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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 …

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, …

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 …

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) (δ¹³C_CH4 and δ¹³C_DIC) 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 δ¹³C_DIC profile and a much sharper (angular) minimum in the δ¹³C_CH4 profile, both …

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 …

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 …

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 …

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 …

Validation Of Integrated Coast-Ocean Model Cche2d-Coast And Development Of Wind Model, Afshin Gazerzadeh

Electronic Theses and Dissertations

The eastern and southern coastlines of the United States are two of the most cyclone-prone areas of the world. The effects of tropical cyclones vary mainly depending on wind intensity and geological features of the coast that it is crossing. Higher winds potentially generate higher storm surges and consequently larger floods occur along the coastlines. Therefore, it is critical to accurately predict winds, storm surge, and waves associated with a hurricane. In the present study, an integrated coastal and ocean process model, CCHE2D-Coast, is validated by assessing the model’s capabilities in simulating coast-ocean circulations driven by the astronomical tides on …

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 …

Relative Resistance To Breaking Of Pinus Taeda L. And Pinus Palustris, Cory Glenn Garms

LSU Master's Theses

Patterns from hurricane damage give an indication that longleaf pine (Pinus palustris) is more windfirm than loblolly pine (Pinus taeda). Tree windfirmess has been attributed to many factors including species and material properties like wood strength and stiffness. Because longleaf pine wood is stronger and stiffer than loblolly pine wood, this study used static winching methodology to see if these properties account for differences in windfirmness by measuring bending force required to break stems (MMAX). Stress-strain diagrams were constructed for pulled trees to explore how they behave under increasing loads. Based on these diagrams, it appears that living trees can …

Breaking Wind, Todd William Pentico

Graduate Theses and Dissertations

Breaking Wind is a research project and thesis exhibition composed of a series of ceramic objects in conjunction with paintings that explore the systems that dictate belief, the motives that drive curiosity, and biological connection to our surroundings. The work uses the context of the gallery and devices used in museums such as plinths, shelves, and wall text to reinforce the idealized and fictive into something believable.

In the work, Breaking Wind refers to a clumsy breakdown and rethinking of the seemingly simple natural phenomenon, wind. Wind is understood as a natural occurrence that has no origin or any innate …

Surface And Airborne Arsenic Concentrations In A Recreational Site Near Las Vegas, Nevada, Usa, Dirk Goossens, Brenda J. Buck, Yuanxin Teng, Brett T. Mclaurin

Geoscience Faculty Research

Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from …

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 φ_w(σ, N, f_h) 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 f_h. In the open Atlantic Ocean, the relatively strong horizontal layering in density supports the φ_w that is found in semiequilibrium under the degradation of the lowest internal wave mode. This φ_w is not constant with frequency; however, its variance increases between σ = f and its peak near σ = (0.5 …

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. …

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 …

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 …

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 …

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 …

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 …

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 …

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, …

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 …

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 …

Close On The Wind: An Environmental Military History Examining Wind’S Influence On The Early United States Navy, Scott J. Beehler

Department of History: Dissertations, Theses, and Student Research

Utilizing General Carl von Clausewitz’s theory of friction in combat, Close on the Wind examines wind’s historical influence on early United States naval warfare, specifically small scale engagements fought during the Quasi War, First Barbary War, and the War of 1812. To accomplish this, the thesis first engages in a scientific discussion of wind, concentrating on how it occurs and what forces dictate its velocity and direction. The examination goes on to also present the types of wind that period sailing vessels encountered, including global, regional, and local patterns, as well as how wind influenced the practice of sailing and …

Avoided Water Cost Of Electricity Generation For Solar Pv And Wind Technologies In Southern California, Matthew Cohen

Master's Theses

The objective of this thesis is to provide a foundation for evaluating the water costs associated with electricity production to calculate the avoided water cost of energy for solar PV and wind technologies relative to coal, natural gas, nuclear, geothermal, concentrated solar thermal, and biomass. Water consumption is estimated for energy production (fuel extraction and preparation) and electricity generation (power plant operation) using the best available information from published articles. The quantity of water consumed for electricity production is monetized for a Southern California case study based on the water rates of Metropolitan Water District of Southern California (MET), which …

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 …

Some Influences Of Remote Topography On Western Boundary Currents, Michael A. Spall

Journal of Marine Research

The influence of topography in a basin interior on the separation and time-dependence of strongly nonlinear western boundary currents is explored using a shallow water numerical model and scaling theory. In the linear limit, the western boundary current follows the western boundary to the latitude of the gap in the interior topography where it then separates from the coast and flows eastward in a narrow jet. As nonlinearity is increased, the flow initially remains steady but develops a series of stationary meanders extending off the western boundary at the separation latitude. For strongly nonlinear flows the solutions become time-dependent. The …

Symmetric Instability Of Cross-Stream Varying Currents, Joseph Pedlosky

Journal of Marine Research

The symmetric instability of a simple shear flow in which the velocity is a linear function of the vertical coordinate but which varies slowly in the cross-stream direction is studied using an asymptotic analytical method. Explicit analytical solutions are found for the evolution of the envelope of the developing linear instability. Although the problem with no lateral variation yields cell-like instabilities growing in place, the lateral variation of the shear produces time dependence and cross-stream propagation of the envelope and accompanying cells. A similar solution is derived for the case of laterally uniform shear in a current whose depth slowly …

Available Energy Of The World Ocean, Peter R. Bannon, Raymond G. Najjar

Journal of Marine Research

The available energy of the ocean is the excess of the sum of the ocean's internal and gravitational energies with respect to its equilibrium state, which is in thermodynamic equilibrium and has the same total entropy as the ocean. The equilibrium state for the world ocean is rigorously determined to be an isothermal ocean with a temperature of 3.66˚C and a horizontally uniform absolute salinity that increases monotonically from 27.30 g kg^–1 at the surface to 47.39 g kg^–1 at a depth of 5.5 km. This salinity profile is consistent with a uniform relative chemical potential of 47.44 …