scholarly journals Phytoplankton Biodiversity in Two Tropical, High Mountain Lakes in Central Mexico

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 42
Author(s):  
Estela Cuna ◽  
Javier Alcocer ◽  
Martha Gaytán ◽  
Margarita Caballero

Lakes El Sol and La Luna, inside the crater of the Nevado de Toluca volcano, Central Mexico, are the only two perennial high mountain lakes [HML] in the country. HML are considered among the most comparable ecosystems worldwide. These lakes are “extreme” environments with diluted, oligotrophic, and cold waters exposed to high UV radiation doses. In this paper, we document the phytoplankton species inhabiting these two extreme tropical ecosystems. The phytoplankton diversity of Lakes El Sol and La Luna is low compared to the global phytoplankton diversity from other Mexican inland waters. Nonetheless, the phytoplankton diversity turned out to be high compared to other HML worldwide, both temperate and tropical. The phytoplankton community in Lake El Sol was formed by 92 morphospecies and in Lake La Luna by 63; in both, the most diverse groups were Bacillariophyceae and Chlorophyceae. All species found in Lake La Luna were present in Lake El Sol, but 29 species present in Lake El Sol were absent in Lake La Luna. Nevertheless, 57% of the most frequent and abundant taxa in Lake El Sol were rare in La Luna, and 47% of the most frequent and abundant taxa in Lake La Luna were rare in Lake El Sol. Associated with their shallowness and polymictic thermal pattern, 87.5% of the Bacillariophyceae morphospecies are tychoplantonic, while the remaining 12.5% are truly planktonic. Dominant taxa were Chlorophyceae in Lake El Sol and Cyanobacteria in Lake La Luna. The most extreme conditions of Lake La Luna (ultraoligotrophy, very low pH, high ultraviolet radiation) most likely explained the differences in the dominant species composition and lower species richness compared to Lake El Sol. Herein, we provide for the first time a taxonomic list of the phytoplankton community of Lakes El Sol and La Luna. This information constitutes a baseline needed to use these HML as sentinels of global and climate change.

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 243
Author(s):  
Javier Alcocer ◽  
Luis A. Oseguera ◽  
Diana Ibarra-Morales ◽  
Elva Escobar ◽  
Lucero García-Cid

High-mountain lakes are among the most comparable ecosystems globally and recognized sentinels of global change. The present study pursued to identify how the benthic macroinvertebrates (BMI) communities of two tropical, high mountain lakes, El Sol and La Luna, Central Mexico, have been affected by global/regional environmental pressures. We compared the environmental characteristics and the BMI communities between 2000–2001 and 2017–2018. We identified three principal environmental changes (the air and water temperature increased, the lakes’ water level declined, and the pH augmented and became more variable), and four principal ecological changes in the BMI communities [a species richness reduction (7 to 4), a composition change, and a dominant species replacement all of them in Lake El Sol, a species richness increase (2 to 4) in Lake La Luna, and a drastic reduction in density (38% and 90%) and biomass (92%) in both lakes]. The air and water temperature increased 0.5 °C, and lakes water level declined 1.5 m, all suggesting an outcome of climate change. Contrarily to the expected acidification associated with acid precipitation, both lakes deacidified, and the annual pH fluctuation augmented. The causes of the deacidification and the deleterious impacts on the BMI communities remained to be identified.


2021 ◽  
Author(s):  
Liliana García-Solorio ◽  
Claudia Muro ◽  
Isaías De La Rosa ◽  
Omar Amador-Muñoz ◽  
Guadalupe Ponce-Vélez

Abstract Pollution levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the El Sol and the La Luna alpine lakes. The lakes are located in central Mexico, in the crater of the Nevado de Toluca volcano. The El Sol and the La Luna lakes are extremely relevant in Mexico and in the world because they are recognized as pristine regions and environmental reservoirs. Samples of atmospheric aerosol, sediment, plankton, and Tubifex tubifex were collected at three different sample locations for three years (2017, 2018, and 2019) at three different times of year, meaning that the weather conditions at the time of sampling were different. Pollutants were analysed by gas chromatography–mass spectrometry with negative chemical ionisation (GC-MS/NCI). Endosulfan was the most frequent and abundant pollutant, showing the highest peaks of all. Atmospheric aerosol revealed Σ2 = 45 pg/m3, including α and β, while sediment lakes displayed α, β and endosulfan sulphate as Σ3 = 1963 pg/g, whereas plankton and Tubifex tubifex showed Σ2 = 576 pg/g and 540 pg/g for α and β respectively. Results of endosulfan ratios (α/β) and (α-β/endosulfan sulphate) suggest that both fresh and old discharges continue to arrive at the lakesThis study shows for the first time the pollution levels of OCP and PCB in high mountain lakes in Mexico. These results that must be considered by policy makers to mitigate their use in the various productive activities of the region.


2020 ◽  
Vol 42 (2) ◽  
pp. 105-118
Author(s):  
Javier Alcocer ◽  
Clara N Delgado ◽  
Ruben Sommaruga

Abstract We compared temporal changes in the concentration of photoprotective compounds (PCs) in zooplankton of two adjacent (600 m apart) tropical high mountain lakes, El Sol and La Luna. The lakes have the same geological origin, age and drainage basin. However, they differ in underwater light and UV penetration and in the presence of Oncorhynchus mykiss, only found in El Sol. Whereas Daphnia ambigua from the clear La Luna had carotenoids and melanin, in El Sol, the same species lacked pigmentation. The copepod Leptodiaptomus cuauhtemoci was only found in El Sol and relied on accumulation of MAAs and carotenoids. The maximum concentration of PCs was found over the period with highest incident ultraviolet radiation (UVR). Our data suggest that tropical species of zooplankton respond to UVR by accumulating PCs that are too different in relation to exposure to UVR. However, we cannot discard the possibility that the presence of fish in Lake El Sol influences also their phenotypical and behavioral responses. Overall, zooplankton exhibited an ample phenotypic plasticity in the type and concentrations of PCs in response to the high and variable doses of UVR prevailing in low-latitude lakes, similar to the zooplankton of their high-latitude counterparts.


1999 ◽  
Vol 58 (2) ◽  
pp. 152 ◽  
Author(s):  
Brigitte HINDER ◽  
Matthias GABATHULER ◽  
Beatrice STEINER ◽  
Kurt HANSELMANN ◽  
Hans R. PREISIG

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 491
Author(s):  
Roberta Piscia ◽  
Sara Bovio ◽  
Marina Manca ◽  
Andrea Lami ◽  
Piero Guilizzoni

High mountain lakes are biodiversity treasures. They host endemic taxa, adapted to live in extreme environments. Among adaptations, production of diapausing eggs allows for overcoming the cold season. These diapausing eggs can rest in the sediments, providing a biotic reservoir known as an egg bank. Here, we estimated changes in abundance of the egg bank in two lakes in the Khumbu Region of the Himalayas, during the last ca. 1100 and 500 years, respectively, by analyzing two sediment cores. We tested viability of the diapausing eggs extracted from different layers of the sediment cores under laboratory conditions. We found that only diapausing eggs of the Monogont rotifer Hexarthra bulgarica nepalensis were able to hatch, thus suggesting that a permanent egg bank is lacking for the other taxa of the lakes, not least for the two Daphnia species described from these sites. Our results confirm previous studies suggesting that in high mountain lakes, the production of diapausing is mainly devoted to seasonal recruitment, therefore leading to a nonpermanent egg bank. The different ability of different taxa to leave viable diapausing eggs in the sediments of high mountain lakes therefore poses serious constraints to capability of buffering risk of biodiversity loss in these extremely fragile environments.


2014 ◽  
Vol 73 (3) ◽  
Author(s):  
Renata Trevisan ◽  
Marco Picarella ◽  
Frank B. Dazzo ◽  
Stefano Bona ◽  
Giuseppe Morabito ◽  
...  

2001 ◽  
Vol 1 ◽  
pp. 609-611 ◽  
Author(s):  
Joan O. Grimalt ◽  
Pilar Fernandez ◽  
Rosa M. Vilanova

High mountain areas have recently been observed to be polluted by organochlorine compounds (OC) despite their isolation. These persistent pollutants arrive at these remote regions through atmospheric transport. However, the mechanisms involving the accumulation of these compounds from the atmospheric pool to the lacustrine systems still need to be elucidated. These mechanisms must be related to the processes involving the transfer of these pollutant from low to high latitudes[1] as described in the global distillation effect[2].


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