scholarly journals Evaluation of the Egg Bank of Two Small Himalayan Lakes

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 491
Author(s):  
Roberta Piscia ◽  
Sara Bovio ◽  
Marina Manca ◽  
Andrea Lami ◽  
Piero Guilizzoni
Keyword(s):  
Sediment Cores ◽  
Extreme Environments ◽  
Biodiversity Loss ◽  
Cold Season ◽  
Mountain Lakes ◽  
High Mountain ◽  
High Mountain Lakes ◽  
Egg Bank ◽  
Diapausing Eggs ◽  
Himalayan Lakes

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.

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
Keyword(s):  
Phytoplankton Community ◽  
Extreme Environments ◽  
Mountain Lakes ◽  
Central Mexico ◽  
High Mountain ◽  
High Mountain Lakes ◽  
Phytoplankton Diversity ◽  
Nevado De Toluca ◽  
Diverse Groups ◽  
La Luna

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.

scholarly journals Responses of Benthic Macroinvertebrate Communities of Two Tropical, High-Mountain Lakes to Climate Change and Deacidification

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 243
Author(s):  
Javier Alcocer ◽  
Luis A. Oseguera ◽  
Diana Ibarra-Morales ◽  
Elva Escobar ◽  
Lucero García-Cid
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Water Temperature ◽  
Water Level ◽  
Environmental Changes ◽  
Mountain Lakes ◽  
High Mountain ◽  
Macroinvertebrate Communities ◽  
High Mountain Lakes ◽  
La Luna

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.

scholarly journals Using a morpho-functional approach to assess phytoplankton dynamics in two adjacent high-mountain lakes: a 10-year survey

2014 ◽  
Vol 73 (3) ◽  
Author(s):  
Renata Trevisan ◽  
Marco Picarella ◽  
Frank B. Dazzo ◽  
Stefano Bona ◽  
Giuseppe Morabito ◽  
...  
Keyword(s):  
Functional Approach ◽  
Mountain Lakes ◽  
High Mountain ◽  
Phytoplankton Dynamics ◽  
High Mountain Lakes

scholarly journals Trapping of Organochlorine Compounds in High Mountain Lakes

2001 ◽  
Vol 1 ◽  
pp. 609-611 ◽  
Author(s):  
Joan O. Grimalt ◽  
Pilar Fernandez ◽  
Rosa M. Vilanova
Keyword(s):  
Atmospheric Transport ◽  
Mountain Lakes ◽  
Organochlorine Compounds ◽  
High Mountain ◽  
High Latitudes ◽  
High Mountain Lakes ◽  
Mountain Areas ◽  
Persistent Pollutants

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].

scholarly journals Perspectives for an integrated understanding of tropical and temperate high-mountain lakes

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
Jordi Catalan ◽  
John C. Donato Rondón
Keyword(s):  
Global Change ◽  
Freshwater Ecosystems ◽  
Mountain Lakes ◽  
Molecular Techniques ◽  
Mountain Lake ◽  
Tropical Lakes ◽  
High Mountain ◽  
Essential Difference ◽  
High Mountain Lakes ◽  
High Mountain Lake

<p>High mountain lakes are extreme freshwater ecosystems and excellent sentinels of current global change. They are likely among the most comparable ecosystems across the world. The largest contrast occurs between lakes in temperate and tropical areas. The main difference arises from the seasonal patterns of heat exchange and the external loadings (carbon, phosphorus, metals). The consequence is a water column structure based on temperature, in temperate lakes, and oxygen, in tropical lakes. This essential difference implies that, in tropical lakes, one can expect a more sustained productivity throughout the year; a higher nutrient internal loading based on the mineralization of external organic matter; higher nitrification-denitrification potential related to the oxyclines; and a higher metal mobilization due to the permanently reduced bottom layer. Quantifying and linking these and other biogeochemical pathways to particular groups of organisms is in the current agenda of high-mountain limnology. The intrinsic difficulties of the taxonomic study of many of the organisms inhabiting these systems can be now overcome with the use of molecular techniques. These techniques will not only provide a much less ambiguous taxonomic knowledge of the microscopic world, but also will unveil new biogeochemical pathways that are difficult to measure chemically and will solve biogeographical puzzles of the distribution of some macroscopic organism, tracing the relationship with other areas. Daily variability and vertical gradients in the tropics are the main factors of phytoplankton species turnover in tropical lakes; whereas seasonality is the main driver in temperate communities. The study of phytoplankton in high-mountain lakes only makes sense in an integrated view of the microscopic ecosystem. A large part of the plankton biomass is in heterotrophic, and mixotrophic organisms and prokaryotes compete for dissolved resources with eukaryotic autotrophs. In fact, high-mountain lake systems are excellent model ecosystems for applying an investigation linking airshed to sediments functional views. Additionally, the study of the mountain lakes districts as functional metacommunity units may reveal key differences in the distribution of organisms of limited (slow) dispersal. We propose that limnological studies at tropical and temperate high mountain lakes should adhere to a common general paradigm. In which biogeochemical processes are framed by the airshed-to-sediment continuum concept and the biogeographical processes in the functional lake district concept. The solid understanding of the fundamental limnological processes will facilitate stronger contributions to the assessment of the impacts of the on-going global change in remote areas.</p>

Photoreactivity of Dissolved Organic Matter from High-Mountain Lakes of Sierra Nevada, Spain

2001 ◽  
Vol 33 (4) ◽  
pp. 426 ◽  
Author(s):  
I. Reche ◽  
E. Pulido-Villena ◽  
J. M. Conde-Porcuna ◽  
P. Carrillo
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sierra Nevada ◽  
Mountain Lakes ◽  
High Mountain ◽  
High Mountain Lakes

Zooplankton advective losses may affect chlorophyll-a concentrations in fishless high-mountain lakes

Limnetica ◽  
2019 ◽  
Vol 38 (1) ◽  
pp. 55-65
Author(s):  
Rafael Morales-Baquero ◽  
Carmen Pérez-Martínez ◽  
Eloísa Ramos-Rodríguez ◽  
Pedro Sánchez-Castillo ◽  
Manuel Villar-Argaiz ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Mountain Lakes ◽  
High Mountain ◽  
High Mountain Lakes
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