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Chlorophyll

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Articles 1 - 30 of 113

Full-Text Articles in Physical Sciences and Mathematics

A Comparison Of Adenosine Triphosphate With Other Metrics Of Microbial Biomass In A Gradient From The North Atlantic To The Chesapeake Bay, Alexander B. Bochdansky, Amber A. Beecher, Joshua R. Calderon, Alison N. Stouffer, Nyjaee N. Washington Jan 2024

A Comparison Of Adenosine Triphosphate With Other Metrics Of Microbial Biomass In A Gradient From The North Atlantic To The Chesapeake Bay, Alexander B. Bochdansky, Amber A. Beecher, Joshua R. Calderon, Alison N. Stouffer, Nyjaee N. Washington

OES Faculty Publications

A new, simplified protocol for determining particulate adenosine triphosphate (ATP) levels allows for the assessment of microbial biomass distribution in aquatic systems at a high temporal and spatial resolution. A comparison of ATP data with related variables, such as particulate carbon, nitrogen, chlorophyll, and turbidity in pelagic samples, yielded significant and strong correlations in a gradient from the tributaries of the Chesapeake Bay (sigma-t = 8) to the open North Atlantic (sigma-t = 29). Correlations varied between ATP and biomass depending on the microscopic method employed. Despite the much greater effort involved, biomass determined by microscopy correlated poorly with other …

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Unraveling Sources Of Cyanate In The Marine Environment: Insights From Cyanate Distributions And Production During The Photochemical Degradation Of Dissolved Organic Matter, Rui Wang, Jihua Liu, Yongle Xu, Li Liu, Kenneth Mopper Jan 2024

Unraveling Sources Of Cyanate In The Marine Environment: Insights From Cyanate Distributions And Production During The Photochemical Degradation Of Dissolved Organic Matter, Rui Wang, Jihua Liu, Yongle Xu, Li Liu, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Cyanate is a nitrogen and energy source for diverse marine microorganisms, playing important roles in the nitrogen cycle. Despite the extensive research on cyanate utilization, the sources of this nitrogen compound remain largely enigmatic. To unravel the sources of cyanate, distributions and production of cyanate during photochemical degradation of natural dissolved organic matter (DOM) were investigated across various environments, including freshwater, estuarine, coastal areas in Florida, and the continental and slope regions of the North American mid-Atlantic Ocean (NATL). Cyanate production was also examined during the photochemical degradation of exudates from a typical strain of Synechococcus, an important phytoplankton …

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Enhancing Urban Water Quality Through Biological-Chemical Treatment: Aquatic Macroinvertebrate Community And Temporal Chlorophyll-A Response, Matthew Chaffee Dec 2023

Enhancing Urban Water Quality Through Biological-Chemical Treatment: Aquatic Macroinvertebrate Community And Temporal Chlorophyll-A Response, Matthew Chaffee

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

With a growing human population, urbanization is impeding a plethora of natural waterways. Of these, urban ponds play a vital role in nutrient sequestration, flood prevention, and habitat sanctuaries. However, nutrient loading can reduce habitat effectiveness and promote harmful algae blooms. To reduce internal nutrient loads, a biological-chemical treatment strategy consisting of floating treatment wetlands (FTWs) and lanthanum were applied to two urban retention ponds, Densmore and Wilderness Ridge Ponds. To measure effectiveness, chlorophyll-a samples were collected and correlated with Sentinel-2. A novel band algorithm termed 3BR1 produced a strong correlation (R2 = 0.72) to physical chlorophyll-a …

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Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken Jan 2023

Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken

CCPO Publications

Upward advection or mixing of iron-rich deep waters due to circulation changes driven by the rate of basal ice shelf melt was shown to be a primary control on chlorophyll a production in coastal polynyas over the Antarctic continental shelf. Here, the effects of atmospheric changes projected in 2100 on this relationship were examined with a 5-km resolution ocean/sea ice/ice shelf model of the Southern Ocean with different simulated dissolved iron sources and idealized biological uptake. The atmospheric changes are added as idealized increments to the forcing. Inclusion of a poleward shift and strengthening of the winds, increased precipitation, and …

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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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Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining Jan 2023

Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining

OES Faculty Publications

Particulate phases transport trace metals (TM) and thereby exert a major control on TM distribution in the ocean. Particulate TMs can be classified by their origin as lithogenic (crustal material), biogenic (cellular), or authigenic (formed in situ), but distinguishing these fractions analytically in field samples is a challenge often addressed using operational definitions and assumptions. These different phases require accurate characterization because they have distinct roles in the biogeochemical iron cycle. Particles collected from the upper 2,000 m of the northwest subtropical Atlantic Ocean over four seasonal cruises throughout 2019 were digested with a chemical leach to operationally distinguish labile …

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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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Phytoplankton Bloom Stages Estimated From Chlorophyll Pigment Proportions Suggest Delayed Summer Production In Low Sea Ice Years In The Northern Bering Sea, Clare B. Gaffey, Karen E. Frey, Lee W. Cooper, Jacqueline M. Grebmeier Jan 2022

Phytoplankton Bloom Stages Estimated From Chlorophyll Pigment Proportions Suggest Delayed Summer Production In Low Sea Ice Years In The Northern Bering Sea, Clare B. Gaffey, Karen E. Frey, Lee W. Cooper, Jacqueline M. Grebmeier

Geography

Decreased sea ice cover in the northern Bering Sea has altered annual phytoplankton phenology owing to an expansion of open water duration and its impact on ocean stratification. Limitations of satellite remote sensing such as the inability to detect bloom activity throughout the water column, under ice, and in cloudy conditions dictate the need for shipboard based measurements to provide more information on bloom dynamics. In this study, we adapted remote sensing land cover classification techniques to provide a new means to determine bloom stage from shipboard samples. Specifically, we used multiyear satellite time series of chlorophyll a to determine …

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Sidebar: Observations Of Declining Primary Productivity In The Western Bering Strait, Karen E. Frey, Jaclyn Clement Kinney, Larry V. Stock, Robert Osinski Jan 2022

Sidebar: Observations Of Declining Primary Productivity In The Western Bering Strait, Karen E. Frey, Jaclyn Clement Kinney, Larry V. Stock, Robert Osinski

Geography

No abstract provided.

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Revisiting The Use Of Red And Near-Infrared Reflectances In Vegetation Studies And Numerical Climate Models, Garik Gutman, Sergii Skakun, Anatoly Gitelson Jun 2021

Revisiting The Use Of Red And Near-Infrared Reflectances In Vegetation Studies And Numerical Climate Models, Garik Gutman, Sergii Skakun, Anatoly Gitelson

School of Natural Resources: Faculty Publications

Surface reflectance data acquired in red and near-infrared spectra by remote sensing sensors are traditionally applied to construct various vegetation indices (VIs), which are related to vegetation biophysical parameters. Most VIs use pre-defined weights (usually equal to 1) for the red and NIR reflectance values, therefore constraining particular weights for red and NIR during the VI design phase, and potentially limiting capabilities of the VI to explain an independent variable. In this paper, we propose an approach to estimate biophysical variables, such as Leaf Area Index (LAI), Canopy Chlorophyll Content (CCC) and Fraction of Photosynthetically Active Radiation (FPAR) absorbed by …

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Vignette 02: Lower Trophic Levels In The Salish Sea, Ian Perry May 2021

Vignette 02: Lower Trophic Levels In The Salish Sea, Ian Perry

Institute Publications

Plankton form the base of the pelagic marine food web in the Salish Sea, and are eaten by fishes, marine mammals, and seabirds. Plankton include microscopic plants (phytoplankton) and very small animals (zooplankton). This vignette presents an overview of monitoring observations of phytoplankton and zooplankton distribution and biomass in the Strait of Georgia. Climate change may lead to unusual and unexpected patterns of phytoplankton and zooplankton in the future.

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Ecophysio-Optical Traits Of Semiarid Nebraska Grasslands Under Different Juniperus Virginiana And Pinus Ponderosa Canopy Covers, Anastasios Mazis, Julie A. Fowler, Jeremy Hiller, Yuzhen Zhou, Brian Wardlow, David A. Wedin, Tala Awada Jan 2021

Ecophysio-Optical Traits Of Semiarid Nebraska Grasslands Under Different Juniperus Virginiana And Pinus Ponderosa Canopy Covers, Anastasios Mazis, Julie A. Fowler, Jeremy Hiller, Yuzhen Zhou, Brian Wardlow, David A. Wedin, Tala Awada

School of Natural Resources: Faculty Publications

Despite conservation efforts in the U.S. Great Plains, woody species have continued to expand at an unprecedented rate, threatening key ecosystem services and resilience. Cross-scale monitoring of these grasslands is key to successful integrative management strategies. In this study we measured plant optical traits derived from hyperspectral proximal sensing techniques with a field spectrometer, coupled with field-based measurements, including fluorescence and chlorophyll content, to determine the impacts of Juniperus virginiana and Pinus ponderosa expansion on grasslands health in Nebraska Sandhills, and investigated the use of optical-based approaches as indicators of successful monitoring of grasslands. Our results showed that higher woody …

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Synoptic Mesoscale To Basin Scale Variability In Biological Productivity And Chlorophyll In The Kuroshio Extension Region, Sophie Clayton, Hilary I. Palevsky, Luanne Thompson, Paul D. Quay Jan 2021

Synoptic Mesoscale To Basin Scale Variability In Biological Productivity And Chlorophyll In The Kuroshio Extension Region, Sophie Clayton, Hilary I. Palevsky, Luanne Thompson, Paul D. Quay

OES Faculty Publications

The Kuroshio current separates from the Japanese coast to become the eastward flowing Kuroshio Extension (KE) characterized by a strong latitudinal density front, high levels of mesoscale (eddy) energy, and high chlorophyll a (Chl). While satellite measurements of Chl show evidence of the impact of mesoscale eddies on the standing stock of phytoplankton, there have been very limited synoptic, spatially resolved in situ estimates of productivity in this region. Here, we present underway measurements of oxygen/argon supersaturation (ΔO2/Ar), a tracer of net biological productivity, for the KE made in spring, summer, and early autumn. We find large seasonal differences in …

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Chlorophyll Absorption And Phytoplankton Size Information Inferred From Hyperspectral Particulate Beam Attenuation, Henry F. Houskeeper, David Draper, Raphael M. Kudela, Emmanuel Boss Aug 2020

Chlorophyll Absorption And Phytoplankton Size Information Inferred From Hyperspectral Particulate Beam Attenuation, Henry F. Houskeeper, David Draper, Raphael M. Kudela, Emmanuel Boss

Marine Sciences Faculty Scholarship

Electromagnetic theory predicts spectral dependencies in extinction efficiency near a narrow absorption band for a particle with an index of refraction close to that of the medium in which it is immersed. These absorption band effects are anticipated in oceanographic beam-attenuation (beam-c) spectra, primarily due to the narrow red peak in absorption produced by the phytoplankton photopigment, chlorophyll a (Chl a). Here we present a method to obtain Chl a absorption and size information by analyzing an eigendecomposition of hyperspectral beam-c residuals measured in marine surface waters by an automatic underway system. We find that three principal modes capture more …

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Accuracy Of The Generic Equation To Convert Cci To Chlorophyll Concentration In The Apogee Model Mc-100 Chlorophyll Concentration Meter, Shuyang Zhen, Paul Kusuma May 2020

Accuracy Of The Generic Equation To Convert Cci To Chlorophyll Concentration In The Apogee Model Mc-100 Chlorophyll Concentration Meter, Shuyang Zhen, Paul Kusuma

Techniques and Instruments

Chlorophyll strongly absorbs photons below 700 nm and transmits above 700 nm. Because of this property, chlorophyll concentration can be estimated by measuring the ratio of transmitted photons though a leaf at specific wavelengths. Chlorophyll concentration is then calculated using empirical relationships.

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Phytoplankton Phenology In The North Atlantic: Insights From Profiling Float Measurements, Bo Yang, Emmanuel S. Boss, Nils Haëntjens, Matthew C. Long, Michael J. Behrenfeld, Rachel Eveleth, Scott C. Doney Apr 2020

Phytoplankton Phenology In The North Atlantic: Insights From Profiling Float Measurements, Bo Yang, Emmanuel S. Boss, Nils Haëntjens, Matthew C. Long, Michael J. Behrenfeld, Rachel Eveleth, Scott C. Doney

Marine Sciences Faculty Scholarship

There was a typographical error in Equation (1) of our article, where the first term in the denominator should be 0.022 rather than 0.22. The fully corrected equation should be: (Formula presented.). The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

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Analysis Of Iron Sources In Antarctic Continental Shelf Waters, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken Jan 2020

Analysis Of Iron Sources In Antarctic Continental Shelf Waters, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken

CCPO Publications

Previous studies showed that satellite‐derived estimates of chlorophyll a in coastal polynyas over the Antarctic continental shelf are correlated with the basal melt rate of adjacent ice shelves. A 5‐km resolution ocean/sea ice/ice shelf model of the Southern Ocean is used to examine mechanisms that supply the limiting micronutrient iron to Antarctic continental shelf surface waters. Four sources of dissolved iron are simulated with independent tracers, assumptions about the source iron concentration for each tracer, and an idealized summer biological uptake. Iron from ice shelf melt provides about 6% of the total dissolved iron in surface waters. The contribution from …

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Dynamics Of Prochlorococcus Diversity And Photoacclimation During Short-Term Shifts In Water Column Stratification At Station Aloha, Anne W. Thompson, Ger Van Den Engh, Nathan A. Ahlgren, Kathleen Kouba, Samantha Ward, Samuel T. Wilson, David M. Karl Dec 2018

Dynamics Of Prochlorococcus Diversity And Photoacclimation During Short-Term Shifts In Water Column Stratification At Station Aloha, Anne W. Thompson, Ger Van Den Engh, Nathan A. Ahlgren, Kathleen Kouba, Samantha Ward, Samuel T. Wilson, David M. Karl

Biology Faculty Publications and Presentations

The cyanobacterium Prochlorococcus is the dominant phototroph in surface waters of the vast oligotrophic oceans, the foundation of marine food webs, and an important component of global biogeochemical cycles. The prominence of Prochlorococcus across the environmental gradients of the open ocean is attributed to its extensive genetic diversity and flexible chlorophyll physiology, enabling light capture over a wide range of intensities. What remains unknown is the balance between temporal dynamics of genetic diversity and chlorophyll physiology in the ability of Prochlorococcus to respond to a variety of short (approximately 1 day) and longer (months to year) changes in the environment. …

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A Climatological Dataset Of Nutrient, Chlorophyll, And Particulate Matter Distributions On The Ross Sea Continental Shelf Derived From Cruise-Based Measurements Spanning 1967 To 2016, Walker O. Smith Jr., Daniel E. Kaufman Oct 2018

A Climatological Dataset Of Nutrient, Chlorophyll, And Particulate Matter Distributions On The Ross Sea Continental Shelf Derived From Cruise-Based Measurements Spanning 1967 To 2016, Walker O. Smith Jr., Daniel E. Kaufman

Data

This dataset includes data used in the publication Smith and Kaufman (2018), Progress in Oceanography, which examines the temporal and spatial distributions of nutrients and particulate matter in the Ross Sea continental Shelf using cruise-based observations, and compares the resulting annual productivity estimates with previously reported satellite-based estimates. Specifically, these data represent distributions of nutrients, chlorophyll, particulate organic carbon, particulate organic nitrogen, and biogenic silica that were compiled from 42 cruises (from 1967 - 2016) to the Ross Sea continental shelf to generate a comprehensive climatological dataset for November, December, January, and February. This climatology provides a novel look at …

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Chlorophyll Concentration And Optical Absorption Spectra Of Particulate And Dissolved Material, Collected At Several Depths On Deepend Cruises Dp05 From January-December 2017, Chuanmin Hu Jan 2018

Chlorophyll Concentration And Optical Absorption Spectra Of Particulate And Dissolved Material, Collected At Several Depths On Deepend Cruises Dp05 From January-December 2017, Chuanmin Hu

DEEPEND Datasets

The optical absorption spectra from seawater’s particulate and dissolved components can be used to compute the penetration of light to various depths, estimate the proportion of living to non-living particulate matter, assess photosynthetic light availability and the type of phytoplankton present, and to validate satellite or airborne ocean color measurements. Chlorophyll and phaeopigment concentrations are often used to estimate the amount of phytoplankton present, and to allow extrapolation of in situ fluorometric measurements. Water was collected using a CTD rosette near the surface and from several depths at each sampling station occupied by the DEEPEND cruise DP05 (see GRIIDC dataset …

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Utilizing A Consumer-Grade Camera System To Quantify Surface Reflectance, Joseph J. Lehnert Aug 2017

Utilizing A Consumer-Grade Camera System To Quantify Surface Reflectance, Joseph J. Lehnert

Department of Geography: Dissertations, Theses, and Student Research

Consumer-grade camera systems are often employed in aerial remote sensing to provide insight into patterns and processes of interest to science and industry, a trend that has largely been encouraged by the rapid growth of the small unmanned aircraft system (sUAS) industry. However, little research exists on the ability of these systems to accurately measure surface reflectance in specific wavebands, a crucial consideration for many remote sensing applications. This research was conducted on the premise that with proper equipment and calibration techniques consumer-grade cameras would be capable of accurately measuring surface reflectance in user-defined wavebands of interest. A stereo-pair, Fujifilm …

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Chlorophyll Concentration And Optical Absorption Spectra Of Particulate And Dissolved Material, Collected At Several Depths On Deepend Cruises Dp03 And Dp04 From January-December 2016, Chuanmin Hu, Jenifer Cannizzaro, David English Mar 2017

Chlorophyll Concentration And Optical Absorption Spectra Of Particulate And Dissolved Material, Collected At Several Depths On Deepend Cruises Dp03 And Dp04 From January-December 2016, Chuanmin Hu, Jenifer Cannizzaro, David English

DEEPEND Datasets

The optical absorption spectra from seawater’s particulate and dissolved components can be used to compute the penetration of light to various depths, estimate the proportion of living to non-living particulate matter, assess photosynthetic light availability and the type of phytoplankton present, and the validate of satellite or airborne ocean color measurements. Chlorophyll and phaeopigment concentrations are often used to estimate the amount of phytoplankton present, and to allow extrapolation of in situ fluorometric measurements. Water was collected using a CTD rosette near the surface and from several depths at each sampling station occupied by the DEEPEND cruises DP03 & DP04 …

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Multiple Drivers Of Seasonal Change In Pri: Implications For Photosynthesis 2. Stand Level, Anatoly A. Gitelson, John A. Gamon, Alexei E. Solovchenko Jan 2017

Multiple Drivers Of Seasonal Change In Pri: Implications For Photosynthesis 2. Stand Level, Anatoly A. Gitelson, John A. Gamon, Alexei E. Solovchenko

Biological Systems Engineering: Papers and Publications

The goal of this study was to explore the relationships between stand-level photochemical reflectance index (PRI) and canopy structure/ pigment pools, as well as light use efficiency (LUE) of photosynthetically active vegetation focusing on seasonal or ontogenetic time frames. PRI was originally designed as a means of assessing the xanthophyll cycle and LUE over short (e.g. diurnal) time frames, and few studies have explored the drivers of PRI over longer, seasonal time frames, particularly in crops having different photosynthetic pathways or canopy structures. Consequently, our purpose was to understand and quantify the drivers of PRI responses over seasonal time scales …

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Underway Spectrophotometry Along The Atlantic Meridional Transect Reveals High Performance In Satellite Chlorophyll Retrievals, Robert J.W. Brewin, Giorgio Dall'olmo, Silvia Pardo, Virginie Van Dongen-Vogels, Emmanuel S. Boss Sep 2016

Underway Spectrophotometry Along The Atlantic Meridional Transect Reveals High Performance In Satellite Chlorophyll Retrievals, Robert J.W. Brewin, Giorgio Dall'olmo, Silvia Pardo, Virginie Van Dongen-Vogels, Emmanuel S. Boss

Marine Sciences Faculty Scholarship

To evaluate the performance of ocean-colour retrievals of total chlorophyll-a concentration requires direct comparison with concomitant and co-located in situ data. For global comparisons, these in situ match-ups should be ideally representative of the distribution of total chlorophyll-a concentration in the global ocean. The oligotrophic gyres constitute the majority of oceanic water, yet are under-sampled due to their inaccessibility and under-represented in global in situ databases. The Atlantic Meridional Transect (AMT) is one of only a few programmes that consistently sample oligotrophic waters. In this paper, we used a spectrophotometer on two AMT cruises (AMT19 and AMT22) to continuously measure …

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Siderophore-Based Microbial Adaptations To Iron Scarcity Across The Eastern Pacific Ocean, Rene M. Boiteau, Daniel R. Mende, Nicholas J. Hawco, Matthew R. Mcilvin, Jessica N. Fitzsimmons, Peter N. Sedwick Jan 2016

Siderophore-Based Microbial Adaptations To Iron Scarcity Across The Eastern Pacific Ocean, Rene M. Boiteau, Daniel R. Mende, Nicholas J. Hawco, Matthew R. Mcilvin, Jessica N. Fitzsimmons, Peter N. Sedwick

OES Faculty Publications

Nearly all iron dissolved in the ocean is complexed by strong organic ligands of unknown composition. The effect of ligand composition on microbial iron acquisition is poorly understood, but amendment experiments using model ligands show they can facilitate or impede iron uptake depending on their identity. Here we show that siderophores, organic compounds synthesized by microbes to facilitate iron uptake, are a dynamic component of the marine ligand pool in the eastern tropical Pacific Ocean. Siderophore concentrations in iron-deficient waters averaged 9 pM, up to fivefold higher than in iron-rich coastal and nutrient-depleted oligotrophic waters, and were dominated by amphibactins, …

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Bear Lake Limnology & Nutrient Limnology, Wayne A. Wurtsbaugh Sep 2015

Bear Lake Limnology & Nutrient Limnology, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.

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Regional Ocean-Colour Chlorophyll Algorithms For The Red Sea, Robert J.W. Brewin, Dionysios E. Raitsos, Giorgio Dall'olmo, Nikolaos Zarokanellos, Thomas Jackson, Marie Fanny Racault, Emmanuel S. Boss, Shubha Sathyendranath, Burt H. Jones, Ibrahim Hoteit Aug 2015

Regional Ocean-Colour Chlorophyll Algorithms For The Red Sea, Robert J.W. Brewin, Dionysios E. Raitsos, Giorgio Dall'olmo, Nikolaos Zarokanellos, Thomas Jackson, Marie Fanny Racault, Emmanuel S. Boss, Shubha Sathyendranath, Burt H. Jones, Ibrahim Hoteit

Marine Sciences Faculty Scholarship

The Red Sea is a semi-enclosed tropical marine ecosystem that stretches from the Gulf of Suez and Gulf of Aqaba in the north, to the Gulf of Aden in the south. Despite its ecological and economic importance, its biological environment is relatively unexplored. Satellite ocean-colour estimates of chlorophyll concentration (an index of phytoplankton biomass) offer an observational platform to monitor the health of the Red Sea. However, little is known about the optical properties of the region. In this paper, we investigate the optical properties of the Red Sea in the context of satellite ocean-colour estimates of chlorophyll concentration. Making …

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Dissolved Oxygen Dynamics During A Phytoplankton Bloom In The Ross Sea Polyna, Bastien Y. Queste, Karen J. Heywood, Walker O. Smith Jr., Daniel E. Kaufman, Timothy D. Jickells, Michael S. Dinniman Jan 2015

Dissolved Oxygen Dynamics During A Phytoplankton Bloom In The Ross Sea Polyna, Bastien Y. Queste, Karen J. Heywood, Walker O. Smith Jr., Daniel E. Kaufman, Timothy D. Jickells, Michael S. Dinniman

CCPO Publications

The Ross Sea polynya is one of the most productive regions in the Southern Ocean. However, limited access and high spatio-temporal variability of physical and biological processes limit the use of conventional oceanographic methods to measure early season primary productivity. High-resolution observations from two Seagliders provide insights into the timing of a bloom in the southern Ross Sea polynya in December 2010. Changes in chlorophyll and oxygen concentrations are used to assess bloom dynamics. Using a ratio of dissolved oxygen to carbon, net primary production is estimated over the duration of the bloom showing a sensitive balance between net autotrophy …

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Estimation Of Crop Gross Primary Production (Gpp): I. Impact Of Modisobservation Footprint And Impact Of Vegetation Brdf Characteristics, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiangming Xiao, Andrew E. Suyker, Shashi Verma, Bin Tan, Elizabeth M. Middleton Jan 2014

Estimation Of Crop Gross Primary Production (Gpp): I. Impact Of Modisobservation Footprint And Impact Of Vegetation Brdf Characteristics, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiangming Xiao, Andrew E. Suyker, Shashi Verma, Bin Tan, Elizabeth M. Middleton

School of Natural Resources: Faculty Publications

Accurate estimation of gross primary production (GPP) is essential for carbon cycle and climate change studies. Three AmeriFlux crop sites of maize and soybean were selected for this study. Two of the sites were irrigated and the other one was rainfed. The normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), the green band chlorophyll index (CIgreen), and the green band wide dynamic range vegetation index (WDRVIgreen) were computed from the moderate resolution imaging spectroradiometer (MODIS) surface reflectance data. We examined the impacts of the MODIS observation footprint and the vegetation bidirectional reflectance distribution function …

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In Situ Measurements Of Phytoplankton Fluorescence Using Low Cost Electronics, Thomas Leeuw, Emmanuel S. Boss, Dana L. Wright Jan 2013

In Situ Measurements Of Phytoplankton Fluorescence Using Low Cost Electronics, Thomas Leeuw, Emmanuel S. Boss, Dana L. Wright

Marine Sciences Faculty Scholarship

Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open …

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