Prymnesium parvum Carter, a haptophyte species capable of forming harmful algal blooms (HABs), has been identified in fresh and brackish water habitats worldwide. In Texas, P. parvum blooms have diminished local community revenues from losses to tourism, fishing, and hatchery production. In this thesis, P. parvum dynamics were studied using in-situ microcosm experiments at Lake Possum Kingdom, Texas during three seasons (fall, winter, spring) in 2004-2005. Specifically, nutrient additions were used to test the hypothesis that increased nutrient levels would not enhance P. parvum's ability to invade phytoplankton communities. In addition to full nutrient additions to levels of f/2 media, other treatments included nutrient additions deficient in either nitrogen (N) or phosphorus (P). Additionally, barley straw extract was tested as a growth inhibitor to prevent P. parvum blooms. Furthermore, P. parvum initial population density was examined to test the hypothesis that increased initial populations could promote an increase in P. parvum population densities. Findings indicated that P. parvum populations in Lake Possum Kingdom would not likely gain a selective advantage over other species when inorganic nutrients (nitrogen and phosphorus) were not limiting. P. parvum did, however, gain an advantage during both N- and P-limited conditions as indicated by toxicity, cell concentrations, and bulk phytoplankton community shifts. Furthermore, P. parvum blooms in Lake Possum Kingdom would likely not be inhibited by barley straw extract application. Initial population densities affected the final population density, but only when initial populations were low. A method to quickly and accurately detect the presence of P. parvum is needed due to P. parvum's potential to cause toxic and lethal blooms. This thesis tested whether P. parvum photopigments are conservative regardless of growth conditions and could be used to quantify the relative abundance of P. parvum in mixed community samples. If biomarker pigments are conservative, then an optimized version of CHEMTAX could be employed as an alternative diagnostic tool to microscopy for enumeration of P. parvum. However, P. parvum pigments in the Texas strain were not conservative throughout the growth cycle and therefore may not be a reliable indicator of cell abundance.

Prymnesium parvum Carter, a haptophyte species capable of forming harmful algal blooms (HABs), has been identified in fresh and brackish water habitats worldwide. In Texas, P. parvum blooms have diminished local community revenues from losses to tourism, fishing, and hatchery production. In this thesis, P. parvum dynamics were studied using in-situ microcosm experiments at Lake Possum Kingdom, Texas during three seasons (fall, winter, spring) in 2004-2005. Specifically, nutrient additions were used to test the hypothesis that increased nutrient levels would not enhance P. parvum's ability to invade phytoplankton communities. In addition to full nutrient additions to levels of f/2 media, other treatments included nutrient additions deficient in either nitrogen (N) or phosphorus (P). Additionally, barley straw extract was tested as a growth inhibitor to prevent P. parvum blooms. Furthermore, P. parvum initial population density was examined to test the hypothesis that increased initial populations could promote an increase in P. parvum population densities. Findings indicated that P. parvum populations in Lake Possum Kingdom would not likely gain a selective advantage over other species when inorganic nutrients (nitrogen and phosphorus) were not limiting. P. parvum did, however, gain an advantage during both N- and P-limited conditions as indicated by toxicity, cell concentrations, and bulk phytoplankton community shifts. Furthermore, P. parvum blooms in Lake Possum Kingdom would likely not be inhibited by barley straw extract application. Initial population densities affected the final population density, but only when initial populations were low. A method to quickly and accurately detect the presence of P. parvum is needed due to P. parvum's potential to cause toxic and lethal blooms. This thesis tested whether P. parvum photopigments are conservative regardless of growth conditions and could be used to quantify the relative abundance of P. parvum in mixed community samples. If biomarker pigments are conservative, then an optimized version of CHEMTAX could be employed as an alternative diagnostic tool to microscopy for enumeration of P. parvum. However, P. parvum pigments in the Texas strain were not conservative throughout the growth cycle and therefore may not be a reliable indicator of cell abundance.

The aim of this study was to use pigments to determine freshwater phytoplankton composition . The samples were collected from freshwater lakes in the Czech Republic and Germany. The pigment analyses were conducted using the High Performance Liquid Chromatography (HPLC). The HPLC data were processed by computer program CHEMTAX to calculate the composition of phytoplankton. The obtained pigment data were compared with standard light microscopy which was used to obtain more detailed taxonomic resolution.

Las aguas costeras y estuarinas se caracterizan por una gran variabilidad, espacial y temporal, en sus características hidrológicas, físicas y químicas, que se refleja en la complejidad de la dinámica de sus comunidades fitoplanctónicas. Además, las zonas costeras están sometidas a una elevada presión antrópica, cuyo principal efecto es el aumento de los aportes de nutrientes de origen terrestre a las aguas receptoras, en las que puede llegar a provocar problemas de eutrofización. El objetivo de esta tesis es caracterizar la variabilidad espacial de las comunidades fitoplanctónicas en aguas costeras y de transición caracterizadas por distintas fuentes de entrada de nutrientes. Obtener información sobre el funcionamiento de estos ecosistemas es necesario para orientar las medidas de gestión necesarias para mejorar la calidad de sus aguas. En la presente tesis se realiza la clasificación taxonómica del fitoplancton con el software CHEMTAX a partir de las concentraciones de pigmentos fotosintéticos halladas por cromatografía líquida de alta resolución en muestras de aguas costeras. Frente a las técnicas tradicionales de microscopía, esta metodología presenta una serie de ventajas entre las que cabe destacar el menor coste, la mayor rapidez y precisión. Además, se realiza una primera aproximación al uso de imágenes de satélite de alta resolución espacial, para estimar los niveles de clorofila a, parámetro indicador de la biomasa fitoplanctónica. La principal ventaja de esta técnica es que permite obtener una visión sinóptica de una determinada zona de estudio que no es posible obtener con las técnicas tradicionales de muestreo. Las características que presentan estas técnicas hacen de ellas buenas candidatas para las exigencias de monitoreo de la Directiva Marco del Agua. Los resultados de esta tesis indican que los principales problemas de calidad de aguas se dan en las áreas con un menor intercambio y dilución con el mar. En la presente tesis estas áreas están rep / Sebastiá Frasquet, MT. (2012). Pigmentos indicadores: caracterización de la comunidad fitoplanctónica en ecosistemas marinos costeros [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16001 / Palancia