Basic limnology of 30 continental waterbodies of the Transmexican Volcanic Belt across climatic and environmental gradients

Abstract

RESUMEN Empleando metodologías estandarizadas se estudiaron 30 cuerpos de agua en la Faja Volcánica Transmexicana a lo largo de un gradiente altitudinal (737 a 4283 msnm) y climatológico. Los lagos se incluyen en tres categorías: tectónicos (4), volcánicos (11 cráteres o maars, 7 represas volcánicas) y presas (8).]. In thirteen lakes, nutrient levels could be limiting primary productivity, mostly P, but also N and Si. Half of the lakes (16) were eutrophic or hypertrophic and most of these were also shallow (< 8 m) and correlated with warm, moist conditions. Ninety-seven taxa of aquatic organisms (phytoplankton, and surface sediment diatoms, testate amoebae, cladoceran and ostracodes) were reported, which could potentially be used as bioindicators. Principal component analysis (PCA) showed that temperature and precipitation were the main environmental gradients related to the lakes' limnological characteristics: colder climates related with lowest TDS (< 100 mg/L); dry climates with subsaline and hyposaline lakes, and warm-moist climates with eutrophic and hypertrophic lakes. Through the Procrustes technique we obtained indications that general geographic variables were important for some of the lakes, whereas the local factors were significant for others. It is through the knowledge of the basic limnology and biodiversity of Mexican lakes that more complex or detailed studies can be proposed leading to a better understanding, management, and conservation of water resources.

Ecological drivers of testate amoeba diversity in tropical water bodies of central Mexico

“…It covers over 160,000 km 2 , ranging in width from 90 to 230 km. Because of its uneven topography, there are many water bodies along the TMVB, varying widely in altitude and local weather conditions (Ferrari et al, 2012;Sigala et al, 2017). Several human populations have settled near these water bodies, using them for different purposes, such as sources of drinking water, or for economic and even recreational activities.…”

“…1) that covered different environmental gradients; these water bodies were recently described by Sigala et al (2017). Seventeen of these water bodies are volcanic in origin, eight are dam reservoirs and four are tectonic; their depths range from 0.5 to 65 m, with the volcanic lakes being the deepest.…”

“…Extractions were made using methanol (90%), concentrations were measured with a spectrophotometer (Thermo Scientific Genesys 20 Visible) and determined using Holden's equations (Meeks, 1974). Detailed information of the water bodies such as their location, sampling, field measurements, water chemistry and nutrients analysis are described in Sigala et al (2017). …”

“…3). Lake Aljojuca (site 2L) is a subsaline lake (Sigala et al, 2017) due to its high total dissolved solids values, whereas the others displayed lower values and are freshwater bodies. Values of pH were high for most of our 29 sites, with 27L being the most basic.…”

“…The Trans-Mexican Volcanic Belt (TMVB) is the largest Neogenic volcanic arch in North America, crossing central Mexico from east to west. Its topographical heterogeneity has favored the formation of several water bodies that vary in origin, area, depth, trophic state and salinity along its extension (Davies et al, 2002;Armienta et al, 2008;Sigala et al, 2017). These conditions make these water bodies ideal for ecological and paleoecological studies because their sediments likely retain a detailed record of climate and environmental changes, both natural and anthropogenic.…”