Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Estuaries

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 151 - 180 of 2567

Full-Text Articles in Entire DC Network

Carbon Cycling In Santa Barbara Basin Sediments: A Modeling Study, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton Jan 2016

Carbon Cycling In Santa Barbara Basin Sediments: A Modeling Study, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton

Journal of Marine Research

The primary input of organic matter to almost all marine sediments comes from deposition at the sediment surface. However, in many continental margin settings, reduced carbon can also be added to sediments from below—for example, from “deep” geologic hydrocarbon reservoirs derived from ancient source rocks or from the decomposition of deeply buried gas hydrate deposits. To examine the impact of these two differing reduced carbon inputs on sediment biogeochemistry, a modified reaction-transport model for anoxic marine sediments is described here and applied to data from sediment cores in Santa Barbara Basin to a depth of 4.6 m. Excellent model fits …

Go to article

Mechanisms Controlling Vertical Variability Of Subsurface Chlorophyll Maxima In A Mode-Water Eddy, Qian P. Li, Dennis A. Hansell Jan 2016

Mechanisms Controlling Vertical Variability Of Subsurface Chlorophyll Maxima In A Mode-Water Eddy, Qian P. Li, Dennis A. Hansell

Journal of Marine Research

An intense subsurface chlorophyll enhancement was found repeatedly within the core of a mode-water eddy during a 2-month period. Two controls on chlorophyll concentrations in this deep chlorophyll maximum (DCM) layer are noted: chlorophyll concentration is controlled by nutrients at low nutrient concentrations and by light when nutrients are saturating. To synthesize these results, a simple one-dimensional nutrient-phytoplankton model is developed by including the effects of phytoplankton self-shading for light attenuation, depth-dependent phytoplankton specific loss, and density-associated nutrient fluctuation in the deep layer. The model is parameterized using eddy data including not only vertical diffusivity, sinking velocity, and chlorophyll-to-carbon ratios, …

Go to article

Convective Mixing By Internal Waves In The Puerto Rico Trench, Hans Van Haren, Louis Gostiaux Jan 2016

Convective Mixing By Internal Waves In The Puerto Rico Trench, Hans Van Haren, Louis Gostiaux

Journal of Marine Research

A 2.4 km long deep-sea mooring was deployed for 14 months in the Puerto Rico Trench, the deepest part of the Atlantic Ocean. Below its top buoyancy package, the mooring line held a 200 m long string of high-resolution temperature sensors and a current meter. Over the instrumented range between 6,004 and 6,204 m, waters are very weakly stratified, with local buoyancy frequency equaling about 1.9 times the semidiurnal tidal frequency. Besides quiescent waters, the detailed observations show regular vertical turbulent overturning associated with periodic warming and driven by internal tidal and inertial waves. During such episodes, the 4-day and …

Go to article

Methane Dynamics In Santa Barbara Basin (Usa) Sediments As Examined With A Reaction-Transport Model, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton Jan 2016

Methane Dynamics In Santa Barbara Basin (Usa) Sediments As Examined With A Reaction-Transport Model, David J. Burdige, Tomoko Komada, Cédric Magen, Jeffrey P. Chanton

Journal of Marine Research

Here we describe a new reaction-transport model that quantitatively examines δ13C profiles of pore-water methane and dissolved inorganic carbon (DIC) (δ13CCH4 and δ13CDIC) in the anoxic sediments of the Santa Barbara Basin (California Borderland region). Best-fit solutions of the model to these data suggest that CO2 reduction is the predominant form of methanogenesis in these sediments. These solutions also accurately reproduce the isotope depth profiles, including a broad minimum in the δ13CDIC profile and a much sharper (angular) minimum in the δ13CCH4 profile, both …

Go to article

Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (Inbox): Part 2. Biogeochemical Responses To Eddies And Typhoons Revealed From The S1 Mooring And Shipboard Measurements, Ryuichiro Inoue, Makio C. Honda, Tetsuichi Fujiki, Kazuhiko Matsumoto, Shinya Kouketsu, Toshio Suga, Toshiro Saino Jan 2016

Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (Inbox): Part 2. Biogeochemical Responses To Eddies And Typhoons Revealed From The S1 Mooring And Shipboard Measurements, Ryuichiro Inoue, Makio C. Honda, Tetsuichi Fujiki, Kazuhiko Matsumoto, Shinya Kouketsu, Toshio Suga, Toshiro Saino

Journal of Marine Research

An interdisciplinary project called S1-INBOX (Western North Pacific Integrated PhysicalBiogeochemical Ocean Observation Experiment conducted around the S1 biogeochemical mooring site) was carried out during the summer of 2011 in the oligotrophic, subtropical North Pacific Ocean near biogeochemical mooring S1 (30° N, 145° E). Results from the S1 mooring during S1-INBOX revealed a large export flux at a depth of 200 m, a high chlorophyll a concentration in the deep chlorophyll maximum layer, and a high potential photochemical efficiency of photosystem II. These phenomena were associated with vertical uplift of isopycnal surfaces at the edge of a cyclonic eddy and a …

Go to article

Residual Water Transport In The Marsdiep Tidal Inlet Inferred From Observations And A Numerical Model, Maximiliano G. Sassi, Theo Gerkema, Matias Duran-Matute, Janine J. Nauw Jan 2016

Residual Water Transport In The Marsdiep Tidal Inlet Inferred From Observations And A Numerical Model, Maximiliano G. Sassi, Theo Gerkema, Matias Duran-Matute, Janine J. Nauw

Journal of Marine Research

At tidal inlets, large amounts of water are exchanged with the adjacent sea during the tidal cycle. The residual flows, the net effect of ebb and flood, are generally small compared with the gross flux; they vary in magnitude and sign from one tidal period to the other; and their long-term mean varies from year to year. Here, we focus on the temporal variability of the residual flows in the Marsdiep tidal inlet, which is the western-most inlet of the Wadden Sea, a tidal lagoon along the coasts of the Netherlands, Germany, and Denmark. We compare the transport from a …

Go to article

The Effect Of Wind Direction On Cross-Shelf Transport On An Initially Stratified Inner Shelf, Rachel M. Horwitz, Steven J. Lentz Jan 2016

The Effect Of Wind Direction On Cross-Shelf Transport On An Initially Stratified Inner Shelf, Rachel M. Horwitz, Steven J. Lentz

Journal of Marine Research

Cross-shelf and along-shelf wind stresses both independently have been shown to drive transport across the inner shelf. We investigate how the circulation and density fields respond to simultaneous cross- and along-shelf wind forcing using a set of model experiments on an initially stratified inner shelf. For all wind directions with a downwelling along-shelf component, the inner shelf is unstratified and the cross-shelf wind dominates transport. For wind directions with an upwelling along-shelf component, the inner shelf can be stratified and the transition from inner to midshelf occurs over a wide swath of shelf. In this transition region, the effects of …

Go to article

Vorticity Dynamics Near Sharp Topographic Features, Bruno Deremble, William K. Dewar, Eric P. Chassignet Jan 2016

Vorticity Dynamics Near Sharp Topographic Features, Bruno Deremble, William K. Dewar, Eric P. Chassignet

Journal of Marine Research

In ocean models, the interaction with boundaries is often parameterized as it involves small-scale processes that are usually hard to capture in a large-scale model. However, such interactions can play important roles in the model dynamics. For example, the choice of boundary conditions (free-slip vs. no-slip) has a direct impact on the vorticity (enstrophy) budget: with no-slip boundary conditions, vorticity is injected into the system, whereas with free-slip boundary conditions, there should be no vorticity injection as long as the coastline is smooth. However, we show here that at boundary singularities (e.g., corners), vorticity is injected into the domain even …

Go to article

Wind-Driven Flow Over Topography, Michael A. Spall Jan 2016

Wind-Driven Flow Over Topography, Michael A. Spall

Journal of Marine Research

The space and time scales over which wind forcing can directly drive flows over regions of closed topographic contours are explored using an idealized numerical model and theory. It is shown that stratification limits the vertical scale of the mean flow but also results in an enhanced recirculation strength in shallow water by distorting the isopycnals in the bottom boundary layer. Time-dependent forcing can drive flows that extend deeper than the mean flow because the initial response is primarily barotropic. This response is limited at low frequencies by baroclinic Rossby wave propagation. It is expected that these wind-driven flows might …

Go to article

Balanus Eburneus (Crustacea: Cirripedia) As A Potential Indicator Of Estuarine System Recovery In South Texas: A Study Of Recruitment, Growth And Stable Isotopes, Crystal Martinez Dec 2015

Balanus Eburneus (Crustacea: Cirripedia) As A Potential Indicator Of Estuarine System Recovery In South Texas: A Study Of Recruitment, Growth And Stable Isotopes, Crystal Martinez

Theses and Dissertations

Population characteristics of the barnacle Balanus eburneus were analyzed with the purpose of exploring its potential use as a discriminating indicator among sites exhibiting different disturbances or stages of recovery. The study was conducted from May 2012 to May 2013 at four estuaries in the Lower Laguna Madre, TX including a) Bahia Grande, currently under restoration and divided into Bahia Grande North and Bahia Grande South, b) San Martin Lake, which receives runoff water and c) South Bay, a relatively undisturbed reference estuary. In general, similar barnacle recruitment and growth trends in Bahia Grande South and South Bay were explained …

Go to article

Fluctuating Asymmetry In Menidia Beryllina Before And After The 2010 Deepwater Horizon Oil Spill, Savannah A. Michaelsen, Jacob F. Schaefer, Mark S. Peterson Feb 2015

Fluctuating Asymmetry In Menidia Beryllina Before And After The 2010 Deepwater Horizon Oil Spill, Savannah A. Michaelsen, Jacob F. Schaefer, Mark S. Peterson

Faculty Publications

Assessing the impacts of the Deepwater Horizon oil spill with a dependable baseline comparison can provide reliable insight into environmental stressors on organisms that were potentially affected by the spill. Fluctuating asymmetry (small, non-random deviations from perfect bilateral symmetry) is an informative metric sensitive to contaminants that can be used to assess environmental stress levels. For this study, the well-studied and common Gulf of Mexico estuarine fish, Menidia beryllina, was used with pre and post-oil spill collections. Comparisons of fluctuating asymmetry in three traits (eye diameter, pectoral fin length, and pelvic fin length) were made pre and post-oil spill …

Go to article

A Composite Vertical Current Spectrum For Strongly And Weakly Stratified Seas And Oceans, Hans Van Haren Jan 2015

A Composite Vertical Current Spectrum For Strongly And Weakly Stratified Seas And Oceans, Hans Van Haren

Journal of Marine Research

An overall frequency (σ) spectrum φw(σ, N, fh) is composed for vertical current (w) observations from ocean areas with different stratifications represented by large, 100 m scale buoyancy frequency N. The horizontal Coriolis parameter is denoted by fh. In the open Atlantic Ocean, the relatively strong horizontal layering in density supports the φw that is found in semiequilibrium under the degradation of the lowest internal wave mode. This φw is not constant with frequency; however, its variance increases between σ = f and its peak near σ = (0.5 …

Go to article

Species Diversity Patterns Of Marine Plankton And Benthos In Chinese Bays: Baseline Prior To Large-Scale Development, Weiwei Yu, Bin Chen, Paolo F. Ricci, Luoping Zhang, Jianguo Du, Zhiyuan Ma Jan 2015

Species Diversity Patterns Of Marine Plankton And Benthos In Chinese Bays: Baseline Prior To Large-Scale Development, Weiwei Yu, Bin Chen, Paolo F. Ricci, Luoping Zhang, Jianguo Du, Zhiyuan Ma

Journal of Marine Research

More than 28,000 marine species have been recorded in China, which accounts for approximately 10% of all marine organisms in the world and plays a potentially important role in protecting global marine biodiversity. However, knowledge of marine biodiversity patterns in China is limited, and in particular, no comparative diversity analysis has been carried out for Chinese bays. In this study, national-scale species diversity patterns of coastal bays were examined on the basis of investigations for approximately 81 bays throughout the entire Chinese coastline in the 1980s and the early 1990s, revealing the baseline of diversity patterns prior to large-scale development. …

Go to article

Intertidal Percolation Through Beach Sands As A Source Of 224,223 Ra To Long Island Sound, New York, And Connecticut, United States, Henry Bokuniewicz, J. Kirk Cochran, Jordi Garcia-Orellana, Valenti Rodellas, John Wallace Daniel, Christina Heilbrun Jan 2015

Intertidal Percolation Through Beach Sands As A Source Of 224,223 Ra To Long Island Sound, New York, And Connecticut, United States, Henry Bokuniewicz, J. Kirk Cochran, Jordi Garcia-Orellana, Valenti Rodellas, John Wallace Daniel, Christina Heilbrun

Journal of Marine Research

Along tidal coasts, seawater circulated through the intertidal beach contributes to submarine groundwater discharge (SGD) and its associated geochemical signature. The short-lived radium isotopes, 223Ra (half-life = 11.4 d) and 224Ra (half-life = 3.66 d), were used to quantify this component of SGD in a large estuary, Long Island Sound (LIS), New York, United States. The tide is semidiurnal with a range of approximately 2 m. Concentrations in beach pore waters ranged from 97 to 678 disintegrations per minute (dpm) 224Ra 100 L–1, whereas concentrations in open coastal waters ranged from approximately 12 to 69 …

Go to article

Nitrogen Substrate–Dependent Nitrous Oxide Cycling In Salt Marsh Sediments, Qixing Ji, Andrew R. Babbin, Xuefeng Peng, Jennifer L. Bowen, Bess B. Ward Jan 2015

Nitrogen Substrate–Dependent Nitrous Oxide Cycling In Salt Marsh Sediments, Qixing Ji, Andrew R. Babbin, Xuefeng Peng, Jennifer L. Bowen, Bess B. Ward

Journal of Marine Research

Nitrous oxide (N2O) is important to Earth's climate because it is a strong absorber of radiation and an important ozone depletion agent. Increasing anthropogenic nitrogen input into the marine environment, especially to coastal waters, has led to increasing N2O emissions. Identifying the nitrogen compounds that serve as substrates for N2O production in coastal waters reveals important pathways and helps us understand their control by environmental factors. In this study, sediments were collected from a long-term fertilization site in Great Sippewissett Marsh, Falmouth, Massachusetts. The 15N tracer incubation time course experiments were conducted and …

Go to article

Distinguishing Turbulent Overturns In High-Sampling-Rate Moored Thermistor String Observations, Hans Van Haren, Louis Gostiaux Jan 2015

Distinguishing Turbulent Overturns In High-Sampling-Rate Moored Thermistor String Observations, Hans Van Haren, Louis Gostiaux

Journal of Marine Research

Turbulent overturns are distinguished from salinity-compensated intrusions in high-resolution moored thermistor string observations. The buoyancy frequency N is used to make the time dimensionless, "t*." This results in a primary, visual means to easily compare the duration of overturns with N, the natural frequency that separates internal waves from turbulent overturns. As a secondary means, the shapes of overturns are investigated. Above various sloping topography between 500 and 1,000 m water depth where the buoyancy period varies between ∼1,300 and 2,600 s, vertical overturns of ∼40 m last Δt* =0.2–0.4. This corresponds with the timescale …

Go to article

Spiciness, Trevor J. Mcdougall, Oliver A. Krzysik Jan 2015

Spiciness, Trevor J. Mcdougall, Oliver A. Krzysik

Journal of Marine Research

We define and present algorithms for spiciness, which is an oceanographic variable whose isopycnal variations reflect isopycnal water-mass contrasts in density units. Discussion of spiciness in the oceanographic literature has often concentrated on its supposed orthogonality to isopycnals on the salinity-temperature diagram and how this orthogonal nature means that spiciness is a “passive” thermodynamic variable. Here we show that this “orthogonal” property is devoid of physical meaning. Moreover, it is emphasized that the notion of “orthogonality” on the salinity-temperature diagram does not give rise to a passive thermodynamic variable. Rather, the passive nature of variations of any thermodynamic variable is …

Go to article

The Influence Of Anoxia And Substrate Availability On N2o Cycling By Denitrification In The Upper Boundary Of The Oxygen Minimum Zone Off Northern Chile, Maribeb Castro-González, Laura Farías Jan 2015

The Influence Of Anoxia And Substrate Availability On N2o Cycling By Denitrification In The Upper Boundary Of The Oxygen Minimum Zone Off Northern Chile, Maribeb Castro-González, Laura Farías

Journal of Marine Research

Strong accumulations of N2O at oxyclines are some of the most conspicuous features of the world's oceans. However, the origin of these maxima, and the relative contribution of nitrification and denitrification in N2O cycling, remains unclear. In order to gain insight into the importance of denitrification and factors regulating N2O cycling at upper oxyclines in the eastern South Pacific, the production and consumption of N2O by denitrification were measured using a classical acetylene method under induced anoxia with the addition of an electron acceptor (nitrite) and donors (sodium acetate and glucose). The …

Go to article

Low-Frequency Variability Of The Separated Western Boundary Current In Response To A Seasonal Wind Stress In A 2.5-Layer Model With Outcropping, Jérôme Sirven, Sabine Férvrier, Christophe Herbaut Jan 2015

Low-Frequency Variability Of The Separated Western Boundary Current In Response To A Seasonal Wind Stress In A 2.5-Layer Model With Outcropping, Jérôme Sirven, Sabine Férvrier, Christophe Herbaut

Journal of Marine Research

The response of the separated western boundary current to a seasonally varying wind stress is studied in a 2.5-layer model where the second layer outcrops. The model is eddy permitting with a resolution of one-sixth of a degree, and the geometry of the basin is idealized. The response is studied for two mean states: the first one is only wind driven, whereas the second one takes into account the existence of a meridional overturning circulation. The separation latitude and the mean path followed by the separated western boundary current are shifted northward of approximately 2° when the overturning circulation is …

Go to article

The Wall-Layer Dynamics In A Weakly Stratified Tidal Bottom Boundary Layer, I. Lozovatsky, S. U. P. Jinadasa, H. J. S. Fernando, J.-H. Lee, Chang Su Hong Jan 2015

The Wall-Layer Dynamics In A Weakly Stratified Tidal Bottom Boundary Layer, I. Lozovatsky, S. U. P. Jinadasa, H. J. S. Fernando, J.-H. Lee, Chang Su Hong

Journal of Marine Research

The application of the classical logarithmic layer model for wall-bounded shear flows to marine bottom boundary layer (BBL) usually leads to an overestimation of the friction velocity u* due possibly to the influence of form drag, stratification, and rotation of the flow vector. To gain insights on the BBL velocity scaling, acoustic Doppler current profiler (ADCP) measurements taken in the East China Sea were analyzed (a total of 270 sixteen-minute averaged velocity profiles). Single and double log-layer models, a log-wake model, and a modified log-layer (MLL) model that accounts for stratification in the upper part of the BBL (Perlin, …

Go to article

Sandy Sediment Budget Of The Midcoast Of Rio Grande Do Sul, Brazil, Lucas Marchi De Motta, Elírio Ernestino Toldo Jr., Luiz Emílio De Sá Brito De Ameida, José Carlos Nunes Jan 2015

Sandy Sediment Budget Of The Midcoast Of Rio Grande Do Sul, Brazil, Lucas Marchi De Motta, Elírio Ernestino Toldo Jr., Luiz Emílio De Sá Brito De Ameida, José Carlos Nunes

Journal of Marine Research

Calculation of the coastal sediment budget involves estimation of the timing and intensity of processes of erosion, transport, and deposition, as well as an understanding of local and regional sediment dynamics. The modern sedimentary deposits present in the coastal zone constitute the physical basis of coastal ecosystems. Knowledge of the dynamics of these sediments from the source to sink area, through regional sediment management, is critical to understanding the long-term stability of the coastal zone and the fate of these important natural resources. In this article, the littoral cell concept has been applied to the midcoast of Rio Grande do …

Go to article

Water Masses And Nutrient Sources To The Gulf Of Maine, David W. Townsend, Neal R. Pettigrew, Maura A. Thomas, Mark G. Neary, Dennis J. Mcgillicuddy Jr., James O'Donnell Jan 2015

Water Masses And Nutrient Sources To The Gulf Of Maine, David W. Townsend, Neal R. Pettigrew, Maura A. Thomas, Mark G. Neary, Dennis J. Mcgillicuddy Jr., James O'Donnell

Journal of Marine Research

The Gulf of Maine, a semienclosed basin on the continental shelf of the northwest Atlantic Ocean, is fed by surface and deep water flows from outside the gulf: Scotian Shelf Water (SSW) from the Nova Scotian shelf that enters the gulf at the surface and slope water that enters at depth and along the bottom through the Northeast Channel. There are two distinct types of slope water, Labrador Slope Water (LSW) and Warm Slope Water (WSW); it is these deep water masses that are the major source of dissolved inorganic nutrients to the gulf. It has been known for some …

Go to article

The Fish Kill Mechanism Of The Harmful Raphidophyte Chattonella Subsalsa, Amy E. Grogan Jan 2015

The Fish Kill Mechanism Of The Harmful Raphidophyte Chattonella Subsalsa, Amy E. Grogan

Electronic Theses and Dissertations

Harmful algae blooms (HABs) and toxins associated with HAB species are a significant threat to the health of marine species and coastal environments. In the South Carolina coastal zone, HABs have proliferated with intensified anthropogenic eutrophication in coastal waters. The raphidophyte species Chattonella subsalsa is a prominent cause of algal blooms resulting in fish kills in South Carolina. Though C. subsalsa is a known ichthyotoxic alga, the fish kill mechanism of this species remains unidentified. C. subsalsa is likely to elicit fish mortality via one of two mechanisms: (1) gill damage induced by cell contact irritation or (2) the production …

Go to article

Tide-Dependent Predation Patterns Of Piscivorous Fishes In Shallow Estuarine Creeks, Matthew Ross Helms Jan 2015

Tide-Dependent Predation Patterns Of Piscivorous Fishes In Shallow Estuarine Creeks, Matthew Ross Helms

Electronic Theses and Dissertations

The distribution and foraging behavior of predatory salt marsh fishes is shaped by the movements of prey, many of whom seek shelter in shallow and tributary creeks. I hypothesized that the distribution of piscivorous fishes in marsh creek channels would differ with proximity to the mouths of intertidal creeks and with tidal stage. Custom-built trotlines baited with live minnows were deployed during four discrete tidal stages at two microhabitats in main creek channels: (1) adjacent to intertidal creek mouths, and (2) along straight banks in North Inlet estuary, South Carolina. Catch-per-unit-effort of predatory fishes was significantly higher (Wilcoxon signed-rank tests, …

Go to article

Characterization Of Sediment Microbial Communities And Analysis Of Biogeochemical Responses To Eutrophication In Southeastern Estuaries, Gary Alon Blakeney Dec 2014

Characterization Of Sediment Microbial Communities And Analysis Of Biogeochemical Responses To Eutrophication In Southeastern Estuaries, Gary Alon Blakeney

Theses and Dissertations

Estuaries are valuable economic resources to humans. However, changes in these ecosystems, such as alteration in nutrient availability, can impose eutrophic pressures. Traditionally, estuaries have been monitored through chemical analyses that measure factors such as sediment oxygen demand (SOD) and reduced forms of Fe(II), Mn(II), and H2S. These methods are time consuming and have been proven to be unreliable. This study was conducted to determine if using T-RFLP analysis could be used as a proxy for some of the current methods used to monitor eutrophication. Using SPSS to perform a principle component analysis, it was determined that connections can be …

Go to article

Ontogenetic Diet Shifts And Prey Preference Of A Generalist Predatory Fish, Brittany Jalene Scharf Jul 2014

Ontogenetic Diet Shifts And Prey Preference Of A Generalist Predatory Fish, Brittany Jalene Scharf

USF Tampa Graduate Theses and Dissertations

Marine ecosystems are highly dynamic and contain a diverse faunal assemblage that are subject to various natural and anthropogenic variability. Globally, seagrass ecosystems are located adjacent to coastal areas that are heavily impacted by human development and urbanization potentially altering the community structure within these ecosystem. Complex food webs connect many components of these systems, often in unexpected ways, and are ultimately based on one of two pathways: benthic (i.e., seagrass, epiphytes, microalgae, detritus) and planktonic (i.e., phytoplankton). Understanding the pathway which the food web is based gives further insight regarding the biological balance of the ecosystem; thus it is …

Go to article

Assessing The Impact Of Seasonal Variations On The Density Structure Of A Weak Freshwater Plume, Daniel Kelsey-Wilkinson Jul 2014

Assessing The Impact Of Seasonal Variations On The Density Structure Of A Weak Freshwater Plume, Daniel Kelsey-Wilkinson

The Plymouth Student Scientist

Freshwater plumes are features of periodically intense salinity stratification created by an ebbing tide. The dynamics of these features are important for biological events, such as the spring bloom. Using an undulating towed Conductivity-Temperature-Depth (CTD) probe with a fluorometer attached, repeated sections were completed beyond Plymouth breakwater to a moored scientific station 9.6km offshore. These data were then gridded using linear interpolation and a density ratio was calculated at 3 positions: behind the plume, plume front and in front of the plume. The ratios of influence which thermohaline properties contribute to the density structure of a water column under seasonal …

Go to article

The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera May 2014

The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera

Dissertations

Estuaries are dynamic regions in which there can be significant modification of the riverine flux of trace elements to the open ocean due to various geochemical, physical, and biological processes. Additionally, estuaries are often subject to anthropogenic inputs of trace elements. The first portion of this study investigated the source, behavior, and sediment interaction of anthropogenic stable cesium (Cs) in St. Louis Bay (SLB), MS. A consistent increase in stable Cs concentration was noticed in sediment cores starting from a period when a titanium dioxide refinery on SLB started operations. Weak correlation between Cs and clay percentage and strong correlations …

Go to article

Long-Term Warming And The Size And Phenology Of Long Island Sound Plankton, Edward Rice Feb 2014

Long-Term Warming And The Size And Phenology Of Long Island Sound Plankton, Edward Rice

Dissertations, Theses, and Capstone Projects

In coastal ecosystems with decades of eutrophication and other anthropogenic stressors, the impact of climate change on planktonic communities can be difficult to detect. A time-series of monthly surface water temperatures in the Central Basin of Long Island Sound (LIS) from the late 1940s until 2012 indicates a warming rate of 0.03°C per year, with recent summer temperatures increasing most consistently. During this warming trend, the proportion of chlorophyll produced by smaller phytoplankton and flagellates appears to be higher during warmer summer and fall months, enabling an increase in annual chlorophyll despite static nutrient levels. The phenology of phytoplankton and …

Go to article

Diffuse Reflectance Of Foams, M. A. Devetzoglou, J. R. G. Evans Jan 2014

Diffuse Reflectance Of Foams, M. A. Devetzoglou, J. R. G. Evans

Journal of Marine Research

There have been few studies of the optical properties of foams but the results of these investigations are of particular relevance to current discussions about climate restoration by means of oceanic foam because they indicate the influence of foam raft number on albedo. The diffuse reflectance of foams prepared from eight surfactants was measured in a 0°/45° geometry with a collimated, solar simulation light source and a photodiode by reference to barium sulphate white standards. Reflectance, or albedo, in the range of 0.5 to 0.59 was recorded for foams prepared with sodium dodecyl sulphate (SDS), methyl cellulose, and TWEEN 20 …

Go to article

First Prev Next Last