Invasion of Ceratium furcoides in subtropical lakes in Uruguay: Environmental drivers and fish kill record during its bloom

Abstract

The invasive freshwater dino agellate Ceratium furcoides is extending its distribution in South America with increasing environmental impacts associated with its blooms. We here report two events related to C. furcoides distribution expansion in Uruguay: 1) the rst appearance and main environmental drivers (physico-chemical variables, extreme wind events and zooplankton composition) of the bloom of C. furcoides in 2012 in a subtropical eutrophic shallow lake (Lake Blanca, Uruguay), and 2) the sh kill event of Prochilodus lineatus likely caused by C. furcoides in 2016 in a deep eutrophic lake (Puente de las Americas, Uruguay), which is the rst sh kill attributable to C. furcoides registered in the world.The bloom of C. furcoides in Lake Blanca started in spring 2012 (October) during a clear water period with high phytoplankton species replacement after a cyanobacterial bloom of Raphidiopsis raciborskii. Extreme wind events during this period resuspended cysts from the sediments, which likely started the C. furcoides bloom. High nutrient availability and low zooplankton grazing, allowed the bloom to expand and reach 96% of the phytoplankton biomass. Our results further indicate that the sh kill of Prochilodus lineatus in Lake Puente de las Americas was likely promoted by the high biomass of C. furcoides bloom, causing gill damage and clogging together with oxygen depletion in the benthic zone. Our study is the earliest record of C. furcoides in Uruguay and it shows the drastic consequences of C. furcoides bloom in freshwaters and its potential of inducing massive sh kills.

Invasion strategies and establishment of Ceratium dinoflagellate in subtropical watersheds of Southern Brazil and its interaction with Microcystis cyanobacteria: I. Hydrographic Region of Uruguay

“…Other studies have shown the success of the invasion of C. furcoides in aquatic bodies in the subtropical region(Cavalcante et al, 2013(Cavalcante et al, , 2016Silva et al, 2018;Silva et al, 2019).Although high temperatures may bene t Ceratium, this is not a determining factor for its expansion, as the dino agellate maintains intermediate densities in later years (2016 onwards). This coincides with other studies, such as in Lake Blanca, Uruguay(Pacheco et al, 2021), where high temperatures were important during the initial stages of a bloom but not necessary to maintain it. C. furcoides has complex distribution and expansion patterns, usually colonizing freshwaters from basins that are geographically close(Moreira et al, 2015;Silva et al, 2018;Pacheco et al, 2021).Common phytoplankton dispersants such as wind, animals, and humans could play a part on the expansion of the dino agellate as they can be a very effective disperse…”

“…This coincides with other studies, such as in Lake Blanca, Uruguay(Pacheco et al, 2021), where high temperatures were important during the initial stages of a bloom but not necessary to maintain it. C. furcoides has complex distribution and expansion patterns, usually colonizing freshwaters from basins that are geographically close(Moreira et al, 2015;Silva et al, 2018;Pacheco et al, 2021).Common phytoplankton dispersants such as wind, animals, and humans could play a part on the expansion of the dino agellate as they can be a very effective disperse…”

“…With regard to environmental variables, only in Dom Pedrito cyanobacteria and Ceratium were correlated with maximum temperature (0.48 and 0.45, respectively). The results also suggest that the temperature range for the occurrence of the species is much wider than expected (between 18 and 22°C, according to Meichtry-de-Zaburlin et al, 2016), as we found the species in environments with temperatures as high as 34,5°C and as low as 3,6°C, provide that the spatial and temporal scales are expanded, as in this study Pacheco et al (2021). showed the species in temperatures ranging from 18 to 28,4°C in a Uruguayan lakes; however, in tropical area in Brazil, where the temperature variation is short, Severiano et al (2022) evidenced C. furcoides in warm environments (around 26-28°C).Furthermore, seems that high temperatures associated with high precipitation rates may spark the growth of Ceratium in these spring, as large densities occurred in years where these meteorological variables were high (2013 to 2015).…”

Carbon fluxes in subtropical shallow lakes: contrasting regimes differ in CH4 emissions

“…and a permanent clear water regime. The dominant phytoplankton taxonomic groups, in this lake, have changed through the years from cyanobacteria to chlorophytes (Kruk et al, 2006;Pacheco et al, 2010), with one event of a Ceratium furcoides (Levander) bloom in 2012 (Pacheco et al, 2021). The community of consumers in the clear-vegetated lake is diverse; the zooplankton community is dominated by small-bodied cladocerans and copepods, with occasional occurrence of Daphnia spp.…”

“…The community of consumers in the clear-vegetated lake is diverse; the zooplankton community is dominated by small-bodied cladocerans and copepods, with occasional occurrence of Daphnia spp. and other larger-bodied species, the diverse fish community dominated by small-bodied species with a high biomass (Pacheco et al, 2021). Lake Capilla (location: 34°49 0 18.5 00 S-54°37 0 48.7 00 W, area: 1 ha), hereinafter referred to as 'phytoplankton-turbid', is a small, young (less than 15 years) artificially constructed lake that is in a turbid state due to high phytoplankton biomass.…”