Tetraselmis suecica is a green microalga that thrives under a wide range of conditions, used in t... more Tetraselmis suecica is a green microalga that thrives under a wide range of conditions, used in the commercial culture of fish, mollusk, and crustacean larvae for supplementing the demand for fertilizers. Its pigments have applications in human health care as drug products, vitamins, and cosmetics. Growth and pigment concentration of T. suecica were evaluated in experimental cultures with different nutrient concentrations and light intensities to determine the most appropriate culture conditions to optimize the production of biomass and pigments. Chlorophyll-a, chlorophyll-b, lutein, violaxanthin, α, β-carotene, and neoxanthin concentrations were evaluated under three different nutrient conditions (441.5/18.1, 883/36.3, and 1766/76.2 μM of NaNO3/NaH2PO4) and four light intensities (50, 150, 300, and 750 μmol quanta m-2 s-1). Increases in either or both of these factors lead to increases in the concentration of all pigments. Chlorophyll-a reached up to 5×103 mg m-3, chlorophyll-b up ...
This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic c... more This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic composition in the surface waters of Todos Santos Bay, a semi-enclosed bay within the upwelling zone of the Baja California peninsula (México). Two methodological approaches (microscopy and chemotaxonomy [CHEMTAX]) were used to describe the variability of some genera and species (observed under the microscope) and the importance of those groups that cannot be observed microscopically. Phytoplankton biomarker pigments were measured with high-resolution liquid chromatography and used as input to run the CHEMTAX software to determine the contribution of the main phytoplankton groups to chlorophyll-a (Chl-a). The microscopic analyses showed that diatoms and dinoflagellates comprised 65 and 33% of the total cells, respectively. Dinoflagellates were most abundant in the inner bay and during cold months; the most frequent and abundant genera were Tripos, Protoperidinium, and Prorocentrum. Among ...
This study is dedicated to the understanding of time and space variability of bio-optical variabl... more This study is dedicated to the understanding of time and space variability of bio-optical variables at a coastal station off Baja California Peninsula (ANTARES Baja California station, 31.75 o N/116.96 o W). The sampling procedure begun in May 2007 and in this presentation we will report changes observed in the absorption properties by three components of seawater (phytoplankton, detritus and chromophoric-dissolved-organic-matter or CDOM) in the photic zone in relation to changes in environmental conditions (inorganic nutrient) and phytoplankton community structure. Chlorophyll-a concentration (Chla) ranged from 0.04 to 1.44 mg m-3 with a strong vertical variability related to advective processes and the depth of the nutricline. Diatoms and dinoflagellates were the dominant fraction which was evaluated by HPLC pigment concentration (Fucoxanthin and Peridinin respectively). At low Chla phytoplankton community structure there are a higher proportion of small cells that were identified...
Algunas consideraciones tecnicas sobre la toma de muestra, almacenamiento tipo de fijador y metod... more Algunas consideraciones tecnicas sobre la toma de muestra, almacenamiento tipo de fijador y metodologia de conteo en muestras de agua para la evalución de la Taxocenosis fitoplanctonica en aguas costeras. Esta es una manual del Cuerpo Academico de Ecologia del Fitoplancton FCM-UABC en su serie White Papers
En este capítulo los autores proponen una nueva aproximación para evaluar florecimientos algales ... more En este capítulo los autores proponen una nueva aproximación para evaluar florecimientos algales nocivos tomando en cuenta las propiedades ópticas inherentes y aparentes de los cuerpos de agua, en especial del fitoplancton y sus productos de degradación. Los datos que llevan al desarrollo de la aproximación son obtenidos en la Península de Yucatán pero se propone la aproximación para cualquier tipo de agua y de florecimientos.
ABSTRACT Vertical distribution of chlorophyll a (Chla) in the euphotic zone has been described an... more ABSTRACT Vertical distribution of chlorophyll a (Chla) in the euphotic zone has been described and modeled by a Gaussian curve representing those cases where there is a single Chla maximum (surface or subsurface). This has led to the rejection of profiles with more than one chlorophyll peak, resulting in the removal of up to 18% of the profiles. The aim of this article is to propose an alternative equation to fit vertical Chla profiles, including those with two maxima in the euphotic zone. A total of 315 vertical profiles of Chla from the 2011 CALCOFI four-cruise series in the California Current were evaluated. Since Chla profiles show various shapes, it was decided to try four models: single Gaussian curve (single maximum) with and without gradient and double Gaussian curves (two maxima) also with and without gradient, which were fitted using Genetic Algorithms. The model that fitted Chla profiles best was the double maximum with gradient model, which is the one with the lowest root mean square error and was able to fit almost all Chla profiles in the CalCoFi area. This model has the ability to fit the vertical chlorophyll profiles with one or two maxima, including those that occur with a gradient with depth. Although the models were tested using data from the California Current, we recommend using the model in other ocean regions where double chlorophyll maximums occur.
Tetraselmis suecica is a green microalga that thrives under a wide range of conditions, used in t... more Tetraselmis suecica is a green microalga that thrives under a wide range of conditions, used in the commercial culture of fish, mollusk, and crustacean larvae for supplementing the demand for fertilizers. Its pigments have applications in human health care as drug products, vitamins, and cosmetics. Growth and pigment concentration of T. suecica were evaluated in experimental cultures with different nutrient concentrations and light intensities to determine the most appropriate culture conditions to optimize the production of biomass and pigments. Chlorophyll-a, chlorophyll-b, lutein, violaxanthin, α, β-carotene, and neoxanthin concentrations were evaluated under three different nutrient conditions (441.5/18.1, 883/36.3, and 1766/76.2 μM of NaNO3/NaH2PO4) and four light intensities (50, 150, 300, and 750 μmol quanta m-2 s-1). Increases in either or both of these factors lead to increases in the concentration of all pigments. Chlorophyll-a reached up to 5×103 mg m-3, chlorophyll-b up ...
This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic c... more This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic composition in the surface waters of Todos Santos Bay, a semi-enclosed bay within the upwelling zone of the Baja California peninsula (México). Two methodological approaches (microscopy and chemotaxonomy [CHEMTAX]) were used to describe the variability of some genera and species (observed under the microscope) and the importance of those groups that cannot be observed microscopically. Phytoplankton biomarker pigments were measured with high-resolution liquid chromatography and used as input to run the CHEMTAX software to determine the contribution of the main phytoplankton groups to chlorophyll-a (Chl-a). The microscopic analyses showed that diatoms and dinoflagellates comprised 65 and 33% of the total cells, respectively. Dinoflagellates were most abundant in the inner bay and during cold months; the most frequent and abundant genera were Tripos, Protoperidinium, and Prorocentrum. Among ...
This study is dedicated to the understanding of time and space variability of bio-optical variabl... more This study is dedicated to the understanding of time and space variability of bio-optical variables at a coastal station off Baja California Peninsula (ANTARES Baja California station, 31.75 o N/116.96 o W). The sampling procedure begun in May 2007 and in this presentation we will report changes observed in the absorption properties by three components of seawater (phytoplankton, detritus and chromophoric-dissolved-organic-matter or CDOM) in the photic zone in relation to changes in environmental conditions (inorganic nutrient) and phytoplankton community structure. Chlorophyll-a concentration (Chla) ranged from 0.04 to 1.44 mg m-3 with a strong vertical variability related to advective processes and the depth of the nutricline. Diatoms and dinoflagellates were the dominant fraction which was evaluated by HPLC pigment concentration (Fucoxanthin and Peridinin respectively). At low Chla phytoplankton community structure there are a higher proportion of small cells that were identified...
Algunas consideraciones tecnicas sobre la toma de muestra, almacenamiento tipo de fijador y metod... more Algunas consideraciones tecnicas sobre la toma de muestra, almacenamiento tipo de fijador y metodologia de conteo en muestras de agua para la evalución de la Taxocenosis fitoplanctonica en aguas costeras. Esta es una manual del Cuerpo Academico de Ecologia del Fitoplancton FCM-UABC en su serie White Papers
En este capítulo los autores proponen una nueva aproximación para evaluar florecimientos algales ... more En este capítulo los autores proponen una nueva aproximación para evaluar florecimientos algales nocivos tomando en cuenta las propiedades ópticas inherentes y aparentes de los cuerpos de agua, en especial del fitoplancton y sus productos de degradación. Los datos que llevan al desarrollo de la aproximación son obtenidos en la Península de Yucatán pero se propone la aproximación para cualquier tipo de agua y de florecimientos.
ABSTRACT Vertical distribution of chlorophyll a (Chla) in the euphotic zone has been described an... more ABSTRACT Vertical distribution of chlorophyll a (Chla) in the euphotic zone has been described and modeled by a Gaussian curve representing those cases where there is a single Chla maximum (surface or subsurface). This has led to the rejection of profiles with more than one chlorophyll peak, resulting in the removal of up to 18% of the profiles. The aim of this article is to propose an alternative equation to fit vertical Chla profiles, including those with two maxima in the euphotic zone. A total of 315 vertical profiles of Chla from the 2011 CALCOFI four-cruise series in the California Current were evaluated. Since Chla profiles show various shapes, it was decided to try four models: single Gaussian curve (single maximum) with and without gradient and double Gaussian curves (two maxima) also with and without gradient, which were fitted using Genetic Algorithms. The model that fitted Chla profiles best was the double maximum with gradient model, which is the one with the lowest root mean square error and was able to fit almost all Chla profiles in the CalCoFi area. This model has the ability to fit the vertical chlorophyll profiles with one or two maxima, including those that occur with a gradient with depth. Although the models were tested using data from the California Current, we recommend using the model in other ocean regions where double chlorophyll maximums occur.
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Papers by Adriana González-Silvera