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2019

Faculty Publications

Oceanography and Atmospheric Sciences and Meteorology

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Articles 1 - 27 of 27

Full-Text Articles in Physical Sciences and Mathematics

Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner Dec 2019

Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner

Faculty Publications

Iron is an essential micronutrient that limits primary production in up to 40% of the surface ocean and influences carbon dioxide uptake and climate change. Dissolved iron is mostly associated with loosely characterised organic molecules, called ligands, which define key aspects of the iron cycle such as its residence time, distribution and bioavailability to plankton. Models based on in situ ligand distributions and the behaviour of purified compounds include long-lived ligands in the deep ocean, bioreactive ligands in the surface ocean and photochemical processes as important components of the iron cycle. Herein, we further characterise biologically refractory ligands in dissolved …


Dynamic Accretion Beneath A Slow-Spreading Ridge Segment: Iodp Hole 1473a And The Atlantis Bank Oceanic Core Complex, Henry J.B. Dick, Christopher J. Macleod, Peter Blum, Natsue Abe, Donna K. Blackman, Julie A. Bowles, M.J. Cheadle, K. Cho, Jakub Ciazela, Jeremy Deans, Virginia P. Edgcomb, C. Ferrando, Lyderic France, B. Ghosh, Benoit Ildefonse, Barbara John, Mark A. Kendrick, J. Koepke, James A.M. Leong, C. Liu, Q. Ma, T. Morishita, A. Morris, J.H. Natland, T. Nozaka, O. Pluemper, A. Sanflippo, J.B. Sylvan, Maurice A. Tivey, R. Tribuzio, G. Viegas Dec 2019

Dynamic Accretion Beneath A Slow-Spreading Ridge Segment: Iodp Hole 1473a And The Atlantis Bank Oceanic Core Complex, Henry J.B. Dick, Christopher J. Macleod, Peter Blum, Natsue Abe, Donna K. Blackman, Julie A. Bowles, M.J. Cheadle, K. Cho, Jakub Ciazela, Jeremy Deans, Virginia P. Edgcomb, C. Ferrando, Lyderic France, B. Ghosh, Benoit Ildefonse, Barbara John, Mark A. Kendrick, J. Koepke, James A.M. Leong, C. Liu, Q. Ma, T. Morishita, A. Morris, J.H. Natland, T. Nozaka, O. Pluemper, A. Sanflippo, J.B. Sylvan, Maurice A. Tivey, R. Tribuzio, G. Viegas

Faculty Publications

809 deep IODP Hole U1473A at Atlantis Bank, SWIR, is 2.2 km from 1,508‐m Hole 735B and 1.4 from 158‐m Hole 1105A. With mapping, it provides the first 3‐D view of the upper levels of a 660‐km2 lower crustal batholith. It is laterally and vertically zoned, representing a complex interplay of cyclic intrusion, and ongoing deformation, with kilometer‐scale upward and lateral migration of interstial melt. Transform wall dives over the gabbro‐peridotite contact found only evolved gabbro intruded directly into the mantle near the transform. There was no high‐level melt lens, rather the gabbros crystallized at depth, and then emplaced …


E700xd Portable Doppler Radar Energy Systems Analysis, Brandon M. Bailey [*], Torrey J. Wagner, Jada Williams Dec 2019

E700xd Portable Doppler Radar Energy Systems Analysis, Brandon M. Bailey [*], Torrey J. Wagner, Jada Williams

Faculty Publications

Occurring in industrialized nations, inexpensive and abundantly available power is routinely taken for granted. However, energy resilience and to a lesser extent price are key concerns when considering potential solutions for disaster response, disaster relief, or military operations. The Department of Defense (DoD) currently uses a 5 kW generator to power the E700XD portable Doppler radar system when grid power is unavailable [1]. While the radar has an approximate power consumption of 2.5 kW, there is a potential for higher demand due to weather conditions [2]. This paper examines the cost of operating a currently installed generator, compared to the …


Gulf Of Mexico Hypoxia: Past, Present, And Future, Nancy N. Rabalais, R. Eugene Turner Nov 2019

Gulf Of Mexico Hypoxia: Past, Present, And Future, Nancy N. Rabalais, R. Eugene Turner

Faculty Publications

One of the largest human-caused areas of bottom-water oxygen deficiency in the coastal ocean is on the northern Gulf of Mexico continental shelf adjacent to the Mississippi River, which discharges nitrogen and phosphorus loads into its surface waters. The beginnings of seasonal hypoxia (≤2 mg l−1 dissolved oxygen) in this area was in the 1950s with an acceleration in the worsening of severity during the 1970s. Currently, the bottom area of hypoxic areas can approach 23,000 km2, and the volume, 140 km3. Ecosystems, people, and economies are now at risk within the Mississippi River watershed and in the northern Gulf …


Age And Growth Of Hardhead Catfish And Gafftopsail Catfish In Coastal Louisiana, Usa, Shane Flinn, Stephen Midway Oct 2019

Age And Growth Of Hardhead Catfish And Gafftopsail Catfish In Coastal Louisiana, Usa, Shane Flinn, Stephen Midway

Faculty Publications

The Hardhead Catfish Ariopsis felis and Gafftopsail Catfish Bagre marinus are marine catfishes that have low recreational and commercial landings in U.S. waters, although they are among the most abundant species in coastal waters of the Gulf of Mexico. Few biological studies exist on marine catfishes, with most studies focusing on their unique reproductive biology. This study evaluated weight-length relationships for Gafftopsail Catfish (n = 264) and Hardhead Catfish (n = 823) sampled from across coastal Louisiana, USA, during 2016-2018; subsamples (93 and 266, respectively) were aged using lapilli for age and growth analyses. Hardhead Catfish showed a small but …


The Tensile Root Strength Of Spartina Patens Varies With Soil Texture And Atrazine Concentration, Lauris O. Hollis, R. Eugene Turner Sep 2019

The Tensile Root Strength Of Spartina Patens Varies With Soil Texture And Atrazine Concentration, Lauris O. Hollis, R. Eugene Turner

Faculty Publications

The widely used agricultural herbicide atrazine enters wetlands and may potentially affect wetland plants that provide critical reinforcement of soil strength and contribute to ecosystem stability in ways that may vary among soil types. We conducted greenhouse experiments using four levels of atrazine doses and three different soil textures to test for differences between control and experimental treatments and interactive effects of soil texture and atrazine exposure by using the tensile root strength of the coastal wetland emergent macrophyte Spartina patens as the response variable. The tensile root strength of S. patens was not affected after 50days of atrazine exposure …


Drivers And Impacts Of Water Level Fluctuations In The Mississippi River Delta: Implications For Delta Restoration, Matthew Hiatt, John W. Day, Robert V. Rohli, John Andrew Nyman Aug 2019

Drivers And Impacts Of Water Level Fluctuations In The Mississippi River Delta: Implications For Delta Restoration, Matthew Hiatt, John W. Day, Robert V. Rohli, John Andrew Nyman

Faculty Publications

This review synthesizes the knowledge regarding the environmental forces affecting water level variability in the coastal waters of the Mississippi River delta and relates these fluctuations to planned river diversions. Water level fluctuations vary significantly across temporal and spatial scales, and are subject to influences from river flow, tides, vegetation, atmospheric forcing, climate change, and anthropogenic activities. Human impacts have strongly affected water level variability in the Mississippi River delta and other deltas worldwide. Collectively, the research reviewed in this article is important for enhancing environmental, economic, and social resilience and sustainability by assessing, mitigating, and adapting to geophysical changes …


Calibration Of The Lisst-Vsf To Derive The Volume Scattering Functions In Clear Waters, Lianbo Hu, Xiaodong Zhang, Yuanheng Xiong, Ming-Xia He Aug 2019

Calibration Of The Lisst-Vsf To Derive The Volume Scattering Functions In Clear Waters, Lianbo Hu, Xiaodong Zhang, Yuanheng Xiong, Ming-Xia He

Faculty Publications

The recently commercialized LISST-VSF instrument measures the volume scattering function (VSF) from 0.1° to 15° with a traditional laser diffraction unit (LISST) and from 15° to 155° with an eyeball component. Between these two optical components, only the LISST unit is calibrated. The eyeball measurements are scaled using the VSFs at 15° that are measured by both components. As this relative calibration relies on a valid measurement at 15° by the LISST, it might fail in clear oceanic waters, where the forward scattering is relative weak either due to a lack of large particles or an overall low concentration of …


The Effects Of Oil On Blue Crab And Periwinkle Snail Interactions: A Mesocosm Study, Elizabeth M. Robinson, Nancy N. Rabalais Aug 2019

The Effects Of Oil On Blue Crab And Periwinkle Snail Interactions: A Mesocosm Study, Elizabeth M. Robinson, Nancy N. Rabalais

Faculty Publications

We examined the sub-lethal effect of Macondo oil from the Deepwater Horizon oil spill on predator-prey interactions using blue crabs (Callinectes sapidus) and periwinkle snails (Littoraria irrorata). A 2 x 2 factorial mesocosm design determined the effect of oil (no oil vs. oil) and blue crabs (no blue crab predator vs. one blue crab predator) on periwinkle snail climbing and survival. Sixteen mesocosm tanks were used in the experiment, which were replicated three times. Each tank contained water, sand, and Spartina marsh stems. The sixteen tanks were divided between two, temperature-controlled chambers to separate oil treatments (no oil vs. oil). …


A Compilation Of Global Bio-Optical In Situ Data For Ocean-Colour Satellite Applications: Version Two, André Valente, Shubha Sathyendranath, Vanda Brotas, Steve Groom, Michael Grant, Malcolm Taberner, David Antoine, Robert Arnone, William M. Balch, Kathryn Baker, Ray Barlow, Simon Bélanger, Jean-François Berthon, Şükrü Beşiktepe, Yngve Borsheim, Astrid Bracher, Vittorio Brando, Elisabetta Canuti, Francisco Chavez, Andrés Cianca, Hervé Claustre, Lesley Clementson, Richard Crout, Robert Frounin, Carlos García-Soto, Stuart W. Gibb, Richard Gould, Stanford B. Hooker, Mati Kahru, Milton Kampel, Holger Klein, Susanne Kratzer, Raphael Kudela, Jesus Ledesma, Hubert Loisel, Patricia Matrai, David Mckee, Brian G. Mitchell, Tiffany Moisan, Frank Muller-Karger, Leonie O'Dowd, Michael Ondrusek, Trevor Platt, Alex J. Poulton, Michael Repecaud, Thomas Schroeder, Timothy Smyth, Denise Smyth-Wright, Heidi M. Sosik, Michael Twardoski, Vincenzo Vellucci, Kenneth Voss, Jeremy Werdell, Marcel Wernand, Simon Wright, Giuseppe Zibordi Jul 2019

A Compilation Of Global Bio-Optical In Situ Data For Ocean-Colour Satellite Applications: Version Two, André Valente, Shubha Sathyendranath, Vanda Brotas, Steve Groom, Michael Grant, Malcolm Taberner, David Antoine, Robert Arnone, William M. Balch, Kathryn Baker, Ray Barlow, Simon Bélanger, Jean-François Berthon, Şükrü Beşiktepe, Yngve Borsheim, Astrid Bracher, Vittorio Brando, Elisabetta Canuti, Francisco Chavez, Andrés Cianca, Hervé Claustre, Lesley Clementson, Richard Crout, Robert Frounin, Carlos García-Soto, Stuart W. Gibb, Richard Gould, Stanford B. Hooker, Mati Kahru, Milton Kampel, Holger Klein, Susanne Kratzer, Raphael Kudela, Jesus Ledesma, Hubert Loisel, Patricia Matrai, David Mckee, Brian G. Mitchell, Tiffany Moisan, Frank Muller-Karger, Leonie O'Dowd, Michael Ondrusek, Trevor Platt, Alex J. Poulton, Michael Repecaud, Thomas Schroeder, Timothy Smyth, Denise Smyth-Wright, Heidi M. Sosik, Michael Twardoski, Vincenzo Vellucci, Kenneth Voss, Jeremy Werdell, Marcel Wernand, Simon Wright, Giuseppe Zibordi

Faculty Publications

A global compilation of in situ data is useful to evaluate the quality of ocean-colour satellite data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (including, inter alia, MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT and GeP&CO) and span the period from 1997 to 2018. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties, spectral diffuse attenuation coefficients and total suspended matter. The data were from …


Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance Jul 2019

Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance

Faculty Publications

Uncertainty regarding the movement and population exchange of Atlantic bluefin tuna (Thunnus thynnus) from the two primary spawning areas (Gulf of Mexico, Mediterranean Sea) is increasingly implicated as a major impediment for the conservation of this species. Here, two mixture methods were applied to natural chemical markers (delta O-18 and delta C-13) in otoliths (ear stones) to comprehensively investigate the nature and degree of transoceanic movement and mixing of eastern and western populations in several areas of the North Atlantic Ocean that potentially represent mixing hotspots. Areas investigated occurred on both sides of the 45 degrees W management boundary as …


A Sustained Ocean Observing System In The Indian Ocean For Climate Related Scientific Knowledge And Societal Needs, J.C. Hermes, Y. Masumoto, L.M. Beal, M.K. Roxy, J. Vialard, M. Andres, H. Annamalai, S. Behera, N. D'Adamo, T. Doi, M. Feng, W. Han, N. Hardman-Mountford, H. Hendon, R. Hood, S. Kido, C. Lee, T. Lee, M. Lengaigne, J. Li, R. Lumpkin, K.N. Navaneeth, B. Milligan, M.J. Mcphaden, M. Ravichandran, T. Shinoda, A. Singh, B. Sloyan, P.G. Strutton, A.C. Subramanian, S. Thurston, T. Tozuka, C.C. Ummenhofer, A.S. Unnikrishnan, R. Venkatesan, D. Wang, J. Wiggert, L. Yu, W. Yu Jun 2019

A Sustained Ocean Observing System In The Indian Ocean For Climate Related Scientific Knowledge And Societal Needs, J.C. Hermes, Y. Masumoto, L.M. Beal, M.K. Roxy, J. Vialard, M. Andres, H. Annamalai, S. Behera, N. D'Adamo, T. Doi, M. Feng, W. Han, N. Hardman-Mountford, H. Hendon, R. Hood, S. Kido, C. Lee, T. Lee, M. Lengaigne, J. Li, R. Lumpkin, K.N. Navaneeth, B. Milligan, M.J. Mcphaden, M. Ravichandran, T. Shinoda, A. Singh, B. Sloyan, P.G. Strutton, A.C. Subramanian, S. Thurston, T. Tozuka, C.C. Ummenhofer, A.S. Unnikrishnan, R. Venkatesan, D. Wang, J. Wiggert, L. Yu, W. Yu

Faculty Publications

The Indian Ocean is warming faster than any of the global oceans and its climate is uniquely driven by the presence of a landmass at low latitudes, which causes monsoonal winds and reversing currents. The food, water, and energy security in the Indian Ocean rim countries and islands are intrinsically tied to its climate, with marine environmental goods and services, as well as trade within the basin, underpinning their economies. Hence, there are a range of societal needs for Indian Ocean observation arising from the influence of regional phenomena and climate change on, for instance, marine ecosystems, monsoon rains, and …


Modeling Atmosphere-Ocean Radiative Transfer: A Pace Mission Perspective, Jacek Chowdhary, Peng-Wang Zhai, Emmanuel Boss, Heidi Dierssen, Robert Frouin, Amir Ibrahim, Zhongping Lee, Lorraine A. Remer, Michael Twardowski, Feng Xu, Xiaodong Zhang, Matteo Ottaviani, William Reed Espinosa, Didier Ramon Jun 2019

Modeling Atmosphere-Ocean Radiative Transfer: A Pace Mission Perspective, Jacek Chowdhary, Peng-Wang Zhai, Emmanuel Boss, Heidi Dierssen, Robert Frouin, Amir Ibrahim, Zhongping Lee, Lorraine A. Remer, Michael Twardowski, Feng Xu, Xiaodong Zhang, Matteo Ottaviani, William Reed Espinosa, Didier Ramon

Faculty Publications

The research frontiers of radiative transfer (RT) in coupled atmosphere-ocean systems are explored to enable new science and specifically to support the upcoming Plankton, Aerosol, Cloud ocean Ecosystem (PACE) satellite mission. Given (i) the multitude of atmospheric and oceanic constituents at any given moment that each exhibits a large variety of physical and chemical properties and (ii) the diversity of light-matter interactions (scattering, absorption, and emission), tackling all outstanding RT aspects related to interpreting and/or simulating light reflected by atmosphere-ocean systems becomes impossible. Instead, we focus on both theoretical and experimental studies of RT topics important to the science threshold …


Deep-Ocean Mixing Driving By Small-Scale Internal Tides, Clément Vic, Alberto C. Naveira Garabato, J.A. Mattias Green, Amy F. Waterhouse, Angélique Melet, Casimir De Lavergne, Maarten C. Buijsman, Gordon R. Stephenson May 2019

Deep-Ocean Mixing Driving By Small-Scale Internal Tides, Clément Vic, Alberto C. Naveira Garabato, J.A. Mattias Green, Amy F. Waterhouse, Angélique Melet, Casimir De Lavergne, Maarten C. Buijsman, Gordon R. Stephenson

Faculty Publications

Turbulent mixing in the ocean is key to regulate the transport of heat, freshwater and biogeochemical tracers, with strong implications for Earth's climate. In the deep ocean, tides supply much of the mechanical energy required to sustain mixing via the generation of internal waves, known as internal tides, whose fate-the relative importance of their local versus remote breaking into turbulence-remains uncertain. Here, we combine a semi-analytical model of internal tide generation with satellite and in situ measurements to show that from an energetic viewpoint, small-scale internal tides, hitherto overlooked, account for the bulk (>50%) of global internal tide generation, …


Spatial Variations In Chlorophyll A, C, N, And P In A Louisiana Estuary From 1994 To 2016, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee May 2019

Spatial Variations In Chlorophyll A, C, N, And P In A Louisiana Estuary From 1994 To 2016, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee

Faculty Publications

Intense sampling of an estuary can reveal relative spatial changes that are significant irrespective of whether or not the estuary is eutrophic, micro- or meso-tidal, disturbed, or restored. This waterscape' perspective is analogous to a landscape perspective. We collected monthly water samples in the Barataria Basin watershed from 1994 to 2016 at 37 stations along a 129km transect from 1km offshore to a freshwater stream. The average Chlorophyll a (Chl) concentration from 267 trips was supported from both nitrogen-fixing cyanobacteria in a freshwater lake and partially from nutrients in seaward sources. Estuarine salinity was correlated with the discharge of the …


An Objective Procedure For Delineating The Circumpolar Vortex, Nazla Bushra, Robert V. Rohli May 2019

An Objective Procedure For Delineating The Circumpolar Vortex, Nazla Bushra, Robert V. Rohli

Faculty Publications

The broad-scale, steering atmospheric circulation in the Northern Hemisphere, represented by the tropospheric circumpolar vortex (CPV), is an important driver of environmental processes. The area and circularity of the CPV are analyzed hereby delineating the leading edge of the CPV at the steepest 500-hPa geopotential height gradient globally. The daily CPV area and circularity were aggregated to monthly averages for contrast with measurements identified in previous research for the overlapping period of record (1979-2001). Accuracy of representation of the CPV is assessed through correlations to air-sea teleconnections known to be associated with broad-scale, extratropical steering circulation. Correlation to monthly teleconnection …


Reef Rover: A Low-Cost Small Autonomous Unmanned Surface Vehicle (Usv) For Mapping And Monitoring Coral Reefs, George Raber, Steven R. Schill Apr 2019

Reef Rover: A Low-Cost Small Autonomous Unmanned Surface Vehicle (Usv) For Mapping And Monitoring Coral Reefs, George Raber, Steven R. Schill

Faculty Publications

In the effort to design a more repeatable and consistent platform to collect data for Structure from Motion (SfM) monitoring of coral reefs and other benthic habitats, we explore the use of recent advances in open source Global Positioning System (GPS)-guided drone technology to design and test a low-cost and transportable small unmanned surface vehicle (sUSV). The vehicle operates using Ardupilot open source software and can be used by local scientists and marine managers to map and monitor marine environments in shallow areas (<20>m) with commensurate visibility. The imaging system uses two Sony a6300 mirrorless cameras to collect stereo …


Atmospheric Propagation Of High Energy Lasers: Thermal Blooming Simulation, Jonathan Gustafsson, Benjamin F. Akers, Jonah A. Reeger, Sivaguru S. Sritharan Apr 2019

Atmospheric Propagation Of High Energy Lasers: Thermal Blooming Simulation, Jonathan Gustafsson, Benjamin F. Akers, Jonah A. Reeger, Sivaguru S. Sritharan

Faculty Publications

High Energy Laser (HEL) propagation through turbulent atmosphere is examined via numerical simulation. The beam propagation is modeled with the paraxial equation, which in turn is written as a system of equations for a quantum fluid, via the Madelung transform. A finite volume solver is applied to the quantum fluid equations, which supports sharp gradients in beam intensity. The atmosphere is modeled via a coupled advection-diffusion equation whose initial data have Kolmogorov spectrum. In this model the combined effects of thermal blooming, beam slewing, and deep turbulence are simulated.


Autonomous Seawater PCo2 And Ph Time Series From 40 Surface Buoys And The Emergence Of Anthropogenic Trends, Adrienne J. Sutton, Richard A. Feely, Stacy Maenner-Jones, Sylvia Musielwicz, John Osborne, Colin Dietrich, Natalie Monacci, Jessica Cross, Randy Bott, Alex Kozyr, Andreas J. Andersson, Nicholas R. Bates, Wei-Jun Cai, Meghan F. Cronin, Eric H. De Carlo, Burke Hales, Stephan D. Howden, Charity M. Lee, Derek P. Manzello, Michael J. Mcphaden, Melissa Meléndez, John B. Mickett, Jan A. Newton, Scott E. Noakes, Jae Hoon Noh, Solveig R. Olafsdottir, Joseph E. Salisbury, Uwe Send, Thomas W. Trull, Douglas C. Vandemark, Robert A. Weller Mar 2019

Autonomous Seawater PCo2 And Ph Time Series From 40 Surface Buoys And The Emergence Of Anthropogenic Trends, Adrienne J. Sutton, Richard A. Feely, Stacy Maenner-Jones, Sylvia Musielwicz, John Osborne, Colin Dietrich, Natalie Monacci, Jessica Cross, Randy Bott, Alex Kozyr, Andreas J. Andersson, Nicholas R. Bates, Wei-Jun Cai, Meghan F. Cronin, Eric H. De Carlo, Burke Hales, Stephan D. Howden, Charity M. Lee, Derek P. Manzello, Michael J. Mcphaden, Melissa Meléndez, John B. Mickett, Jan A. Newton, Scott E. Noakes, Jae Hoon Noh, Solveig R. Olafsdottir, Joseph E. Salisbury, Uwe Send, Thomas W. Trull, Douglas C. Vandemark, Robert A. Weller

Faculty Publications

Ship-based time series, some now approaching over 3 decades long, are critical climate records that have dramatically improved our ability to characterize natural and anthropogenic drivers of ocean carbon dioxide (CO2) uptake and biogeochemical processes. Advancements in autonomous marine carbon sensors and technologies over the last 2 decades have led to the expansion of observations at fixed time series sites, thereby improving the capability of characterizing sub-seasonal variability in the ocean. Here , we present a data product of 40 individual autonomous moored surface ocean pCO2 (partial pressure of CO2) time series established between …


Vertical Marine Snow Distribution In The Stratified Hypersaline, And Anoxic Orca Basin (Gulf Of Mexico), Arne Diercks, Kai Ziervogel, Ryan Sibert, Samantha B. Joye, Vernon Asper Feb 2019

Vertical Marine Snow Distribution In The Stratified Hypersaline, And Anoxic Orca Basin (Gulf Of Mexico), Arne Diercks, Kai Ziervogel, Ryan Sibert, Samantha B. Joye, Vernon Asper

Faculty Publications

We present a complete description of the depth distribution of marine snow in Orca Basin (Gulf of Mexico), from sea surface through the pycnocline to within 10 m of the seafloor. Orca Basin is an intriguing location for studying marine snow because of its unique geological and hydrographic setting: the deepest ~200 m of the basin are filled with anoxic hypersaline brine. A typical deep ocean profile of marine snow distribution was observed from the sea surface to the pycnocline, namely a surface maximum in total particle number and midwater minimum. However, instead of a nepheloid (particle-rich) layer positioned near …


A Multiscale Approach To High-Resolution Ocean Profile Observations Within A 4dvar Analysis System, Matthew J. Carrier, John J. Osborne, Hans E. Ngodock, Scott R. Smith, Innocent Souopgui, Joseph M. D'Addezio Feb 2019

A Multiscale Approach To High-Resolution Ocean Profile Observations Within A 4dvar Analysis System, Matthew J. Carrier, John J. Osborne, Hans E. Ngodock, Scott R. Smith, Innocent Souopgui, Joseph M. D'Addezio

Faculty Publications

Most ocean data assimilation systems are tuned to process and assimilate observations to constrain features on the order of the mesoscale and larger. Typically this involves removal of observations or computing averaged observations. This procedure, while necessary, eliminates many observations from the analysis step and can reduce the overall effectiveness of a particular observing platform. Simply including these observations is not an option as doing so can produce an overdetermined, ill-conditioned problem that is more difficult to solve. An approach, presented here, aims to avoid such issues while at the same time increasing the number of observations within the assimilation. …


In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann Feb 2019

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann

Faculty Publications

The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin is complex. Previous studies attributed dolomitization to various diagenetic factors and environments. In this study, high-resolution, in situ laser ablation inductively coupled mass spectrometry analysis of rare earth element patterns of dolomite was used to assess the diagenetic fluids responsible for dolomitization of the Ordovician Decorah Formation. Integrated geochemical data and petrographic evidence suggest that the dolostones are formed in two different diagenetic realms: shallow burial and hydrothermal. Shallow burial dolomites exhibit three distinct rare earth element patterns. Dolomite from the middle portion of the Guttenberg Member exhibits light …


Enso-Induced Co-Variability Of Salinity, Plantkton Biomass And Coastal Currents In The Northern Gulf Of Mexico, Fabian A. Gomez, Sang-Ki Lee, Frank J. Hernandez Jr., Luciano M. Chiaverano, Frank E. Muller-Karger, Yanyun Liu, John T. Lamkin Jan 2019

Enso-Induced Co-Variability Of Salinity, Plantkton Biomass And Coastal Currents In The Northern Gulf Of Mexico, Fabian A. Gomez, Sang-Ki Lee, Frank J. Hernandez Jr., Luciano M. Chiaverano, Frank E. Muller-Karger, Yanyun Liu, John T. Lamkin

Faculty Publications

The northern Gulf of Mexico (GoM) is a region strongly influenced by river discharges of freshwater and nutrients, which promote a highly productive coastal ecosystem that host commercially valuable marine species. A variety of climate and weather processes could potentially influence the river discharges into the northern GoM. However, their impacts on the coastal ecosystem remain poorly described. By using a regional ocean-biogeochemical model, complemented with satellite and in situ observations, here we show that El Niño - Southern Oscillation (ENSO) is a main driver of the interannual variability in salinity and plankton biomass during winter and spring. Composite analysis …


Role Of The Atchafalaya River Basin In Regulating Export Fluxes Of Dissolved Organic Carbon, Nutrients, And Trace Elements To The Louisiana Shelf, Dongjoo Joung, Laodong Guo, Alan M. Shiller Jan 2019

Role Of The Atchafalaya River Basin In Regulating Export Fluxes Of Dissolved Organic Carbon, Nutrients, And Trace Elements To The Louisiana Shelf, Dongjoo Joung, Laodong Guo, Alan M. Shiller

Faculty Publications

The abundance and fluxes of selected dissolved trace elements (TE), nutrients, and dissolved organic carbon (DOC) were quantified in the Atchafalaya River Basin to better understand its influence on the chemical regime of the Louisiana Shelf, a region where bottom water hypoxia occurs annually during late spring to early fall. Water samples were collected from throughout the entire Atchafalaya River Basin including from the Mississippi and Red Rivers as well as basin swamp waters during April and November 2010, and June 2011, which represent “typical” high and low, and “unusual” high river discharges, respectively. Within the total dissolved (< 0.45 µm) pool, most of the TEs were mainly partitioned to the < 0.02 µm dissolved phase with the exception of Cr, Cs, Fe, Pb and Zn which were dominantly in the colloidal (0.02-0.45 µm) phase. In the Atchafalaya River, seasonal concentration variations in nutrients, DOC and most TEs were similar to those in the Mississippi River, reflecting a major contribution of water from the Mississippi River. Contributions of the Red River to the Atchafalaya River’s DOC and nutrients were estimated to be 1-35%, similar to previous estimates for this system. The Red River contribution to the fluxes of Co, Cr, Cs, Fe, Mn, Pb, Rb, and Zn was generally disproportionally high (>20%), …


Effects Of Shoal Margin Collapses On The Morphodynamics Of A Sandy Estuary, M. R. Hiatt Jan 2019

Effects Of Shoal Margin Collapses On The Morphodynamics Of A Sandy Estuary, M. R. Hiatt

Faculty Publications

Shoal margin collapses of several million cubic meters have occurred in the Western Scheldt estuary, the Netherlands, on average five times a year over the last decades. While these collapses involve significant volumes of material, their effect on the channel-shoal morphology is unknown. We hypothesize that collapses dynamicize the channel-shoal interactions, which could impact the ecological functioning, flood safety, and navigation in the estuary. The objective is to investigate how locations, probability, type, and volume of shoal margin collapse affect the channel-shoal dynamics. We implemented an empirically validated parameterization for shoal margin collapses and tested its effect on simulated estuary …


Variations In The Abundance And Distribution Of Aggregates In The Ross Sea, Antarctica, Vernon L. Asper, Walker O. Smith Jan 2019

Variations In The Abundance And Distribution Of Aggregates In The Ross Sea, Antarctica, Vernon L. Asper, Walker O. Smith

Faculty Publications

The vertical distribution and temporal changes in aggregate abundance and sizes were measured in the Ross Sea, Antarctica between 2002 and 2005 to acquire a more complete understanding of the mechanisms and rates of carbon export from the euphotic layer. Aggregate abundance was determined by photographic techniques, and water column parameters (temperature, salinity, fluorescence, transmissometry) were assessed from CTD profiles. During the first three years the numbers of aggregates increased seasonally, being much more abundant within the upper 200 m in late summer than in early summer from 50 to 100 m (12.5 L–1 in early summer vs. 42.9 …


Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen Jan 2019

Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen

Faculty Publications

Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …