Oceanography and Atmospheric Sciences and Meteorology Commons^™

Role Of Macroscopic Particles In Deep-Sea Oxygen Consumption, Alexander B. Bochdansky, Hendrik M. Van Aken, Gerhard J. Herndl

OES Faculty Publications

Macroscopic particles (> 500 µg), including marine snow, large migrating zooplankton, and their fast-sinking fecal pellets, represent primary vehicles of organic carbon flux from the surface to the deep sea. In contrast, freely suspended microscopic particles such as bacteria and protists do not sink, and they contribute the largest portion of metabolism in the upper ocean. In bathy- and abyssopelagic layers of the ocean (2,000-6,000 m), however, microscopic particles may not dominate oxygen consumption. In a section across the tropical Atlantic, we show that macroscopic particle peaks occurred frequently in the deep sea, whereas microscopic particles were barely detectable. In …

Causes Of Tropical Atlantic Paleo-Salinity Variation During Periods Of Reduced Amoc, Xiuquan Wan, Ping Chang, Matthew W. Schmidt

OES Faculty Publications

During periods of reduced Atlantic meridional overturning circulation (AMOC) associated with a freshening of northern North Atlantic surface water, paleo proxy records indicate a corresponding surface salinity increase over the entire tropical Atlantic. Although latitudinal-shifts in the mean position of the Atlantic Intertropical Convergence Zone (ITCZ) can explain certain features of the paleo salinity reconstructions, this mechanism does not offer an explanation for the reconstructed basin-wide paleo-salinity response to AMOC change. Here, we present new results from general circulation model simulations that suggest the sea surface salinity (SSS) increase in the tropical north Atlantic during periods of weakened AMOC is …

Integration Of Paleotempestology With Coastal Risk And Vulnerability Assessment: Case Studies From The Dominican Republic And Nicaragua, Devyani Kar

LSU Doctoral Dissertations

Hurricanes account for a significant portion of damages, injuries, and fatalities in the Caribbean. The Dominican Republic has had 3 major hurricane strikes in this century resulting in loss of lives for thousands of people and billions of US $ in economic loss. Major hurricanes had been relatively infrequent in north-eastern Nicaragua’s modern history until Hurricane Felix, a Category 5 storm, made landfall in the north-east in 2007. It caused 130 confirmed deaths and brought devastation to many villages. These events highlight a need for re-evaluation of hurricane risk based on a more comprehensive and long-term hurricane history. Using paleotempestological …

Modeling The Impacts Of Pulsed Riverine Inflows On Hydrodynamics And Water Quality In The Barataria Bay Estuary, Anindita Das

LSU Doctoral Dissertations

Eutrophication and coastal wetland loss are the major environmental problems affecting estuaries around the world. In Louisiana, controlled diversions of the Mississippi River water back into coastal wetlands are thought to be an important engineering solution that could reverse coastal land loss. There are concerns, however, that freshwater diversions may increase nutrient inputs and create severe eutrophication problems in estuaries and wetlands adjacent to the diversion sites. My dissertation research concerns modeling the effects of the observed and hypothetical freshwater diversion discharges on the hydrodynamics, salinity and water quality in the Barataria estuary, a deltaic estuary in south Louisiana. This …

Landscape Patterns Of Community Structure, Biomass And Net Primary Productivity Of Mangrove Forests In The Florida Coastal Everglades As A Function Of Resource, Regulators, Hydroperiod, And Hurricane Distrubance, Edward Castaneda

LSU Doctoral Dissertations

Spatial and temporal patterns of mangrove vegetation in the Florida Coastal Everglades (FCE) reflect a major interplay of resources, regulators and hydroperiod gradients. I investigated landscape patterns of community structure, biomass and NPP of mangroves along two FCE estuaries: Shark River and Taylor River. I also evaluated whether pulsing events such as Hurricane Wilma are significant to soil nutrient inventories and vertical accretion of mangroves in FCE. There was a higher forest structural complexity of mangroves in Shark River relative to Taylor River. The biomass root:shoot ratio was 17 times higher in Taylor River relative to Shark River, indicating that …

Analysis And Modeling Of Hurricane Impacts On A Coastal Louisiana Lake Bottom, Angelina Freeman

LSU Doctoral Dissertations

Tropical cyclone impacts on wetland, terrestrial, and shelf systems have been previously studied and reasonably delineated, but little is known about the response of coastal lakes to storm events. For the first time, tropical cyclone impacts on a shallow coastal lake in the Louisiana coastal plain have been studied using direct lines of evidence and numerical modeling. Using side-scan sonar, CHIRP subbottom and echo sounder bathymetric profiles, the lake bottom and shallow subsurface of Sister Lake was imaged pre- and post-Hurricanes Katrina and Rita to provide a geologic framework for assessing the effects of these storms. Box cores were collected …

The Effects Of A Freshwater Diversion Of Nekton Species Biomass Distributions, Food Web Pathways, And Community Structure In A Louisiana Estuary, Kim De Mutsert

LSU Doctoral Dissertations

A current method to restore Louisiana’s estuaries includes reintroducing freshwater and sediments to wetlands that are hydrologically isolated from the Mississippi River due to the construction of levees. In this dissertation, I examined effects of the second largest freshwater diversion in Louisiana, the Caernarvon Freshwater Diversion (CFD), on estuarine nekton in Breton Sound. Before focusing on Breton Sound, I examined the status of nekton communities in the northern Gulf of Mexico (GOM), and Louisiana wetlands in particular, using the mean trophic level index (MTLI). I demonstrated that commercial targeting caused the previously reported low and declining MTLI from the GOM. …

Analysis Of Atmospheric Boundary Layer Characteristics And The Synoptic-Scale Weather Pattern At The Potosi, Wi Slams Monitor, Sean K. Newlin

Honors Program Theses

Boundary layer parameters were analyzed for high impact fine-particulate pollution days for the years 2006 through 2009 in Potosi, Wisconsin. Potosi has seen recent 24-hour PM2.s design values at or near the National Ambient Air Quality Standards (NAAQS) of 35 micrograms per cubic meter. Every sampling date in the years 2006 through 2009 with a 24- hour PM2.5 particulate concentration above the year's trend line was studied as were the cleanest 10 days of each year. In particular, composite upper air profiles were constructed using observations from the nearby radiosonde stations, surface and S00mb weather maps were retrieved, the virtual …

Evidence For Recent Population Bottlenecks In Northern Spotted Owls (Strix Occidentalis Caurina), W. Chris Funk, Eric D. Forsman, Matthew Johnson, Thomas D. Mullins, Susan M. Haig

United States Geological Survey: Staff Publications

The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the US Endangered Species Act. Despite protection of its remaining forest habitat, recent field studies show continued declines of northern spotted owls. One potential threat to northern spotted owls which has not yet been shown is loss of genetic variation from population bottlenecks. Bottlenecks can increase the probability of mating among related individuals, potentially causing inbreeding depression, and can decrease adaptive potential. Here we report evidence for recent bottlenecks in northern spotted owls using a large genetic dataset (352 individuals …

Tree-Ring Dates And Demographic Change In The Southern Colorado Plateau And Rio Grande Regions, Michael S. Berry, Larry Benson

United States Geological Survey: Staff Publications

In this chapter, tree-ring dates from the southern Colorado Plateau, Mogollon Highlands, and Rio Grande areas (fig. 3-1) (hereafter referred to as the study area) are used to estimate regional-scale timber-harvesting and construction activities between AD 600 and 1600 (the Basketmaker III through Pueblo IV periods). Within that time span, we focus our attention particularly on the AD 1045-1300 period, a time when anomalously wet periods alternated with megadroughts (fig. 3.2). Treering- date distributions (histograms) for eight archaeological subregions within the study area have been created using a database of more than twenty-four thousand tree-ring dates from archaeological sites. These …

Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta L. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato

United States Geological Survey: Staff Publications

The creation and use of a globally available database of DNA sequences from a standardized gene region has been proposed as a tool for species identification, assessing genetic diversity and monitoring the legal and illegal trade in wildlife species. Here, we contribute to the Barcode of Life Data System and test whether a short region of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene would reliably distinguish among a suite of commonly hunted African and South American mammal and reptile species. We used universal primers to generate reference barcode sequences of 645 bp for 23 species from five vertebrate …

Model Of Sprite Luminous Trail Caused By Increasing Streamer Current, Ningyu Liu

Aerospace, Physics, and Space Science Faculty Publications

This study investigates a possible physical mechanism responsible for the occurrence of the luminous trail of sprite streamers, which is also known as "afterglow." According to streamer modeling results, when sprite streamers propagate with expansion, acceleration and brightening, the total current flowing through the streamer body also increases. The increasing current results in the rise of the electric field in the streamer channel far behind the streamer head, which leads to effective production of N₂ excited states by electron impact excitation and then the glowing trail.

Tsunami Hazard And Total Risk In The Caribbean Basin, X. William Proenza, George A. Maul

Ocean Engineering and Marine Sciences Faculty Publications

Deadly western North Atlantic Ocean tsunami events in the last centuries have occurred along the east coast of Canada, the United States, most Caribbean islands, and the North Atlantic Coast of South America. The catastrophic Indian Ocean tsunami of 2004 reminded natural hazards managers that tsunami risk is endemic to all oceans. Total Risk is defined as hazard (frequency of tsunami events) times measures of elements at risk (human exposure) times measures of vulnerability (preparedness) in a given epoch (Nott, 2006). While the tsunami hazard in the Caribbean (averaging 19 ± 22 years between deadly events) is lower than Pacific …

Image Analysis For Water Surface & Subsurface Feature Detection In Shallow Waters, Charles R. Bostater Jr., James Jones, Heather Frystacky, Mate Kovacs, Oszkar Jozsa

Ocean Engineering and Marine Sciences Faculty Publications

Carefully collected airborne imagery demonstrates the ability to see water surface features as well as shallow bottom features such as submerged vegetation and manmade targets. Traditional photogrammetric imagery and airborne digital imagery both suffer from a loss in image clarity due to a number of factors, including capillary and small gravity waves, the water column or in-situ constituents. The use of submerged as well as surface man-made calibration targets deployed during airborne or in-situ subsurface image acquisitions forms a preliminary basis for correcting imagery in order to improve subsurface and surface features and their detection. Methods presented as well as …

Lsuhsc Facilities Biweekly Update: January 2010, Lsuhsc Property And Facilities Management

LSUHSC Facilities Biweekly Updates: 2010

LSUHSC Facilities Biweekly Updates from January 15 and 29, 2010.

These updates describe damage and a timeline of repairs at the LSU Health Sciences Center - New Orleans campus due to Hurricane Katrina which made landfall August 29, 2005.

Lsuhsc Facilities Daily Update: January 2010, Lsuhsc Property And Facilities Management

LSUHSC Facilities Daily Updates: 2010

LSUHSC Facilities Daily Updates from January 2010.

These updates describe damage and a timeline of repairs at the LSU Health Sciences Center - New Orleans campus due to Hurricane Katrina which made landfall August 29, 2005.

Trace Metal Biogeochemistry In The Western North Pacific, Peter Lynn Morton

OES Theses and Dissertations

Dissolved and suspended particulate samples collected during the Intergovernmental Oceanographic Commission 2002 Contaminant Baseline Survey were analyzed to determine the surface and vertical distributions of Cd, Co, Cu, Mn, Ni Zn and Pb across the western and central North Pacific.

Dissolved trace metal concentrations were measured using a novel isotope dilution-ICP-MS method after extraction over an 8-hydroxyquinoline resin column and validated through the use of the SAFe consensus reference materials. Filtered suspended particulate matter was digested using an HCl/HNO3/HF mixture and analyzed by HR-ICP-MS to obtain total particulate concentrations for the trace metals and other tracer elements such as Al, …

Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this study, we report measurements of CFC-12 (CCl2F2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for the presence of modern air entrapped in the shallow ice core samples that likely contained open pores at the time of collection. We propose that this is due to closure of the open pores …

Climatological Aspects Of The Optical Properties Of Fine/Coarse Mode Aerosol Mixtures, Thomas F. Eck, B. N. Holben, Aliaksandyr Sinyuk, R. T. Pinker, P. Goloub, H. Chen, B. Chatenet, Z. Li, Ramesh P. Singh, Sachchida N. Tripathi, J. S. Reid, D. M. Giles, O. Dubovik, N. T. O'Neill, A. Smirnov, P. Wang, X. Xia

Mathematics, Physics, and Computer Science Faculty Articles and Research

Aerosol mixtures composed of coarse mode desert dust combined with fine mode combustion generated aerosols (from fossil fuel and biomass burning sources) were investigated at three locations that are in and/or downwind of major global aerosol emission source regions. Multiyear monitoring data at Aerosol Robotic Network sites in Beijing (central eastern China), Kanpur (Indo-Gangetic Plain, northern India), and Ilorin (Nigeria, Sudanian zone of West Africa) were utilized to study the climatological characteristics of aerosol optical properties. Multiyear climatological averages of spectral single scattering albedo (SSA) versus fine mode fraction (FMF) of aerosol optical depth at 675 nm at all three …

Complementary Nature Of Surface And Atmospheric Parameters Associated With Haiti Earthquake Of 12 January 2010, Ramesh P. Singh, Waseem Mehdi, Manish Sharma

Mathematics, Physics, and Computer Science Faculty Articles and Research

The present paper describes surface (surface air temperature) and atmospheric parameters (relative humidity, surface latent heat flux) over the epicenter (18A degrees 27A ' 25A ' A ' N 72A degrees 31A ' 59A ' A ' W) of Haiti earthquake of 12 January 2010. Our analysis shows pronounced changes in surface and atmospheric parameters few days prior to the main earthquake event. Changes in relative humidity are found from the surface up to an altitude of 500 hPa clearly show atmospheric perturbations associated with the earthquake event. The purpose of this paper is to show complementary nature of the …