The Development Of A Fluorescence-Based Reverse Flow Injection Analysis (Rfia) Method For Quantifying Ammonium At Nanomolar Concentrations In Oligotrophic Seawater,
2015
University of South Florida
The Development Of A Fluorescence-Based Reverse Flow Injection Analysis (Rfia) Method For Quantifying Ammonium At Nanomolar Concentrations In Oligotrophic Seawater, William Abbott
USF Tampa Graduate Theses and Dissertations
The goal of this thesis was to adopt a reverse flow injection analysis (rFIA) technique to the fluorometric analysis of the reaction o-phthaldialdehyde (OPA) with ammonium, allowing accurate measurements of ammonium concentrations lower than the detection limit of the widely used indophenol blue (IPB) colorimetric method while accounting for the background fluorescence of seawater. Ammonium is considered an essential nutrient for primary productivity, especially in the nutrient depleted surface ocean where as the most reduced form of dissolved inorganic nitrogen, it is readily assimilated via metabolic pathways. Challenges in the quantification of ammonium require more sensitive analytical techniques for …
Influence Of Water Column Stratification And Nutrient Gradients On The Migratory Behavior Of The Red Tide Dinoflagellate, Karenia Brevis,
2015
University of South Florida
Influence Of Water Column Stratification And Nutrient Gradients On The Migratory Behavior Of The Red Tide Dinoflagellate, Karenia Brevis, Matthew Garrett
USF Tampa Graduate Theses and Dissertations
Diel vertical migration (DVM) can offer motile phytoplankton a competitive advantage over other phytoplankton species. DVM has been well documented in the harmful dinoflagellate, Karenia brevis; however, the extent to which changes in nutrient regimes and density stratification modify migration patterns has not been thoroughly investigated. A 2 m experimental column was constructed with sensors and sampling ports at four depths to obtain fluorescence and temperature measurements and discrete water samples. The environmental parameters of the experimental column represented temperature and nutrient conditions found on the West Florida Shelf (WFS), where Karenia blooms frequently occur. Results demonstrated a clear …
Dissolved Nutrient Distributions In The Gulf Of Mexico Following The Deepwater Horizon Oil Spill,
2015
University of South Florida
Dissolved Nutrient Distributions In The Gulf Of Mexico Following The Deepwater Horizon Oil Spill, Ashley Ann Parks
USF Tampa Graduate Theses and Dissertations
The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM) in the spring of 2010 introduced 4.4 million of barrels of oil to the ecosystem. Some biodegradation of the oil occurs when microorganisms, particularly bacteria, metabolize the oil as a carbon source. During this process, the microbes also require nutrients for energy. An introduction of oil at this magnitude has the ability to induce large blooms of microbes, which in turn can affect nutrient concentrations. Microbial petroleum degradation decreases nutrient concentrations, whereas the microbial assimilation and decay of organic matter increase nutrient concentrations. This study assessed whether any …
Temporal Variation In Optical Properties Of Chromophoric Dissolved Organic Matter (Cdom) In Southern California Coastal Waters With Nearshore Kelp And Seagrass,
2015
Chapman University
Temporal Variation In Optical Properties Of Chromophoric Dissolved Organic Matter (Cdom) In Southern California Coastal Waters With Nearshore Kelp And Seagrass, Catherine D. Clark, Warren J. De Bruyn, Paige Aiona
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Optical properties of chromophoric dissolved organic matter (CDOM) were measured in surf zone waters in diurnal field studies at a Southern California beach with nearshore kelp and seagrass beds and intertidal plant wrack. Absorption coefficients (aCDOM(300 nm)) ranged from 0.35 m21 to 3.7 m21 with short-term variability<1 h, increases at ebb and flood tides and higher values (6 m21) during an offshore storm event. Spectral slopes (S) ranged from 0.0028 nm21 to 0.017 nm21, with higher values after the storm; S was generally inversely correlated with aCDOM(300 nm). 3-D excitation–emission matrix spectra (EEMs) for samples with lower S values had humic-type peaks associated with terrestrial material (A, C), marine microbial material (M) and protein peaks, characteristic of freshly produced organic material. Samples with high S values had no or reduced protein peaks, consistent with aged material. Fluorescent indexes (f450/f500 >2.5, BIX>1.1) were consistent with microbial aquatic sources. Leachates of senescent kelp and seagrass had protein and humic-type EEM peaks. After solar simulator irradiation (4 h), protein peaks rapidly photochemically degraded, humic-type peak C increased in intensity and peak M disappeared. Optical characteristics of kelp leachates were most similar to field samples, …
Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae,
Bacillariophyta), A New Diatom From Ho Ba Bê,
Bac Kan Province, Northern Viêt Nam,
2015
University of Nebraska-Lincoln
Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae, Bacillariophyta), A New Diatom From Ho Ba Bê, Bac Kan Province, Northern Viêt Nam, D. Marie Weide
Department of Earth and Atmospheric Sciences: Faculty Publications
A new species of Aulacoseira Thwaites is described from piston core samples from Ho Ba Bê in the karst region of northern Viêt Nam. Although it closely resembles Aulacoaseira subborealis (Nygaard) Denys, Muylaert & Krammer, A. stevensiae Weide sp. nov. is designated a new species based mainly on morphological differences in the spines, including invariably inclined spines that are rounded, differences in the Ringleiste, areola pattern and overall size. Aulacoseira stevensiae is present throughout a core that spans the last 500 years. It was a major component of the diatom community, but the populations have recently decreased, possibly being outcompeted …
Field Observations And Novel Methodologies For Carbon System Assessments In Coastal Waters,
2015
University of South Florida
Field Observations And Novel Methodologies For Carbon System Assessments In Coastal Waters, Bo Yang
USF Tampa Graduate Theses and Dissertations
Coastal zones receive massive terrestrial inputs of nutrients and organic matter, and play an important role in biogeochemical cycles. The interactions of river inputs, ocean currents, atmospheric exchanges, anthropogenic influences, and biologically active ecosystems make CO2 system studies in coastal waters highly challenging. This work focuses on improving our understanding of the CO2 system in coastal waters through (1) development of a new methodology for measurements of CO2 system parameters in the field; (2) observations of large spatial and temporal CO2 system variations in coastal waters; and (3) characterization of the influence of organics on CO …
Techniques For Payload Stabilization For Improved Photography During Stratospheric Balloon Flights,
2015
University of Minnesota - Twin Cities / MN Space Grant
Techniques For Payload Stabilization For Improved Photography During Stratospheric Balloon Flights, James Flaten, Christopher Gosch, Joseph (Benjamin) Habeck
2017 Academic High Altitude Conference
Payload-box rotation and swing are perennial challenges to achieving high-quality photography (typically videography) during weather-balloon flights to “near-space” (AKA the stratosphere). Continuous camera motion can lead to blurred still photos, nearly-impossible-to-watch video footage, and precludes time-exposure photography required for most astronomical imaging even though altitudes are reached where the daytime sky appears black. Apparently-random payload rotation, persisting even at altitude, can often exceed servo rotation rates and frustrate attempts to do active camera pointing. Here we discuss mostly-passive payload stabilization strategies we, and our collaborators, have used to mitigate and dampen both swing and rotation of suspended payloads on high-altitude …
Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments,
2015
University College London
Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, Francesco Iacoviello, Giovanna Giorgetti, Isabella Turbanti Memmi, Sandra Passchier
ANDRILL Research and Publications
The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL— SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6–20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene and it collected …
Sfa Weather Station-March 2015,
2015
Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University
Sfa Weather Station-March 2015, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University
Weather Station Data
No abstract provided.
Sfa Weather Station-February 2015,
2015
Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University
Sfa Weather Station-February 2015, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University
Weather Station Data
No abstract provided.
Multi-Scale Evaluation Of Light Use Efficiency In Modis Gross Primary Productivity For Croplands In The Midwestern United States,
2015
Tsinghua University, Beijing
Multi-Scale Evaluation Of Light Use Efficiency In Modis Gross Primary Productivity For Croplands In The Midwestern United States, Qinchuan Xin, Mark Broich, Andrew E. Suyker, Le Yu, Peng Gong
School of Natural Resources: Faculty Publications
Satellite remote sensing provides continuous observations of land surfaces, thereby offering opportunities for large-scale monitoring of terrestrial productivity. Production Efficiency Models (PEMs) have been widely used in satellite-based studies to simulate carbon exchanges between the atmosphere and ecosystems. However, model parameterization of the maximum light use efficiency (ε*GPP) varies considerably for croplands in agricultural studies at different scales. In this study, we evaluate cropland ε*GPP in the MODIS Gross Primary Productivity (GPP) model (MOD17) using in situ measurements and inventory datasets across the Midwestern US. The site-scale calibration using 28 site-years tower measurements derives ε*GPP values …
Dimethylsulfide Gas Transfer Coefficients From Algal Blooms In The Southern Ocean,
2015
University of California - Irvine
Dimethylsulfide Gas Transfer Coefficients From Algal Blooms In The Southern Ocean, T. G. Bell, Warren J. De Bruyn, Christa A. Marandino, S. D. Miller, C. S. Law, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Air-sea dimethylsulfide (DMS) fluxes and bulk air-sea gradients were measured over the Southern Ocean in February-March 2012 during the Surface Ocean Aerosol Production (SOAP) study. The cruise encountered three distinct phytoplankton bloom regions, consisting of two blooms with moderate DMS levels, and a high biomass, dinoflagellate-dominated bloom with high seawater DMS levels (> 15 nM). Gas transfer coefficients were considerably scattered at wind speeds above 5 m s(-1). Bin averaging the data resulted in a linear relationship between wind speed and mean gas transfer velocity consistent with that previously observed. However, the wind-speed-binned gas transfer data distribution at all wind …
The Simulation & Evaluation Of Surge Hazard Using A Response Surface Method In The New York Bight,
2015
University of North Florida
The Simulation & Evaluation Of Surge Hazard Using A Response Surface Method In The New York Bight, Michael H. Bredesen
UNF Graduate Theses and Dissertations
Atmospheric features, such as tropical cyclones, act as a driving mechanism for many of the major hazards affecting coastal areas around the world. Accurate and efficient quantification of tropical cyclone surge hazard is essential to the development of resilient coastal communities, particularly given continued sea level trend concerns. Recent major tropical cyclones that have impacted the northeastern portion of the United States have resulted in devastating flooding in New York City, the most densely populated city in the US. As a part of national effort to re-evaluate coastal inundation hazards, the Federal Emergency Management Agency used the Joint Probability Method …
On Underestimation Of Global Vulnerability To Tree Mortality
And Forest Die-Off From Hotter Drought In The Anthropocene,
2015
USGS Fort Collins Science Center, Los Alamos NM
On Underestimation Of Global Vulnerability To Tree Mortality And Forest Die-Off From Hotter Drought In The Anthropocene, Craig D. Allen, David D. Breshears, Nate G. Mcdowell
United States Geological Survey: Staff Publications
Patterns, mechanisms, projections, and consequences of tree mortality and associated broadscale forest die-off due to drought accompanied by warmer temperatures—‘‘hotter drought’’, an emerging characteristic of the Anthropocene—are the focus of rapidly expanding literature. Despite recent observational, experimental, and modeling studies suggesting increased vulnerability of trees to hotter drought and associated pests and pathogens, substantial debate remains among research, management and policy-making communities regarding future tree mortality risks. We summarize key mortalityrelevant findings, differentiating between those implying lesser versus greater levels of vulnerability. Evidence suggesting lesser vulnerability includes forest benefits of elevated [CO2] and increased water-use efficiency; observed and modeled increases …
Comparison Of Isotope-Based Biomass Pathways With Groundfish Community Structure In The Eastern Gulf Of Mexico,
2015
University of South Florida
Comparison Of Isotope-Based Biomass Pathways With Groundfish Community Structure In The Eastern Gulf Of Mexico, Sheri Ann Huelster
USF Tampa Graduate Theses and Dissertations
This study compared traditional community analysis with stable-isotope trophic analysis to define process-based trophic elements of community structure in the eastern Gulf of Mexico, and developed a predictive capability regarding changes to fish community structure that would be expected from increasing eutrophication. Specifically, it used an existing trawl survey program (SEAMAP) to compare invertebrate herbivore (sponge and sea urchin) isotopes with groundfish isotopes, and then compared the resulting spatial patterns with spatial variation in community structure, as identified by cluster analysis. The comparison was applied to seven NMFS survey zones that extended offshore from the Caloosahatchee River, FL northwest to …
The Non-Lethal Effects Of Climate Change On The Territoriality Of Lottia Gigantea,
2014
Chapman University
The Non-Lethal Effects Of Climate Change On The Territoriality Of Lottia Gigantea, Tracey Gunanto, Christina Chavez, Jessica Martinez, William G. Wright
Student Scholar Symposium Abstracts and Posters
The intertidal zone has been described as ground zero for global warming. Here, the owl limpet, Lottia gigantea, adapted to the cool ocean temperatures, must withstand a few hours of baking sun during day-time low tides. This hardship is predicted to increase in frequency and severity in the future as the globe warms. Our research hypothesized that heat events compromise territorial behavior of L. gigantea. All observations and experiments were performed at Inspiration Point near Newport Beach, California. We measured the natural radiant temperature of tagged limpets during day-time low tides using a field-calibrated infrared “thermogun”. We also …
Long Term Ground Based Precipitation Data Analysis: Spatial And Temporal Variability,
2014
Chapman University
Long Term Ground Based Precipitation Data Analysis: Spatial And Temporal Variability, Luciano Rodriguez, Cyril S. Rakovski, Hesham El-Askary, Mohamed Allali
Student Scholar Symposium Abstracts and Posters
California is an area of diverse topography and has what many scientists call a Mediterranean climate. Various precipitation patterns exist due to El Niño Southern Oscillation (ENSO) which can cause abnormal precipitation or droughts. As temperature increases mainly due to the increase of CO2 in the atmosphere, it is rapidly changing the climate of not only California but the world. An increase in temperature is leading to droughts in certain areas as other areas are experiencing heavy rainfall/flooding. Droughts in return are providing a foundation for fires harming the ecosystem and nearby population. Various natural hazards can be induced due …
Sfa Weather Station-December 2014,
2014
Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University
Sfa Weather Station-December 2014, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University
Weather Station Data
No abstract provided.
Sfa Weather Station-November 2014,
2014
Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University
Sfa Weather Station-November 2014, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University
Weather Station Data
No abstract provided.
Sfa Weather Station-October 2014,
2014
Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University
Sfa Weather Station-October 2014, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University
Weather Station Data
No abstract provided.
