. Mcmanus

OES Faculty Publications

The mean state and variability of the tropical Pacificis influenced by the depth of the thermocline. During the Last Glacial Maximum (~21,000 years ago), the zonal sea surface temperature gradient across the equatorial Pacific was reduced and productivity was generally lower than modern. To understand the thermocline depth’s role in determining the Last Glacial Maximum tropical mean state, we reconstruct the upper ocean δ18O profile from multiple species of planktic foraminifera. We synthesize existing records of surface and subsurface dwelling foraminifera to reconstruct the vertical δ18O gradient throughout the eastern equatorial Pacific. We find the thermocline …

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The Geotraces Intermediate Data Product 2017, Reiner Schlitzer, Robert F. Anderson, Elena Masferrer Dodas, Maeve Lohan, Walter Geibert, Alessandro Tagliabue, Andrew Bowie, Gregory A. Cutter, Peter N. Sedwick, Bettina Sohst Aug 2018

The Geotraces Intermediate Data Product 2017, Reiner Schlitzer, Robert F. Anderson, Elena Masferrer Dodas, Maeve Lohan, Walter Geibert, Alessandro Tagliabue, Andrew Bowie, Gregory A. Cutter, Peter N. Sedwick, Bettina Sohst

OES Faculty Publications

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and …

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Advances In Amino Acid Analysis For Marine Related Matrices And Its Application To Coastal Shelf Settings In The Canadian Arctic, Rachel M. Mcmahon Jul 2018

Advances In Amino Acid Analysis For Marine Related Matrices And Its Application To Coastal Shelf Settings In The Canadian Arctic, Rachel M. Mcmahon

OES Theses and Dissertations

Amino acids comprise up to 50% of organic matter in cellular material and are a major fraction of oceanic organic carbon. Amino acids are also considered highly labile during organic matter recycling, making them useful proxies for organic carbon cycling. Nevertheless, analysis of individual amino acids has been burdened by lengthy derivatization and complex analysis since the 1950s. In this thesis, I describe the modification of advanced analytical techniques, developed in the biomedical field, for analysis of marine matrices which allow the determination of at least 40 amino acids without the need for lengthy sample preparation and derivatization, twice the …

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Production And Composition Of Pyrogenic Dissolved Organic Matter From A Logical Series Of Laboratory-Generated Chars, Kyle W. Bostick, Andrew R. Zimmerman, Andrew S. Wozniak, Siddhartha Mitra, Patrick G. Hatcher Apr 2018

Production And Composition Of Pyrogenic Dissolved Organic Matter From A Logical Series Of Laboratory-Generated Chars, Kyle W. Bostick, Andrew R. Zimmerman, Andrew S. Wozniak, Siddhartha Mitra, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Though pyrogenic carbon (pyC) has been assumed to be predominantly stable, degradation and transfers of pyC between various pools have been found to influence its cycling and longevity in the environment. Dissolution via leaching may be the main control on loss processes such as microbial or abiotic oxidation, mineral sorption, or export to aquatic systems. Yet, little is known about the controls on pyrogenic dissolved organic matter (pyDOM) generation or composition. Here, the yield and composition of pyDOM generated through batch leaching of a thermal series of oak and grass biochars, as well as several non-pyrogenic reference materials, was compared …

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Biogeochemical Cycling Of Selenium In The Arctic Ocean, Kyle M. Mcquiggan Apr 2018

Biogeochemical Cycling Of Selenium In The Arctic Ocean, Kyle M. Mcquiggan

OES Theses and Dissertations

Changes in the global climate may have a pronounced effect on the biogeochemical cycling of trace elements like selenium (Se) in the Arctic Ocean. This study described the first quantitative examination of the biogeochemical cycle of selenium in the Amerasian Basin, providing the baseline from which future changes can be identified. Aerosol, dissolved and particulate water samples were collected for Se determinations during the U.S. GEOTRACES GN01 Arctic expedition that sampled the two parts of the Amerasian Basin in 2015: The Makarov Basin on the way to the North Pole and the Canada Basin on the return trip to Dutch …

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