Oceanography Commons^™

Cruise Data For Neuston Net And Paired Bongo Net Tows From 47 Stations In The Northern Gulf Of Mexico From R/V Pelican Cruise Lf2017a July 2017, Jay R. Rooker, R.J. David Wells

DEEPEND Datasets

Shelf and slope waters in the Deep Water Horizon oil spill (DWHOS) area are known to serve as critical spawning, nursery, and foraging habitat of several important oceanic species including billfishes (e.g. blue marlin, white marlin, sailfish), tunas (bluefin tuna, yellowfin tuna), and other pelagic taxa (swordfish, dolphinfishes). The aim of this component was to further investigate potential ecological effects of the DWHOS on pelagic fishes during the early life period. Larval fishes were sampled from 48 stations in the northern Gulf of Mexico and cruise data was collected at each site including latitude/longitude, date, time and environmental data (sea …

Selenium Distribution And Cycling In The Eastern Equatorial Pacific Ocean, Zoe Wambaugh

OES Theses and Dissertations

Oxygen minimum zones in oceanic waters have become increasingly important to the marine environment and society. Low oxygen waters affect not only the distribution and abundance of marine organisms, but also impact the solubility and transport of trace elements that are of biological importance, with the chemical speciation and solubility depending on the actual redox poise of the waters. One redox sensitive trace element of interest is selenium, which can be both toxic and essential for organisms, depending on its chemical speciation. In 2013, the US GEOTRACES program completed the GP16 transect from Peru to Tahiti, going through the oxygen …

Distributions Of Polychaetes As A Function Of Sediment Composition In A Subtropical Lagoon, Anthony William Cox

Theses and Dissertations

Fine-grained organic-rich sediments (FGORS) in the Indian River Lagoon (IRL), Florida, the human activities and nutrient inputs and have a varied composition, including water content, silt-clay content, and organic matter. When these constituents reach, by weight, 75%, 60% dry, and 10% dry, respectively, this is sometimes referred to as IRL “muck”. Many polychaetes inhabit the benthic sediments of estuaries and must tolerate various degrees of FGORS. The Cox IRL Muck Index (CMI) is proposed as a mechanism for determining the organic sediment tolerances of infaunal species in a simple and direct manner. IRL muck will have a minimum CMI of …

Counting Crabs: Assessment Of Mangrove Crab Diversity And Density Among Three Sites In Ushongo, Tanzania, Clarasophia Gust

Independent Study Project (ISP) Collection

This study assessed the density and diversity of crabs across three mangrove forest zones in Ushongo, Tanzania. The aim was to understand variance in the composition and distribution of mangrove crabs in relation to mangrove tree composition gradients in the area. Sites were measured using a 200m line transect and 40-plot method. Data was also collected from a sand beach habitat to compare to the diversity and distribution of mangrove habitats. Diversity was analyzed using Simpson’s Index of Diversity and an ANOVA test on the average number of species found per plot in each site. Density was analyzed using an …

Bacteria Mitigation In Sponge Mariculture, Jambiani Zanzibar, Claire Johnston

Independent Study Project (ISP) Collection

The declining seaweed industry coupled with efforts by the NGO Marine Cultures have led to the establishment of sponge mariculture in Jambiani, Zanzibar. However, growing cyanobacteria levels have substantially increased sponge mortality rates. In order to determine successful cyanobacteria mitigation treatments, six populations of farm ropes, support lines, and sponges were (a) untreated, (b) manually cleaned or submerged in solutions of (c) 2% hydrogen peroxide, (d) 4% hydrogen peroxide, (e) 50 g/L salt, or (f) 70 g/L salt. No conclusions were drawn from rope treatments, no techniques were effective for support line treatments, and both concentrations of hydrogen peroxide were …

Asean And The South China Sea: Approaches To Resolving The Conflict, Jennifer Jie Li

Independent Study Project (ISP) Collection

In recent years, tensions have escalated between actors in the South China Sea, one of which is the Association for Southeast Asian Nations (ASEAN), the region’s primary intergovernmental organization. The purpose of this report is to determine the effectiveness of ASEAN in resolving the South China Sea disputes and to clarify how geopolitical factors have impacted the organization’s actions. Through an analysis of evolving maritime claims and the current state of affairs, this paper suggests that ASEAN must be involved in any attempt to resolve the conflict peacefully. Acknowledging the importance of the diplomatic channels that ASEAN has created to …

Light Rare Earth Element Depletion During Deepwater Horizon Blowout Methanotrophy, Alan M. Shiller, Eric W. Chan, D.J. Joung, Molly Redmond, John D. Kessler

Faculty Publications

Rare earth elements have generally not been thought to have a biological role. However, recent work has demonstrated that the light REEs (LREEs: La, Ce, Pr, and Nd) are essential for at least some methanotrophs, being co-factors in the XoxF type of methanol dehydrogenase (MDH). We show here that dissolved LREEs were significantly removed in a submerged plume of methane-rich water during the Deepwater Horizon (DWH) well blowout. Furthermore, incubation experiments conducted with naturally methane-enriched waters from hydrocarbon seeps in the vicinity of the DWH wellhead also showed LREE removal concurrent with methane consumption. Metagenomic sequencing of incubation …

A Synergistic Approach For Evaluating Climate Model Output For Ecological Applications, Rachel D. Cavanagh, Eugene J. Murphy, Thomas J. Bracegirdle, John Turner, Cheryl A. Knowland, Stuart P. Corney, Walker O. Smith Jr., Claire M. Waluda, Nadine M. Johnston, Richard G. J. Bellerby, Eileen E. Hofmann

CCPO Publications

Increasing concern about the impacts of climate change on ecosystems is prompting ecologists and ecosystem managers to seek reliable projections of physical drivers of change. The use of global climate models in ecology is growing, although drawing ecologically meaningful conclusions can be problematic. The expertise required to access and interpret output from climate and earth system models is hampering progress in utilizing them most effectively to determine the wider implications of climate change. To address this issue, we present a joint approach between climate scientists and ecologists that explores key challenges and opportunities for progress. As an exemplar, our focus …

Vertical And Cross-Shore Distributions Of Barnacle Larvae In La Jolla, Ca Nearshore Waters: Implications For Larval Transport Processes, Malloree Lynn Hagerty

Theses

Many marine organisms begin their lives as tiny larvae that are at the mercy of ocean currents. Understanding the transport and subsequent dispersal of larvae is crucial, as it drives population connectivity in the ocean. Larval transport is a complex process involving both physical motions of the water and larval behavior. Vertical positioning is especially important because currents vary throughout the water column, and larvae at different depths will be advected differently. With swimming speeds insufficient to swim against currents, marine larvae can mediate cross-shore transport by controlling their depth distributions. Thus, the overall objective of this study was to …

A Recent Project Shows That The Microbial Carbon Pump Is A Primary Mechanism Driving Ocean Carbon Uptake, Jing M. Chen, Louis Legendre, Ronald Benner

Faculty Publications

No abstract provided.

A Lab-On-Chip Phosphate Analyzer For Long-Term In Situ Monitoring At Fixed Observatories: Optimization And Performance Evaluation In Estuarine And Oligotrophic Coastal Waters, Maxime Grand, Geraldine Clinton-Bailey, Alexander Beaton, Allison Schaap, Thomas Johengen, Mario Tamburri, Douglas Connelly, Matthew Mowlem, Eric Achterberg

Faculty Publications

The development of phosphate sensors suitable for long-term in situdeployments in natural waters, is essential to improve our understanding of the distribution, fluxes, and biogeochemical role of this key nutrient in a changing ocean. Here, we describe the optimization of the molybdenum blue method for in situ work using a lab-on-chip (LOC) analyzer and evaluate its performance in the laboratory and at two contrasting field sites. The in situ performance of the LOC sensor is evaluated using hourly time-series data from a 56-day trial in Southampton Water (UK), as well as a month-long deployment in the subtropical oligotrophic waters of …

Environmentally-Driven Variation In The Population Dynamics Of Gulf Menhaden (Brevoortia Patronus), Grant D. Adams

Master's Theses

Gulf Menhaden (Brevoortia patronus) is an abundant forage fish distributed throughout the Northern Gulf of Mexico (NGOM). Gulf Menhaden support the second largest fishery, by weight, in the United States and represent a key linkage between upper and lower trophic levels. Variation in the population dynamics can, therefore, pose consequences for the ecology and economy in the NGOM. Here we aim to understand variation in the individual and population dynamics of Gulf Menhaden throughout ontogeny and how such variation relates to environmental processes. We utilized a suite of fishery-dependent and –independent, remote sensing, modeled, and in situ data …

Distributions, Sources, And Transformations Of Dissolved And Particulate Iron On The Ross Sea Continental Shelf During Summer, Chris M. Marsay, Pamela M. Barrett, Dennis J. Mcgillicuddy Jr., Peter N. Sedwick

OES Faculty Publications

We report water column dissolved iron (dFe) and particulate iron (pFe) concentrations from 50 stations sampled across the Ross Sea during austral summer (January-February) of 2012. Concentrations of dFe and pFe were measured in each of the major Ross Sea water masses, including the Ice Shelf Water and off-shelf Circumpolar Deep Water. Despite significant lateral variations in hydrography, macronutrient depletion, and primary productivity across several different regions on the continental shelf, dFe concentrations were consistently low (<0.1 nM) in surface waters, with only a handful of stations showing elevated concentrations (0.20-0.45 nM) in areas of melting sea ice and near the Franklin Island platform. Across the study region, pFe associated with suspended biogenic material approximately doubled the inventory of bioavailable iron in surface waters. Our data reveal that the majority of the summertime iron inventory in the Ross Sea resides in dense shelf waters, with highest concentrations within 50 m of the seafloor. Higher dFe concentrations near the seafloor are accompanied by an increased contribution to pFe from authigenic and/or scavenged iron. Particulate manganese is also influenced by sediment resuspension near the seafloor but, unlike pFe, is increasingly associated with authigenic material higher in the water column. Together, these results suggest that following depletion of the dFe derived from wintertime convective mixing and sea ice melt, recycling of pFe in the upper water column plays an important role in sustaining the summertime phytoplankton bloom in the Ross Sea polynya.

Synergistic Use Of Remote Sensing And Modeling To Assess An Anomalously High Chlorophyll-A Event During Summer 2015 In The South Central Red Sea, Wenzhao Li, Hesham El-Askary, K. P. Manikandan, Mohamed A. Qurban, Michael J. Garay, Olga V. Kalishnikova

Mathematics, Physics, and Computer Science Faculty Articles and Research

An anomalously high chlorophyll-a (Chl-a) event (>2 mg/m3) during June 2015 in the South Central Red Sea (17.5° to 22°N, 37° to 42°E) was observed using Moderate Resolution Imaging Spectroradiometer (MODIS) data from the Terra and Aqua satellite platforms. This differs from the low Chl-a values (<0.5 mg/m3) usually encountered over the same region during summertime. To assess this anomaly and possible causes, we used a wide range of oceanographical and meteorological datasets, including Chl-a concentrations, sea surface temperature (SST), sea surface height (SSH), mixed layer depth (MLD), ocean current velocity and aerosol optical depth (AOD) obtained from different sensors and models. Findings confirmed this anomalous behavior in the spatial domain using Hovmöller data analysis techniques, while a time series analysis addressed monthly and daily variability. Our analysis suggests that a combination of factors controlling nutrient supply contributed to the anomalous phytoplankton growth. These factors include horizontal transfer of upwelling water through eddy circulation and possible mineral fertilization from atmospheric dust deposition. Coral reefs might have provided extra nutrient supply, yet this is out of the scope of our analysis. We thought that dust deposition from a coastal dust jet event in late June, coinciding with the phytoplankton blooms in the area under investigation, might have also contributed as shown by our AOD findings. However, a lag cross correlation showed a two- month lag between strong dust outbreak and the high Chl-a anomaly. The high Chl-a concentration at the edge of the eddy emphasizes the importance of horizontal advection in fertilizing oligotrophic (nutrient poor) Red Sea waters.

Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. De Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Simultaneous air–sea fluxes and concentration differences of dimethylsulfide (DMS) and carbon dioxide (CO2/ were measured during a summertime North Atlantic cruise in 2011. This data set reveals significant differences between the gas transfer velocities of these two gases (1kw/ over a range of wind speeds up to 21ms􀀀1. These differences occur at and above the approximate wind speed threshold when waves begin breaking. Whitecap fraction (a proxy for bubbles) was also measured and has a positive relationship with 1kw, consistent with enhanced bubble-mediated transfer of the less soluble CO2 relative to that of the more soluble DMS. However, the correlation …

Influence Of Tides And Mesoscale Eddies In The Ross Sea, Stefanie Lynn Mack

OES Theses and Dissertations

The Ross Sea is the most biologically productive region in the Southern Ocean. Primary production is controlled by dissolved iron (dFe), a limiting micronutrient. The main focus of this thesis, motivated by the PRISM-RS project, is to investigate how tides and mesoscale eddies affect the pathways of dFe to the surface ocean.

A regional ocean model with four hindcast simulations are used. Tidal forcing is added to simulations and mesoscale eddies are resolved by changing the horizontal grid resolution from 5 to 1.5 km. Simulations cover 1.5 years, ending at the time of the PRISM-RS cruise in early 2012. An …

Analysis Of Virginia Barrier Island Shoreline Movement And Correlations To Sea Level, Wave Height Changes, And Teleconnection Patterns, James Daniel Haluska

OES Theses and Dissertations

The Virginia barrier islands stretch from Assateague Island in the north to Fisherman’s Island in the south. This string of islands is subject to frequent North Atlantic extra-tropical storm and hurricane influence. In addition, sea level rise has the potential to cause continued shoreline loss and inlet widening for this island group. This dissertation describes the effect of sea level rise, changes in wave height, and teleconnection pattern (AO, NAO, and MEI) correlations to shoreline location changes to the islands and inlet location and width changes. Locations of island shorelines were determined from satellite and aircraft images using ArcGIS software …

Robustness Of Observation-Based Decadal Sea Level Variability In The Indo-Pacific Ocean, A. G. Nidheesh, M. Lengaigne, J. Vialard, T. Izumo, A. S. Unnikrishnan, B. Meyssignac, B. Hamlington, C. De Boyer Montegut

OES Faculty Publications

We examine the consistency of Indo-Pacific decadal sea level variability in 10 gridded, observation-based sea level products for the 1960-2010 period. Decadal sea level variations are robust in the Pacific, with more than 50% of variance explained by decadal modulation of two flavors of El Nino-Southern Oscillation (classical ENSO and Modoki). Amplitude of decadal sea level variability is weaker in the Indian Ocean than in the Pacific. All data sets indicate a transmission of decadal sea level signals from the western Pacific to the northwest Australian coast through the Indonesian throughflow. The southern tropical Indian Ocean sea level variability is …

Investigating Physical Processes Associated With Chesapeake Bay And Changjiang Estuary, Arash Niroomandi

Civil & Environmental Engineering Theses & Dissertations

Coastal and estuaries are landforms that not only have great impacts on large marine ecosystem, but also play a significant role in moderating or aggravating natural hazards and erosion risks that are expected to increase with climate change. This dissertation explores some of the concerns associated with coasts and coastal systems. In the second chapter, a thirty seven year wave hindcast (1979-2015) in Chesapeake Bay using NCEP's Climate Forecast System Reanalysis (CFSR) wind is presented. The long-term significant wave heights are generated by the third-generation nearshore wave model SWAN, which is validated using the wave height measurements at buoy stations …

Strategies For Environmental Education For Youths And Adults, Chumbe Island Coral Park, Zanzibar, Samantha Pfeffer

Independent Study Project (ISP) Collection

Chumbe Island Coral Park (CHICOP) is a privately-owned business that strives to follow the best principles of ecotourism, conservation, and environmental education. Their environmental education initiative is award-winning and has affected thousands of students and community members in Zanzibar. This study looked at the environmental education techniques that CHICOP already has in place by observing two pre-visits, three island-visits and one-post visit, and determined where there was a need for enhanced and new techniques for teaching about the environment. Evidence of climate change on Chumbe Island was also recorded to aid in the educational tools and to create a database …