Using genetic markers to monitor toxic cyanobacterial communities at the volcanic-origin lakes of Amatitlán and Atitlán, Guatemala
Start Date
23-5-2022 5:45 PM
End Date
23-5-2022 7:00 PM
Abstract
The lakes Amatitlán and Atitlán are two of the biggest freshwater ecosystems in Guatemala. Over 1000 years, lake Amatitlán has experienced cultural eutrophication, and within the last 50, toxigenic Microcystis spp are responsible for permanent cyanobacterial blooms. Also, eutrophication has increased in the oligotrophic lake Atitlán, and since 2010, with the appearance of Limnoraphis robusta blooms. Similar environmental conditions derived from their volcanic origin, could imply the accelerated deterioration of Atitlán, and thus, reliable detection methods should be implemented to better understand cyanotoxin production in both lakes. Here, we used molecular markers for the detection of genes involved in the synthesis of cyanotoxins in mentioned lakes. Sequencing analysis showed that in Amatitlán, Microcystis (16S rRNA) dominated and presented toxigenic genotypes with potential production of microcystins (mcyE) and anatoxins (anaC), and the concentration of microcystins reached 4.05 mg L-1 (HPLC analysis). In the case of Atitlán, the mcyE gene was detected for the first time with homology to Microcystis, during a bloom dominated by L. robusta. Our results evidence that the use of cyanotoxin gene markers can be incorporated in ongoing monitoring efforts for early detection of toxic cyanobacteria, and the importance to include prevention solutions focused on reducing nutrient loading.
Using genetic markers to monitor toxic cyanobacterial communities at the volcanic-origin lakes of Amatitlán and Atitlán, Guatemala
The lakes Amatitlán and Atitlán are two of the biggest freshwater ecosystems in Guatemala. Over 1000 years, lake Amatitlán has experienced cultural eutrophication, and within the last 50, toxigenic Microcystis spp are responsible for permanent cyanobacterial blooms. Also, eutrophication has increased in the oligotrophic lake Atitlán, and since 2010, with the appearance of Limnoraphis robusta blooms. Similar environmental conditions derived from their volcanic origin, could imply the accelerated deterioration of Atitlán, and thus, reliable detection methods should be implemented to better understand cyanotoxin production in both lakes. Here, we used molecular markers for the detection of genes involved in the synthesis of cyanotoxins in mentioned lakes. Sequencing analysis showed that in Amatitlán, Microcystis (16S rRNA) dominated and presented toxigenic genotypes with potential production of microcystins (mcyE) and anatoxins (anaC), and the concentration of microcystins reached 4.05 mg L-1 (HPLC analysis). In the case of Atitlán, the mcyE gene was detected for the first time with homology to Microcystis, during a bloom dominated by L. robusta. Our results evidence that the use of cyanotoxin gene markers can be incorporated in ongoing monitoring efforts for early detection of toxic cyanobacteria, and the importance to include prevention solutions focused on reducing nutrient loading.