Index Catalog // ScholarsArchive@OSU

Role of Trichodesmium spp. in the productivity of the subtropical North Pacific Ocean

Creator:: Letelier, Ricardo M. and Karl, David M.
Abstract:: The concentrations of filamentous diazotroph Trichodesmium spp., present as free trichomes and in colonial assemblages, were measured at approximately monthly intervals at Stn ALOHA (22°45'N, 158°00'W) between October 1989 and December 1992. The average abundance of filaments in the upper 45 m of the water column was highly variable ranging...
Resource Type:: Article
Full Text:: subtropical North Pacific Ocean Ricardo M. L e t e l i e r l . * , David M. ~ a r l ~ ' co l lege of

Trichodesmium spp. physiology and nutrient fluxes in the North Pacific subtropical gyre

Creator:: Letelier, Ricardo M. and Karl, David M.
Abstract:: The potential role of the diazotrophic cyanobacterium Trichodesmium spp. In nitrogen and phosphorus dynamics of the euphotic zone of the North Pacific subtropical gyre was investigated as one component of the Hawaii Ocean Time-series (HOT) program. Experiments were conducted with natural samples collected at Stn ALOHA (22° 45’ N, 158°...
Resource Type:: Article

Light driven seasonal patterns of chlorophyll and nitrate in the lower euphotic zone of the North Pacific Subtropical Gyre

Creator:: Letelier, Ricardo M., Karl, David M., Abbott, Mark R., and Bidigare, Robert R.
Abstract:: The euphotic zone below the deep chlorophyll maximum layer (DCML) at Station ALOHA (a long-term oligotrophic habitat assessment; 22º45′N, 158º00′W) transects the nearly permanently stratified upper thermocline. Hence, seasonal changes in solar radiation control the balance between photosynthesis and respiration in this lightlimited region. Combining profiles of radiance reflectance, algal...
Resource Type:: Article
Full Text:: Letelier, Ricardo M., David M. Karl, Mark R. Abbott, and Robert R

The role of dissolved organic matter release in the productivity of the oligotrophic North Pacific Ocean

Creator:: Karl, David M., Hebel, Dale V., Björkman, K., and Letelier, Ricardo M.
Abstract:: Based on a long-term set of observations and measurements at a station in the subtropical North Pacific Ocean, it now appears that contemporaneous rates of primary production in low-nutrient open ocean regions and perhaps in the ocean as a whole may be greater than had been considered in field studies...
Resource Type:: Article
Full Text:: KARL, DAVID M., DALE V. HEBEL, K. BJÖRKMAN, AND R. M. LETELIER

Jet stream intraseasonal oscillations drive dominant ecosystem variations in Oregon’s summertime coastal upwelling system

Creator:: Bane, John M., Spitz, Yvette H., Letelier, Ricardo M., and Peterson, William T.
Abstract:: Summertime wind stress along the coast of the northwestern United States typically exhibits intraseasonal oscillations (ISOs) with periods from ≈15 to 40 days, as well as fluctuations on the 2- to 6-day “weather-band” and 1-day diurnal time scales. Coastal upwelling of cool, nutrient-rich water is driven by extended periods of...
Resource Type:: Article
Full Text:: ‡, Ricardo M. Letelier‡, and William T. Peterson§ *Department of Marine Sciences, University of North

Chlorophyll natural fluorescence response to upwelling events in the Southern Ocean

Creator:: Letelier, Ricardo M., Abbott, Mark R., and Karl, David M.
Abstract:: Variability of solar-induced (natural) fluorescence and chlorophyll were measured on scales of hours to weeks in the upper layer of a cyclonic eddy located south of the Antarctic Polar Front using a free-floating drifter. The fluorescence signal was analyzed both in terms of chlorophyll concentration and as an indicator of...
Resource Type:: Article

Modeling carbohydrate ballasting by Trichodesmium spp.

Creator:: White, Angelicque E., Spitz, Yvette H., and Letelier, Ricardo M.
Abstract:: We report the development of a numerical model simulating vertical movement of the cyanobacterium Trichodesmium spp. Given a range of physiological parameters derived from the literature, resultant model solutions allow us to explore the ecological significance of vertical migration by Trichodesmium colonies in a stratified oligotrophic oceanic system such as...
Resource Type:: Article
Full Text:: carbohydrate ballasting by Trichodesmium spp. Angelicque E. White*, Yvette H. Spitz, Ricardo M. Letelier

Autonomous observations of in vivo fluorescence and particle backscattering in an oceanic oxygen minimum zone

Creator:: Whitmire, Amanda L., Letelier, Ricardo M., Villagran, Victor, and Ulloa, Osvaldo
Abstract:: The eastern South Pacific (ESP) oxygen minimum zone (OMZ) is a permanent hydrographic feature located directly off the coasts of northern Chile and Peru. The ESP OMZ reaches from coastal waters out to thousands of kilometers offshore, and can extend from the near surface to depths greater than 700 m....
Resource Type:: Article
Full Text:: particle backscattering in an oceanic oxygen minimum zone A. L. Whitmire,1,* R. M. Letelier,1 V

Parameterizing the natural fluorescence kinetics of Thalassiosira weissflogii

Creator:: Laney, Samuel R., Letelier, Ricardo M., and Abbott, Mark R.
Abstract:: We examined variability in the natural fluorescence yield of a neritic diatom, Thalassiosira weissflogii, in continuous cultures. In this species, kinetics in natural fluorescence yield over time scales less than a photoperiod were characterized by sharp decreases, occurring at irradiance intensities that presumably coincide with the onset of nonphotochemical fluorescence...
Resource Type:: Article
Full Text:: Laney, S. R., R. M. Letelier, and M. R. Abbott. Parameterizing the

GradovilleMaryCEOASPhysiologicalResponseCrocosphaera.pdf

Creator:: Gradoville, Mary R., White, Angelicque E., and Letelier, Ricardo M.
Abstract:: We investigated the effects of elevated pCO₂ on cultures of the unicellular N₂-fixing cyanobacterium Crocosphaera watsonii WH8501. Using CO₂-enriched air, cultures grown in batch mode under high light intensity were exposed to initial conditions approximating current atmospheric CO₂ concentrations (~400 ppm) as well as CO₂ levels corresponding to low- and...
Full Text:: *, Angelicque E. White, Ricardo M. Letelier Oregon State University, College of Earth, Ocean, and Atmospheric

Analysis of a Method to Estimate Chlorophyll-a Concentration from Irradiance Measurements at Varying Depths

Creator:: Nahorniak, Jasmine S., Abbott, Mark R., Letelier, Ricardo M., and Pegau, W. Scott
Abstract:: A model to estimate chlorophyll-a concentration and yellow substance absorption at 440 nm from irradiance measurements made at varying depths is examined. The derivation of the model, requiring irradiance measurements at three wavebands, is presented and tested on data collected in oligotrophic (with low chlorophyll concentrations) waters and in coastal...
Resource Type:: Article
Full Text:: Concentration from Irradiance Measurements at Varying Depths JASMINE S. NAHORNIAK, MARK R. ABBOTT, RICARDO M

Summer surface waters in the Gulf of California: Prime habitat for biological N₂ fixation

Creator:: White, Angelicque E., Prahl, Fredrick G., Letelier, Ricardo M., and Popp, Brian N.
Abstract:: We report significant rates of dinitrogen (N₂) fixation in the central basins of the Gulf of California (GC) during July–August 2005. Mixing model estimates based upon δ¹⁵N values of particulate matter in the surface mixed layer indicate that N₂ fixation provides as much as 35% to 48% of the phytoplankton-based...
Resource Type:: Article
Full Text:: : Prime habitat for biological N2 fixation Angelicque E. White,1 Fredrick G. Prahl,1 Ricardo M. Letelier

Flexible elemental stoichiometry in Trichodesmium spp. and its ecological implications

Creator:: White, Angelicque E., Spitz, Yvette, Karl, David, and Letelier, Ricardo M.
Abstract:: We conducted laboratory experiments to assess the bioelemental plasticity of cultures of Trichodesmium IMS101 under phosphorus (P)-replete, P-restricted, and light-limited conditions. The results reveal a high degree of stoichiometric flexibility. Specifically, Trichodesmium IMS101 is capable of growth with carbon (C) : nitrogen (N) : P ratios of C₅₈₅±₅₆ : N₉₀±₁₀...
Resource Type:: Article
Full Text:: Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822 Ricardo M. Letelier College

Using lasers to probe the transient light absorption by proteorhodopsin in marine bacterioplankton

Creator:: Desiderio, Russell A., Laney, Samuel R., Letelier, Ricardo M., and Giovannoni, Stephen J.
Abstract:: We constructed an experimental apparatus that used lasers to provide the probe beams for measuring the transient absorption kinetics of bacterioplankton that contain proteorhodopsin, a microbial protein that binds retinal and is analogous to animal rhodopsin. With this approach we were able to observe photocycles characteristic of functioning retinylidene ion...
Resource Type:: Article
Full Text:: proteorhodopsin in marine bacterioplankton Russell A. Desiderio,1,* Samuel R. Laney,1,3 Ricardo M. Letelier,1 and

Light-induced growth of phytoplankton collected during the winter from the benthic boundary layer off Oregon, USA

Creator:: Wetz, Michael S., Wheeler, Patricia A., and Letelier, Ricardo M.
Abstract:: Despite the importance of the spring phytoplankton bloom off Oregon as a food source for zooplankton, little is known about the sources of phytoplankton seed stock for the bloom or its timing. Experiments were conducted in the late winter to determine if the benthic boundary layer (BBL) could be a...
Resource Type:: Article
Full Text:: from the benthic boundary layer off Oregon, USA Michael S. Wetz*, Patricia A. Wheeler, Ricardo M

GradovilleMaryCEOASPhysiologicalResponseCrocosphaera_TableS1.pdf

Creator:: Gradoville, Mary R., White, Angelicque E., and Letelier, Ricardo M.
Abstract:: We investigated the effects of elevated pCO₂ on cultures of the unicellular N₂-fixing cyanobacterium Crocosphaera watsonii WH8501. Using CO₂-enriched air, cultures grown in batch mode under high light intensity were exposed to initial conditions approximating current atmospheric CO₂ concentrations (~400 ppm) as well as CO₂ levels corresponding to low- and...

Physiological Response of Crocosphaera watsonii to Enhanced and Fluctuating Carbon Dioxide Conditions

Creator:: Gradoville, Mary R., White, Angelicque E., and Letelier, Ricardo M.
Abstract:: We investigated the effects of elevated pCO₂ on cultures of the unicellular N₂-fixing cyanobacterium Crocosphaera watsonii WH8501. Using CO₂-enriched air, cultures grown in batch mode under high light intensity were exposed to initial conditions approximating current atmospheric CO₂ concentrations (~400 ppm) as well as CO₂ levels corresponding to low- and...
Resource Type:: Article

LetelierRicardoCEOASPairedWindwardLeeward.pdf

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...
Full Text:: ., Church, M. J., Karl, D. M., Sadler, D. W., & Letelier, R. M. (2014). Paired windward and leeward

Experimental assessment of diazotroph responses to elevated seawater pCO₂ in the North Pacific Subtropical Gyre

Creator:: Böttjer, Daniela, Karl, David M., Letelier, Ricardo M., Viviani, Donn A., and Church, Matthew J.
Abstract:: We examined short-term (24–72 h) responses of naturally occurringmarine N2 fixing microorganisms (termed diazotrophs) to abrupt increases in the partial pressure of carbon dioxide (pCO2) in seawater during nine incubation experiments conducted between May 2010 and September 2012 at Station ALOHA (A Long-term Oligotrophic Habitat Assessment) (22°45′N, 158°W) in the...
Resource Type:: Article
Full Text:: elevated seawater pCO₂ in the North Pacific Subtropical Gyre Böttjer, D., D. M. Karl, R. M. Letelier, D

LetelierRicardoCEOASPairedWindwardLeeward_SupportingInformation.zip

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...

Paired windward and leeward biogeochemical time series reveal consistent surface ocean CO₂ trends across the Hawaiian Ridge

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...
Resource Type:: Article

Diversity trumps acidification : lack of evidence for carbon dioxide enhancement of Trichodesmium community nitrogen or carbon fixation at Station ALOHA

Creator:: Gradoville, Mary R., White, Angelicque E., Böttjer, Daniela, Church, Matthew J., and Letelier, Ricardo M.
Abstract:: We conducted 11 independent short-term carbon dioxide (CO₂) manipulation experiments using colonies of the filamentous cyanobacteria Trichodesmium isolated on three cruises in the North Pacific Subtropical Gyre (NPSG). Dinitrogen (N₂) and carbon (C) fixation rates of these colonies were compared over CO₂ conditions ranging from ~ 18 Pa (equivalent to...
Resource Type:: Article
Full Text:: . Church,2 and Ricardo M. Letelier 1 1 Oregon State University, College of Earth, Ocean, and Atmospheric

Temporal variability of phytoplankton community structure based on pigment analysis

Creator:: Letelier, Ricardo M., Bidigare, Robert R., Hebel, Dale V., Ondrusek, M., Winn, C. D., and Karl, David M.
Abstract:: Algal chlorophyll and carotenoid distributions were measured periodically in the euphotic zone of Sta. ALOHA (22º45′N, 158º00′W) between February 1989 and October 1991 to document the variability in phytoplankton abundance and composition. The annual mean depth-integrated (O-200 db) concentration of Chl a displayed significant interannual variability. Seasonal patterns in Chl...
Resource Type:: Article
Full Text:: LETELIER, R. M., R. R. BIDIGARE, D. V. HEBEL, M. ONDRUSEK, C. D

Phenology of particle size distributions and primary productivity in the North Pacific subtropical gyre (Station ALOHA)

Creator:: White, Angelicque E., Letelier, Ricardo M., Whitmire, Amanda L., Barone, Benedetto, Bidigare, Robert R., Church, Matthew J., and Karl, David M.
Abstract:: The particle size distribution (PSD) is a critical aspect of the oceanic ecosystem. Local variability in the PSD can be indicative of shifts in microbial community structure and reveal patterns in cell growth and loss. The PSD also plays a central role in particle export by influencing settling speed. Satellite-based...
Resource Type:: Article
Full Text:: ., Letelier, R. M., Whitmire, A. L., Barone, B., Bidigare, R. R., Church, M. J., & Karl, D. M. (2015

Particle distributions and dynamics in the euphotic zone of the North Pacific Subtropical Gyre

Creator:: Barone, Benedetto, Bidigare, Robert R., Church, Matthew J., Karl, David M., Letelier, Ricardo M., and White, Angelicque E.
Abstract:: During the summer of 2012, we used laser diffractometry to investigate the temporal and vertical variability of the particle size spectrum (1.25–100 µm in equivalent diameter) in the euphotic zone of the North Pacific Subtropical Gyre. Particles measured with this optical method accounted for ∼40% of the particulate carbon stocks...
Resource Type:: Article
Full Text:: ., Letelier, R. M., & White, A. E. (2015). Particle distributions and dynamics in the euphotic zone of the

Impact of climate forcing on ecosystem processes in the North Pacific Subtropical Gyre

Creator:: Corno, Guido, Karl, David M., Church, Matthew J., Letelier, Ricardo M., Lukas, Roger, Bidigare, Robert R., and Abbott, Mark R.
Abstract:: Measurements at the Hawaii Ocean Time-series (HOT) Station ALOHA (22 degrees 45'N, 158 degrees W) have revealed a significant, approximately 50% increase in euphotic zone depth-integrated rates of primary production ( PP; mol C fixed m(-2) d(-1)) based on in situ C-14 experiments. The character of the nearly two-decade increasing...
Resource Type:: Article
Full Text:: Ricardo M. Letelier,1 Roger Lukas,3 Robert R. Bidigare,4 and Mark R. Abbott1 Received 24 May 2006

Role of late winter mesoscale events in the biogeochemical variability of the upper water column of the North Pacific Subtropical Gyre

Creator:: Letelier, Ricardo M., Karl, David M., Abbott, Mark R., Flament, P., Freilich, Michael H., Lukas, Roger, and Strub, P. Ted
Abstract:: Continuous records of upper water column (0–150 m) temperature profiles, spectral distribution of downwelling irradiance, and phytoplankton solar-induced fluorescence at 25 m depth were obtained during the inaugural deployment of the Hawaii Air-sea Logging Experiment, A Long-term Oligotrophic Habitat Assessment (HALE ALOHA) mooring, near the Hawaii Ocean Time-series (HOT) Station...
Resource Type:: Article

Physicochemical and biological controls on primary and net community production across northeast Pacific seascapes

Creator:: Kavanaugh, Maria T., Emerson, Steven R., Hales, Burke, Lockwood, Deirdre M., Quay, Paul D., and Letelier, Ricardo M.
Abstract:: The subarctic-subtropical transition zone in the North Pacific represents the second largest sink of atmospheric carbon dioxide in the world ocean, yet the relative importance of physical and biological processes in this uptake is debated. In a step toward understanding the spatiotemporal variability of environmental, physiological, and ecological factors that...
Resource Type:: Article
Full Text:: Paul D. Quay,2 and Ricardo M. Letelier 3 1 Department of Marine Chemistry and Geochemistry, Woods Hole

Juranek LaurieCEOASShortTermVariability.pdf

Creator:: Wilson, Samuel T., Barone, Benedetto, Ascani, Francois, Juranek, Laurie W., Letelier, Ricardo M., White, Angelicque E., and et al.
Abstract:: Time-series observations are critical to understand the structure, function, and dynamics of marine ecosystems. The Hawaii Ocean Time-series program has maintained near-monthly sampling at Station ALOHA (22°45′N, 158°00′W) in the oligotrophic North Pacific Subtropical Gyre (NPSG) since 1988 and has identified ecosystem variability over seasonal to interannual timescales. To further...
Full Text:: Ferrón1,2, Jessica N. Fitzsimmons1,6, LaurieW. Juranek7, Zbigniew S. Kolber1,8, Ricardo M. Letelier1,7

Juranek LaurieCEOASShortTermVariabilitySupplement.pdf

Creator:: Wilson, Samuel T., Barone, Benedetto, Ascani, Francois, Juranek, Laurie W., Letelier, Ricardo M., White, Angelicque E., and et al.
Abstract:: Time-series observations are critical to understand the structure, function, and dynamics of marine ecosystems. The Hawaii Ocean Time-series program has maintained near-monthly sampling at Station ALOHA (22°45′N, 158°00′W) in the oligotrophic North Pacific Subtropical Gyre (NPSG) since 1988 and has identified ecosystem variability over seasonal to interannual timescales. To further...
Full Text:: . Kolber8, Ricardo M. Letelier7, Sandra Martínez-Garcia1,2, David P. Nicholson9, Kelvin J. Richards1

Validation of Terra-MODIS phytoplankton chlorophyll fluorescence line height

Creator:: Hoge, Frank E., Lyon, Paul E., Swift, Robert N., Yungel, James K., Abbott, Mark R., Letelier, Ricardo M., and Esaias, Wayne E.
Abstract:: The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft contains spectral bands that allow retrieval of solar-induced phytoplankton chlorophyll fluorescence emission radiance. Concurrent airborne laser-induced (and water-Raman normalized) phytoplankton chlorophyll fluorescence data is used to successfully validate the MODIS chlorophyll fluorescence line height (FLH) retrievals within Gulf Stream, continental...
Resource Type:: Article
Full Text:: . Swift, James K. Yungel, Mark R. Abbott, Ricardo M. Letelier, Wayne E. Esaias The Moderate Resolution

Addition of inorganic or organic phosphorus enhances nitrogen and carbon fixation in the oligotrophic North Pacific

Creator:: Watkins-Brandt, Katie S., Letelier, Ricardo M., Spitz, Yvette H., Church, Matthew J., Böttjer, Daniela, and White, Angelicque E.
Abstract:: We present a spatially extensive record of dinitrogen (N₂) fixation rates and distributions of N₂ fixing microorganisms along with the results of exogenous phosphorus (P) addition experiments conducted during a series of cruises in the North Pacific Subtropical Gyre (NPSG). We measured the N₂ and carbon (C) fixation rates of...
Resource Type:: Article
Full Text:: -Brandt1, Ricardo M. Letelier1, Yvette H. Spitz1, Matthew J. Church2, Daniela Böttjer2, Angelicque E

An Open Ocean Trial of Controlled Upwelling Using Wave Pump Technology

Creator:: White, Angelicque, Bjorkman, Karin, Grabowski, Eric, Letelier, Ricardo, Poulos, Steve, Watkins, Blake, and Karl, David
Abstract:: In 1976, John D. Isaacs proposed to use wave energy to invert the density structure of the ocean and pump deep, nutrient-rich water into the sunlit surface layers. The basic principle is simple: a length of tubing attached to a surface buoy at the top, and a one-way valve at...
Resource Type:: Article
Full Text:: Technology, University of Hawaii at Manoa, Honolulu, Hawaii RICARDO LETELIER College of Oceanic and

Satellite-based prediction of pCO₂ in coastal waters of the eastern North Pacific

Creator:: Hales, Burke, Strutton, Peter G., Saraceno, Martin, Letelier, Ricardo, Takahashi, Taro, Feely, Richard, Sabine, Christopher, and Chavez, Francisco
Abstract:: Continental margin carbon cycling is complex, highly variable over a range of space and time scales, and forced by multiple physical and biogeochemical drivers. Predictions of globally significant air–sea CO₂ fluxes in these regions have been extrapolated based on very sparse data sets. We present here a method for predicting...
Resource Type:: Article
Full Text:: Pacific Burke Hales a,⇑, Peter G. Strutton g, Martin Saraceno b,c, Ricardo Letelier a, Taro Takahashi d

Influence of Rossby waves on nutrient dynamics and the plankton community structure in the North Pacific subtropical gyre

Creator:: Sakamoto, Carole M., Karl, David M., Jannasch, Hans W., Bidigare, Robert R., Letelier, Ricardo M., Walz, Peter M., Ryan, John P., Polito, Paulo S., and Johnson, Kenneth S.
Abstract:: Nitrate concentrations, chlorophyll a (Chl a) fluorescence, radiance, salinity, and temperature were measured on the Hawaii Air-Sea Logging Experiment, A Long-Term Oligotrophic Habitat Assessment (HALE ALOHA) mooring located near the Hawaii Ocean Time-Series (HOT) Program’s Station ALOHA (22°45’N; 158°W). Nitrate concentrations were determined with OsmoAnalyzers deployed at depths of 120...
Resource Type:: Article
Full Text:: . Karl,2 Hans W. Jannasch,1 Robert R. Bidigare,2 Ricardo M. Letelier,3 Peter M. Walz,1 John P. Ryan,1

Satellite-derived variability in chlorophyll, wind stress, sea surface height, and temperature in the northern California Current System

Creator:: Venegas, Roberto M., Strub, P. Ted, Beier, Emilio, Letelier, Ricardo M., Thomas, Andrew C., Cowles, Timothy J., James, Corinne, Soto-Mardones, Luis, and Cabrera, Carlos
Abstract:: Satellite-derived data provide the temporal means and seasonal and nonseasonal variability of four physical and biological parameters off Oregon and Washington (41°–48.5°N). Eight years of data (1998–2005) are available for surface chlorophyll concentrations, sea surface temperature (SST), and sea surface height, while six years of data (2000–2005) are available for...
Resource Type:: Article
Full Text:: . Venegas,1 P. Ted Strub,1 Emilio Beier,2 Ricardo Letelier,1,3 Andrew C. Thomas,4 Timothy Cowles,1 Corinne

Initiation of the spring phytoplankton increase in the Antarctic Polar Front Zone at 170°W

Creator:: Landry, Michael R., Brown, Susan L., Selph, Karen E., Abbott, Mark R., Letelier, Ricardo M., Christensen, Stephanie, Bidigare, Robert R., and Casciotti, K.
Abstract:: During austral summer 1997, satellite imagery revealed enhanced chlorophyll associated with the Antarctic Polar Front at 170°W. Phytoplankton growth conditions during the early stages of the spring increase were investigated on the Antarctic Environment and Southern Ocean Process Study Survey I cruise using flow cytometry (FCM) and microscopy to characterize...
Resource Type:: Article
Full Text:: were designed as discussed by Abbott and Letelier [1998] and drogued at 15 m to follow upper ocean

Simulating the global distribution of nitrogen isotopes in the ocean

Creator:: Somes, Christopher J., Schmittner, Andreas, Galbraith, Eric D., Lehmann, Moritz F., Altabet, Mark A., Montoya, Joseph P., Letelier, Ricardo M., Mix, Alan C., Bourbonnais, Annie, and Eby, Michael
Abstract:: We present a new nitrogen isotope model incorporated into the three-dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, 14N and 15N, in the nitrate (NO3−), phytoplankton, zooplankton, and detritus variables of the...
Resource Type:: Article
Full Text:: ,2 Moritz F. Lehmann,3 3 Mark A. Altabet,4 Joseph P. Montoya,5 Ricardo M. Letelier,1 Alan C. Mix,1

Numerical experiments on the effects of a meridional ridge on the transmission of energy by barotropic Rossby waves

Creator:: Matano, Ricardo P.
Abstract:: Analytical and numerical models are used to study the effects of a meridional ridge on the propagation of barotropic Rossby waves produced by distant wind stress forcing. The analytical model illustrates the qualitative aspects of the problem by solving a simplified form of the potential vorticity equation. The analytical results...
Resource Type:: Article

Does eddy-eddy interaction control surface phytoplankton distribution and carbon export in the North Pacific Subtropical Gyre?

Creator:: Guidi, Lionel, Calil, Paulo H. R., Duhamel, Solange, Bjoerkman, Karin M., Doney, Scott C., Jackson, George A., Li, Binglin, Church, Matthew J., Tozzi, Sasha, Kolber, Zbigniew S., Richards, Kelvin J., Fong, Allison A., Letelier, Ricardo M., Gorsky, Gabriel, Stemmann, Lars, and Karl, David M.
Abstract:: In the North Pacific Subtropical Gyre (NPSG), the regular occurrence of summer phytoplankton blooms contributes to marine ecosystem productivity and the annual carbon export. The mechanisms underlying the formation, maintenance, and decay of these blooms remain largely unknown; nitrogen fixation, episodic vertical mixing of nutrients, and meso- (<100 km) and...
Resource Type:: Article
Full Text:: . Richards,1,2 Allison A. Fong,1,2 Ricardo M. Letelier,2,9 Gabriel Gorsky,10 Lars Stemmann,10 and David M

Spatial and Spectral Resolution Considerations for Imaging Coastal Waters

Creator:: Davis, Curtiss O., Kavanaugh, Maria, Letelier, Ricardo, Bissett, W. Paul, and Kohler, David
Abstract:: Current ocean color sensors, for example SeaWiFS and MODIS, are well suited for sampling the open ocean. However, coastal environments are spatially and optically more complex and require more frequent sampling and higher spatial resolution sensors with additional spectral channels. We have conducted experiments with data from Hyperion and airborne...
Resource Type:: Article

Short-term variability in euphotic zone biogeochemistry and primary productivity at Station ALOHA: A case study of summer 2012

Creator:: Wilson, Samuel T., Barone, Benedetto, Ascani, Francois, Bidigare, Robert R., Church, Matthew J., del Valle, Daniela A., Dyhrman, Sonya T., Ferrón, Sara, Fitzsimmons, Jessica N., Juranek, Laurie W., Kolber, Zbigniew S., Letelier, Ricardo M., Martínez‐García, Sandra, Nicholson, David P., Richards, Kelvin J., Rii, Yoshimi M., Rouco, Mónica, Viviani, Donn A., White, Angelicque E., Zehr, Jonathan P., and Karl, David M.
Abstract:: Time-series observations are critical to understand the structure, function, and dynamics of marine ecosystems. The Hawaii Ocean Time-series program has maintained near-monthly sampling at Station ALOHA (22°45′N, 158°00′W) in the oligotrophic North Pacific Subtropical Gyre (NPSG) since 1988 and has identified ecosystem variability over seasonal to interannual timescales. To further...
Resource Type:: Article

A dynamic partial order model of electrolyte solutions

Creator:: Pytkowicz, Ricardo M. (Ricardo Marcos), 1929-, Johnson, K., and Curtis, C.
Abstract:: The purpose of this work was to develop a dynamic partial order model of II electrolyte solutions which avoids inconsistencies present in the Debye-1-Iuckel and 1n related theories. It is shown that our results are consistent with activity coefficient data in aqueous electrolyte solutions. The main features of our work...
Resource Type:: Technical Report
Full Text:: . d) A Dynamic Partial Order Model of Electrolyte Solutions R. M. Pytkowicz, K. Johnson, and C

A two-way nested simulation of the oceanic circulation in the Southwestern Atlantic

Creator:: Combes, Vincent and Matano, Ricardo P.
Abstract:: This article presents the results of a high-resolution (1/12°), two-way nested simulation of the oceanic circulation in the southwestern Atlantic region. A comparison between the model results and extant observations indicates that the nested model has skill in reproducing the best-known aspects of the regional circulation, e.g., the volume transport...
Resource Type:: Article
Full Text:: oceanic circulation in the Southwestern Atlantic Vincent Combes1 and Ricardo P. Matano1 1College of Earth

The Low-Frequency Variability of the Southern Ocean Circulation

Creator:: Giarolla, Emanuel and Matano, Ricardo P.
Abstract:: Abstract: Long time series of sea surface height (SSH), sea surface temperature, and wind stress curl are used to determine the main modes of low-frequency variability of the Southern Ocean (SO) circulation. The dominant mode is a trend of increasing SSH at an average rate of 3.3 mm yr(-1). Similar...
Resource Type:: Article
Full Text:: Southern Ocean Circulation EMANUEL GIAROLLA CPTEC/INPE, S~ao Jos�e dos Campos, Brazil RICARDO P. MATANO

Trends in the Brazil/Malvinas Confluence region

Creator:: Combes, Vincent and Matano, Ricardo P.
Abstract:: Observations show abrupt changes in the oceanic circulation of the southwestern Atlantic. These studies report a southward drift of the Brazil/Malvinas Confluence (BMC) and a change in the spectral characteristics of the Malvinas Current (MC) transport. We address the cause of these changes using the result of a high-resolution numerical...
Resource Type:: Article
Full Text:: /sa-termsofuse Trends in the Brazil/Malvinas Confluence region Vincent Combes1 and Ricardo P

Agave salmiana Plant Communities in Central Mexico as Affected by Commercial Use

Creator:: Martinez Salvador, Martin, Mata-Gonzalez, Ricardo, Morales Nieto, Carlos, and Valdez-Cepeda, Ricardo
Abstract:: Agave salmiana is a native plant species harvested for the commercial production of mezcal (Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were...
Resource Type:: Article
Full Text:: -González, Carlos Morales Nieto, Ricardo Valdez-3 Cepeda 4 5 6 M. Martínez Salvador, C. Morales

Formation and pathways of the intermediate water in the Parallel Ocean Circulation Model's Southern Ocean

Creator:: Schouten, Mathijs W. and Matano, Ricardo P.
Abstract:: The formation mechanisms and pathways of intermediate water in the Southern Ocean are analyzed from output of a high-resolution ocean general circulation model. Deep winter mixed layer formation in the Southern Ocean is diagnosed from the model results and is found to be mostly consistent with observations. Diapycnal water mass...
Resource Type:: Article
Full Text:: in the Parallel Ocean Circulation Model’s Southern Ocean Mathijs W. Schouten1,2 and Ricardo P

An efficient method to estimate processing rates in streams

Creator:: Gonz alez-Pinz on, Ricardo and Haggerty, Roy
Abstract:: We provide an efficient method to estimate processing rates through simple algebraic relationships derived from the transient storage model equations. The method is based on the transport equations, but eliminates the need to calibrate highly uncertain (and intermediate) parameters. We demonstrate that under some common stream transport conditions dispersion does...
Resource Type:: Article
Full Text:: processing rates in streams Ricardo Gonz�alez-Pinz�on1,2 and Roy Haggerty1 Received 26 April 2013; revised

Quantifying spatial differences in metabolism in headwater streams

Creator:: Gonzalez-Pinzon, Ricardo, Haggerty, Roy, and Argerich, Alba
Abstract:: Stream functioning includes simultaneous interaction among solute transport, nutrient processing, and metabolism. Metabolism is measured with methods that have limited spatial representativeness and are highly uncertain. These problems restrict development of methods for up-scaling biological processes that mediate nutrient processing. We used the resazurin–resorufin (Raz-Rru) tracer system to estimate metabolism...
Resource Type:: Article
Full Text:: September 2014 2 3 Quantifying spatial differences in metabolism in headwater streams 4 5 Ricardo

Search Constraints

Search Results

Limit your search