Glacial-Interglacial geochemical record from Lake Chalco, a high altitude tropical site in Central Mexico

2012 ◽  
Vol 279-280 ◽  
pp. 292-293
Author(s):  
Socorro Lozano Garcia
Keyword(s):  
High Altitude ◽  
Central Mexico

Phenology ofParalemanea mexicana(Batrachospermales, Rhodophyta) in a high-altitude stream in central Mexico

2013 ◽  
Vol 62 (2) ◽  
pp. 86-93 ◽  
Author(s):  
Javier Carmona Jiménez ◽  
Miriam Guadalupe Bojorge García ◽  
Rocío Ramírez Rodríguez
Keyword(s):  
High Altitude ◽  
Central Mexico

scholarly journals Description of larvae of Mexican Calosoma Weber, 1801 species, with faunal records (Coleoptera Carabidae Carabini)

2021 ◽  
pp. 83-104
Author(s):  
Augusto Vigna Taglianti ◽  
Sandro Bruschi ◽  
Andrea Di Giulio
Keyword(s):  
High Altitude ◽  
Relevant Literature ◽  
Central Mexico ◽  
Cold Climates ◽  
Geographic Isolation ◽  
Geographic Barriers ◽  
First Time

On the basis of the materials collected on site, the larvae of six species of Mexican Calosoma, namely Calosoma (Callitropa) porosifrons Bates, 1891, and five species of the subgenus Carabomimus Kolbe, 1895 are figured and described for the first time. Though these larvae are quite similar for most characters, some important differences can be found in the two subgenera Callitropa Motschulsky, 1865 and Carabomimus, confirming the distinctness of these taxa. Through an accurate study of the collected adult specimens and of the relevant literature, the distribution of the population afferent to each of these same species is clarified. With the occasion, the distribution of all Mexican Calosoma, is discussed, distinguishing between winged species, usually widely spread, and apterous species, linked to humid, temperate or semi-cold climates. In this context, the distribution of the subgenus Carabomimus, appears to be more sensitive to the influence of geographic barriers and the differentiation of the species was clearly helped by geographic isolation at high altitude in the volcanic massif of central Mexico.

Indoor Radon and Annual Effective Doses at a High Altitude Region in Central Mexico

2005 ◽  
Vol 5 (8) ◽  
pp. 1356-1362 ◽  
Author(s):  
M.I. Gaso ◽  
N. Segovia . ◽  
S. Pulinets . ◽  
A. Leyva . ◽  
G. Ponciano . ◽  
...  
Keyword(s):  
High Altitude ◽  
Indoor Radon ◽  
Central Mexico ◽  
Effective Doses

Phenology ofSirodotia suecica(Batrachospermaceae, Rhodophyta) in a high-altitude stream in central Mexico

2009 ◽  
Vol 57 (2) ◽  
pp. 118-126 ◽  
Author(s):  
Javier Carmona ◽  
Miriam Bojorge-García ◽  
Yenny Beltrán ◽  
Rocio Ramírez-Rodríguez
Keyword(s):  
High Altitude ◽  
Central Mexico

scholarly journals Brachionus paranguensis sp. nov. (Rotifera, Monogononta), a member of the L group of the Brachionus plicatilis complex

ZooKeys ◽  
2019 ◽  
Vol 880 ◽  
pp. 1-23 ◽  
Author(s):  
Gerardo Guerrero-Jiménez ◽  
Patrizia Elena Vannucchi ◽  
Marcelo Silva-Briano ◽  
Araceli Adabache-Ortiz ◽  
Roberto Rico-Martínez ◽  
...  
Keyword(s):  
New Species ◽  
High Altitude ◽  
Species Complex ◽  
Crater Lake ◽  
Brachionus Plicatilis ◽  
Integrated Approach ◽  
Central Mexico ◽  
Formal Description ◽  
Dna Taxonomy ◽  
A New Species

The Brachionus plicatilis complex represents the most studied group of rotifers, although the systematics of the species complex has not been completely clarified. Many studies have been conducted trying to explore the diversity within the complex, leading to the recognition of three major morphotypes: large (L), small-medium (SM), and small (SS). Currently six species have been described and classified under these types and another nine taxa have been identified but not formally described. Within the L group, three species have been officially described [B. plicatilis s.s. (L1), B. manjavacas (L2), and B. asplanchnoidis (L3)], while a formal description of L4, unofficially known as B. ‘Nevada’, is still lacking. In the present study, a new species, Brachionus paranguensissp. nov., is formally described and presented as a representative of the L4 clade. The species has been named after a high altitude saline crater lake from Central Mexico, where the specimens were collected. An integrated approach using DNA taxonomy through COI and ITS1 markers, morphology, and ecology was used to confirm the identity of the new species.

The Holocene history of a tropical high-altitude lake in central Mexico

The Holocene ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 865-877
Author(s):  
Margarita Caballero ◽  
Edyta Zawisza ◽  
Martín Hernández ◽  
Socorro Lozano-García ◽  
Juan Pablo Ruiz-Córdova ◽  
...  
Keyword(s):  
High Altitude ◽  
Early Stage ◽  
Sediment Accumulation ◽  
Ice Age ◽  
Central Mexico ◽  
Diatom Assemblages ◽  
Cold Event ◽  
High Altitude Lakes ◽  
Nutrient Levels ◽  
The Impact

High-altitude lakes are sensitive to modern and past climate changes. Given their low-water temperatures, alkalinity, and nutrient levels, small climatic differences can strongly affect their water chemistry, and/or biodiversity. In central Mexico, there are only two high-altitude lakes, and both are within the crater of the Nevado de Toluca volcano. Here, we present a paleolimnological record from one of these lakes: La Luna. Previous paleoenvironmental work showed that it was sensitive to the Little Ice Age (LIA) cooling. Our results show that sediment accumulation began ~6900 to 6100 cal. yr BP under periglacial conditions and that lake conditions were established ~6000 cal. yr BP. One tephra layer was dated to ~5600 cal. yr BP, with no evidence of more recent volcanic activity. The early stages of this lake (6000–4700 cal. yr BP) contained Cladocera and diatom assemblages with different species composition than modern assemblages. This early stage community structure was related to more mesic conditions and cooler winters inferred by the high abundance of planktonic Aulacoseira nivaloides and of Chydorus cf. sphaericus. The establishment of modern limnological conditions after 4700 cal. yr BP is inferred from Cladocera and diatom assemblages similar to recent samples. A reduction in A. nivaloides and low magnetic-susceptibility values suggest lower lakes levels, a trend consistent with lower available moisture in central Mexico after 4000 cal. yr BP. The rest of the sequence shows the impact of two cold periods, the first one around 3000 cal. yr BP, identified by a new increase in Chydorus cf. sphaericus. The second was the larger impact associated with the LIA (AD 1350–1910), and an increase in Cavinula pseudoscutiformis and Pinnularia microstauron suggesting an increase in lake water pH. Also, organic matter and photosynthetic pigments increased during this period showing an increase in nutrient levels and productivity. Finally, the coldest interval during the LIA (AD 1570–1890) is identified by an important reduction in arboreal pollen concentration which points to a wider environmental impact of this cold event.

scholarly journals Initial Time Of Two High Altitude Crater Lakes (Nevado De Toluca, Central Mexico) Recorded In Subfossil Cladocera

2015 ◽  
Vol 32 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Krystyna Szeroczyńska ◽  
Edyta Zawisza ◽  
Marta Wojewódka
Keyword(s):  
High Altitude ◽  
Bottom Sediments ◽  
Initial Time ◽  
Central Mexico ◽  
Sediment Layer ◽  
Radiocarbon Dates ◽  
Crater Lakes ◽  
Subfossil Cladocera ◽  
Cladocera Remains ◽  
Nevado De Toluca

Abstract The objective of this study was the recognition and reconstruction of the origin of two high altitude lakes and the ecological conditions of their early existence based on subfossil Cladocera and chemical analyses. The study focused on the oldest lacustrine sediments from Lake Sol and Lake Luna, located in the crater of Volcano Nevado de Toluca (Central Mexico). The Nevado de Toluca crater developed approximately 12 ka yr BP. According to the literature, the volcano was last active approximately 3.3 ka yr BP, and the lakes developed after that eruption. The remains of nine Cladocera species were found in the bottom sediments of both lakes. The most dominant taxa were two endemic littoral species: Alona manueli and Iliocryptus nevadensis. The total frequency of Cladocera specimens in both of the sediment cores was very low. No Cladocera remains were recorded in the sediment layer at depths between 123–103 m from Lake Luna. The results of the lithological and geochemical analyses showed that this sediment layer was composed of allochthonous material, probably originating from slid down from the volcanic cone. This was suggested by the content of silica (up to 13%), iron (up to 12%), and titanium (up to 4%). The Cladocera remains recorded in the bottom sediments suggested that both reservoirs developed as freshwater lakes at the beginning of the sedimentation. The calibrated radiocarbon dates obtained for the bottom samples were 4040 to 3990 yr BP for Lake Luna (129 cm) and 4485 to 4485 yr BP for Lake Sol (89 cm). The obtained ages were older than the dates of the last eruption, which occurred approximately 3300 yr BP. This result was likely related to the type of radiocarbon dated materials (charcoals).

Volcanic stratigraphy of a high-altitude Mammuthus columbi (Tlacotenco, Sierra Chichinautzin), Central México

2015 ◽  
Vol 77 (3) ◽  
Author(s):  
Marie-Noelle Guilbaud ◽  
Lilia Arana-Salinas ◽  
Claus Siebe ◽  
Luis Alberto Barba-Pingarrón ◽  
Agustín Ortiz
Keyword(s):  
High Altitude ◽  
Central Mexico ◽  
Volcanic Stratigraphy

Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

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