Cyanobacterial blooms in Lake Atitlan, Guatemala

Abstract

a b s t r a c tLake Atitlan, one of the most important lakes not only in Central America but in the whole world, is facing serious problems with increasing water pollution. Over the last several decades, the uncontrolled nutrient input into the lake has lead to high P levels and low N:P ratios, initiating cyanobacterial blooms. The first bloom occurred in December of 2008, followed by more extensive bloom in October 2009. The blooms are formed by cyanobacteria from the rare planktic Lyngbya hieronymusii/birgei/robusta complex. Based on the species morphology, the Atitlan population corresponds to L. robusta and this is the first case of reported bloom of this species worldwide. Remote sensing images documented that at the maximum bloom development, 40% of the 137 km 2 of the lake area were covered by dense patches of Lyngbya, with the chlorophyll a concentration reaching over 100 g L −1 . The only toxins detected in the 2009 bloom were trace levels of cylindrospermopsin and saxitoxin with 12 and 58 ng g −1 , respectively. The nitrogen fixation followed a pattern expected in non-heterocytous cyanobacteria, i.e., the nitrogenase activity was minimal during the day, while during the night the activity reached 2.2 nmol C 2 H 4 g Ch a −1 h −1 . Delta 15 N of −0.86‰ was well in the range given for nitrogen fixing organisms. The cell C, N and P content was 36.7%, 5.9% and 0.9%, respectively, resulting in the molar ratio of 105:14.4:1. A well designed and executed lake monitoring program, strict control of nutrient input into the lake, and public education are the necessary prerequisites for potential prevention of even more severe blooms than the one from 2009.

Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors

“…This toxin was produced by blooms of Cylindrospermopsis and Lyngbya in Brazil, Mexico, Guatemala and Nigeria (Lagos et al, 1999;Bouvy et al, 1999;Molica et al, 2005;dos Anjos et al, 2006;Berry and Lind, 2010;Rejmánková et al, 2011;Sant'Anna et al, 2011). Comparisons of the neurotoxic Cylindrospermopsis strains from Brazil and Mexico revealed the Brazilian strain to have acute neurotoxicity from the presence of saxitoxin, neosaxitoxin and decarbamoylsaxitoxin and the Mexican strains isolated were found to be non-toxic .…”

“…blooms were recorded in Guatemala and Nigeria, with the species from Guatemala (L. hieronymusii, L. birgei, and L. robusta) producing saxitoxins and cylindrospermopsins and the species from Nigeria (Lyngbya sp.) producing only saxitoxins (Odokuma and Isirima, 2007;Rejmánková et al, 2011). These bloom-forming species were rare or absent in other tropical regions.…”

“…The levels of cylindrospermopsin and saxitoxin recorded from Guatemala were relatively low (CYN: 0.6 to 1.2 ng l -1 , STX: 2.9 to 5.8 ng L -1 ) and thus, do not appear to pose an immediate danger in water supplies. However, these blooms should be monitored for any changes in toxin production level (Rejmánková et al, 2011). The level of saxitoxins in blooms of Lyngbya sp.…”

“…Since that incident some studies have been carried out on several reservoirs in South and Central America documenting blooms and progenitor species (Díaz-Pardo et al, 1998;Lind and Davalos-Lind, 2002;Ramirez et al, 2002;Bittencourt-Oliveira et al, 2005;Frias et al, 2006;Merino-Ibarra et al, 2007;Berry and Lind, 2010;Vasconcelos et al, 2010;Rejmánková et al, 2011). A review by Dorr et al (2010) revealed that there has been increased cyanobacterial bloom occurrence in water bodies in South America requiring better methods for screening and testing of cyanobacterial toxins.…”

Regime shift in the littoral ecosystem of volcanic Lake Atitlán in Central America: combined role of stochastic event and invasive plant species

“…Like many volcanic lakes (Diaz, Pedrozo, Reynolds, & Temporetti, 2007), Lake Atitlan is nitrogen-limited (as indicated by low N and low N:P ratios in Table 1). Nitrogen limitation has been explored in relation to phytoplankton, specifically cyanobacteria and N-fixation (Corman et al, 2015;Rejmankova et al, 2011) Table 1 comparing TN in littoral versus pelagial). Clearly, N F I G U R E 8 Proportion of macroinvertebrate taxa and individuals associated with five macrophyte species: Eichhornia crassipes, Hydrilla verticillata, Ceratophyllum demersum, Azolla filliculoides and Potamogeton sp limitation has not prevented the spread of invasive species in Lake Atitlan as both natives and invasives seem capable of utilising various mechanisms to overcome it.…”