RESUMO
The diurnal vertical migration of Cochlodinium polykrikoides (C. polykrikoides), which caused a red tide in the Korean coastal waters of the East Sea/Sea of Japan in September 2003, was examined by determining the time-dependent changes in the density of living cells in relation to the depth of the water column. The ascent of this species into the surface layer (depth of water, 2 m) occurred during 1400- 1500. The descent started at 1600 and a high distribution rate (86%) at 15-20 m was observed at 0300. During the ascent, the cells were widely distributed at each depth level from 0600 hr and at 0800-1100, the cells were primarily distributed in the middle layer (0-6 m). The concentration of dissolved inorganic nitrogen was generally <2.86 μmol l -1, but at 1400-1500, the concentration in the surface layer reduced to <0.14 μmol l -1. Moreover, the concentration gradually increased as the depth increased to > 5 m. These results showed that the nutrientconsumption rate associated with the proliferation of C. polykrikoides during a red tide is more influenced by the inorganic-nitrogen resources rather than the inorganic-phosphorus compounds.
RESUMO
We examined the survival rate of Cochlodinium polykrikoides after yellow loess addition and conducted culture experiments to investigate the possibility that red tides may be caused by C. polykrikoides individuals that are precipitated when loess is added. At least 15% of the C. polykrikoides cells that precipitated to the bottom layer either by the addition of loess or no addition survived for 1 week at all growth phases, rather than disappearing immediately after precipitating. However, no live cells were observed after 20 days, regardless of phase or loess addition. In the exponential phase, the number of C. polykrikoides cells increased to >2886 cells ml-1 after loess was added. However, in the stationary phase, the number of cells did not increase until 18 days. In the exponential phase, those C. polykrikoides that survived precipitation caused by scattering loess on cultures did not appear to have the ability to cause red tides again because of the short red tide periods in the field, long lag time after loess addition, and low survival rate after loess addition.
RESUMO
Algal blooms at Banderas Bay, México (2000-2001), from SeaWiFS-sensor-data. Algal blooms for the period of 2000 and 2001 at Banderas Bay, México, were analyzed from SeaWiFS-ocean-color-sensor derived information. These events were related with the maximum chlorophyll week anomalies (ASi; a proxy variable constructed for the analysis of chlorophyll temporal variation in the bay). The winter-spring blooms were multispecific, while the summer-fall blooms were monospecific. Two proposals are made: 1) Winter-spring blooms are strongly related with mesoescale processes, due to their apparent temporal synchrony with the high chlorophyll levels in the coastal region from Sinaloa to Jalisco states; 2) Cochlodinium polykrikoides (Margalef 1961) blooms during the summer-fall periods could be induced by local conditions and the influence of previous events on the ecosystem. Rev. Biol. Trop. 56 (4): 1653-1664. Epub 2008 December 12.
Se analizaron las proliferaciones algales ocurridas en Bahía de Banderas, México, durante los años 2000 y 2001 a partir de información derivada del sensor de color del océano SeaWiFS. Estos eventos estuvieron relacionados con los máximos niveles de Anomalías Semanales de Clorofila (As i; variable construida para analizar la variación temporal de la clorofila dentro de la bahía). Las proliferaciones ocurridas en los periodos invierno-primavera fueron multiespecíficos, mientras que en verano-otoño fueron dominadas por una sola especie. Se plantean dos propuestas: 1) las proliferaciones algales de invierno-primavera están fuertemente relacionadas a procesos de mesoescala dada su aparente sincronía temporal con altos niveles de clorofila en las costas de Sinaloa a Jalisco; 2) mientras que las proliferaciones de Cochlodinium polykrikoides durante los periodos verano-otoño son favorecidas por el efecto de otras proliferaciones algales previas sobre el ecosistema y por condiciones predominantemente locales en la bahía.