Oceanography Commons^™

Fukushima Daiichi-Derived Radionuclides In The Ocean: Transport, Fate, And Impacts, Ken O. Buesseler, Minhan Dai, Michio Aoyama, Claudia R. Benítez-Nelson,, Sabine S. Charmasson, Kathryn A. Higley, Vladimir S. Maderich, Pere Masqué, Paul J. Morris, Deborah H. Oughton, John N. Smith

Research outputs 2014 to 2021

The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is …

Mapping The Nonstationary Internal Tide With Satellite Altimetry, Edward Zaron

Civil and Environmental Engineering Faculty Publications and Presentations

t Temporal variability of the internal tide has been inferred from the 23 year long combined records of the TOPEX/Poseidon, Jason-1, and Jason-2 satellite altimeters by combining harmonic analysis with an analysis of along-track wavenumber spectra of sea-surface height (SSH). Conventional harmonic analysis is first applied to estimate and remove the stationary components of the tide at each point along the reference ground tracks. The wavenumber spectrum of the residual SSH is then computed, and the variance in a neighborhood around the wavenumber of the mode-1 baroclinic M2 tide is interpreted as the sum of noise, broadband nontidal processes, and …

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

The variability of the upper water hydrographic structure, the efficacy of the different schemes for estimating the mixed layer depth (MLD), the inter-comparability estimation of the MLDs and diurnal and intra-annual MLD climatology in the tropical waters in the northern South China Sea were accessed in 702 depth-profiles of potential temperature (θ) and salinity collected in 64 cruises between 17.5 and 18.5°N and 115.3 and 116.3°E from 1997 to 2013. The hydrographic structure may be subdivided into three principal types: the classical type, with quasi-isopycnal surface mixed layer followed by an abrupt increase in the depth-gradient in θ and potential …

Investigating Coral Bleaching In A Changing Climate: Our State Of Understanding And Opportunities To Push The Field Forward, Mark E. Warner, Daniel Barshis, Sarah Davies, Andréa G. Grottoli, Todd C. Lajeunesse, Robert Van Woesik

Biological Sciences Faculty Publications

[First Paragraph]

Coral reefs throughout the world are facing the consequences of large-scale changes in Earth’s climate. In particular, ocean warming is leading to frequent coral bleaching, which is threatening the long-term stability of coral reefs. Coral bleaching is a stress response that results in the disassociation of the mutualistic symbioses (i.e., dysbiosis) between corals and their endosymbiotic algae (Symbiodinium spp.). In the past two decades, there have been four substantial bleaching events, which have affected large geographic areas across the globe, including the worst recorded bleaching event on the Great Barrier Reef in 2016 (Berkelmans et al. 2004; Eakin …

Marsh-Exported Dissolved Organic Matter Fate In Estuaries, Laura Ann Logozzo

Dissertations and Theses

Dissolved organic matter (DOM) is a significant driver of estuarine productivity and nutrient cycling. The colored component of DOM, chromophoric dissolved organic matter (CDOM), impacts coastal optical properties, ocean color, and light attenuation. While marshes are largely considered sinks for carbon due to their high productivity and low soil carbon degradation rates, laterally they are sources of carbon as optically and chemically distinct DOM to surrounding aquatic ecosystems; these inputs are often essential in sustaining a net heterotrophic system. However, the photoreactivity and bioavailability of marsh-exported DOM is largely uncategorized, thus making it difficult to quantify its impacts on estuarine …

Addressing Calcium Carbonate Cycling In Blue Carbon Accounting, Peter I. Macreadie, Oscar Serrano, Damien T. Maher, Carlos M. Duarte, John Beardall

Research outputs 2014 to 2021

Scientific Significance Statement

There is considerable interest in measuring the capacity of the world's ecosystems to trap and store excess atmospheric carbon dioxide to mitigate human‐induced climate change. Blue carbon describes the carbon storage potential of vegetated coastal ecosystems including tidal marshes, mangroves, and seagrasses. Efforts are now underway to include blue carbon in global carbon offset schemes by managing these ecosystems to enhance carbon sequestration by focusing on their effect on organic carbon processing. However, it is unclear what role inorganic carbon processing in blue carbon ecosystems plays in their overall carbon sequestration. Here, we argue that there are …

Historical Reconstructions Of Water Quality In The Kimberley Using Sediment Records. Report Of 2.2.9 Prepared For The Kimberley Marine Research Program, John Keesing, Dongyan Liu, Zineng Yuan, Yajun Peng, Yujue Wang, Pierre Richard, Pere Masque, Yingjun Chen, Yin Fang

Research outputs 2014 to 2021

This project made use of a suite of palaeoecological approaches to reconstruct a chronology of change in coastal water quality over the last approximately 100 years. The biogeochemical proxies addressed phytoplankton composition and biomass, temperature and terrestrial influences. Where possible these were matched to historical land/water use, meteorological or hydrological observational records.

The project examined sediment cores from three coastal locations in the Kimberley region, Koolama Bay (King George River), Cygnet Bay and Roebuck Bay. Each sampling location provided a contrast with which to evaluate changes over either a spatial or temporal gradient of human or natural influences.

Aims

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Phytoplankton Plastid Proteomics: Cracking Open Diatoms To Understand Plastid Biochemistry Under Iron Limitation, Skyler J. Nunn, Phoebe Dreux Chappell, Kristofer Gomes, Anasthasia Bonderenko, Bethany D. Jenkins, Brook L. Nunn

OES Faculty Publications

Diatoms, such as Thalassiosira pseudonana, are important oceanic primary producers, as they sequester carbon dioxide (CO₂) out of the atmosphere, die, and precipitate to the ocean floor. In many areas of the world’s oceans, phytoplankton, such as diatoms, are limited in growth by the availability of iron (Fe). Fe is an essential nutrient for phytoplankton, as it is central in the electron transport chain component of photosynthesis. Through this study, we examined if Fe-limitation makes a significant difference in the proteins expressed within the chloroplast, the power source for diatoms. Here, we utilized a new plastid isolation technique specific …

Elevated Trace Metal Content Of Prokaryotic Communities Associated With Marine Oxygen Deficient Zones, Daniel C. Ohnemus, Sara Rauschenberg, Gregory A. Cutter, Jessica N. Fitzsimmons, Robert M. Sherrell, Benjamin S. Twining

OES Faculty Publications

Little is known about the trace metal content of marine prokaryotes, in part due to their co-occurrence with more abundant particulate phases in the upper ocean, such as phytoplankton and biogenic detritus, lithogenic minerals, and authigenic Mn and Fe oxyhydroxides. We attempt to isolate these biomass signals in particulate data from the US GEOTRACES Eastern Pacific Zonal Transect (cruise GP16) in the Eastern Tropical South Pacific (ETSP), which exhibited consistent maxima in P and other bioactive trace metals, and minima in particulate Mn, in the oxygen deficient zones (ODZs) of 13 stations. Nitrite maxima and nitrate deficits indicated the presence …

Critical Decisions In Metaproteomics: Achieving High Confidence Protein Annotations In A Sea Of Unknowns, Emma Timmins-Schiffman, Damon H. May, Molly Mikan, Michael Riffle, Chris Frazar, H. R. Harvey, William S. Noble, Brook L. Nunn

OES Faculty Publications

No abstract provided.

Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann

OES Faculty Publications

Coral reefs are built of calcium carbonate (CaCO₃) produced biogenically by a diversity of calcifying plants, animals, and microbes. As the ocean warms and acidifies, there is mounting concern that declining calcification rates could shift coral reef CaCO3 budgets from net accretion to net dissolution. We quantified net ecosystem calcification (NEC) and production (NEP) on Dongsha Atoll, northern South China Sea, over a 2 week period that included a transient bleaching event. Peak daytime pH on the wide, shallow reef flat during the nonbleaching period was ~8.5, significantly elevated above that of the surrounding open ocean (~8.0-8.1) as …

Impact Of Glacial/Interglacial Sea Level Change On The Ocean Nitrogen Cycle, Haojia Ren, Daniel M. Sigman, Alfredo Martínez-García, Robert F. Anderson, Chen Min-Te, Ana Christina Ravelo, Marietta Straub, George T. F. Wong, Gerald H. Haug

OES Faculty Publications

The continental shelves are the most biologically dynamic regions of the ocean, and they are extensive worldwide, especially in the western North Pacific. Their area has varied dramatically over the glacial/interglacial cycles of the last million years, but the effects of this variation on ocean biological and chemical processes remain poorly understood. Conversion of nitrate to N2 by denitrification in sediments accounts for half or more of the removal of biologically available nitrogen ("fixed N") from the ocean. The emergence of continental shelves during ice ages and their flooding during interglacials have been hypothesized to drive changes in sedimentary denitrification. …

Eukaryotic Microbes, Principally Fungi And Labyrinthulomycetes, Dominate Biomass On Bathypelagic Marine Snow, Alexander B. Bochdansky, Melissa A. Clouse, Gerhard J. Herndl

OES Faculty Publications

In the bathypelagic realm of the ocean, the role of marine snow as a carbon and energy source for the deep-sea biota and as a potential hotspot of microbial diversity and activity has not received adequate attention. Here, we collected bathypelagic marine snow by gentle gravity filtration of sea water onto μm filters from similar to 1000 to 3900 m to investigate the relative distribution of eukaryotic microbes. Compared with sediment traps that select for fast-sinking particles, this method collects particles unbiased by settling velocity. While prokaryotes numerically exceeded eukaryotes on marine snow, eukaryotic microbes belonging to two very distant …

Spatial Patterns Of Sea Level Variability Associated With Natural Internal Climate Modes, Weiqing Han, Gerald A. Meehl, Detlef Stammer, Aixue Hu, Benjamin Hamlington, Jessica Kenigson, Hindumathi Palanisamy, Philip Thompson

OES Faculty Publications

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth's climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes …

Ecological Connectivity Of Kimberley Marine Communities. Synthesis Report Of Project 1.1.3 Prepared For The Kimberley Marine Research Program, Zoe Richards, Oliver Berry, Jim Underwood, Kathryn Mcmahon, Mike Travers, Glenn Moore, Udhi Hernawan, Joseph Dibattista, Richard Evans, James Gilmour

Research outputs 2014 to 2021

The overarching objective of KMRP Project 1.1.3 (Ecological Connectivity of Kimberley Marine Communities) was to provide the first estimates of ecological connectivity across multiple spatial scales for a suite of model/priority marine organisms in the Kimberley. More specifically, this project aimed to provide species-specific estimates of realised connectivity at a reef-scale ( < 1 > km), inter-reef scale (1-100 km) and inter-region scale (100 + km) through genetic analyses of seven key animals and plants with contrasting dispersive life histories that are representative of common taxa.

The Effects Of Thermal Stress On Fluorescent Protein Expression In An Indo-Pacific Scleractinian Coral Species, Acropora Tenuis, Anna Knochel

Independent Study Project (ISP) Collection

The scleractinian coral species that so heavily define tropical coral reefs are increasingly threatened by anthropogenic global warming. Rising sea surface temperatures in combination with light stress causes the photosynthetic breakdown of the coral’s algal symbiont, Symbiodinium. Corals have developed a number of physiological responses to handle acute stressors, such as the production of ultraviolet-protecting amino acids, heat shock proteins, the ability to shift symbionts, and the production of fluorescent proteins. The latter has been thought to play a photoprotective role in the coral holobiont, and studies have shown evidence that corals orient these pigments to divert harmful light away …

Effect Of Small-Scale Continental Shelf Bathymetry On Storm Surge Generation, Sunni A. Siqueira

LSU New Orleans Theses and Dissertations

Idealized bathymetries were subjected to idealized cyclones in order to measure the storm surge response to a range of bathymetry features, under various storm conditions. Ten bathymetries were considered, including eight shoals, one pit, and a featureless reference domain. Six storms (two different sizes/intensities and three different landfall directions) were used as meteorological forcing. The bathymetry features influenced local surge response during pre- and post-peak surge conditions. However, peak surge and surge at the coast were not meaningfully affected by the presence of the bathymetry features considered. The effect of three bathymetry feature parameters on surge response was analyzed (i.e. …

Effects Of Temperature On Activity Of Aquatic Hyphomycetes: A Microcosm Study, Kyra Harrington‌‌

Honors Theses

Predicted increases in temperature under climate change scenarios are expected to affect not only atmospheric and water temperatures, but also the rate of heterotrophic activity and carbon dynamics and retention in ecosystems. The magnitude of the increase in metabolic activity of living organisms with increased temperature can be predicted by the Metabolic Theory of Ecology, however, multiple factors can cause deviations from simple predictions. The goal of this study is to assess the temperature sensitivity of aquatic hyphomycetes and fungi-mediated leaf litter decomposition by following responses to temperature of fungal biomass accrual, respiration and decomposition rates in laboratory microcosms simulating …

Sea Surface Temperature Rises Shift Migration Patterns Due To Ecosystem Changes, Alexia Skrbic, Hesham El-Askary

Student Scholar Symposium Abstracts and Posters

The continuing climate change is negatively impacting ecosystems, specifically oceans which are declining and food webs are being altered by the increase of greenhouse gases. The increase of the carbon dioxide and other greenhouse gases is increasing sea surface temperature of the world’s oceans. Certain organisms lower on the food chain like phytoplankton and zooplankton are directly affected by the warming which alters how they process nutrients and their productivity. The limited amount of these primary producers in the oceans and specifically the location they inhabit directly affects all the organisms above them on the food chain. Several marine animals …

The Tolerance Of Benthic Infauna To Fine-Grained Organic Rich Sediments In A Shallow Subtropical Estuary, Daniel Christopher Hope

Theses and Dissertations

Fine-grained organic-rich sediments (FGORS) from anthropogenic impacts are a growing concern for bays and estuaries around the world. This study explores the relationships between infaunal community diversity and species’ abundances with FGORS in the Indian River Lagoon and its tributaries. To examine these potential relationships, infauna were collected monthly using a Petit Ponar grab at 16 stations in the central Indian River Lagoon from October 2015 to August 2016. Abundant taxa in these sediments include polychaete worms (e.g., the polychaete Nereis succinea), molluscs (e.g., clam Parastarte triquetra), and arthropods (e.g., the tanaid Leptochelia dubia) with densities as high as 5.3x10⁴ …