Oceanography Commons^™

Change Points Detected In Decadal And Seasonal Trends Of Outlet Glacier Terminus Positions Across West Greenland, Ashley V. York, Karen E. Frey, Sadegh Jamali, Sarah B. Das

Geography

We investigated the change in terminus position between 1985 and 2015 of 17 marine-terminating glaciers that drain into Disko and Uummannaq Bays, West Greenland, by manually digitizing over 5000 individual frontal positions from over 1200 Landsat images. We find that 15 of 17 glacier termini retreated over the study period, with ~80% of this retreat occurring since 2000. Increased frequency of Landsat observations since 2000 allowed for further investigation of the seasonal variability in terminus position. We identified 10 actively retreating glaciers based on a significant positive relationship between glaciers with cumulative retreat >300 m since 2000 and their average …

Ice Algae Resource Utilization By Benthic Macro- And Megafaunal Communities On The Pacific Arctic Shelf Determined Through Lipid Biomarker Analysis, Chelsea Wegner Koch, Lee W. Cooper, Jacqueline M. Grebmeier, Karen Frey, Thomas A. Brown

Geography

We studied ice algae utilization by benthic fauna from the northern Bering and Chukchi Seas using highly branched isoprenoid (HBI) biomarkers. We assessed whether various food acquisition strategies influence the observed HBI signatures. The proportion of phytoplankton to ice algae-sourced HBIs was determined through the H-Print approach that is presumed to reflect the percentage of sea ice organic carbon (iPOC) incorporated into tissues, relative to phytoplankton organic carbon. Cluster analysis separated 3 groups based on location and feeding strategy that were significantly influenced by annual sea ice persistence. Ice algae utilization was most significant in the northeast Chukchi Sea, where …

Standardized Short-Term Acute Heat Stress Assays Resolve Historical Differences In Coral Thermotolerance Across Microhabitat Reef Sites, Christian R. Voolstra, Carol Buitrago-López, Gabriela Perna, Anny Cárdenas, Benjamin C. C. Hume, Nils Rädecker, Daniel J. Barshis

Biological Sciences Faculty Publications

Coral bleaching is one of the main drivers of reef degradation. Most corals bleach and suffer mortality at just 1–2°C above their maximum monthly mean temperatures, but some species and genotypes resist or recover better than others. Here, we conducted a series of 18‐hr short‐term acute heat stress assays side‐by‐side with a 21‐day long‐term heat stress experiment to assess the ability of both approaches to resolve coral thermotolerance differences reflective of in situ reef temperature thresholds. Using a suite of physiological parameters (photosynthetic efficiency, coral whitening, chlorophyll a , host protein, algal symbiont counts, and algal type association), we assessed …

Microbial Degradability Of Terrigenous, Marsh-Exported, And Estuarine Colored Dissolved Organic Matter In Long Island Sound, John R. Supino

Dissertations and Theses

The Long Island Sound is one of the world's most urbanized estuaries, polluted from excess nutrients which impact the quality of water through increased biological productivity. Dissolved organic matter (DOM) is a sensitive indicator of anthropogenic pollution and nutrient enrichment in coastal waters as well as an important part of the carbon cycle and serves as a primary food source for aquatic food webs. Additionally, the colored portion of DOM (CDOM) impacts coastal optical properties, ocean color, and light attenuation. High levels of CDOM have been shown to inhibit the growth of phytoplankton and limit photosynthesis, damaging the food chain …

Gulf Coast Marine Laboratories Past, Present And Future, Donald F. Boesch

Gulf and Caribbean Research

I spent my nearly 50—year career in marine science working at marine laboratories, most of that as a chief executive officer. So, it is appropriate that my reflections are about marine laboratories, rather than my own science. After relating my career course, I turn my attention to the history and development of marine laboratories along the U.S. coast of the Gulf of Mexico (GOM). Surprisingly, the region’s first laboratory was actually constructed in 1903 at Cameron, LA, but operated less than a decade before closing. It was not until after World War II that the university—affiliated marine laboratories of today …

Pelagic Sargassum Prediction And Marine Connectivity In The Tropical Atlantic, Donald R. Johnson, James S. Franks, Hazel A. Oxenford, Shelly-Ann L. Cox

Gulf and Caribbean Research

Since 2011, pelagic Sargassum has experienced extraordinary blooms in the Tropical Atlantic where a system of persistent but seasonally variable currents has retained and consolidated it in large masses. Although beneficial at sea, principally as a unique pelagic habitat, when Sargassum inundates the nearshore environment it can have catastrophic effects on tourism, fisheries, health, and local ecosystems. Providing advanced warning of arrival dates of large masses of Sargassum is critical for enabling preparations and planning for its removal, use, and mitigation. Predictions of arrival time and location involve satellite identification of Sargassum at sea together with ocean current data for …

Microplastic Fragment And Fiber Contamination Of Beach Sediments From Selected Sites In Virginia And North Carolina, Usa, Gabrielle Z. Dodson, A. Katrina Shotorban, Patrick G. Hatcher, Derek Waggoner, Sutapa Ghosal, Nora Noffke

OES Faculty Publications

Microplastic particles (<5 >mm) constitute a growing pollution problem within coastal environments. This study investigated the microplastic presence of estuarine and barrier island beaches in the states of Virginia and North Carolina, USA. Seventeen sediment cores were collected at four study sites and initially tested for microplastic presence by pyrolysis-gas chromatography–mass spectrometry. For the extraction, microplastic particles were first separated from the sediment using a high-density cesium chloride solution (1.88 g/mL). In a second step, an oil extraction collected the remaining microplastic particles of higher densities. Under the light microscope, the extracted microplastic particles were classified based on their morphologies …

Abiotic Formation Of Dissolved Organic Sulfur In Anoxic Sediments Of Santa Barbara Basin, Hussain A. Abdulla, David J. Burdige, Tomoko Komada

OES Faculty Publications

Sulfurization has been found to enhance organic matter preservation and petroleum formation in marine sediments. However, we do not yet have a comprehensive understanding of sulfurization mechanisms. In this study, we investigated several possible mechanisms of dissolved organic sulfur (DOS) formation in the top 4.5 m of anoxic sediments of Santa Barbara Basin (SBB), California Borderland. Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS), we identified chemical formulas of potential dissolved organic matter (DOM) precursors to these DOS compounds. We also examined how the formulas of abiotically formed DOS changed as a function of depth across a major redox …

Towards Sustained Monitoring Of Subsidence At The Coast Using Insar And Gps: An Application In Hampton Roads, Virginia, Brett Buzzanga, David P.S. Bekaert, Ben D. Hamlington, Simran S. Sangha

OES Faculty Publications

Hampton Roads is among the regions along the U.S. Atlantic Coast experiencing high rates of relative sea level rise. Partly to mitigate subsidence from aquifer compaction, Hampton Roads is injecting treated wastewater into the underlying aquifer. However, the GPS (Global Positioning System) station spacing (∼30 km) is too coarse to capture the spatial variability of subsidence and potential uplift from the injection. We present a cost‐effective workflow for generating an InSAR (interferometric synthetic aperture radar) and GPS combined displacement product. We leverage a live, open‐access archive of InSAR products generated from Sentinel‐1 data. We find an overall subsidence rate of …

An Oceanographic Perspective On Early Human Migrations To The Americas, Thomas C. Royer, Bruce Finney

OES Faculty Publications

Early migrants to the Americas were likely seaworthy. Many archaeologists now agree that the first humans who traveled to the Americas more than 15,000 years before present (yr BP) used a coastal North Pacific route. Their initial migration was from northeastern Asia to Beringia where they settled for thousands to more than ten thousand years. Oceanographic conditions during the Last Glacial Maximum (18,000-24,000 yr BP) would have enhanced their boat journeys along the route from Beringia to the Pacific Northwest because the influx of freshwater that drives the opposing Alaska Coastal Current was small, global sea level was at least …

Corrigendum To "Upper Water Structure And Mixed Layer Depth In Tropical Waters: The Seats Station In The Northern South China Sea, Jen-Hua Tai, George T.F. Wong, Xiaoju Pan

OES Faculty Publications

No abstract provided.

Performance Across Worldview-2 And Rapideye For Reproducible Seagrass Mapping, Megan M. Coffer, Blake A. Schaeffer, Richard C. Zimmerman, Victoria Hill, Jiang Li, Kazi A. Islam, Peter J. Whitman

OES Faculty Publications

Satellite remote sensing offers an effective remedy to challenges in ground-based and aerial mapping that have previously impeded quantitative assessments of global seagrass extent. Commercial satellite platforms offer fine spatial resolution, an important consideration in patchy seagrass ecosystems. Currently, no consistent protocol exists for image processing of commercial data, limiting reproducibility and comparison across space and time. Additionally, the radiometric performance of commercial satellite sensors has not been assessed against the dark and variable targets characteristic of coastal waters. This study compared data products derived from two commercial satellites: DigitalGlobe's WorldView-2 and Planet's RapidEye. A single scene from each platform …

Changes At The Edge: Trends In Sea Ice, Ocean Temperature And Ocean Color At The Northwest Atlantic/Southern Arctic Interface, Ashley V. York, Karen E. Frey, Luisa N.C. Young

Geography

Spatial and temporal trends of remotely sensed sea-ice cover, sea surface temperatures, chlorophyll-a concentration and primary production in the Baffin Bay, Davis Strait and Labrador Sea were analyzed for the 1998-2017 period. We found spatial variability in the trends of these cryospheric, biologic and oceanographic phenomena. For example, in the northern Baffin Bay, we observed decreases in annual sea-ice persistence, yet increases along the Labrador Sea-ice edge during winter, with the latter having significant correlations with broader atmospheric patterns. In general, we observed increases in summer sea surface temperatures across the study region, except a small area of cooling along …

Semi-Supervised Adversarial Domain Adaptation For Seagrass Detection Using Multispectral Images In Coastal Areas, Kazi Aminul Islam, Victoria Hill, Blake Schaeffer, Richard Zimmerman, Jiang Li

Electrical & Computer Engineering Faculty Publications

Seagrass form the basis for critically important marine ecosystems. Previously, we implemented a deep convolutional neural network (CNN) model to detect seagrass in multispectral satellite images of three coastal habitats in northern Florida. However, a deep CNN model trained at one location usually does not generalize to other locations due to data distribution shifts. In this paper, we developed a semi-supervised domain adaptation method to generalize a trained deep CNN model to other locations for seagrass detection. First, we utilized a generative adversarial network loss to align marginal data distribution between source domain and target domain using unlabeled data from …

Near-Bottom Currents At Station M In The Northeast Pacific, Thomas Connolly, Paul Mcgill, Richard Henthorn, Drew Burrier, Cynthia Michaud

Faculty Research, Scholarly, and Creative Activity

No abstract provided.

Seagrass Losses Since Mid-20th Century Fuelled Co2 Emissions From Soil Carbon Stocks [Dataset], Cristian Salinas, Carlos M. Duarte, Paul S. Lavery, Pere Masque, Ariane Arias-Ortiz, Javier Leon, David Callaghan, Gary A. Kendrick, Oscar Serrano

Research Datasets

The database compiles published data (in Salinas et al. 2020) on biogeochemical characteristics (density, organic carbon, stable carbon isotopes, sediment grain size) of cores from Posidonia australis and sinuosa soil in Cockburn Sound, Western Australia.

Seasonal And Latitudinal Variations In Sea Ice Algae Deposition In The Northern Bering And Chukchi Seas Determined By Algal Biomarkers, Chelsea Wegner Koch, Lee W. Cooper, Catherine Lalande, Thomas A. Brown, Karen E. Frey, Jacqueline M. Grebmeier

Geography

An assessment of the production, distribution and fate of highly branched isoprenoid (HBI) biomarkers produced by sea ice and pelagic diatoms is necessary to interpret their detection and proportions in the northern Bering and Chukchi Seas. HBIs measured in surface sediments collected from 2012 to 2017 were used to determine the distribution and seasonality of the biomarkers relative to sea ice patterns. A northward gradient of increasing ice algae deposition was observed with localized occurrences of elevated IP25 (sympagic HBI) concentrations from 68–70N and consistently strong sympagic signatures from 71–72.5N. A declining sympagic signature was observed from 2012 to 2017 …

Estimating Carbon Flux From Optically Recording Total Particle Volume At Depths Below The Primary Pycnocline, Alexander B. Bochdansky, Robert B. Dunbar, Dennis A. Hansell, Gerhard J. Herndl

OES Faculty Publications

Optical instruments can rapidly determine numbers and characteristics of water column particles with high sensitivity. Here we show the usefulness of optically assessed total particle volume below the main pycnocline to estimate carbon export in two systems: the open subarctic North Atlantic and the Ross Sea, Antarctica. Both regions exhibit seasonally high phytoplankton production and efficient export (i.e., a strong biological pump). Total particle volumes in the mesopelagic (200-300 m) were significantly correlated with those in the overlying surface mixed layer (50-60 m), indicating that most particles at depth reflect export from the surface. This connectivity, however, is modulated by …

The Vezo Communities And Fisheries Of The Coral Reef Ecosystem In The Bay Of Ranobe, Madagascar, Shane Abeare

LSU New Orleans Theses and Dissertations

Madagascar, a country whose extraordinary levels of endemism and biodiversity are celebrated globally by scientists and laymen alike, yet historically has received surprisingly little research attention, is the setting of the present dissertation. Here, I contribute to the need for applied research by: 1) focusing on the most intensely fished section of the Toliara Barrier Reef, the Bay of Ranobe; 2) characterizing the marine environment, the human population, and the fisheries; and 3) collecting the longest known time-series of data on fisheries of Madagascar, thereby providing a useful baseline for future analyses. In Chapter 1, the bathymetry of the Bay …

On The Frontlines - The Fishermen Of Ibrahim Hyderi, Muhammad Haris Aslam Khan

MSJ Capstone Projects

Climate change has become a matter of recent debate for much of the world. According to a report published by a German watch, a non-governmental organization, in 2019, Pakistan among the five countries at severe risk of climate change disasters.

During the last two decades, Pakistan saw more than 141 extreme climatic catastrophes. Only in 2016, more than 566 people died due to these conditions.

A report published by Asian Development Bank in 2017 indicates Pakistan’s climate change profile. It states that more than 1,600 people have lost their lives in the super flood of 2010 alone. A loss of …