Adriana Gonzalez-Silvera

Autonomous University of Baja California | UABC · Facultad de Ciencias Marinas

Todos Santos Bay (TSB) is located on the northeastern coast of the Baja California peninsula in Mexico. Algal blooms dominated by dinoflagellates in TSB are recurrent and negatively impact the ecosystem of the bay and regional economy. In this study, we analyzed the concentration of chlorophyll a (Chla) and the light absorption coefficients of phyt...

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 o...

Ocean color is the result of absorption and scattering, as light interacts with the water and the optically active constituents. The measurement of ocean color changes enables monitoring of these constituents (dissolved or particulate materials). The main objective of this research is to use digital images to estimate the light attenuation coeffici...

Anthropogenic activities are increasing the atmospheric carbon dioxide (CO2); around a third of the CO2 emitted by these activities has been taken up by the ocean. Nevertheless, this marine ecosystem service of regulation remains largely invisible to society, and not enough is known about regional differences and trends in sea-air CO2 fluxes (FCO2)...

This study reports observations of the horizontal and vertical variation of chlorophyll a (Chla) and the taxonomic composition of phytoplankton at the entrance to the Gulf of California (GC) and its relationship with physicochemical processes. This region is part of the northern boundary of one of the largest shallow Oxygen Minimum Zones in the wor...

Environmental conditions throughout the world ocean are changing in response to fossil fuel emissions and greenhouse warming in the atmosphere. Climate change and high carbon dioxide levels in the atmosphere are causing a domino-like series of changes in ocean conditions, including increased temperature, decreased oxygen content and acidification....

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 wer...

El propósito de este estudio fue caracterizar a la comunidad del fitoplancton en Laguna Ojo de Liebre, un sitio de gran importancia para la biodiversidad de la Reserva de la Biosfera El Vizcaíno. Utilizamos como parámetros la diversidad, abundancia y dominancia de los principales grupos del fitoplancton (microalgas) y las relacionamos con las varia...

This study aimed to describe the interannual climate variability in the West Antarctic Peninsula (WAP) under austral summer conditions. Time series of January sea-surface temperature (SST) at 1 km spatial resolution from satellite-based multi-sensor data from Moderate Resolution Imaging Spectrometer (MODIS) Terra, MODIS Aqua, and Visible Infrared I...

The vertical diffuse attenuation coefficient Kd (PAR) is used for calculating the euphotic zone, the first optical depth that is important for primary productivity models. Currently, Kd PAR can be estimated using an irradiometer or a Secchi disk (SD). The main objective of this work is to define a model that can be applied to a wide range of optica...

In this study, we report the response of phytoplankton community composition to cold and warm interannual events affecting the waters off the Baja California Peninsula from 2007 to 2016 based on data obtained from a single marine station (31.75oN/116.96oW). Included variables were satellite chlorophyll a, sea surface temperature (MODIS/Aqua), upwel...

Para poder interpretar el efecto de distintos fenómenos oceanográficos globales (e.g., El Niño) a escala local es esencial entender los posibles signos de estos fenómenos al cambiar de escala. Para lograr esto, es necesario establecer programas de monitoreo continuos de las variables que puedan ser más sensibles al fenómeno. Estos programas de moni...

This study investigated the relationship between phytoplankton biomass and taxonomic composition and hydrographic variables in the Northeastern Tropical Pacific for June 2015, March 2016, and September 2016. Hydrographic data were measured between surface and 100 m; samples were collected at the surface and the deep chlorophyll maximum (DCM) along...

The baseline of a specific variable defines the average behavior of that variable and it must be built from long data series that represent its spatial and temporal variability. In coastal and marine waters, phytoplankton can produce blooms characterized by a wide range of total cells number or chlorophyll a concentration. Classifying a phytoplankt...

Two semi-analytical algorithms, Generalized Inherent Optical Property (GIOP) and Garver-Siegel-Maritorena (GSM), were evaluated in terms of how well they reproduced the absorption coefficient of phytoplankton (aph(λ)) and dissolved and detrital organic matter (adg(λ)) at three wavelengths (λ of 412, 443, and 488 nm) in a zone with optically complex...

The Yucatán Peninsula hosts worldwide-known tourism destinations that concentrate most of the Mexico tourism activity. In this region, tourism has exponentially increased over the last years, including wildlife oriented tourism. Rapid tourism development, involving the consequent construction of hotels and tourist commodities, is associated with do...

Phytoplankton blooms are sporadic events in time and are isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of bloom or non-bloom, remains an unresolved problem. This research proposes the use...

Variability of the optical properties of the northern Gulf of California (México) were analyzed for the first time based on six cruises performed from spring to summer (March to September) between 2008 and 2013. The changes observed in the absorption by three seawater components (phytoplankton, detritus and chromophoric dissolved organic matter or...

Phytoplankton blooms are sporadic events in time and isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of bloom or non-bloom, remains an unresolved problem. This research proposes the use of...

En la Antártida, las proliferaciones masivas de fitoplancton psicrófilo (extremófilo) causa fenómenos que colorean la nieve del continente de verde, naranja o roja. Esto ocurre durante el verano austral, cuando la nieve comienza a derretirse y la radiación solar es más intensa. Durante la 3ra expedición Antártica colombiana (http://www.programaanta...

This study describes the temporal variability of a coastal station (Antares BC) located off Baja California Peninsula (31.75 o N/116.96 o W, 700 m depth) between 2007 and 2015 to evaluate the influence of interannual processes such as El Niño, La Niña and the "Blob" in phytoplankton pigments, community composition and its size structure. Chlorophyl...

Manual para uso y estimación de los parámetros de fluorescencia con base en un fluorimetro Phyto-PAM

The aim of this book is to assist environmental authorities and technicians in the design of effective environmental monitoring programs.Consensus exists that any good management program must be able to distinguish between natural variability and changes induced by anthropogenic activities. To achieve this goal, it is necessary to implement continu...

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...

The aim of this book is to assist environmental authorities and technicians in the design of effective environmental monitoring programs.Consensus exists that any good management program must be able to distinguish between natural variability and changes induced by anthropogenic activities. To achieve this goal, it is necessary to implement continu...

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...

A time series with weekly sampling was conducted from February 20, to December 16, 2011 at a station in the interior of the San Quintín Bay to estimate seasonal changes in the composition and abundance of phytoplankton. Water temperature was recorded and the upwelling index was calculated for the period. Phytoplankton abundance was estimated and ph...

Bio-optical variables in the Northern Gulf of California were analyzed using in situ and satellite data obtained during a cruise in June 2008. The study area was divided into three bio-optical regions: Upper Gulf (UG), Northern Gulf (NG), and Great Isles (GI). Each region was characterized according to phytoplankton pigment concentration, phytoplan...

In order to estimate the spatial variability of the specific absorption coefficient of phytoplankton in the Northern Gulf of California, two samplings were taken in the spring of 2010 (June 1-8), and 2011 (March 24 to April 1). We collected seawater samples at surface and at depth of chlorophyll maximum. Water temperature varied between 16 to 28 °C...

The objective of this work was to estimate the changes in abundance and composition of phytoplankton in a coastal lagoon in Baja California, México during neap-spring tide conditions. Sampling was conducted from the 7th to the 16th of October 2004. Surface water was collected at 18 stations distributed across the bay during day time at high tide. A...

In order to estimate the spatial and temporal variability of the specific absorption coefficient of phytoplankton (a*ph) in a coastal lagoon, sampling was from 6 to 16 October 2004 in the Bay of San Quintín (Baja California, México). Sampling was organized in two strategies: (1) spatial sampling was performed in 15 stations inside the bay, and (2)...

17.1 Background With the launch of the Coastal Zone Color Scanner (CZCS) in November of 1978, a new era in oceanographic studies began. This was the first instrument dedicated to the measurement of ocean colour using satellite imaging, and its main purpose was to determine whether spectroradiometric observations could be used to identify and quanti...

One of the most important topics in natural resource management is the deter-mination of biogeographic regions (BGR). Each BGR is the result of a particular combination of physical, chemical and biological factors and the variation of one of these factors can have different effects on each region. This characteristic trait makes biogeographic regio...

RESuMEN Se realizaron tres cruceros (noviembre de 2002, y junio y noviembre de 2003) en la costa occidental de Baja California con el objetivo de analizar las variaciones espaciales y temporales del coeficiente de absorción específico de luz por el fitoplancton (a φ(λ)) y la concentración de pigmentos por cromatografía líquida de alta resolución (H...

Santamaría-del-Ángel, E., Millán-Núñez, R., González-Silvera, A., Callejas-Jiménez, M., Cajal-Medrano, R., and Galindo-Bect, M. S. 2011. The response of shrimp fisheries to climate variability off Baja California, México. – ICES Journal of Marine Science, 68: 766–772. The effect of climate variability on the shrimp fishery in the upper Gulf of Cali...

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 compon...

Se realizaron tres cruceros (noviembre de 2002, y junio y noviembre de 2003) en la costa occidental de Baja California con el objetivo de analizar las variaciones espaciales y temporales del coeficiente de absorción específico de luz por el fitoplancton (aφ(λ)) y la concentración de pigmentos por cromatografía líquida de alta resolución (HPLC por s...

Surface mesoscale structures and wind variability in the northern Gulf of California (NGC) were analyzed using data from SeaWiFS (1 km) and QuikSCAT (1 day). The months of February and March were selected as representative of winter and the months of August and September were selected as representative of summer. Chlorophyll-a (Chla) and wind time...

A phytoplankton bloom was detected in the Southern California Current System, off the Baja California Peninsula (Mexico) on June 2003 with chlorophyll-a concentration (TChla) of 10.13 mg m−3. Two stations (D1 and D2) were sampled on June 24, and D2 was resampled 6 days later; chlorophyll-a concentration had decreased by about one half. LAC MODIS-Ch...

A phytoplankton bloom was detected in the Southern California Current System, off the Baja California Peninsula (Mexico) on June 2003 with chlorophyll-a concentration (TChla) of 10.13 mg m À3 . Two stations (D1 and D2) were sampled on June 24, and D2 was resampled 6 days later; chlorophyll-a concentration had decreased by about one half. LAC MODIS-...

We estimated phytoplankton primary productivity (PP) in the euphotic zone of the California Current System using chlorophyll concentration (Chl) from CZCS imagery. The area was divided into two regions, Southern California (SC) and Baja California (BC), with inshore and offshore subregions, and into two seasons, cool and warm. The Chl and PP values...

SeaWiFS ocean-colour products for the Southwestern Atlantic Ocean are evaluated in comparison with in situ bio-optical data collected during the March 10-12, 2002 cruise from Ushuaia to Uruguay. Radiometric measurements and surface water sampling were carried out at 14 stations. The in situ dataset included HPLC chlorophyll-a concentration (chl-a),...

The Great Islands zone, in the Gulf of California, presents high phytoplankton concentration as a result of the high Turbulent Kinetic Energy (TKE). In this work we looked for dynamics zones based on Empirical Orthogonal Function analysis (EOF). The input data were Sea Surface Temperature (SST) and Chlorophyll-a concentration (Chla) from daily MODI...

Introducción Uno de los objetivos de la oceanografía actual es medir y entender los procesos que controlan las fluctuaciones en los flujos de carbono a nivel global. Por tanto, la estimación de la productividad primaria (PP) del fitoplancton es de gran impor-tancia, ya que es el proceso que transforma carbono inorgánico en materia orgánica mediante...

The Mexican Tropical Pacific has oligotrophic characteristics; however, it sustains an abundant biodiversity, mainly because of upwelling promoted by its relatively shallow thermocline, strong winds and mesoscale eddies. These features, together with thermocline depth and stratification variability, are the main factors regulating phytoplankton abu...

We have estimated the spatial variability of phytoplankton specific absorption coefficients (a*ph ) in the water column of the California Current System during November 2002, taking into account the variability in pigment composition and phytoplankton community structure and size. Oligotrophic conditions (surface Chl < 0.2 mg m−3) dominated offshor...

The Mexican Tropical Pacific has oligotrophic characteristics; however, it sustains an abundant biodiversity, mainly because of upwelling promoted by its relatively shallow thermocline, strong winds and mesoscale eddies. These features, together with thermocline depth and stratification variability, are the main factors regulating phytoplankton abu...

Ocean color (OCTS, SeaWiFS) and sea surface temperature (AVHRR) images were used to evaluate spatial and temporal variability of the Brazil-Malvinas Confluence and La Plata Plume (20° to 45°S and 40° to 65°W). The data set covers the period from January 1997 to June 2003. Chlorophyll and SST data were combined using Principal Component Analysis (PC...

Introducción El océano se puede regionalizar con métodos directos o indirectos, lo cual nos faci-lita el estudio de grandes áreas con patrones de variación semejante. Dependiendo de qué se requiere regionalizar, se pueden utilizar diferentes indicadores como la temperatura del agua, masas de agua (diagramas T.S), barreras físicas, tipo de cli-ma (t...

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

Se presentan consideraciones para medir Productividad mencionando tecnicas de oxigeno 14c y PHYTOPAM. Asi mismo se analizan los incubadores de luz artificial y los de luz artificial. Se mencionan lo Modelos Fotosintesis-Irradiancia como la base para construir modelos de Productividad Primera. Por ultimo se menciona como estas estimaciones podrian s...

Tropical and subtropical Atlantic Ocean waters off the coasts of Brazil, Uruguay and Argentina are influenced by a variety of hydrographic processes that lead to a great diversity in the biological system. In situ observations are scarce and sparsely distributed over this zone. Phytoplankton pigment concentrations were estimated utilizing the Coast...

SeaWiFS high-resolution ocean-color images and AVHRR sea-surface temperature were obtained for the period from November 1998 to March 1999. Generation of mesoscale eddies was observed for the region between the Gulf of Tehuantepec and the Gulf of Papagayo (Tropical Pacific Ocean). Eighteen eddies with diameters ranging between 100 and 450 km were i...

Using monthly composites of the ocean color sensor Coastal Zone Color Scanner, we generated time series of pigment concentrations for three transects and 22 lo- cations off Baja California and the southern California coast in order to describe the signature of the Ensenada Front and its seasonal and interannual variability. We used averaging maps o...