Oceanography Commons^™

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 …

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.

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 …

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 …

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 …

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 …

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 …

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 …

Comment On "Using An Adcp To Estimate Turbulent Kinetic Energy Dissipation Rate In Sheltered Coastal Waters", Ann E. Gargett

CCPO Publications

Greene et al. revisit the suggestion that the turbulent kinetic energy dissipation rate could be estimated through a "large-eddy estimate," employing acoustic measurements of velocity fields associated with the largest energy-containing scales of ocean turbulence. While the large-eddy estimate as originally proposed used vertical velocity and a vertical eddy length scale, Greene et al. chose instead to substitute a horizontal length scale for the latter. This comment argues that combining a horizontal scale for length with a vertical velocity scale produces a large-eddy estimate of the dissipation rate that is accurate only if the energy-containing eddies are isotropic, and that …

Micro-Spi Sediment Profile Imaging Micro-Inspector, Andrew P. Corvin, Caleb T. Davies, Matt R. Ferrari

Mechanical Engineering

This project was proposed by Dr. Brian Paavo through a desire to more easily study the benthic sediment layers of the ocean. To do so, he asked us to build a simple and compact machine for use in sediment profile imagery (SPI). Although devices like this already exist, they are all large scale devices that require a ship with a crane to deploy, which is expensive and time consuming. Instead, he desired a “micro” SPI, which is capable of being deployed from a small vessel that can easily navigate shallow waters. Our interpretation of these requirements was as follows: a …

The Effect Of Watershed Runoff And Sediment Resuspension On Turbidity And Sediment Deposition In St. John, Us Virgin Islands: Implications For Watershed And Marine Development And Restoration In Bays With Coral Reefs, Stephen E. Campbell

Theses

In the US Virgin Islands (USVI), land-based (terrigenous) sedimentation has been identified as a major cause of coral stress. Development, such as the building of unpaved roads in steep coastal watersheds, has increased sediment yields and marine terrigenous sedimentation by up to an order of magnitude above background levels. When activated during storm events, ephemeral streams transport sediment from the watershed to coastal waters. Once deposited on the seafloor, resuspension of benthic sediments can further increase turbidity and deposition. However, isolating the relative contributions of runoff and resuspension to turbidity and deposition using conventional sediment trap monitoring has been challenging. …

Larval Rockfish Diversity Abundance Dynamics In Association With A Marine Protected Area In The Southern California Bight, Dustin Chen

Theses

Marine protected areas (MPAs) are areas aimed at protecting natural and cultural resources that are often proposed as a way to alleviate the effects of overfishing on populations of targeted species; these areas have varying degrees of fishing and recreational use restrictions. In order to assess MPA efficacy, it is important to determine the mechanisms by which the presence of MPAs affect reproductive output within and potentially even beyond their boundaries. I attempted to address this through studying the responses of rockfish (Sebastes spp.) larval abundances to the presence of the Cowcod Conservation Areas (CCAs) located within the Southern California …

Use Of First Pelvic, Second Pelvic, And Fourth Anal Rays For Estimating Age Of Muskellunge (Esox Masquinongy), Marinda R. Cornett

Honors Theses

While cleithra are the most popularly used calcified structure used to estimate age of Muskellunge (Esox masquinongy), the use of fin rays as an age estimation structure has been investigated as a nonlethal alternative. My objectives were to: (1) to compare the accuracy and precision of estimating age using first pelvic, second pelvic, and fourth anal rays from 46 known age Muskellunge and (2) to analyze a larger sample (n = 120) of fourth anal rays to estimate age. Ages were estimated blindly by three readers independently from all available structures. Different analyses of precision and accuracy had conflicting results, …

A Multibeam Bathymetric Investigation Of Changes In Bedform Morphology Of The Little River Inlet As A Result Of Hurricane Matthew, Malarie O'Brien

Honors Theses

A hybrid scholarly-research paper on the use of multibeam sonar data in seafloor mapping and seafloor analysis was written to satisfy Honors Program requirements. Literature review of multibeam sonar technology explored the improving concept of mapping the seafloor via acoustic methods. The review also investigated improvements and applications of multibeam data analysis techniques, which have the ability to map the seafloor as well as characterize the seafloor by morphology or sediment content. The review then explored previous studies conducted on the Little River Inlet, SC, finding the inlet to be particularly understudied in the field of sediment morphology. Three multibeam …

Do Halogenated Natural Products Bioaccumulate In Narragansett Bay?, Christine Gardiner, Anna Robuck, Rainer Lohmann

Senior Honors Projects

In recent decades, a new family of chemical compounds has begun to garner research attention—halogenated natural products, or HNPs. These chemicals are produced by algae, bacteria, worms, and sponges, and many are structurally similar to harmful manmade compounds, such as polychlorinated diphenyls (PCBs), or brominated flame retardants (PBDEs), which are known to cause cancer, reproduction issues, endocrine disruption, and death. While HNPs are produced naturally, they are still considered pollutants because of their bioaccumulative behavior and apparent toxicity.

Currently, there is limited research on their presence and effects, with a few studies from Europe and the Pacific highlighting their importance …

Age, Growth, And Reproduction Of Vermilion Snapper (Rhomboplites Aurorubens) In The North-Central Gulf Of Mexico, Trevor Dalton Moncrief

Master's Theses

Vermilion Snapper is a commonly harvested species of reef fish in the northern Gulf of Mexico (GOM). It supports both a large commercial and popular recreational fishery, however knowledge of this fish’s life history is limited spatially. Non-linear curve fitting was used to estimate growth parameters and Akaike information criteria (AIC) was used to determine relative model fit. The 2-parameter von Bertalanffy growth function provided the best model fit and lowest AIC score. Histological examination indicated that Vermilion Snapper are batch spawners with asynchronous oocyte development. Additionally, 17% of Vermilion Snapper in the actively spawning phase containing 24 hour POF’s …

Small-Scale Farming Of Sandfish (Holothuria Scabra) At Unguja Ukuu, Zanzibar, Claire Hacker

Independent Study Project (ISP) Collection

The biological and social components of sandfish farming were studied at Unguja Ukuu, Zanzibar. Measurement of temperature and depth, along with quadrat sampling of substrate and sea cucumbers, led to recommendations for future management of depth, biomass per area, disease and crabs, and substrate. Interviews revealed the role and potential benefits of sea cucumber farming for communities. Several barriers to, and complications with, the expansion of sea cucumber farming were also identified. This study provided information for improvement of this farm and hoped to spread knowledge of sandfish farming to Zanzibaris, who may benefit economically from the practice.

Tourism In Raja Ampat: New Chances And Challenges, Chloe King

Independent Study Project (ISP) Collection

This study focuses on the ways in which the tourism industry in Raja Ampat has contributed to local livelihoods and encouraged the preservation of marine resources, looking specifically at the case of a dive operator and a volunteer tourism operation. The study illuminates the challenges that these operators face when engaging with the local community to protect the environment, and recommends more effective strategies for improving relations between tourism operators and the communities in which they reside. The study ultimately makes the case that the legacy of colonial rule in Western Papua must be a consideration in tourism planning, as …