Distribution of <em>Cylindrospermopsis raciborskii</em> (Cyanobacteria) in Sri Lanka

Abstract

Sri Lanka is a tropical continental island which consists of 103 natural rivers and over ten thousand man-made lakes. Majority of these water resources are known to be contaminated with different types of toxigenic cyanobacteria making water unsuitable for human and animal consumption. Cylindrospermopsis raciborskii, a toxin producing tropical cyanobacterium, recently recorded at high abundances in lentic waters of the country. This species is highly adaptive and exhibit different morphotypes: straight, coiled and sigmoid-shaped trichomes under different environmental conditions. Distribution and abundance of the species is mainly depending on the environmental factors and therefore remedies can be proposed to keep the populations under control. This preliminary study was conducted to understand the prevalence of C. raciborskii, in Sri Lankan reservoirs. Sixty three reservoirs representing all climatic regions with varying environmental conditions were assessed using standard procedures. The results of the study reviewed that C. raciborskii is a dominant cyanobacterium species especially during the dry season in shallow urban reservoirs, terminal reservoirs in large cascades, reservoirs with low flushing rates and deep reservoirs with persistent water stratification. Morphological variations were common in urban and shallow reservoirs that maintain high water retention time. They commonly occur in coiled-shape. However, in eutrophic water bodies they are appeared to support other morphotypes: straight, sigmoid or tricomatous. Further, it was noticed that the cell size of C. raciborskii is exceptionally large (width 3.5 µm and length 7µm) in a high altitudinal wet-zone reservoir that usually maintains temperature range of 10 o C -20 o C throughout the year. The results showed that C. raciborskii is widely distributed all over the country and the presence of several morphotypes signifies its potential for rapid distribution.

Co-occurrence of microcystin and cylindrospermopsin in hypereutrophic Mahakanadarawa and Nachchaduwa reservoirs

“…According to our observations, the spatial distribution pattern of CYN in Mahakanadarawa reservoir is approximately uniform while in Nachchaduwa it showed slight accumulation toward the direction of the South (Figures 4b and 4d). Although we did not observe any of the CYN-producing cyanobacterial species in either of the reservoirs, Wanigatunge et al (2014) and Yatigammana and Perera (2017) have reported the presence of potential CYN-producing cyanobacterial species Cylindrospermopsis raciborskii in Nachchaduwa. However, in this study, we did not observe C. raciborskii or any other CYNproducing species probably due to two reasons, one is the presence of very low densities of such filaments at the time of sampling due to their disappearance.…”

“…At the same time, Mycrocystis was identified as a dominant genus in northern dry zone reservoirs (Jayawardana et al 1998). Several later research reported toxigenic genera Cylindrospermopsis raciborskii as the dominant cyanobacterial community in several northern dry zone reservoirs and its co-occurrence with Microcystis only in Unnichchai tank (Wanigatunge et al 2014;Kulasooriya 2017 andYatigammana andPerera 2017). Further, several other toxin-producing cyanobacteria such as Planktolyngbya, Pseudoanabaena, Anabaena aphanizomenoides (Silva and Wijeyaratne 1999), Phormidium, Oscillatoria (Liyanage et al 2014) and Lyngbya (Shihana et.…”

Effect of cylindrospermopsin on the hepatotoxicity in wistar rats

“…Thus, considering the toxic nature of CYN on human health, the World Health Organization (WHO) established a provisional guideline limit for CYN of 2 µg/L in drinking water (WHO, 2003;SLSI, 2013) and 0.02 µg/kg of body weight/day as the Tolerable Daily Intake (TDI) for humans (Guzman-Guillen et al, 2014). Recently, there have been increasing reports on the number and the intensity of blooms in reservoirs in the North Central, North East, and Uva Provinces of Sri Lanka (Madhushankha et al, 2013;Yatigammana & Perera, 2017;Manage, 2019). Further, scientific research has revealed contamination of the majority of drinking water reservoirs by toxin-producing cyanobacterium M. aeruginosa, Cylindrospermopsis sp., Anabaena sp.…”

Quantitative observations of Cyanobacteria and Dinoflagellata in reservoirs of Sri Lanka

“…These "cyanotoxins" are usually either hepatotoxic or neurotoxic in pathology and have been related to several cases of human sickness and death, as well as various occurrences of animal mortality (Falconer, 2005; Kuiperpolonicum, P. willei, P. volzii and P. aciculiferum have been identified as common freshwater species (Niese et al, 2007). Among them, Peridinium aciculiferum, known to produce a biological toxin, has already been recorded from Sri Lankan drinking water reservoirs (Yatigammana and Perera, 2017;Yatigammana et al, 2011;Sethunge & Pathmalal,2010;Idroos et al, 2017).…”