The Widespread Occurrence Of Coupled Carbonate Dissolution/Reprecipitation In Surface Sediments On The Bahamas Bank,
2010
Old Dominion University
The Widespread Occurrence Of Coupled Carbonate Dissolution/Reprecipitation In Surface Sediments On The Bahamas Bank, David J. Burdige, Xinping Hu, Richard C. Zimmerman
OES Faculty Publications
Using two complimentary approaches (pore water advection/diffusion/reaction modeling and stable isotope mass balance calculations) we show that carbonate dissolution/reprecipitation occurs on early diagenetic time scales across a broad range of sediments on the Great Bahamas Bank. The input of oxygen into the sediments, which strongly controls sediment carbonate dissolution, has two major sources belowground input by seagrasses (that is, seagrass O2 pumping), and permeability-driven advective pore water exchange. The relative importance of these O2 delivery mechanisms depends on both seagrass density, and on how bottom water flow interacts with the seagrass canopy and leads to this advective exchange. …
The Path To Preservation: Using Proteomics To Decipher The Fate Of Diatom Proteins During Microbial Degradation,
2010
Old Dominion University
The Path To Preservation: Using Proteomics To Decipher The Fate Of Diatom Proteins During Microbial Degradation, Brook L. Nunn, Ying S. Ting, Lars Malmström, Yihsuan S. Tsai, Angela Aquier, David R. Goodlett, H. Rodger Harvey
OES Faculty Publications
We drew upon recent advances in tandem mass spectrometry-based proteomic analyses in order to examine the proteins that remain after a diatom bloom enters the stationary phase, precipitates out of the photic zone, and is subjected to microbial degradation over a 23-d period within a controlled laboratory environment. Proteins were identified from tandem mass spectra searched against three different protein databases in order to track proteins from Thalassiosira pseudonana and any potential bacterial contributions. A rapid loss of diatom protein was observed over the incubation period; 75% of the proteins initially identified were not detected after 72 h of exposure …
Effect Of The Heterotrophic Dinoflagellate Oxyrrhis Marina And The Copepod Acartia Tonsa On Vertical Carbon Flux In And Around Thin Layers Of The Phytoflagellate Isochrysis Galbana,
2010
Old Dominion University
Effect Of The Heterotrophic Dinoflagellate Oxyrrhis Marina And The Copepod Acartia Tonsa On Vertical Carbon Flux In And Around Thin Layers Of The Phytoflagellate Isochrysis Galbana, A. B. Bochdansky, S. M. Bollens, G. C. Rollwagen-Bollens, A. H. Gibson
OES Faculty Publications
Dynamics of material and energy flow through food webs differ when resources are allocated in patches in comparison to situations in which the same resources are distributed evenly throughout the water column. Thin layers of plankton are special cases of such resource patches. While previous studies have predominantly focused on the response of organisms to these layers, we investigated how 2 types of grazers in turn affect thin layers. In an experimental study with tightly controlled environmental conditions, we monitored the redistribution of particulate organic (POC), dissolved organic (DOC) and inorganic (DIC) carbon from thin layers of Isochrysis galbana. …
Role Of Macroscopic Particles In Deep-Sea Oxygen Consumption,
2010
Old Dominion University
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,
2010
Old Dominion University
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 …
Comparison Of In Situ And Columnar Aerosol Spectral Measurements During Texaqs-Gomaccs 2006: Testing Parameterizations For Estimating Aerosol Fine Mode Properties,
2010
Portland State University
Comparison Of In Situ And Columnar Aerosol Spectral Measurements During Texaqs-Gomaccs 2006: Testing Parameterizations For Estimating Aerosol Fine Mode Properties, Dean B. Atkinson, Paola Massoli, Norman T. O'Neill, Patricia K. Quinn, Sarah D. Brooks, Barry Lefer
Chemistry Faculty Publications and Presentations
During the 2006 Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS 2006), the optical, chemical and microphysical properties of atmospheric aerosols were measured on multiple mobile platforms and at ground based stations. In situ measurements of the aerosol light extinction coefficient (σep) were performed by two multi-wavelength cavity ring-down (CRD) instruments, one located on board the NOAA R/V Ronald H. Brown (RHB) and the other located at the University of Houston, Moody Tower (UHMT). An AERONET sunphotometer was also located at the UHMT to measure the columnar aerosol optical depth (AOD). The σep data …
Analysis Of Atmospheric Boundary Layer Characteristics And The Synoptic-Scale Weather Pattern At The Potosi, Wi Slams Monitor,
2010
University of Northern Iowa
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 …
Pharmaceutical Compounds In Treatment Wetlands: Potential Removal And Effects On Microbial Processes,
2010
Louisiana State University and Agricultural and Mechanical College
Pharmaceutical Compounds In Treatment Wetlands: Potential Removal And Effects On Microbial Processes, Jeremy Landon Conkle
LSU Doctoral Dissertations
active compounds (PhACs) have been detected in the aquatic environment as a result of loading from various sources. In Louisiana, USA, many municipalities treat wastewater using natural systems, such as lagoons and wetlands, rather than using conventional wastewater treatment technologies and may discharge PhACs into the environment. These treatment systems are not designed to remove PhACs from wastewater, nor is it currently a regulatory requirement. Research on the fate of PhACs in the environment is needed to understand impacts on Louisiana’s important coastal system. Wastewater sampling for PhACs at the Mandeville, LA wastewater treatment plant (WWTP) determined that this system …
The Effects Of A Freshwater Diversion Of Nekton Species Biomass Distributions, Food Web Pathways, And Community Structure In A Louisiana Estuary,
2010
Louisiana State University and Agricultural and Mechanical College
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. …
Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands,
2010
Louisiana State University and Agricultural and Mechanical College
Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands, Jonathan M. Willis
LSU Doctoral Dissertations
With the expansion of the human population and associated industries there is a concomitant increase in both resource utilization and the production of waste and deleterious by-products. Mercury is a naturally-occurring toxic metal with a complicated and unique biogeochemical cycle, and is often a contaminant of ecotoxicological concern in unindustrialized aquatic habitats. The research described herein was designed to elucidate multiple aspects regarding the behavior of mercury in oligohaline wetland habitats, particularly with respect to edaphic and vegetative effects, through a monitoring and characterization study as well as a series of manipulative experiments. The observational study, conducted in the wetlands …
Patterns Of Habitat Suitability And Abundance Trends Of Current And Candidate Coastal Fish Species Of Concern In Louisiana,
2010
Louisiana State University and Agricultural and Mechanical College
Patterns Of Habitat Suitability And Abundance Trends Of Current And Candidate Coastal Fish Species Of Concern In Louisiana, Elin Rose Sandy
LSU Master's Theses
Louisiana’s estuaries and coastal waters play an important role in providing habitat for several estuarine-dependent species and also serve as a nursery for the juveniles of several other species. The current rate of land loss in Louisiana and the decline of estuarine-dependent species force us to improve our understanding of the recruitment of these species into Louisiana’s estuaries. Habitat suitabilities were developed for several fish species of concern (SOC) and other estuarine-dependent species across three environmental gradients, abundance patterns were developed for seasons, five-year intervals, and coastal study areas (CSAs). Chi-square analyses and ANOVAs were then used to test for …
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,
2010
Louisiana State University and Agricultural and Mechanical College
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 …
Integration Of Paleotempestology With Coastal Risk And Vulnerability Assessment: Case Studies From The Dominican Republic And Nicaragua,
2010
Louisiana State University and Agricultural and Mechanical College
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 …
Geological Analysis And Hydrodynamic Modeling Of Tropical Cyclone Influence: Northeastern Gulf Of Mexico Inner Shelf,
2010
Louisiana State University and Agricultural and Mechanical College
Geological Analysis And Hydrodynamic Modeling Of Tropical Cyclone Influence: Northeastern Gulf Of Mexico Inner Shelf, Amy Lynn Spaziani
LSU Master's Theses
The need to characterize offshore resources as borrow areas for beach restoration has initiated interest of the impact of storms to the inner continental shelf. While numerous studies have investigated the response of coastal systems to major storms, very little is known about the geological response of inner shelves to frequent and intense storms. This approach integrated a geological study with modeling of hydrodynamics during recent storms, in order to relate trends in the geological signature to physical forcing mechanisms during storms. First, waves and hydrodynamic conditions were modeled during two major recent storms that made landfall in the northeastern …
Hepatotoxic Cyanobacterial Blooms In Louisiana's Estuaries: Analysis Of Risk To Blue Crab (Callinectes Sapidus) Following Exposure To Microcystins,
2010
Louisiana State University and Agricultural and Mechanical College
Hepatotoxic Cyanobacterial Blooms In Louisiana's Estuaries: Analysis Of Risk To Blue Crab (Callinectes Sapidus) Following Exposure To Microcystins, Ana Cristina Garcia
LSU Master's Theses
The most common toxins detected following freshwater harmful algal blooms are microcystins, a group of hepatotoxins produced by cyanobacteria (e.g., Microcystis and Anabaena spp.). Preference for filter-feeding prey, including bivalves, makes the blue crab, Callinectes sapidus, vulnerable to microcystin contamination and makes the commercially important crab a potential vector of microcystins. I used a combination of field and laboratory studies to determine blue crab vulnerability to microcystin contamination and consequent impacts on crab physiology. Samples collected from a hyper-eutrophic freshwater lake, Lac des Allemands, Louisiana, were analyzed for cyanobacterial abundances and microcystins in surface water and blue crabs using light-microscopy …
Analysis And Modeling Of Hurricane Impacts On A Coastal Louisiana Lake Bottom,
2010
Louisiana State University and Agricultural and Mechanical College
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 …
Variations In Synechococcus Cell Quotas Of Phosphorus, Sulfur, Manganese, Iron, Nickel, And Zinc Within Mesoscale Eddies In The Sargasso Sea,
2010
Old Dominion University
Variations In Synechococcus Cell Quotas Of Phosphorus, Sulfur, Manganese, Iron, Nickel, And Zinc Within Mesoscale Eddies In The Sargasso Sea, Benjamin S. Twining, Daliangelis Nunez-Milland, Stefan Vogt, Rodney S. Johnson, Peter N. Sedwick
OES Faculty Publications
The quotas of P, S, Mn, Fe, Ni, and Zn in individual Synechococcus cells collected from the surface and deep chlorophyll maximum (DCM) layer of three mesoscale eddies in the Sargasso Sea were measured using synchrotron X-ray fluorescence microscopy. Cells in a mode-water eddy had significantly higher P (57 +/- 10 amol) and Mn (28 +/- 7 zmol) cell quotas than cells collected from a cyclone (22 +/- 2 amol and 10 +/- 1 zmol, respectively) or anticyclone (25 +/- 3 amol and 18 +/- 3 zmol, respectively). Conversely, Ni and Zn quotas were significantly higher in the cells from …
Physical And Microbial Responses Of Dredged Sediment To Two-Soil-Stabilizing Amendments, Xanthan Gum And Guar Gum, For Use In Coastal Wetland Restoration,
2010
Louisiana State University and Agricultural and Mechanical College
Physical And Microbial Responses Of Dredged Sediment To Two-Soil-Stabilizing Amendments, Xanthan Gum And Guar Gum, For Use In Coastal Wetland Restoration, Lauren Land
LSU Master's Theses
In wetland sediments, organic matter provides a substrate for microbial activity. During metabolism, microbes release extracellular polymeric substances, which accumulate to bind soil particles. A similar concept can be implemented on a large scale to reduce wetland loss in Louisiana. Hypothetically, hydraulically dredged sediment can be amended with polymer and deposited on subsiding marshes as a restoration method where the polymer increases sediment stabilization until plants become established. This lab study focused on investigating the influence of natural polymer additions on particle aggregation to increase sediment stability and the effects on microbial activity. Sediments from three sites (i.e. freshwater, intermediate, …
Climate Change And Freshwater Resources In Oregon,
2010
Portland State University
Climate Change And Freshwater Resources In Oregon, Heejun Chang, Julie Jones
Institute for Sustainable Solutions Publications and Presentations
Climate change will affect various sectors of water resources in Oregon in the 21st century. The observed trends in streamflow show significant declines in September flow and, although not significant, increases in March flow in many transient rain-snow basins. These streamflow trends are associated with rising temperature and coincident declines in snowpack in spring in the latter half of the 20th century. While there are no distinct trends in high precipitation events, such events are associated with climate variability such as ENSO and PDO. Effects of ENSO and PDO are more pronounced at the beginning and end of the wet …
Modeling The Impacts Of Pulsed Riverine Inflows On Hydrodynamics And Water Quality In The Barataria Bay Estuary,
2010
Louisiana State University and Agricultural and Mechanical College
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 …
