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Full-Text Articles in Physical Sciences and Mathematics

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Harold G. Marshall, Lubomira Burchardt Jul 2005

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Harold G. Marshall, Lubomira Burchardt

Virginia Journal of Science

Phytoplankton composition and the range of seasonal patterns of abundance are presented for the tidal freshwater regions in two Virginia rivers based on data accumulated monthly from 1986 through 1999. Diatoms dominated the flora during spring, summer, and fall, whereas, other taxonomic categories were more representative when the river flow rates decreased, allowing for a more stable water system and increased residency time within this tidal region during summer and early fall. This summer/fall period was associated with increased water temperatures, higher productivity rates and chlorophyll levels, increased total phytoplankton abundance and species diversity. The major components of the summer …


Modeling The Effects Of Physical And Biogeochemical Processes On Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean, Baris Salihoglu Jul 2005

Modeling The Effects Of Physical And Biogeochemical Processes On Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean, Baris Salihoglu

OES Theses and Dissertations

The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at 0°N, 140°W. This research objective was addressed using a one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have …


Absorption And Backscattering In The Beaufort And Chukchi Seas, Jian Wang, Glenn F. Cota, David A. Ruble Jan 2005

Absorption And Backscattering In The Beaufort And Chukchi Seas, Jian Wang, Glenn F. Cota, David A. Ruble

CCPO Publications

Bio-optical observations were made during August 2000 in the Beaufort and Chukchi Seas. Chlorophyll a concentration (Chl) ranged from 0.068 to 18.5 mg chl m-3. Both total particulate and phytoplankton absorption at 443 nm were closely correlated with chlorophyll concentration. Linear spectral relationships were observed for phytoplankton absorption. The chlorophyll-specific absorption of phytoplankton at 443 nm was nearly constant at 0.013 m2 (mg chl)-1, but particulate absorption due to nonpigmented particulates at 443 nm was highly variable. There was no strong correlation between chlorophyll concentration and absorption by soluble materials or nonpigmented particulates. Absorption, scattering, …


The Role Of Feeding Behavior In Sustaining Copepod Populations In The Tropical Ocean, J. D. Wiggert, A. G. E. Haskell, G.-A. Paffenhofer, E. E. Hofmann, J. M. Klinck Jan 2005

The Role Of Feeding Behavior In Sustaining Copepod Populations In The Tropical Ocean, J. D. Wiggert, A. G. E. Haskell, G.-A. Paffenhofer, E. E. Hofmann, J. M. Klinck

CCPO Publications

A fundamental question regarding marine copepods is how the many species coexist and persist in the oligotrophic environment (i.e. Hutchinson’s paradox). This question is addressed with a stochastic, object-oriented Lagrangian model that explicitly simulates the distinct foraging behaviors of three prominent tropical species: Clausocalanus furcatus, Paracalanus aculeatus and Oithona plumifera. The model also individually tracks all prey cells. Each particle’s motion combines sinking, turbulent diffusion and active swimming when applicable. The model successfully simulates observed size partitioned carbon uptake rates. Based on the model results, the wide-ranging translational ambit employed by C. furcatus is best suited for the acquisition …


Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak Jan 2005

Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak

Biological Sciences Faculty Publications

Phytoplankton abundance and composition relationships within the surface layer changed over short time periods (4-6 hours) in comparison with more constant associations at 2 cm below the surface. Both strata had a diverse algal flora (>50 taxa), but no distinct neuston assemblage characterized the surface layer algal composition over the 24-hour study. The similarity between the two strata indicated the floral composition of the surface layer came from the water column algae below the surface. Chlorophytes, diatoms, cyanobacteria, and cryptophytes represented the most abundant algal categories for both strata with a total mean phytoplankton abundance of 3,566 cells ml …


A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu Jan 2005

A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu

OES Faculty Publications

A distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth integrated chlorophyll-a and primary production were elevated to 0.3 mg/m3, ~35 mg/m2 and 300 mg-C/m2/d, respectively, in the winter but stayed low, at 0.1 mg/m3, ~15 mg/m2 and 110 mg-C/m2/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became …


Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Usa, Harold G. Marshall, Lubomira Burchardt Jan 2005

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Usa, Harold G. Marshall, Lubomira Burchardt

Biological Sciences Faculty Publications

Phytoplankton composition and the range of seasonal patterns of abundance are presented for the tidal freshwater regions in two Virginia rivers based on data accumulated monthly from 1986 through 1999. Diatoms dominated the flora during spring, summer, and fall, whereas, other taxonomic categories were more representative when the river flow rates decreased, allowing for a more stable water system and increased residency time within this tidal region during summer and early fall. This summer/fall period was associated with increased water temperatures, higher productivity rates and chlorophyll levels, increased total phytoplankton abundance and species diversity. The major components of the summer …