RESUMO
An assessment of the major pigments and neurotoxins and a description of the phytoplankton community were carried out within the coastal region of Rio de Janeiro State (Brazil), during winter and the following spring of 2018. Overall, six stations were investigated for oceanographic conditions (with CTD casts). Filtered water samples were used to estimate the chlorophyll a (CHL-a), carotenoids (CAR), and phycobiliproteins (PHY) using UV-Vis spectrophotometry, as well as the quantification of saxitoxins (STX) and domoic acid (DA), through High Performance Liquid Chromatography (HPLC). Planktonic organisms were counted using sedimentation chambers of different volumes and an inverted microscope. A cluster analysis, SIMPER, and ANOSIM were applied to the phytoplankton data along with diversity indexes, and non-parametric statistics to phycotoxins and pigments. There was a significant difference between the winter and spring phytoplankton community, associated with the mixed layer depth (r2 = -0.626, p < 0.05) and temperature (r2 = 0.641, p < 0.05). Phytoplankton biomass and C:CHL-a indicated a higher production during the winter than in spring, with the potentially toxic genus Pseudo-nitzschia responsible for 12.79% of autotrophic abundance (SIMPER output). Pigments showed a slight increase in CAR during spring, while PHY remained at trace concentrations. Both the DA and STX were quantified in winter and spring, but with significant differences only for STX between the sampling periods. Among the 71 taxa, 11 were identified as potentially toxic with an emphasis on STX-producing dinoflagellates and cyanobacteria, such as Alexandrium sp., Gymnodinium spp. along with Trichodesmium spp. Season-related environmental variability may be the major driving force modulating the mixed assemblage of species that support different levels of phycotoxins.
Assuntos
Monitoramento Ambiental , Toxinas Marinhas/toxicidade , Fitoplâncton , Biomassa , Brasil , Clorofila A , Cianobactérias , Diatomáceas , Dinoflagellida , Ácido Caínico/análogos & derivados , Toxinas Marinhas/análise , Neurotoxinas , Estações do Ano , Água do Mar , TrichodesmiumRESUMO
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.
Assuntos
Fitoplâncton/microbiologia , Trichodesmium/crescimento & desenvolvimento , Filipinas , Estações do Ano , Monitoramento Ambiental , BaíasRESUMO
Since 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 Pseudo-nitzschia 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, Cochlodinium polykrikoides, and Noctiluca scintillans.