One year weekly dynamics of limnological conditions and phytoplankton in Lake Bonilla, Costa Rica

Abstract:The detailed response of tropical lake phytoplankton to weather variations has been little studied, but it seems that composition varies in response to rain and wind variability over the course of the year. In order to gather more evidence on this variation, the weekly variability of phytoplankton composition was studied in Lake Bonilla, a low land (380 masl) 30 m deep tropical lake, from April 2010 to May 2011. Temperature variation at several depths was recorded automatically, and measurements of dissolved oxygen, water transparency, and nutrients were performed several times during the study period. The lake showed a warm monomictic pattern, with deep mixing occurring during the hemispherical winter, especially after a heavy rain period in December 2010. Phytoplankton was dominated by a few species: a colonial Cyanobacteria (Aphanocapsa sp., functional group F) and two colonial Chlorococcaceae (Botryococcus braunii and Eutetramorus tetrasporus, both in the functional group K). Their relative dominance shifted throughout the year, following changes in water column conditions in response to weather variations. Although changes in main functional groups indicate a shift in resource availability rather than energy, it was clear that attention should also be given to particular species adaptations beyond those used for establishing functional groups. Rev. Biol. Trop. 64 (4): 1771-1781. Epub 2016 December 01.

Resumen:La respuesta detallada del fitoplancton de lagos tropicales a las variaciones climáticas ha sido poco estudiada, sin embargo al parecer la composición de especies varía en respuesta a la variabilidad de la precipitación y de los vientos a lo largo del año. Con el fin de recabar más evidencia de esta variación, se estudió semanalmente la composición del fitoplancton en el lago Bonilla, un lago tropical de zonas bajas (380 msnm), de 30 m de profundidad, entre abril 2010 y mayo 2011. Se registró la temperatura del agua a varias profundidades, y se realizaron mediciones de oxígeno disuelto en la columna de agua, trasparencia del agua y concentración de nutrientes varias veces a lo largo del año de estudio. El lago es monomíctico cálido, con una mezcla profunda durante el invierno hemisférico, especialmente luego de un periodo de fuertes precipitaciones en diciembre 2010. El fitoplancton estuvo dominado por pocas especies: una Cyanobacteria colonial (Aphanocapsa sp., grupo funcional F), y dos Chlorococcaceae coloniales (Botryococcus braunii y Eutetramorus tetrasporus, ambas del grupo funcional K). Sus abundancias relativas cambiaron a lo largo del año, siguiendo los cambios en las condiciones de la columna de agua que es influenciada por variaciones en el tiempo atmosférico. Aunque los cambios en los grupos funcionales indican que hubo un cambio en la disponibilidad de recursos en vez de energía radiante, fue evidente que se debe prestar también atención a las adaptaciones particulares de las especies más allá de las que se usan normalmente para establecer los grupos funcionales.

Bloom of Trichodesmium (Oscillatoriales, Phormidiaceae) and seasonality of potentially harmful phytoplankton in San Pedro Bay, Leyte, Philippines / Proliferación de Trichodesmium (Oscillatoriales: Euphorbiaceae) y estacionalidad de fitoplancton potencialmente dañino en Bahía San Pedro, Leyte, Filipinas

AbstractSince 1983, San Pedro Bay in the Philippines had been reported to be the site of episodic Pyrodinium bahamense var. compressum blooms that caused paralytic shellfish poisoning in its nearby coastal communities. This bay is also subjected to numerous storms; the strongest was super typhoon Haiyan in November 8, 2013. For the first time, the seasonal dynamics of potentially toxic and harmful phytoplankton in this bay is elucidated. This is also the first record of a bloom of the cyanobacteria, Trichodesmium erythraeum that reached 70 000 colonies/L in April 2013 in this area. There were other 19 potentially toxic and harmful phytoplankton encountered during the sampling period. These consisted of a haptophyte, Phaeocystis globosa, the diatom Pseudonitzschia and 17 dinoflagellates. Seven of these harmful algae had densities high enough to be traced through time. Normally, diatoms abound during the dry season. But Pseudo-nitzschia increased in abundance during the wet season of 2012 and 2013. The dinoflagellates and Phaeocystis globosa behaved as expected and exhibited a relative increase in cell density during the rainy season of both years too. High nutrient availability during this season must have influenced the behavior of the phytoplankton despite differences in temperature and light intensity among seasons. Other notable but rare harmful species found only in plankton net tows during the study were Pyrodinium bahamense var. compressum, Alexandrium tamiyavanichii, Cochlodiniumpolykrikoides, and Noctiluca scintillans. Rev. Biol. Trop. 64 (2): 897-911. Epub 2016 June 01.

ResumenDesde 1983, la Bahía de San Pedro en Filipinas ha sido reportada como un sitio de proliferación de Pyrodinium bahamense var. compressum que causó intoxicación paralítica en sus comunidades costeras cercanas. Esta bahía también está sometida a numerosas tormentas; entre las más fuertes se presentó un súper tifón en Haiyan, el 8 de noviembre 2013. Por primera vez, se explica la dinámica estacional del fitoplancton potencialmente tóxico y dañino en esta bahía. Este es también el primer registro en esta área de una proliferación de cianobacterias (Trichodesmium erythraeum) que alcanzó 70 000 colonias/L en abril 2013. Durante el periodo de muestreo se presentaron otras 19 proliferaciones de fitoplancton potencialmente tóxicas y dañinas. Estos consistían en una haptófita, Phaeocystis globosa, la diatomea Pseudo-nitzschia y 17 dinoflagelados. Siete de estas algas nocivas tenían densidades suficientemente altas como para ser rastreadas a través del tiempo. Normalmente, las diatomeas abundan durante la estación seca. Pero Pseudo-nitzschia aumentó en abundancia durante la temporada de lluvias de 2012 y 2013. Los dinoflagelados y Phaeocystis globosa se comportaron como se esperaba y exhibieron un aumento relativo de la densidad celular durante la temporada de lluvias en los dos años. La alta disponibilidad de nutrientes durante esta temporada debe haber influido en el comportamiento del fitoplancton a pesar de las diferencias en la temperatura y la intensidad de la luz entre estaciones. Otras especies nocivas notables, pero raras que se encontraron sólo en las redes de arrastre de plancton durante el estudio fueron: Pyrodinium bahamense var. compressum, Alexandriumtamiyavanichii, Cochlodinium polykrikoides y Noctiluca scintillans.

Relaciones entre las abundancias del bacterioplancton y del fitoplancton en tres ecosistemas lénticos de los Andes Colombianos / Relations between bacterioplankton and phytoplankton abundance in three lentic ecosystems in the Colombian Andes

We analyzed relations among phytoplankton and total bacterioplankton fractions in three lentic ecosystems (Neusa and Prado dams, and Fúquene lagoon) with different physicochemical characteristics, in the Andes of Colombia. Samplings were made in three sites of each water body during three surveys. Neusa dam (meso to oligotrophic) had the lowest bacterial concentration; Prado dam (eutrophic) had a high bacterial and algal abundance, and the Fúquene lagoon (mesotrophic) had lower concentrations of phytoplankton but a high relative concentration of bacteria, probably because of its particular conditions: high organic matter and low nutrient levels in the water. There was a negative correlation of total bacterioplankton with the phytoplankton (Pearson = -0.4479, p = 0.019, n=27) and a positive correlation between phytoplankton and heterotrophic bacteria (Pearson = 0.3866, p = 0.062, n=24) and between total bacterioplankton and DBOs (Pearson = 0.4088, p = 0.034, n=27). Apparently, total bacterioplankton and phytoplankton were not coupling, but cultivable bacteria and the phytoplankton had some degree of relationship.

Toxic cyanobacteria strains isolated from blooms in the Guadiana River (southwestern Spain)

This paper describes the occurrence of toxic cyanobacteria along the Guadiana River over its course between Mérida and Badajoz (Extremadura, Spain). Water sampling for phytoplankton quantification and toxin analysis was carried out regularly between 1999 and 2001 in six different locations, including two shallow, slow-flowing river sites, two streamed river sites and two drinking water reservoirs. The cyanobacterial community differed significantly between these locations, especially during the summer. The predominant genera were Microcystis, Oscillatoria, Aphanizomenon and Anabaena. Using an ELISA assay the total microcystin contents of natural water samples from the most eutrophic locations ranged from 0.10 _ 21.86 mg mcyst-LR equivalentúL-1 in Valdelacalzada and 0.10-11.3 µg mcyst-LR equivalentúL-1 in Vitonogales, and a seasonal variation of toxin content was observed. The amount of microcystins produced by each strain was determined by ELISA assay and the detection and identification of microcystin variants of three toxic strains of Microcystis aeruginosa was performed by high performance liquid chromatography (HPLC). The analysis of microcystins of the cultured strains revealed that toxin production was variable among different strains of M. aeruginosa isolated either from different blooms or from the same bloom.

Marea roja: perspectiva histórica / Red tide: historical perspective

En la Marea Roja existen los conceptos de discoloración del agua del mar que generalmente provoca la mortalidad de la fauna marina y el de florecimiento de algas nocivas que causa la toxicidad en los seres humanos. Se presentan: el registro de discoloraciones a nivel mundial muy resumido y el registro de Chile que incluye las primeras descripciones de los investigadores Poepping en 1827 y Darwin en 1835 y que llega hasta 1985. En los florecimientos tóxicos se describen los tipos de toxinas conocidas: ciguatoxina, venerupin shelfish poison; VNM = veneno neurológico de mariscos; VPM = veneno paralizante de mariscos; VDM = veneno diarreico de mariscos y VAM = veneno amnésico de mariscos