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Articles 421 - 450 of 3959

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Influence Of Vacuum Condition On Rapid Chloride Migration (Rcm) Test For Chloride Penetration Resistance Of Concrete, Chih-Yen Lin, Chun-Fu Chang, Chung-Chia Yang Mar 2023

Influence Of Vacuum Condition On Rapid Chloride Migration (Rcm) Test For Chloride Penetration Resistance Of Concrete, Chih-Yen Lin, Chun-Fu Chang, Chung-Chia Yang

Journal of Marine Science and Technology–Taiwan

NT Build 492 regulates that the pressure be set at 7.5–37.5 torr and be maintained for 3 h for vacuum processing. This large range of acceptable vacuum pressure is awkward for research, and 3 h of pump-down time may be excessive. In this study, vacuum conditions were divided into vacuum pressure and pump-down time groups: various vacuum pressures and pump-down times were used to preprocess specimens to explore the effect of vacuum conditions on the RCM test. The salt ponding test was also conducted to identify the optimal vacuum conditions. It is shown that the relationship between vacuum pressure and …

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Exhaust Noise Elimination Using Silencers Fortified With Perforated Tubes, Extended Tubes, Penetrable Resin Inlet And Orifice Plate, Min-Chie Chiu, Ho-Chih Cheng Mar 2023

Exhaust Noise Elimination Using Silencers Fortified With Perforated Tubes, Extended Tubes, Penetrable Resin Inlet And Orifice Plate, Min-Chie Chiu, Ho-Chih Cheng

Journal of Marine Science and Technology–Taiwan

Pneumatic equipment in marine diesel engine and associated piping system often emit extremely high level of noises when releasing pressure. Concerning the crew’s hearing health, discovering an efficient noise silencing device becomes essential. A silencer fortified with extended tubes, perforated tubes, orifice plate, and penetrable resin inlet is presented in order to competently dampen the blown-up noises. A simplified objective function by means of FEM, Artificial Neural Networks (ANNs), and a Genetic Algorithm (GA) is established to enable the numerical calculation when using a finite element method. Three silencer designs, silencer A (with element A, a penetrable resin inlet), B …

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Deep Learning–Based, Oceantdlx Sea Ice Detection Model For Sar Image, Liu Lin, Li Wanwu, Li Hang, Sun Yi Mar 2023

Deep Learning–Based, Oceantdlx Sea Ice Detection Model For Sar Image, Liu Lin, Li Wanwu, Li Hang, Sun Yi

Journal of Marine Science and Technology–Taiwan

This study constructs four deep-learning OceanTDLx series models and uses a WinR-AdaGrad gradient descent algorithm to train and optimize the constructed models. Through an analysis of the loss, accuracy, and time consumption of the four models (i.e., OceanTDL2, OceanTDL3, OceanTDL5 and OceanTDL8), we reveal that the models’ performance does not improve when the number of layers is increased and that OceanTDL5 provides the optimal performance. OceanTDL5 is compared with OceanTDA9 (a model that we previously constructed), and the curves for training loss_batch and training accuracy_batch indicate that OceanTDL5 is more suitable than OceanTDA9 for detecting distributed targets, particularly semi-melted sea …

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Application Of Unmanned Aerial Vehicle–Based Infrared Images In Determining Characteristics Of Sea Surface Temperature Distribution, Hsing-Yu Wang, Hui-Ming Fang, Yun-Chih Chiang Mar 2023

Application Of Unmanned Aerial Vehicle–Based Infrared Images In Determining Characteristics Of Sea Surface Temperature Distribution, Hsing-Yu Wang, Hui-Ming Fang, Yun-Chih Chiang

Journal of Marine Science and Technology–Taiwan

This study investigated the temperature field of a body of water by using rotary-wing unmanned aerial vehicles (DJI Mavic 2 Enterprise Dual) comprising visible light and infrared cameras to determine sea temperature distribution. With a flight height of 150 m, image overlap of 80%, and image resolution of 4.75 cm/pixel, the proposed method was more effective than the conventional portable conductivity–temperature–depth device in rapidly measuring sea surface temperature and determining sea temperature distribution. The discharged heated water of the Hoping Power Plant traveled 100–330 m from the wastewater outfall and then gradually diffused in the range of 100–490 m before …

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Margalefidinium Polykrikoides Cyst Resuspension In The Lafayette River, A Sub-Tributary Of The Chesapeake Bay, Gabrielle Greaney, Eduardo Perez Vega, Katherine Crider, Dreux Chappell, Kimberly Powell, Richard Hale, Peter Bernhardt, Margaret Mulholland Mar 2023

Margalefidinium Polykrikoides Cyst Resuspension In The Lafayette River, A Sub-Tributary Of The Chesapeake Bay, Gabrielle Greaney, Eduardo Perez Vega, Katherine Crider, Dreux Chappell, Kimberly Powell, Richard Hale, Peter Bernhardt, Margaret Mulholland

Undergraduate Research Symposium

Harmful Algal Blooms are a collection of algae in a body of water that can cause serious environmental issues and health problems in both people and aquatic organisms. Dinoflagellates are microscopic, unicellular, and eukaryotic organisms that are well known for forming harmful algal blooms because of eutrophication. Coastal Virginia suffers from HABs in the Chesapeake Bay and its tributaries. A common species of dinoflagellate, known as Margalefidinium polykrikoides exists in the Chesapeake Bay. The purpose of this study is to determine if sediment resuspension produced by wind generated surface gravity waves cause cysts (dinoflagellate resting stages) to be suspended into …

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Carbon Farming: A Preliminary Economic Analysis Of Carbon Credits For No-Till And Cover Crops, Drew Havens, Richard K. Perrin, Lilyan E. Fulginiti Mar 2023

Carbon Farming: A Preliminary Economic Analysis Of Carbon Credits For No-Till And Cover Crops, Drew Havens, Richard K. Perrin, Lilyan E. Fulginiti

Cornhusker Economics

Summary Based on experimental data about the amount of carbon sequestered and estimated implementation costs, our preliminary results show that the average cost of sequestering carbon via no-till (about $22 per ton of CO2e) appears to be much lower than the $51 per ton social value of sequestering that ton. In contrast, our preliminary results show that the average costs of sequestration via adoption of cover crops is much higher, about $60 per ton. Depending on how accurate soil carbon models are in predicting sequestration on individual fields to qualify them for enrollment, reimbursement costs for planting cover …

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Movement, Behavior, And Trophic Ecology Of A Pelagic Predator Guild In The Eastern Tropical Pacific Ocean, Ryan Keith Logan Mar 2023

Movement, Behavior, And Trophic Ecology Of A Pelagic Predator Guild In The Eastern Tropical Pacific Ocean, Ryan Keith Logan

All HCAS Student Capstones, Theses, and Dissertations

Pelagic apex predators exert strong influences on ecological communities, and often support valuable commercial or recreational fisheries worldwide. Yet, due to their rarity and pelagic lifestyle, many species, such as billfishes, have proven particularly difficult to study at resolutions necessary to define dynamics of recovery from fishery interaction, physical interaction with environmental features and prey exploitation, and competitive interactions among other billfish predators. This leads to a paucity of knowledge on billfish ecology and habitat use, and hinders management efforts. With the ever-improving and miniaturization of technology and oceanographic datasets, the ability to define and quantify these interactions of fish …

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Age, Growth And Maturity Of The Yellow Stingray (Urobatis Jamaicensis), A Biannually Reproductive Tropical Batoid., Jessica Schieber, Daniel P. Fahy, John K. Carlson, David W. Kerstetter Mar 2023

Age, Growth And Maturity Of The Yellow Stingray (Urobatis Jamaicensis), A Biannually Reproductive Tropical Batoid., Jessica Schieber, Daniel P. Fahy, John K. Carlson, David W. Kerstetter

Marine & Environmental Sciences Faculty Articles

Urobatis jamaicensis is a coastal batoid species affected by habitat loss and small-scale exploitation from fisheries and the aquarium trade, yet the life-history information available is limited. This is the first study to assess the vertebral centra from 195 stingrays to estimate age and growth patterns and compare them with the biannual reproductive pattern previously reported for this species. Age-at-size data were compared using five different growth models and found a two-parameter von Bertalanffy growth function (VBGF), the Gompertz model, and a modified VBGF fit best for males, females and sexes combined, respectively. Maturity was achieved before one year. However, …

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Simulation Of Monthly Mean And Monthly Base Flow Of Streamflow Using Random Forests For The Mississippi River Alluvial Plain, 1901 To 2018, Benjamin J. Dietsch, William H. Asquith, Brian K. Breaker, Stephen M. Westenbroek, Wade H. Kress Mar 2023

Simulation Of Monthly Mean And Monthly Base Flow Of Streamflow Using Random Forests For The Mississippi River Alluvial Plain, 1901 To 2018, Benjamin J. Dietsch, William H. Asquith, Brian K. Breaker, Stephen M. Westenbroek, Wade H. Kress

United States Geological Survey: Water Reports and Publications

Improved simulations of streamflow and base flow for selected sites within and adjacent to the Mississippi River Alluvial Plain area are important for modeling groundwater flow because surface-water flows have a substantial effect on groundwater levels. One method for simulating streamflow and base flow, random forest (RF) models, was developed from the data at gaged sites and, in turn, was used to make monthly mean streamflow and base-flow predictions at 162 ungaged sites in the study area. Daily streamflow observations and computed base flow from 247 streamgages were used as the basis for the development of these RF models. RF …

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Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome, Andrew Felton, Gregory R. Goldsmith Feb 2023

Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome, Andrew Felton, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Although drought is known to negatively impact grassland functioning, the timing and magnitude of these impacts within a growing season remains unresolved. Previous small-scale assessments indicate grasslands may only respond to drought during narrow periods within a year; however, large-scale assessments are now needed to uncover the general patterns and determinants of this timing. We combined remote sensing datasets of gross primary productivity and weather to assess the timing and magnitude of grassland responses to drought at 5 km2 temporal resolution across two expansive ecoregions of the western US Great Plains biome: the C4-dominated shortgrass steppe and …

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What Drives Larval Condition For Northern Anchovy (Engraulis Mordax)? Implications For Coastal Pelagic Species Recruitment Fluctuations And Fishery Management Practices, Michelle Robidas Jan 2023

What Drives Larval Condition For Northern Anchovy (Engraulis Mordax)? Implications For Coastal Pelagic Species Recruitment Fluctuations And Fishery Management Practices, Michelle Robidas

Theses

Discerning the causes of population boom and bust cycles for coastal pelagic species (CPS) has been a major focus of fisheries management research for over a century. Year-class strength is contingent on larval survival and condition, which can be influenced by larval size at age and growth rate. These two factors, in turn, can be affected by maternal investment and environmental variables such as water temperature, salinity, oxygen, and chlorophyll a. We evaluated each of these factors from 127 two to eight week-old Northern Anchovy (Engraulis mordax) larvae off the coast of San Diego to San Francisco, …

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Holocene Evolution Of Parabolic Dunes, White River Badlands, South Dakota, Usa, Revealed By High-Resolution Mapping, Paul Evans Baldauf, Gregory S. Baker, Maraina Miles, Patrick Burkhart, Allen Gontz, Madeline Rinka, Michael Levenson Jan 2023

Holocene Evolution Of Parabolic Dunes, White River Badlands, South Dakota, Usa, Revealed By High-Resolution Mapping, Paul Evans Baldauf, Gregory S. Baker, Maraina Miles, Patrick Burkhart, Allen Gontz, Madeline Rinka, Michael Levenson

Marine & Environmental Sciences Faculty Articles

The White River Badlands (WRB) of South Dakota record eolian activity spanning the late Pleistocene through the latest Holocene (21 ka to modern), reflecting the effects of the last glacial period and Holocene climate fluctuations (Holocene Thermal Maximum, Medieval Climate Anomaly, and Little Ice Age). The WRB dune fields are important paleoclimate indicators in an area of the Great Plains with few climate proxies. The goal of this study is to use 1 m/pixel-resolution digital elevation models from drone imagery to distinguish Early to Middle Holocene parabolic dunes from Late Holocene parabolic dunes. Results indicate that relative ages of dunes …

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Larval Dispersal Patterns And Connectivity Of Acropora On Florida’S Coral Reef And Its Implications For Restoration, Samantha King, Antoine Saint-Amand, Brian K. Walker, Emmanuel Hanert, Joana Figueiredo Jan 2023

Larval Dispersal Patterns And Connectivity Of Acropora On Florida’S Coral Reef And Its Implications For Restoration, Samantha King, Antoine Saint-Amand, Brian K. Walker, Emmanuel Hanert, Joana Figueiredo

Marine & Environmental Sciences Faculty Articles

Since the 1980s, populations of Acropora cervicornis and A. palmata have experienced severe declines due to disease and anthropogenic stressors; resulting in their listing as threatened, and their need for restoration. In this study, larval survival and competency data were collected and used to calibrate a very high-resolution hydrodynamic model (up to 100m) to determine the dispersal patterns of Acropora species along the Florida’s Coral Reef. The resulting connectivity matrices was incorporated into a metapopulation model to compare strategies for restoring Acropora populations. This study found that Florida’s Coral Reef was historically a well-connected system, and that spatially selective restoration …

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Insights From The Management Of Offshore Energy Resources: Toward An Ecosystem-Services Based Management Approach For Deep-Ocean Industries, M. Emilia Bravo, Miriam I. Brandt, Jesse M. A. Van Der Grient, Thomas G. Dahlgren, Patricia Esquete, Sabine Gollner, Daniel O. B. Jones, Lisa A. Levin, Craig R. Mcclain, Bhavani E. Narayanaswamy, Tracey Sutton, Lissette Victorero, Erik E. Cordes Jan 2023

Insights From The Management Of Offshore Energy Resources: Toward An Ecosystem-Services Based Management Approach For Deep-Ocean Industries, M. Emilia Bravo, Miriam I. Brandt, Jesse M. A. Van Der Grient, Thomas G. Dahlgren, Patricia Esquete, Sabine Gollner, Daniel O. B. Jones, Lisa A. Levin, Craig R. Mcclain, Bhavani E. Narayanaswamy, Tracey Sutton, Lissette Victorero, Erik E. Cordes

Marine & Environmental Sciences Faculty Articles

The deep ocean comprises complex ecosystems made up of numerous community and habitat types that provide multiple services that benefit humans. As the industrialization of the deep sea proceeds, a standardized and robust set of methods and metrics need to be developed to monitor the baseline conditions and any anthropogenic and climate change-related impacts on biodiversity, ecosystem function, and ecosystem services. Here, we review what we have learned from studies involving offshore-energy industries, including state-of-the-art technologies and strategies for obtaining reliable metrics of deep-sea biodiversity and ecosystem function. An approach that includes the detection and monitoring of ecosystem services, with …

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Dinitrogen Emissions Dominate Nitrogen Gas Emissions From Soils With Low Oxygen Availability In A Moist Tropical Forest, Maya Almaraz, Peter M. Groffman, Whendee L. Silver, Steven J. Hall, Yang Lin, Christine S. O'Connell, Stephen Porder Jan 2023

Dinitrogen Emissions Dominate Nitrogen Gas Emissions From Soils With Low Oxygen Availability In A Moist Tropical Forest, Maya Almaraz, Peter M. Groffman, Whendee L. Silver, Steven J. Hall, Yang Lin, Christine S. O'Connell, Stephen Porder

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Lowland tropical forest soils are relatively N rich and are the largest global source of N2O (a powerful greenhouse gas) to the atmosphere. Despite the importance of tropical N cycling, there have been few direct measurements of N2 (an inert gas that can serve as an alternate fate for N2O) in tropical soils, limiting our ability to characterize N budgets, manage soils to reduce N2O production, or predict the future role that N limitation to primary productivity will play in buffering against climate change. We collected soils from across macro- and micro-topographic gradients …

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Home Tap Water In Nonmetropolitan Nebraska, Rebecca J. Vogt Jan 2023

Home Tap Water In Nonmetropolitan Nebraska, Rebecca J. Vogt

Cornhusker Economics

Water is an important resource in Nebraska. Most of the drinking water in the state (85%) comes from groundwater sources. Public water sources are required to test their water to ensure it is safe. However, private wells are not subject to any safety or quality standards. Given that, what are the main sources of home tap water for rural Nebraskans? Do they test or treat their water? The 2022 Nebraska Rural Poll examined these questions.

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The Future Of Pandemics: Land Use Controls As Means Of Preventing Zoonotic Disease, Bailey Andree Jan 2023

The Future Of Pandemics: Land Use Controls As Means Of Preventing Zoonotic Disease, Bailey Andree

Pace International Law Review

Zoonotic diseases are increasing in frequency as climate change worsens around the world, with the recent COVID-19 pandemic highlighting the inadequate mechanisms in place to counteract disease spread. This article reviews various zoonotic diseases and their patterns of spread, highlighting land use change as the key driver of disease to demonstrate the need for legal intervention. International land use law is a little-developed subsect of environmental law that holds the key to combating this disease spread, and this article proposes solutions through this legal lens. Land use techniques which may be used to combat disease spread include conservation laws, setback …

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Sea Spray Generation Function Due To Shear-Induced Instabilities Of The Air-Sea Interface Under Tropical Cyclone Conditions, Alexander Soloviev, Breanna Vanderplow Jan 2023

Sea Spray Generation Function Due To Shear-Induced Instabilities Of The Air-Sea Interface Under Tropical Cyclone Conditions, Alexander Soloviev, Breanna Vanderplow

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

The sea surface under tropical cyclone conditions is covered by whitecaps and whiteout material. The whitecap areas are formed by large breaking waves and occupy ~4% of the sea surface (Holthuijsen et al. 2012). These areas produce large amounts of bubble and spray but occupy only a relatively small faction of the sea surface. The whiteout material that covers the rest of the sea surface can be caused by shear-induced instabilities of the Kelvin-Helmholtz (KH) type (Soloviev et al. 2017). The KH type instabilities at the gas-liquid interface have been intensively studied in engineering applications such as atomization of the …

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A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife, Emilio Megías, Manuel García-Román Jan 2023

A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife, Emilio Megías, Manuel García-Román

Journal of Marine Science and Technology–Taiwan

Oceanic islands of volcanic origin tend to have peculiar characteristics, such as: exposure to many wave directions; grouping in archipelagos; steep coastal slopes; and small coastal shelves. All these features require certain considerations in wave climate studies. These types of studies, when wave spectra are not available and have to be performed with parametric data, can be unreliable without an adequate systematic treatment. In this work we propose a methodology consisting of pre-classification according to the peak period and subsequent separation into different sectors according to the geographical fetch. The island of Tenerife is the case study, and in particular …

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The Coral Bleaching Automated Stress System (Cbass): A Low Cost, Portable System For Standardized Empirical Assessments Of Coral Thermal Limits, Nicolas R. Evensen, Katherine E. Parker, Thomas A. Oliver, Stephen R. Palumbi, Cheryl A. Logan, James S. Ryan, Courtney N. Klepac, Gabriela Perna, Mark E. Warner, Christian R. Voolstra, Daniel J. Barshis Jan 2023

The Coral Bleaching Automated Stress System (Cbass): A Low Cost, Portable System For Standardized Empirical Assessments Of Coral Thermal Limits, Nicolas R. Evensen, Katherine E. Parker, Thomas A. Oliver, Stephen R. Palumbi, Cheryl A. Logan, James S. Ryan, Courtney N. Klepac, Gabriela Perna, Mark E. Warner, Christian R. Voolstra, Daniel J. Barshis

Biological Sciences Faculty Publications

Ocean warming is increasingly affecting marine ecosystems across the globe. Reef-building corals are particularly affected by warming, with mass bleaching events increasing in frequency and leading to widespread coral mortality. Yet, some corals can resist or recover from bleaching better than others. Such variability in thermal resilience could be critical to reef persistence; however, the scientific community lacks standardized diagnostic approaches to rapidly and comparatively assess coral thermal vulnerability prior to bleaching events. We present the Coral Bleaching Automated Stress System (CBASS) as a low-cost, open-source, field-portable experimental system for rapid empirical assessment of coral thermal thresholds using standardized temperature …

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Remote Sensing Of Georgia Tidal Marsh Habitats Using Aerial Photography And Planetscope Satellite Imagery, Harrison M. Currin Jan 2023

Remote Sensing Of Georgia Tidal Marsh Habitats Using Aerial Photography And Planetscope Satellite Imagery, Harrison M. Currin

College of Graduate Studies: Theses & Dissertations

Globally, tidal marshes cover about 90,800 km. Within the state of Georgia tidal marshes are primarily located behind the barrier islands and total 1,619 km2. The combination of high salinity environments and daily inundation, and being dependent on river output, make these dynamic systems. Tidal marshes provide numerous ecosystem services such as carbon and nitrogen sequestration, flood control, coastal protection, and numerous biogeochemical processes. Due to their unique position, tidal marshes are under threat from sea level rise, drought, coastal development, and large-scale disturbance events. Tidal freshwater marshes are especially susceptible to these threats due to their geographic …

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Trends In Cyanotoxin Production Potential In China Lake: An Edna Analysis Of Microcystis And Dolichospermum And The Environmental Drivers Of Cyanotoxin Production, Gennifer M. Rubin Jan 2023

Trends In Cyanotoxin Production Potential In China Lake: An Edna Analysis Of Microcystis And Dolichospermum And The Environmental Drivers Of Cyanotoxin Production, Gennifer M. Rubin

Honors Theses

Episodes of cyano-harmful algal blooms (cyano-HABs) are hypothesized to be exacerbated by the effects of climate change. However, the dynamics of the interactions between elements of climate change and toxigenic cyanobacteria proliferation are not well defined. China Lake is the drinking water source for 7 municipalities in the Kennebec County and is one of many lakes in central Maine that has been subjected to high levels of cyano-HABs and microcystin toxin contamination in recent years. Monitoring the toxicity of these blooms in relation to various aspects of climate change may lead to identification of the major drivers of microcystin production …

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Biophysical Interactions Control The Progression Of Harmful Algal Blooms In Chesapeake Bay: A Novel Lagrangian Particle Tracking Model With Mixotrophic Growth And Vertical Migration, Jilian Xiong, Jian Shen, Qubin Qin, Michelle C. Tomlinson, Yinglong J. Zhang, Xun Cai, Fei Yi, Linlin Cui, Margaret R. Mulholland Jan 2023

Biophysical Interactions Control The Progression Of Harmful Algal Blooms In Chesapeake Bay: A Novel Lagrangian Particle Tracking Model With Mixotrophic Growth And Vertical Migration, Jilian Xiong, Jian Shen, Qubin Qin, Michelle C. Tomlinson, Yinglong J. Zhang, Xun Cai, Fei Yi, Linlin Cui, Margaret R. Mulholland

OES Faculty Publications

Climate change and nutrient pollution contribute to the expanding global footprint of harmful algal blooms. To better predict their spatial distributions and disentangle biophysical controls, a novel Lagrangian particle tracking and biological (LPT-Bio) model was developed with a high-resolution numerical model and remote sensing. The LPT-Bio model integrates the advantages of Lagrangian and Eulerian approaches by explicitly simulating algal bloom dynamics, algal biomass change, and diel vertical migrations along predicted trajectories. The model successfully captured the intensity and extent of the 2020 Margalefidinium polykrikoides bloom in the lower Chesapeake Bay and resolved fine-scale structures of bloom patchiness, demonstrating a reliable …

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Nitrite Cycling In The Primary Nitrite Maxima Of The Eastern Tropical North Pacific, Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, Karen L. Casciotti Jan 2023

Nitrite Cycling In The Primary Nitrite Maxima Of The Eastern Tropical North Pacific, Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, Karen L. Casciotti

OES Faculty Publications

The primary nitrite maximum (PNM) is a ubiquitous feature of the upper ocean, where nitrite accumulates in a sharp peak at the base of the euphotic zone. This feature is situated where many chemical and hydrographic properties have strong gradients and the activities of several microbial processes overlap. Near the PNM, four major microbial processes are active in nitrite cycling: ammonia oxidation, nitrite oxidation, nitrate reduction and nitrite uptake. The first two processes are mediated by the nitrifying archaeal/bacterial community, while the second two processes are primarily conducted by phytoplankton. The overlapping spatial habitats and substrate requirements for these microbes …

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The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane Jan 2023

The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane

OES Faculty Publications

It is widely assumed that phytoplankton abundance and productivity decline during temperate winters because of low irradiance and temperatures. However, winter phytoplankton blooms commonly occur in temperate estuaries, but they are often undocumented because of reduced water quality monitoring in winter. The small body of in situ work that has been done on winter blooms suggests they can be of enormous consequence to ecosystems. However, because monitoring is often reduced or stopped altogether during winter, it is unclear how widespread these blooms are or how long they can last. We analyzed an over 30-year record of monthly phytoplankton monitoring samples …

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Providing A Framework For Seagrass Mapping In United States Coastal Ecosystems Using High Spatial Resolution Satellite Imagery, Megan M. Coffer, David D. Graybill, Peter J. Whitman, Blake A. Schaeffer, Wilson B. Salls, Richard C. Zimmerman, Victoria Hill, Marie Cindy Lebrasse, Jiang Li, Darryl J. Keith, James Kaldy, Phil Colarusso, Gary Raulerson, David Ward, W. Judson Kenworthy Jan 2023

Providing A Framework For Seagrass Mapping In United States Coastal Ecosystems Using High Spatial Resolution Satellite Imagery, Megan M. Coffer, David D. Graybill, Peter J. Whitman, Blake A. Schaeffer, Wilson B. Salls, Richard C. Zimmerman, Victoria Hill, Marie Cindy Lebrasse, Jiang Li, Darryl J. Keith, James Kaldy, Phil Colarusso, Gary Raulerson, David Ward, W. Judson Kenworthy

OES Faculty Publications

Seagrasses have been widely recognized for their ecosystem services, but traditional seagrass monitoring approaches emphasizing ground and aerial observations are costly, time-consuming, and lack standardization across datasets. This study leveraged satellite imagery from Maxar's WorldView-2 and WorldView-3 high spatial resolution, commercial satellite platforms to provide a consistent classification approach for monitoring seagrass at eleven study areas across the continental United States, representing geographically, ecologically, and climatically diverse regions. A single satellite image was selected at each of the eleven study areas to correspond temporally to reference data representing seagrass coverage and was classified into four general classes: land, seagrass, no …

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Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins Jan 2023

Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins

OES Faculty Publications

The growth of diatoms in the Southern Ocean, especially the region surrounding the West Antarctic Peninsula, is frequently constrained by low dissolved iron and other trace metal concentrations. This challenge may be overcome by mutualisms between diatoms and co-occurring associated bacteria, in which diatoms produce organic carbon as a substrate for bacterial growth, and bacteria produce siderophores, metal-binding ligands that can supply diatoms with metals upon uptake as well as other useful secondary compounds for diatom growth like vitamins. To examine the relationships between diatoms and bacteria in the plankton (diatom) size class (> 3 mu m), we sampled both …

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Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams Jan 2023

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …

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A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton Jan 2023

A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton

OES Faculty Publications

The California Current System is a diatom‐dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …

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Impact Of Atmospheric Correction On Classification And Quantification Of Seagrass Density From Worldview-2 Imagery, Victoria J. Hill, Richard C. Zimmerman, Paul Bissett, David Kohler, Blake Schaeffer, Megan Coffer, Jiang Li, Kazi Aminul Islam Jan 2023

Impact Of Atmospheric Correction On Classification And Quantification Of Seagrass Density From Worldview-2 Imagery, Victoria J. Hill, Richard C. Zimmerman, Paul Bissett, David Kohler, Blake Schaeffer, Megan Coffer, Jiang Li, Kazi Aminul Islam

OES Faculty Publications

Mapping the seagrass distribution and density in the underwater landscape can improve global Blue Carbon estimates. However, atmospheric absorption and scattering introduce errors in space-based sensors’ retrieval of sea surface reflectance, affecting seagrass presence, density, and above-ground carbon (AGCseagrass) estimates. This study assessed atmospheric correction’s impact on mapping seagrass using WorldView-2 satellite imagery from Saint Joseph Bay, Saint George Sound, and Keaton Beach in Florida, USA. Coincident in situ measurements of water-leaving radiance (Lw), optical properties, and seagrass leaf area index (LAI) were collected. Seagrass classification and the retrieval of LAI were compared after empirical line …

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