Potentially Toxic Dinoflagellates Associated to Seagrass on Isla de Barú, Colombian Caribbean, During El Niño

Abstract

In the last decades, harmful algal blooms (HAB) and toxic events such as ciguatera seem to have increased in frequency and intensity, negatively impacting human health, economy, and marine ecosystems. In Colombia, these events have caused a series of consequences ranging from the death of fish and birds to toxic effects on humans. Although some toxin-producing dinoflagellate species are common in the Caribbean, their dynamics are poorly understood, making the adoption of any regulations difficult. To determine the composition and abundance of dinoflagellates associated with seagrasses we collected 18 samples on Isla de Barú, during 2015. We found ten diatom genera and three dinoflagellate genera, Prorocentrum, Ostreopsis, and Gambierdiscus, that include toxigenic species related to ciguatera and diarrheic shellfish poisoning. Prorocentrum lima was the most abundant dinoflagellate, with average cell densities of 52±48 cells/g substrate wet weight. The temperature hypothesis gains strength as one of the main modulators of dinoflagellate abundance observed in the Caribbean, especially regarding Prorocentrum species and some diatoms such as Mastogloia corsicana and Actinocyclus normanii. This assumption is supported by the Since high positive correlation between El Niño Southern Oscillation and the sea surface temperature in the Caribbean during 2015.

Epidemiology and Toxicology of Ciguatera Poisoning in the Colombian Caribbean

“…Three species of seagrasses, Thalassia testudinum, Syringodium filiforme and Halodule wrightii, were found on Isla de Barú, and T. testudinum was the most abundant and dominant. Although the cell densities of epiphytic dinoflagellates found on Isla de Barú in April and September of 2015 did not show statistically significant differences between sites or months of sampling (p>0.05) [2].…”

“…Ciguatera fish poisoning is prevalent worldwide, estimated more than 50,000 cases in the world. In the Colombian territory it is not part of the mandatory notifiable diseases, it is important to know the origin of Ciguatera fish poisoning which is synthesized by a group of microalgae called dinoflagellates of which around 50 species are producers of Ciguatera fish poisoning, their distribution in cosmopolitan, in their habitat they cover surfaces of reefs and macroalgae [2].…”

“…Prorocentrum lima was the most abundant dinoflagellate, with average cell densities of 52±48 cells/g substrate wet weight. The temperature hypothesis gains strength as one of the main modulators of dinoflagellate abundance observed in the Caribbean, especially regarding Prorocentrum species and some diatoms such as Mastogloia corsicana and Actinocyclus normanii [2].…”

“…Ciguatera is intoxication for ate contaminated fish with dinoflagellate's ladder frame polyether toxins, Ciguatera fish poisoning (CFP) are polyether ladder-formed toxins produced by several species of diatom and dinoflagellate [1], the main genus associated with ciguatoxins produced is Gambierdiscus, addition to Gambierdiscus in colombia have been reported other genus such as: Actinocyclus, Nitzschia, Rhabdonema, and Thalassionema [2]. CFP were first isolated in 1967 from Gymnothorax javanicus [3], in 1989 the Ciguatera was postulated that its accumulated in fish throughout the food webs, as well as, it was elucidated the structure of CFP [4].…”

Epidemiology and Toxicology of Ciguatera Poisoning in the Colombian Caribbean

“…The ladder-like polyethers are produced by polyketide synthases (PKS), and the synthesis of the ladder-like polyethers by PKS starts with acetyl CoA, which is incorporated into long polyethers through a series of sequential condensations with malonyl CoA that are performed by KS domains of the PKS [2]. The main genera associated with the synthesis of ciguatoxins is Gambierdiscus [3]. Ciguatoxins were first isolated in 1967, describing an empirical formula of C 35 H 65 NO 8 by means of Ultra-Micro methods [4,5].…”