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Articles 91 - 120 of 139
Full-Text Articles in Oceanography
Evaluating Seasonal Nutrient Fluxes In Emerging And Eroding Wetlands Of The Louisiana Delta Plain, Kiran Upreti
Evaluating Seasonal Nutrient Fluxes In Emerging And Eroding Wetlands Of The Louisiana Delta Plain, Kiran Upreti
LSU Doctoral Dissertations
Deltaic wetlands can ameliorate high NO3- loads via denitrification, a dominant NO3- reduction pathway in inland and coastal habitats. Dissimilatory Nitrate Reduction to Ammonia (DNRA), in contrast to denitrification, conserves N within the system and has been found to be favored over denitrification with increase in salinity and temperature. There are no studies in the Louisiana Deltaic plain with simultaneous estimation of denitrification and DNRA. Increased P availability has been shown to increase denitrification so it is essential to understand P biogeochemistry when studying N cycle. Here, we evaluated net denitrification using N2:Ar and …
Ecological Response Of Phytoplankton To The Oil Spills In The Oceans, Danling Tang, Jing Sun, Li Zhou, Sufen Wang, Ramesh P. Singh, Gang Pan
Ecological Response Of Phytoplankton To The Oil Spills In The Oceans, Danling Tang, Jing Sun, Li Zhou, Sufen Wang, Ramesh P. Singh, Gang Pan
Mathematics, Physics, and Computer Science Faculty Articles and Research
Oil spills in oceans have substantial influence on marine ecosystems. This study investigates 21 oil spills in the world. Analyzing Chlorophyll-a (Chl-a) from Moderate Resolution Imaging Spectroradiomerer (MODIS) data after Penglai oil spills on 4 June 2011, found a bloom with peak value of Chl-a (13.66 mg m−3) spread over an area of 800 km2 during 18–25 June 2011, and a pronounced increase in the monthly Chl-a concentration (6.40 mg m−3) on June 2012 in the Bohai Sea. Out of the 21 oil spills, 14 blooms were observed, while 11 …
In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann
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 …
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
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. …
Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Terrebonne And Timbalier Bays, Louisiana, Mary Allison Manning
Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Terrebonne And Timbalier Bays, Louisiana, Mary Allison Manning
LSU Master's Theses
I coupled fine-scale environmental data with observed behavior and group composition data to examine overall distribution within the bay system and to characterize the habitat associated with foraging and the presence of calves. Semi-isolated populations of bottlenose dolphins (Tursiops truncatus) along Louisiana’s coast are undergoing increased risks from boat traffic, oil spills, land subsidence, and planned water diversions (CPRA 2017). Characterizing the habitat use of bottlenose dolphins in Terrebonne and Timbalier bays, Louisiana, is important given the likely high site fidelity, small home ranges, and low exchange of individuals with nearby coastal populations (Lane et al. 2015, McDonald …
Iron Fertilization With Enhanced Phytoplankton Productivity Under Minimal Sulfur Compounds And Grazing Control Analysis In Hnlc Region, Tai-Jin Kim, G. H. Hong, D. G. Kim Kim, Mark Baskaran
Iron Fertilization With Enhanced Phytoplankton Productivity Under Minimal Sulfur Compounds And Grazing Control Analysis In Hnlc Region, Tai-Jin Kim, G. H. Hong, D. G. Kim Kim, Mark Baskaran
Environmental Science and Geology Faculty Research Publications
The present study investigated quantitatively the significance of HNLC (high-nutrient low-chlorophyll) regions and its grazing control with the im- proved iron fertilization for climate change. The limitation of iron (Fe) for phytoplankton growth in HNLC regions was confirmed by sulfur compounds (S) such as volcanic ash and hydrogen sulfide (H2S) in batch cultures, whose chemical sediment of Fe3S4 showed 4.06 wt%. The technologies developed for iron fertilization since 1993 till now were not practical to provide sufficient amounts of bioavailable iron due to sedimentary iron sulfides induced by undersea volcanic sulfur compounds. The proposed technology for iron fertilization was improved …
North Atlantic Observed Climatological Mean Absolute Geostrophic Velocity Profiles, Tiago Carrilho Biló
North Atlantic Observed Climatological Mean Absolute Geostrophic Velocity Profiles, Tiago Carrilho Biló
Supplementary Data and Tools
North Atlantic observed climatological mean absolute geostrophic velocity components in meters per second from near the surface (pressure = 2.5 dbar) to near ocean bottom (pressure = 5562.0 dbar). The absolute velocity fields in the upper 2000 dbar of the water column were obtained by referencing an ARGO based mean geostrophic shear with mean velocity estimates at 1000 dbar between 2004-2016. The shear was derived using the so-called Roemmich-Gilson Argo climatology (Roemmich & Gilson, 2009). The referencing procedure was conducted using Argo displacement data referred to as YoMaHa'07 (Lebedev et al., 2007). For regions deeper than 2000 dbar, the velocity …
Temporal And Spatial Scaling Of Dissipation Under Non-Breaking Surface Waves, Mingming Shao, Brian K. Haus, Darek Bogucki, Mohammad Barzegar
Temporal And Spatial Scaling Of Dissipation Under Non-Breaking Surface Waves, Mingming Shao, Brian K. Haus, Darek Bogucki, Mohammad Barzegar
Supplementary Data and Tools
This dataset is associated to the NSF OCE/Physical Oceanography funded project “Laboratory Investigation of Turbulence Generation by Surface Waves”. There are three papers in preparation that will refer to data contained within this archive. The overarching goal of this project was to address a significant knowledge gap regarding the turbulent dissipation of non-breaking surface waves. To accomplish this, a comprehensive study in the SUrge-STructure-Atmosphere-INteraction (SUSTAIN) wind-wave laboratory at the University of Miami was conducted. A combination of established measurement approaches (Particle Image Velocimetry (PIV) and Vertical Microstructure Profiler (VMP)) and new technologies (Optical Turbulence Sensor (OTS)) have been used carry …
Spray Concentration Measurements From Asist For Freshwater And Seawater, Sanchit Mehta, David G. Ortiz-Suslow, Andrew W. Smith, Brian K. Haus
Spray Concentration Measurements From Asist For Freshwater And Seawater, Sanchit Mehta, David G. Ortiz-Suslow, Andrew W. Smith, Brian K. Haus
Supplementary Data and Tools
The size-dependent vertical distribution of spume particles in high wind conditions is necessary to understand their effect on air-sea fluxes of heat and momentum. The predominant focus of previous studies of spray dynamics has been on the marine environment. Spray dynamics in non-seawater bodies have not been extensively studied, and any significant differences between sea and freshwater remain unquantified. To address this gap, we have conducted the first laboratory experiment directly comparing spume concentrations above fresh and real seawater for 10-m equivalent wind speeds of 36-54 m/s. Droplets in the air above the intensely breaking wind-waves were directly observed and …
Assessing The Skill Of The Improved Treatment Of Riverine Freshwater In The Community Earth System Model Relative To A New Salinity Climatology, Qiang Sun, Michael M. Whitney, Frank O. Bryan, Yu-Heng Tseng
Assessing The Skill Of The Improved Treatment Of Riverine Freshwater In The Community Earth System Model Relative To A New Salinity Climatology, Qiang Sun, Michael M. Whitney, Frank O. Bryan, Yu-Heng Tseng
Department of Marine Sciences
Recent studies have explored the sensitivity of global ocean model simulations to the treatment of riverine freshwater and the representation of estuarine processes via an estuary box model (EBM) applied within CESM. This study builds on these efforts by assessing the model skill score relative to a new salinity climatology. The new climatology averages the original observational data of the World Ocean Database directly onto the CESM ocean-component tracer-grid cells without spatial interpolation, smoothing, or other gap-filling techniques to mitigate coastal ocean salinity bias present in the World Ocean Atlas. The mean squared error (MSE) for coastal upper ocean salinity …
Variation In Righting Times Of Holothuria Atra, Stichopus Chloronotus, And Holothuria Edulis In Response To Increased Seawater Temperatures On Heron Reef In The Southern Gbr, Elizabeth Buccheri, Matthias W. Foellmer, Beth A. Christensen, Paul Langi, Stefani Ritter, Esther Wolf, Aaren S. Freeman
Variation In Righting Times Of Holothuria Atra, Stichopus Chloronotus, And Holothuria Edulis In Response To Increased Seawater Temperatures On Heron Reef In The Southern Gbr, Elizabeth Buccheri, Matthias W. Foellmer, Beth A. Christensen, Paul Langi, Stefani Ritter, Esther Wolf, Aaren S. Freeman
School of Earth & Environment Departmental Research
Sea cucumbers can mitigate some impacts of climate change through digestion of benthic sands and production of calcium carbonate. The projected ecological benefits of sea cucumbers in warmer, more acidic oceans are contingent on the capacities of individuals to acclimate and populations to adapt to climatic changes. The goal of this experiment was to evaluate the degree to which warming waters would impact three abundant species of sea cucumbers on the Heron Reef in Queensland, Australia. We conducted a behavioral assay using three species of sea cucumbers, Holothuria atra, Stichopus chloronotus, and Holothuria edulis. Individuals from each species were subjected …
Effects Of Shoal Margin Collapses On The Morphodynamics Of A Sandy Estuary, M. R. Hiatt
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 …
Characterizing Freshwater Phytoplankton Dynamics With Electro-Optical Remote Sensing, Michael Sayers
Characterizing Freshwater Phytoplankton Dynamics With Electro-Optical Remote Sensing, Michael Sayers
Dissertations, Master's Theses and Master's Reports
Freshwater lakes are an important component contributing to ecosystem health and biodiversity on local, regional, and global scales. And while lakes only represent <5% of the global surface area, they are often very productive systems which contribute significantly to carbon cycling dynamics and freshwater fish production on a number of spatial scales. Due to the remote location and sheer size of some of these lakes it has proven difficult to adequately document changes in water quality. Significant challenges exist to adequately monitor water quality, and in particular phytoplankton dynamics, over large spatial and temporal scales using traditional in situ methods. Satellite electro-optical remote sensing offers a potential tool to provide better characterization of phytoplankton dynamics for a variety of freshwater systems. This work resulted in an approach to quantify global summer phytoplankton abundance using a newly developed remote sensing derived chlorophyll-a product. This product was also used in conjunction with a newly created carbon fixation model to assess global freshwater phytoplankton production which provided new insights into the role freshwater systems play in the …
Observations And Scaling Of Tidal Mass Transport Across The Lower Ganges-Brahmaputra Delta Plain: Implications For Delta Management And Sustainability, Richard Hale, Rachel Bain, Steven Goodbred Jr., Jim Best
Observations And Scaling Of Tidal Mass Transport Across The Lower Ganges-Brahmaputra Delta Plain: Implications For Delta Management And Sustainability, Richard Hale, Rachel Bain, Steven Goodbred Jr., Jim Best
OES Faculty Publications
The landscape of southwest Bangladesh, a region constructed primarily by fluvial processes associated with the Ganges River and Brahmaputra River, is now maintained almost exclusively by tidal processes as the fluvial system has migrated east and eliminated the most direct fluvial input. In natural areas such as the Sundarbans National Forest, year-round inundation during spring high tides delivers sufficient sediment that enables vertical accretion to keep pace with relative sea-level rise. However, recent human modification of the landscape in the form of embankment construction has terminated this pathway of sediment delivery for much of the region, resulting in a startling …
Internal Waves Influence The Thermal And Nutrient Environment On A Shallow Coral Reef, Emma C. Reid, Thomas M. Decarlo, Anne L. Cohen, George T.F. Wong, Steven J. Lentz, Aryan Safaie, Austin Hall, Kristen A. Davis
Internal Waves Influence The Thermal And Nutrient Environment On A Shallow Coral Reef, Emma C. Reid, Thomas M. Decarlo, Anne L. Cohen, George T.F. Wong, Steven J. Lentz, Aryan Safaie, Austin Hall, Kristen A. Davis
OES Faculty Publications
Internal waves can influence water properties in coastal ecosystems through the shoreward transport and mixing of subthermocline water into the nearshore region. In June 2014, a field experiment was conducted at Dongsha Atoll in the northern South China Sea to study the impact of internal waves on a coral reef. Instrumentation included a distributed temperature sensing system, which resolved spatially and temporally continuous temperature measurements over a 4‐km cross‐reef section from the lagoon to 50‐m depth on the fore reef. Our observations show that during summer, internal waves shoaling on the shallow atoll regularly transport cold, nutrient‐rich water shoreward, altering …
Flow Reorganization In An Anthropogenically Modified Tidal Channel Network: An Example From The Southwestern Ganges-Brahmaputra-Meghna Delta, R. L. Bain, Rip P. Hale, S. L. Goodbred
Flow Reorganization In An Anthropogenically Modified Tidal Channel Network: An Example From The Southwestern Ganges-Brahmaputra-Meghna Delta, R. L. Bain, Rip P. Hale, S. L. Goodbred
OES Faculty Publications
We examine variations in discharge exchange between two parallel, 1‐ to 2‐km‐wide tidal channels (the Shibsa and the Pussur) in southwestern Bangladesh over spring‐neap, and historical timescales. Our objective is to evaluate how large‐scale, interconnected tidal channel networks respond to anthropogenic perturbation. The study area spans the boundary between the pristine Sundarbans Reserved Forest, where regular inundation of the intertidal platform maintains the fluvially abandoned delta plain, and the anthropogenically modified region to the north, where earthen embankments sequester large areas of formerly intertidal landscape. Estimates of tidal response to the embankment‐driven reduction in basin volume, and hence tidal prism, …
Dinitrogen Fixation Across Physico-Chemical Gradients Of The Eastern Tropical North Pacific Oxygen Deficient Zone, C. R. Selden, M. R. Mulholland, P.W. Bernhardt, B. Widner, A. Macías-Tapia, Q. Ji, A. Jayakumar
Dinitrogen Fixation Across Physico-Chemical Gradients Of The Eastern Tropical North Pacific Oxygen Deficient Zone, C. R. Selden, M. R. Mulholland, P.W. Bernhardt, B. Widner, A. Macías-Tapia, Q. Ji, A. Jayakumar
OES Faculty Publications
The Eastern Tropical North Pacific Ocean hosts one of the world's largest oceanic oxygen deficient zones (ODZs). Hot spots for reactive nitrogen (Nr) removal processes, ODZs generate conditions proposed to promote Nr inputs via dinitrogen (N2) fixation. In this study, we quantified N2 fixation rates by 15N tracer bioassay across oxygen, nutrient, and light gradients within and adjacent to the ODZ. Within subeuphotic oxygen‐deplete waters, N2 fixation was largely undetectable; however, addition of dissolved organic carbon stimulated N2 fixation in suboxic (μmol/kg O2) waters, suggesting that diazotroph communities are …
Global Perspectives On Observing Ocean Boundary Current Systems, Robert E. Todd, Francisco P. Chavez, Sophie Clayton, Sophie Cravatte, Marlos Goes, Michelle Graco, Xiaopei Lin, Janet Sprintall, Nathalie V. Zilberman, Matthew Archer, Javier Arístegui, Magdalena Balmaseda, John M. Bane, Molly O. Baringer, John A. Barth, Lisa M. Beal, Peter Brandt, Paulo H.R. Calil, Edmo Campos, Luca R. Centurioni, Maria Paz Chidichimo, Mauro Cirano, Meghan F. Cronin, Enrique N. Curchitser, Russ E. Davis, Marcus Dengler, Brad Deyoung, Shenfu Dong, Ruben Escribano, Andrea J. Fassbender, Sarah E. Fawcett, Ming Feng, Gustavo J. Goni, Alison R. Gray, Dimitri Gutiérrez, Dave Hebert, Rebecca Hummels, Shin-Ichi Ito, Marjorlaine Krug, François Lacan, Lucas Laurindo, Alban Lazar, Craig M. Lee, Matthieu Lengaigne, Naomi M. Levine, John Middleton, Ivonne Montes, Mike Muglia, Takeyoshi Nagai, Hilary I. Palevsky, Jaine B. Palter, Helen E. Phillips, Alberto Piola, Albert J. Plueddemann, Bo Qiu, Regina R. Rodrigues, Moninya Roughan, Daniel L. Rudnick, Ryan R. Rykaczewski, Martin Saraceno, Harvey Seim, Alex Sen Gupta, Lynne Shannon, Bernadette M. Sloyan, Adrienne J. Sutton, Luanne Thompson, Anja K. Van Der Plas, Denis Volkov, John Wilkin, Dongxiao Zhang, Linlin Zhang
Global Perspectives On Observing Ocean Boundary Current Systems, Robert E. Todd, Francisco P. Chavez, Sophie Clayton, Sophie Cravatte, Marlos Goes, Michelle Graco, Xiaopei Lin, Janet Sprintall, Nathalie V. Zilberman, Matthew Archer, Javier Arístegui, Magdalena Balmaseda, John M. Bane, Molly O. Baringer, John A. Barth, Lisa M. Beal, Peter Brandt, Paulo H.R. Calil, Edmo Campos, Luca R. Centurioni, Maria Paz Chidichimo, Mauro Cirano, Meghan F. Cronin, Enrique N. Curchitser, Russ E. Davis, Marcus Dengler, Brad Deyoung, Shenfu Dong, Ruben Escribano, Andrea J. Fassbender, Sarah E. Fawcett, Ming Feng, Gustavo J. Goni, Alison R. Gray, Dimitri Gutiérrez, Dave Hebert, Rebecca Hummels, Shin-Ichi Ito, Marjorlaine Krug, François Lacan, Lucas Laurindo, Alban Lazar, Craig M. Lee, Matthieu Lengaigne, Naomi M. Levine, John Middleton, Ivonne Montes, Mike Muglia, Takeyoshi Nagai, Hilary I. Palevsky, Jaine B. Palter, Helen E. Phillips, Alberto Piola, Albert J. Plueddemann, Bo Qiu, Regina R. Rodrigues, Moninya Roughan, Daniel L. Rudnick, Ryan R. Rykaczewski, Martin Saraceno, Harvey Seim, Alex Sen Gupta, Lynne Shannon, Bernadette M. Sloyan, Adrienne J. Sutton, Luanne Thompson, Anja K. Van Der Plas, Denis Volkov, John Wilkin, Dongxiao Zhang, Linlin Zhang
OES Faculty Publications
Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. Next steps in the development of boundary current observing systems are considered, leading to …
Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman
Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman
OES Faculty Publications
Gas ebullition from aquatic systems to the atmosphere represents a potentially important fraction of primary production that goes unquantified by measurements of dissolved gas concentrations. Although gas ebullition from photosynthetic surfaces has often been observed, it is rarely quantified. The resulting underestimation of photosynthetic activity may significantly bias the determination of ecosystem trophic status and estimated rates of biogeochemical cycling from in situ measures of dissolved oxygen. Here, we quantified gas ebullition rates in Zostera marina meadows in Virginia, U.S.A. using simple funnel traps and analyzed the oxygen concentration and isotopic composition of the captured gas. Maximum hourly rates of …
Metagenomic Sequencing Identifies Highly Diverse Assemblages Of Dinoflagellate Cysts In Sediments From Ships' Ballast Tanks, Lixia Shang, Zhangxi Hu, Yunyan Deng, Yuyang Liu, Xinyu Zhai, Zhaoyang Chai, Xiaohan Liu, Zifeng Zhan, Fred C. Dobbs, Ying Zhong Tang
Metagenomic Sequencing Identifies Highly Diverse Assemblages Of Dinoflagellate Cysts In Sediments From Ships' Ballast Tanks, Lixia Shang, Zhangxi Hu, Yunyan Deng, Yuyang Liu, Xinyu Zhai, Zhaoyang Chai, Xiaohan Liu, Zifeng Zhan, Fred C. Dobbs, Ying Zhong Tang
OES Faculty Publications
Ships' ballast tanks have long been known as vectors for the introduction of organisms. We applied next-generation sequencing to detect dinoflagellates (mainly as cysts) in 32 ballast tank sediments collected during 2001-2003 from ships entering the Great Lakes or Chesapeake Bay and subsequently archived. Seventy-three dinoflagellates were fully identified to species level by this metagenomic approach and single-cell polymerase chain reaction (PCR)-based sequencing, including 19 toxic species, 36 harmful algal bloom (HAB) forming species, 22 previously unreported as producing cysts, and 55 reported from ballast tank sediments for the first time (including 13 freshwater species), plus 545 operational taxonomic units …
Spatial Structuring And Life History Connectivity Of Antarctic Silverfish Along The Southern Continental Shelf Of The Weddell Sea, Jilda Alicia Caccavo, Julian R. Ashford, Svenja Ryan, Chiara Papetti, Michael Schröder, Lorenzo Zane
Spatial Structuring And Life History Connectivity Of Antarctic Silverfish Along The Southern Continental Shelf Of The Weddell Sea, Jilda Alicia Caccavo, Julian R. Ashford, Svenja Ryan, Chiara Papetti, Michael Schröder, Lorenzo Zane
OES Faculty Publications
A multi-disciplinary approach was employed to examine a physical-biological population hypothesis for a critical forage species, the Antarctic silverfish Pleuragramma antarctica. Caccavo et al. (2018; Sci Rep 8:17856) had shown strong gene flow along the westward Antarctic Slope Current, in addition to spatially recurring length modes that provided evidence for episodic connectivity. In this paper, otolith nucleus chemistry from a subset of fish collected in the southern Weddell Sea as part of a hydrographic survey of the Filchner Trough system was used to test between connectivity scenarios. Nucleus chemistry, which reflects environmental exposure during early life, showed significant …
A Full-Ocean-Depth Rated Modular Lander And Pressure-Retaining Sampler Capable Of Collecting Hadal-Endemic Microbes Under In Situ Conditions, Logan M. Peoples, Matthew Norenberg, David Price, Madeline Mcgoldrick, Mark Novotny, Alexander Bochdansky, Douglas H. Bartlett
A Full-Ocean-Depth Rated Modular Lander And Pressure-Retaining Sampler Capable Of Collecting Hadal-Endemic Microbes Under In Situ Conditions, Logan M. Peoples, Matthew Norenberg, David Price, Madeline Mcgoldrick, Mark Novotny, Alexander Bochdansky, Douglas H. Bartlett
OES Faculty Publications
The hadal zone remains one of the least studied environments because of its inaccessibility, in part because of hydrostatic pressures extending to 110 MPa. Few instruments are capable of sampling from such great depths. We have developed a full-ocean-depth-capable lander that can be fit with sampling packages for the collection of still images, video, motile megafauna, and hadal seawater. One payload includes a pressure-retaining sampler (PRS) able to maintain seawater samples under in situ pressure during recovery. We describe the technical specifications of the lander and the PRS and preliminary results from three deployments at depths in excess of 10,700 …
High Rates Of N² Fixation In Temperate, Western North Atlantic Coastal Waters Expands The Realm Of Marine Diazotrophy, Margaret R. Mulholland, P. W. Bernhardt, Brittany Widner, C. R. Selden, P. D. Chappell, S. Clayton, A. Mannino, K. Hyde
High Rates Of N² Fixation In Temperate, Western North Atlantic Coastal Waters Expands The Realm Of Marine Diazotrophy, Margaret R. Mulholland, P. W. Bernhardt, Brittany Widner, C. R. Selden, P. D. Chappell, S. Clayton, A. Mannino, K. Hyde
OES Faculty Publications
Dinitrogen (N2) fixation can alleviate N limitation of primary productivity by introducing fixed nitrogen (N) to the world's oceans. Although measurements of pelagic marine N2 fixation are predominantly from oligotrophic oceanic regions, where N limitation is thought to favor growth of diazotrophic microbes, here we report high rates of N2 fixation from seven cruises spanning four seasons in temperate, western North Atlantic coastal waters along the North American continental shelf between Cape Hatteras and Nova Scotia, an area representing 6.4% of the North Atlantic continental shelf area. Integrating average areal rates of N2 fixation during …
An Introduction To The 'Oceans And Society: Blue Planet' Initiative, Emily A. Smail, Paul M. Digiacomo, Sophie Seeyave, Samy Djavidnia, Louis Celliers, Pierre-Yves Le Traon, Jeremy Gault, Elva Escobar-Briones, Hans-Peter Plag, Christine Pequignet, Lenore Bajona, Li Zhang, Jay Pearlman, Andy Steven, Jonathan Hodge, Marie-Fanny Racault, Curt Storlazzi, William Skirving, Ron Hoeke, John Marra, Ap Van Dongeren, Frank Muller-Karger, Douglas Cripe, Daniel Takaki
An Introduction To The 'Oceans And Society: Blue Planet' Initiative, Emily A. Smail, Paul M. Digiacomo, Sophie Seeyave, Samy Djavidnia, Louis Celliers, Pierre-Yves Le Traon, Jeremy Gault, Elva Escobar-Briones, Hans-Peter Plag, Christine Pequignet, Lenore Bajona, Li Zhang, Jay Pearlman, Andy Steven, Jonathan Hodge, Marie-Fanny Racault, Curt Storlazzi, William Skirving, Ron Hoeke, John Marra, Ap Van Dongeren, Frank Muller-Karger, Douglas Cripe, Daniel Takaki
OES Faculty Publications
We live on a blue planet, and Earth’s waters benefit many sectors of society. The future of our blue planet is increasingly reliant on the services delivered by marine, coastal and inland waters and on the advancement of effective, evidence-based decisions on sustainable development. ‘Oceans and Society: Blue Planet’ is an initiative of the Group on Earth Observations (GEO) that aims to ensure the sustained development and use of ocean and coastal observations for the benefit of society. The initiative works to advance and exploit synergies among the many observational programmes devoted to ocean and coastal waters; to improve engagement …
The Dominant Global Modes Of Recent Internal Sea Level Variability, Benjamin Dillon Hamlington, Se-Hyeon Cheon, Christopher G. Piecuch, Kristopher B. Karnauskas, Philip R. Thompson, Kwang-Yul Kim, John Thomas Reager, Felix W. Landerer, Thomas Frederikse
The Dominant Global Modes Of Recent Internal Sea Level Variability, Benjamin Dillon Hamlington, Se-Hyeon Cheon, Christopher G. Piecuch, Kristopher B. Karnauskas, Philip R. Thompson, Kwang-Yul Kim, John Thomas Reager, Felix W. Landerer, Thomas Frederikse
OES Faculty Publications
The advances in the modern sea level observing system have allowed for a new level of knowledge of regional and global sea level in recent years. The combination of data from satellite altimeters, Gravity Recovery and Climate Experiment (GRACE) satellites, and Argo profiling floats has provided a clearer picture of the different contributors to sea level change, leading to an improved understanding of how sea level has changed in the present and, by extension, may change in the future. As the overlap between these records has recently extended past a decade in length, it is worth examining the extent to …
Recommended Priorities For Research On Ecological Impacts Of Ocean And Coastal Acidification In The U.S. Mid-Atlantic, Grace K. Saba, Kaitlin A. Goldsmith, Sarah R. Cooley, Daniel Grosse, Shannon L. Meseck, A. Whitman Miller, Beth Phelan, Matthew Poach, Robert Rheault, Kari St. Laurent, Jeremy M. Testa, Judith S. Weis, Richard Zimmerman
Recommended Priorities For Research On Ecological Impacts Of Ocean And Coastal Acidification In The U.S. Mid-Atlantic, Grace K. Saba, Kaitlin A. Goldsmith, Sarah R. Cooley, Daniel Grosse, Shannon L. Meseck, A. Whitman Miller, Beth Phelan, Matthew Poach, Robert Rheault, Kari St. Laurent, Jeremy M. Testa, Judith S. Weis, Richard Zimmerman
OES Faculty Publications
The estuaries and continental shelf system of the United States Mid-Atlantic are subject to ocean acidification driven by atmospheric CO2, and coastal acidification caused by nearshore and land-sea interactions that include biological, chemical, and physical processes. These processes include freshwater and nutrient input from rivers and groundwater; tidally-driven outwelling of nutrients, inorganic carbon, alkalinity; high productivity and respiration; and hypoxia. Hence, these complex dynamic systems exhibit substantial daily, seasonal, and interannual variability that is not well captured by current acidification research on Mid-Atlantic organisms and ecosystems. We present recommendations for research priorities that target better understanding of the …
Metaproteomics Reveal That Rapid Perturbations In Organic Matter Prioritize Functional Restructuring Over Taxonomy In Western Arctic Ocean Microbiomes, Molly P. Mikan, H. Rodger Harvey, Emma Timmins-Schiffman, Michael Riffle, Damon H. May, Ian Salter, William S. Noble, Brook L. Nunn
Metaproteomics Reveal That Rapid Perturbations In Organic Matter Prioritize Functional Restructuring Over Taxonomy In Western Arctic Ocean Microbiomes, Molly P. Mikan, H. Rodger Harvey, Emma Timmins-Schiffman, Michael Riffle, Damon H. May, Ian Salter, William S. Noble, Brook L. Nunn
OES Faculty Publications
We examined metaproteome profiles from two Arctic microbiomes during 10-day shipboard incubations to directly track early functional and taxonomic responses to a simulated algal bloom and an oligotrophic control. Using a novel peptide-based enrichment analysis, significant changes (p-value < 0.01) in biological and molecular functions associated with carbon and nitrogen recycling were observed. Within the first day under both organic matter conditions, Bering Strait surface microbiomes increased protein synthesis, carbohydrate degradation, and cellular redox processes while decreasing C1 metabolism. Taxonomic assignments revealed that the core microbiome collectively responded to algal substrates by assimilating carbon before select taxa utilize and metabolize nitrogen intracellularly. Incubations of Chukchi Sea bottom water microbiomes showed similar, but delayed functional responses to identical treatments. Although 24 functional terms were shared between experimental treatments, the timing, and degree of the remaining responses were highly variable, showing that organic matter perturbation directs community functionality prior to alterations to the taxonomic distribution at the microbiome class level. The dynamic responses of these two oceanic microbial communities have important implications for timing and magnitude of responses to organic perturbations within the Arctic Ocean and how community-level functions may forecast biogeochemical gradients in oceans.
Nitrogen Assimilation In Picocyanobacteria Inhabiting The Oxygen-Deficient Waters Of The Eastern Tropical North And South Pacific, Montserrat Aldunate, Carlos Henriquez-Castillo, Qixing Ji, Jessica Lueders-Dumont, Margaret R. Mulholland, Bess B. Ward, Peter Von Dassow, Osvaldo Ulloa
Nitrogen Assimilation In Picocyanobacteria Inhabiting The Oxygen-Deficient Waters Of The Eastern Tropical North And South Pacific, Montserrat Aldunate, Carlos Henriquez-Castillo, Qixing Ji, Jessica Lueders-Dumont, Margaret R. Mulholland, Bess B. Ward, Peter Von Dassow, Osvaldo Ulloa
OES Faculty Publications
Prochlorococcus and Synechococcus are the most abundant free-living photosynthetic microorganisms in the ocean. Uncultivated lineages of these picocyanobacteria also thrive in the dimly illuminated upper part of oxygen-deficient zones (ODZs), where an important portion of ocean nitrogen (N) loss takes place via denitrification and anaerobic ammonium oxidation. Recent metagenomic studies revealed that ODZ Prochlorococcus have the genetic potential for using different N forms, including nitrate and nitrite, uncommon N sources for Prochlorococcus, but common for Synechococcus. To determine which N sources ODZ picocyanobacteria are actually using in nature, the cellular 15N natural abundance (δ15N) and assimilation rates of …
Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon
Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon
OES Faculty Publications
The observation system has been developed to investigate the rip currents at Haeundae beach using Xband marine radar. X-band radar system can observe shape, size, and velocity of rip currents, which is difficult to obtain through field observation by conventional device. Algorithms which automatically detect locations, shapes, and magnitudes of rip currents were developed using time averaged X-band radar sea clutter images. X-band sea clutter images are transformed through 3D FFT into 2D wave number spectrum and frequency spectrum. Rip current velocities were estimated using differences in wave-number spectra and wave frequency spectra due to Doppler shift. The algorithm was …
Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen
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 …