Oceanography and Atmospheric Sciences and Meteorology Commons^™

Skill Assessment And Optimization Of The Third Generation Wave Models For Applications In Gulf Of Mexico, Seyed Mostafa Siadatmousavi

LSU Doctoral Dissertations

Numerical phase-averaged wave models are the best option to obtain the spatial and temporal distribution of the wave energy over a large domain, such as the Gulf of Mexico. Parallel implementation of unstructured SWAN and WAVEWATCH-III were engaged in this research to evaluate the performance of third generation wave models for different conditions. Met-ocean data from a network of NDBC buoys and WAVCIS stations were used to assess the predictive skills of the wave models. Deep water wave energy dissipation formulations were carefully analyzed and modified to improve the accuracy of the bulk wave parameters. Moreover, the importance of the …

Establishing Baseline Nutrient And Sediment Input In The Lower Cache River Watershed, Ar, A. M. Gilmer, C. A. Rosado-Berrios, J. L. Bouldin

Journal of the Arkansas Academy of Science

Contaminants in waterways continue to be a problem especially in watersheds dominated by land use changes such as agriculture. Clearing the land for agricultural use is needed to support the population; however, agricultural contaminants are cited as contributing the greatest input of suspended solids and nutrients to waterways. Quantifying various contaminants in surface water is useful in determining their origin, thus aiding in their mitigation. This study, focused on the Cache River Watershed, reports pH, dissolved oxygen (DO), conductivity, turbidity, total suspended solids (TSS), NO3 - , NO2 - , and PO4 3- in the lower sub watersheds. It was …

State Of The River Report For The Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, And Contaminants 2012, Environmental Protection Board, City Of Jacksonville, University Of North Florida, Jacksonville University

State of the River Report

No abstract provided.

Hildebrandt Teaches Lessons About Tornadoes, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Standardized Precipitation Index: User Guide, Mark Svoboda, Michael Hayes, Deborah Wood

National Drought Mitigation Center: Faculty Publications

Over the years, there has been much discussion on what drought indices should be used in a particular climate and for what application. Many drought definitions and indices have been developed and attempts have been made to provide some guidance on this issue. With this in mind, the Interregional Workshop on Indices and Early Warning Systems for Drought was organized and held at the University of Nebraska-Lincoln, United States of America, from 8 to 11 December 2009. It was jointly sponsored by the School of Natural Resources (SNR) of the University of Nebraska, the United States National Drought Mitigation Center …

Net Ecosystem Production (Nep) Of The Great Plains, United States, Daniel Howard, Tagir Gilmanov, Yingxin Gu, Bruce Wylie, Li Zhang

Natural Resource Management Faculty Publications

Gross primary production (GPP) and ecosystem respiration (Re) are the fundamental environmental characteristics that promote carbon exchanges with the atmosphere (Chapin and others, 2009), although other exchanges of carbon, such as direct oxidation (Lovett and others, 2006), can modify net ecosystem production (NEP). The accumulation of carbon in terrestrial ecosystems results in systems in which soil organic matter (SOM) carbon often exceeds biomass carbon (Post and Kwon, 2000). This SOM pool exists at a steady state between GPP and Re in ecosystems unless drivers change or the ecosystem endures environmental perturbations (for example, climatic). As indicated by Wilhelm and others …

The Effects Of Climate On The Growth Of Winter Wheat And Spring Barley In An Irish Context, Adrian Kennedy

Theses

The climate of earth is always changing due to natural events, however it is thought that the rapid warming period currently taking place is primarily due human activity to (environmental protection agency 2012). Climate change is altering the environment and this will have consequences for agriculture (Teagasc publications 2012). In this study we examine the relationship between weather and the yield of winter wheat and spring barley in an Irish context using data gathered from 2004-2010 at the Teagasc Oak Park research centre in Carlow. The data was analysed using a mixed effect model to test which if any weather …

A New Phase Speciation Leaching Procedure For The Determination Of Metals In Oxic And Anoxic Sediments, Brandon R. Gipson

OES Theses and Dissertations

Toxic trace elements such as cadmium, lead, chromium, and arsenic released by human activities can accumulate in marine and estuarine sediments, where these metals are often sequestered until local environmental changes (e.g., redox, salinity, and/or pH) allow these elements to be reintroduced into the food web. In order to assess the extent of toxic trace element contamination in sediment, numerous leaching schemes have been developed that separate sediment-bound trace metals into operationally defined geochemical phases. These "phase speciation" leaching schemes are typically designed with the purpose of being used on either oxic or anoxic sediments. However, natural sediments often contain …

Grazing On Synechococcus Spp. By The Red-Tide Dinoflagellate Karenia Brevis: Implications For Bloom Dynamics In The Gulf Of Mexico, Leo A. Procise

OES Theses and Dissertations

Karenia brevis, the toxic dinoflagellate responsible for massive red tides in the Gulf of Mexico (GOM), causes fish kills, shellfish poisoning, and acute respiratory irritation in humans. Bloom initiation and maintenance have been linked to the physical environment as well as various nutrient input mechanisms. To date, efforts to quantify nitrogen (N) sources fueling K. brevis blooms in the GOM have not included mixotrophic grazing although many dinoflagellates, including K. brevis, are known to be capable of mixotrophy. This dissertation reports field and laboratory results demonstrating that natural bloom populations and K. brevisisolates from the West Florida …

Eukaryotic Microbes In The Deep Sea: Abundance, Diversity, And The Effect Of Pressure, Danielle Morgan-Smith

OES Theses and Dissertations

The dark ocean is vast, high in pressure, cold, and scarce in resources, but has been shown to support a diverse and active microbial community wherever it is studied. Such studies, however, are scarce due to the difficulty of sampling at such depths, and are difficult to interpret due to compounding effects of pressure and temperature on physiology. Protists, functionally defined as the microbial portion of the domain Eukarya, are particularly neglected in studies of deep-sea microbiology. Here, I present three studies on microbial eukaryotes in the deep sea: first, a study of the abundance of microbial eukaryotes in the …

Process-Evaluation Of Tropospheric Humidity Simulated By General Circulation Models Using Water Vapor Isotopic Observations: 2. Using Isotopic Diagnostics To Understand The Mid And Upper Tropospheric Moist Bias In The Tropics And Subtropics, Camille Risi, David Noone, John Worden, Christian Frankenberg, Gabriele Stiller, Michael Kiefer, Bernd Funke, Kaley Walker, Peter Bernath, Matthias Schneider, Sandrine Bony, Jeonghoon Lee, Derek Brown, Christophe Sturm

Chemistry & Biochemistry Faculty Publications

Evaluating the representation of processes controlling tropical and subtropical tropospheric relative humidity (RH) in atmospheric general circulation models (GCMs) is crucial to assess the credibility of predicted climate changes. GCMs have long exhibited a moist bias in the tropical and subtropical mid and upper troposphere, which could be due to the mis-representation of cloud processes or of the large-scale circulation, or to excessive diffusion during water vapor transport. The goal of this study is to use observations of the water vapor isotopic ratio to understand the cause of this bias. We compare the three-dimensional distribution of the water vapor isotopic …

Catastrophe And The Life Span Of Coral Reefs, Richard B. Aronson, William F. Precht, Ian G. Macintyre, Lauren T. Toth

Ocean Engineering and Marine Sciences Faculty Publications

A strong earthquake in the western Caribbean in 2009 had a catastrophic impact on uncemented, unconsolidated coral reefs in the central sector of the shelf lagoon of the Belizean barrier reef. In a set of 21 reef sites that had been observed prior to the earthquake, the benthic assemblages of 10 were eradicated, and one was partially damaged, by avalanching of their slopes. Ecological dynamics that had played out over the previous 23 years, including the mass mortalities of two sequentially dominant coral species and a large increase in the cover of an encrusting sponge, were instantaneously rendered moot in …

Power Estimates Associated With Internal Tides From The Monterey Bay Area, Steven M. Jachec

Ocean Engineering and Marine Sciences Faculty Publications

Numerical modeling has proven to be a useful method for simulating internal tides within the coastal ocean. Monterey Bay is a location that experiences energetic semidiurnal internal tides, and they are pronounced within Monterey Submarine Canyon. Numerical simulations and field measurements indicate that the baroclinic energy fluxes there are spatially variable, leading to locations of positive and negative baroclinic energy flux divergences. Results derived from a SUNTANS (Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator) model simulation show that Monterey Submarine Canyon’s baroclinic power is net dissipative (–8.3 MW). However, sources and sinks exist throughout the canyon, and they permeate the …

Gene Transcription In Sea Otters (Enhydra Lutris); Development Of A Diagnostic Tool For Sea Otter And Ecosystem Health, Lizabeth Bowen, A. Keith Miles, Michael Murray, Martin Haulena, Judy Tuttle, William Van Bonn, Lance Adams, James L. Bodkin, Brenda Ballachey, James A. Estes, M. Tim Tinker, Robin Keister, Jeffrey L. Stott

United States Geological Survey: Staff Publications

Gene transcription analysis for diagnosing or monitoring wildlife health requires the ability to distinguish pathophysiological change from natural variation. Herein, we describe methodology for the development of quantitative real-time polymerase chain reaction (qPCR) assays to measure differential transcript levels of multiple immune function genes in the sea otter (Enhydra lutris); sea otter-specific qPCR primer sequences for the genes of interest are defined. We establish a ‘reference’ range of transcripts for each gene in a group of clinically healthy captive and free-ranging sea otters. The 10 genes of interest represent multiple physiological systems that play a role in immuno-modulation, …

Do Bioclimate Variables Improve Performance Of Climate Envelope Models?, James I. Watling, Stephanie S. Romanach, David N. Bucklin, Carolina Speroterra, Laura A. Brandt, Leonard G. Pearlstine, Frank J. Mazzotti

United States Geological Survey: Staff Publications

Climate envelope models are widely used to forecast potential effects of climate change on species distributions. A key issue in climate envelope modeling is the selection of predictor variables that most directly influence species. To determine whether model performance and spatial predictions were related to the selection of predictor variables, we compared models using bioclimate variables with models constructed from monthly climate data for twelve terrestrial vertebrate species in the southeastern USA using two different algorithms (random forests or generalized linear models), and two model selection techniques (using uncorrelated predictors or a subset of user-defined biologically relevant predictor variables). There …

Global Air Temperature Variability Independent Of Sea-Surface Temperature Influences, Andrew C. Comrie, Gregory J. Mccabe

United States Geological Survey: Staff Publications

Mean global surface air temperature (SAT) and sea surface temperature (SST) display substantial variability on timescales ranging from annual to multi-decadal. We review the key recent literature on connections between global SAT and SST variability. Although individual ocean influences on SAT have been recognized, the combined contributions of worldwide SST variability on the global SAT signal have not been clearly identified in observed data.Weanalyze these relations using principal components of detrended SST, and find that removing the underlying combined annual, decadal, and multi-decadal SST variability from the SAT time series reveals a nearly monotonic global warming trend in SAT since …

Gonadal Abnormalities In Frogs (Lithobates Spp.) Collected From Managed Wetlands In An Agricultural Region Of Nebraska, Usa, Diana M. Papoulias, Matt S. Schwarz, Lourdes Mena

United States Geological Survey: Staff Publications

Nebraska’s Rainwater Basin (RWB) provides important wetland habitat for North American migratory birds. Concern exists that pesticide and nutrient runoff from surrounding row-crops enters wetlands degrading water quality and adversely affecting birds and wildlife. Frogs may be especially vulnerable. Plains leopard (Lithobates blairi) metamorphs from RWB wetlands with varying concentrations of pesticides were evaluated for a suite of biomarkers of exposure to endocrine active chemicals. Froglets had ovarian dysgenesis, high rates of testicular oocytes, and female-biased sex ratios however, there was no clear statistical association between pesticide concentrations and biomarkers. Data interpretation was hindered because timing and duration …

History And Evaluation Of National-Scale Geochemical Data Sets For The United States, David B. Smith, Steven M. Smith, John D. Horton

United States Geological Survey: Staff Publications

Six national-scale, or near national-scale, geochemical data sets for soils or stream sediments exist for the United States. The earliest of these, here termed the ‘Shacklette’ data set, was generated by a U.S. Geological Survey (USGS) project conducted from 1961 to 1975. This project used soil collected from a depth of about 20 cm as the sampling medium at 1323 sites throughout the conterminous U.S. The National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance (NUREHSSR) Program of the U.S. Department of Energy was conducted from 1975 to 1984 and collected either stream sediments, lake sediments, or soils at more …

Remote Sensing Of Evapotranspiration For Operational Drought Monitoring Using Principles Of Water And Energy Balance, Gabriel B. Senay, Stefanie Bohms, James P. Verdin

United States Geological Survey: Staff Publications

Evapotranspiration (ET) is an important component of the hydrologic budget because it reflects the exchange of mass and energy between the soil–water–vegetation system and the atmosphere. Prevailing weather conditions influence potential or reference ET through variables such as radiation, temperature, wind, and relativity humidity. In addition to these weather variables, actual ET (ET_a) is also affected by land cover type and condition, as well as soil moisture. The dependence of ET_a on land cover and soil moisture, and its direct relationship with carbon dioxide assimilation in plants, makes it an important variable for monitoring drought, crop yield, …

Development And Application Of Methods Used To Source Prehistoric Southwestern Maize: A Review, Larry Benson

United States Geological Survey: Staff Publications

Archaeological cobs free of mineral contaminants should be used to source the soils in which they were grown. Mineral contaminants often contain much higher concentrations of metals than vegetal materials and can alter a cob’s apparent metal and heavy-isotope content. Cleaning a cob via immersion in an acid solution for more than a few minutes will result in the incongruent and sometimes complete leaching of metals, including strontium (Sr), from the cob. When using ⁸⁷Sr/⁸⁶Sr to determine the location of potential agriculture fields, it is best to either integrate several depth-integrated soil samples or to integrate several …

On Thinning Of Chains In Mcmc, William A. Link, Mitchell J. Eaton

United States Geological Survey: Staff Publications

1. Markov chain Monte Carlo (MCMC) is a simulation technique that has revolutionised the analysis of ecological data, allowing the fitting of complex models in a Bayesian framework. Since 2001, there have been nearly 200 papers using MCMC in publications of the Ecological Society of America and the British Ecological Society, including more than 75 in the journal Ecology and 35 in the Journal of Applied Ecology.

2. We have noted that many authors routinely ‘thin’ their simulations, discarding all but every kth sampled value; of the studies we surveyed with details on MCMC implementation, 40% reported thinning.

3. Thinning …

Spatially Explicit Models For Inference About Density In Unmarked Or Partially Marked Populations, Richard B. Chandler, J. Andrew Royle

United States Geological Survey: Staff Publications

Recently developed spatial capture-recapture (SCR) models represent a major advance over traditional capture-recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Futhermore, unlike nonspatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement that all individuals can be uniquely identified exludes their use in many contexts. In this paper, we develop models for situations in which individual recognition is not possible, thereby allowing SCR concepts to be …

On Thinning Of Chains In Mcmc, William A. Link, Mitchell J. Eaton

United States Geological Survey: Staff Publications

1. Markov chain Monte Carlo (MCMC) is a simulation technique that has revolutionised the analysis of ecological data, allowing the fitting of complex models in a Bayesian framework. Since 2001, there have been nearly 200 papers using MCMC in publications of the Ecological Society of America and the British Ecological Society, including more than 75 in the journal Ecology and 35 in the Journal of Applied Ecology.

2. We have noted that many authors routinely ‘thin’ their simulations, discarding all but every kth sampled value; of the studies we surveyed with details on MCMC implementation, 40% reported thinning.

3. Thinning …

Sea-Level History During The Last Interglacial Complex On San Nicolas Island, California: Implications For Glacial Isostatic Adjustment Processes, Paleozoogeography And Tectonics, Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Jerry X. Mitrovica, Deanna Laurel

United States Geological Survey: Staff Publications

San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ~270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38–36 m (terrace 2a), 33–28 m (terrace 2b), and 13–8 m (terrace 1). Uranium-series dating of solitary corals from these terraces yields three clusters of ages: ~120 ka on terrace 2a (marine isotope stage [MIS] 5.5), ~120 and ~100 ka on terrace 2b (MIS 5.5 and 5.3), and ~80 ka (MIS 5.1) on terrace 1.We …

Tectonic Influences On The Preservation Of Marine Terraces: Old And New Evidence From Santa Catalina Island, California, R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Lindsey T. Groves, John P. Mcgeehan

United States Geological Survey: Staff Publications

The California Channel Islands contain some of the best geologic records of past climate and sea-level changes, recorded in uplifted, fossil-bearing marine terrace deposits. Among the eight California Channel Islands and the nearby Palos Verdes Hills, only Santa Catalina Island does not exhibit prominent emergent marine terraces, though the same terrace-forming processes that acted on the other Channel Islands must also have occurred on Santa Catalina. We re-evaluated previous researchers' field evidence and examined new topographic, bathymetric, and stream-profile data in order to find possible explanations for the lack of obvious marine terrace landforms or deposits on the island today. …

Patterns Of Extinction Risk And Threat For Marine Vertebrates And Habitat-Forming Species In The Tropical Eastern Pacific, Beth A. Polidoro, T. Brooks, Kent E. Carpenter, G. J. Edgar, S Henderson, J. Sanciangco, D. R. Robertson

Biological Sciences Faculty Publications

Marine conservation activities around the globe are largely undertaken in the absence of comprehensive species-specific information. To address this gap, complete regional species assemblages of major marine taxa are being progressively assessed against the Categories and Criteria of the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. The present study is the first analysis of entire major components of the biota of a large marine biogeographic region conducted in the Tropical Eastern Pacific (TEP). It is based on recently completed IUCN Red List assessments for all known species of bony and cartilaginous shorefishes, corals, mangroves, …

Antarctic Surface Melting Dynamics: Enhanced Perspectives From Radar Scatterometer Data, L. D. Trusel, K. E. Frey, S. B. Das

Geography

Antarctic ice sheet surface melting can regionally influence ice shelf stability, mass balance, and glacier dynamics, in addition to modulating near-surface physical and chemical properties over wide areas. Here, we investigate variability in surface melting from 1999 to 2009 using radar backscatter time series from the SeaWinds scatterometer aboard the QuikSCAT satellite. These daily, continent-wide observations are explored in concert with in situ meteorological records to validate a threshold-based melt detection method. Radar backscatter decreases during melting are significantly correlated with in situ positive degree-days as well as meltwater production determined from energy balance modeling at Neumayer Station, East Antarctica. …

Groundwater Surface Trends In The North Florence Dunal Aquifer, Oregon Coast, Usa, Sarah Rebecca Doliber

Dissertations and Theses

The North Florence Dunal Aquifer is the only feasible source for drinking water for the coastal city of Florence, Oregon and Florence's Urban Growth Boundary. High infiltration rates and a shallow groundwater table leave the aquifer highly susceptible to contamination from septic tank effluent, storm runoff, chemical fertilizers and recreational ATV use throughout the dunes. Public interest in the quality and quantity of the aquifer water has been sparked since the City of Florence received a grant from the Environmental Protection Agency for a watershed protection and restoration project. Delineation of the shallow groundwater surface and its relationship to the …

Factors Affecting Short-Term Oxygen Variability In The Northern Gulf Of Mexico Hypoxic Zone, Brenda Leroux Babin

LSU Doctoral Dissertations

Open-water continuous monitoring of DO concentrations at a single station (C6) in the Gulf of Mexico from 1989 to 2008 afforded an excellent opportunity to characterize short-term oxygen variability and to estimate the relative importance of key physical and biological factors controlling the development, persistence, and dissipation of hypoxia. I investigated temporal trends in three aspects of short-term DO variability: respiration rates (i.e., how quickly bottom waters become hypoxic), persistence of hypoxia, and the dissipation of hypoxia (i.e., re-aeration events). I identified the range of respiration rates present at the study site, and showed how these rates vary throughout the …

Identification And Incorporation Of Quantitative Indicators Of Ecosystem Function Into Single-Species Fishery Stock Assessment Models And The Associated Biological Reference Points, Melissa Hedges Monk

LSU Doctoral Dissertations

The move towards an ecosystem approach to fisheries management requires baseline information on the biotic communities and an understanding of the interactions among species. The two objectives of this study were to describe the demersal fish community (DFC) associated with the northwestern Gulf shrimp trawl fishery, and to utilize a multispecies Lotka-Volterra model to examine possible community level effects of fishing. Community level effects include predator-prey interactions and the responses of fish in the same community to fishing pressure. The summer and fall Southeast Area Monitoring and Assessment Program (SEAMAP) bottomfish trawl surveys were used to identify spatial and temporal …