Título del libro: Lake Alchichica Limnology: The Uniqueness Of A Tropical Maar Lake
Título del capítulo: Physicochemical Characteristics
JAVIER ALCOCER DURAND; MARTIN MERINO IBARRA; JORGE ALBERTO RAMIREZ ZIEROLD; LUIS ALBERTO OSEGUERA PEREZ; FERMIN SERGIO CASTILLO SANDOVAL;
Autores externos:
Idioma:
Año de publicación:
2022
Palabras clave:
Dissolved carbon; Nutrients; Oligotrophy; PAR; Particulate carbon; UVR; Warm monomixis; Warm monomixis
Resumen:
The physical and chemical characteristics of Lake Alchichica are tightly coupled to the thermal (mixing-stratification) pattern and the phytoplankton dynamics. Tropical, deep Lake Alchichica is warm monomictic. Although tropical in latitude (19°N), the high-altitude setting of Lake Alchichica (2300 m a.s.l.) tempers water temperature (average 15.8 ± 1.4 °C), with the coldest period (15.1 ± 0.7 °C) during the circulation (January to March), and a warmer period (16.2 ± 1.8 °C) during the stratification (June to December). Full water column mixing occurs in February. Turbidity in Lake Alchichica is biogenic; therefore, lower values of Secchi disk depth (4.5 ± 0.7 m), the euphotic zone (25 ± 4 m), and the UVR and PAR penetration (< 15 m) at the winter circulation and the onset of the stratification period associate to the diatom and Nodularia aff. spumigena blooms, which define the turbid water phase. On the contrary, deepest Secchi disk depth (8.1 ± 1.5 m), euphotic zone (33 ± 5 m), and UVR and PAR penetration (< 30 m) during the well-established stratification characterize the clear water phase. DO concentration in Lake Alchichica ranges widely. At surface, it remains between saturation and oversaturation (6.5-7.5 mg/L, DOSAT = 100-130%), while at deep waters (metalimnion) DO concentrations reach microaerobic (< 1 mg/L) or anoxic conditions (< 0.2 mg/L) during stratification, intensified by the winter diatom bloom. During the well-established and late stratification, the thermo- and oxycline couples at the metalimnion. During mixing, the whole water column remains well-oxygenated (DOSAT > 60%). Lake Alchichica is oligo-to mesotrophic. Along with the stratification, nutrients depleted in the epilimnion while accumulating in the hypolimnion. Throughout the water column circulation, nutrients are high and homogeneously distributed. The winter diatom bloom during circulation depleted total phosphorus until its lowest concentrations. It remains so during the well-established stratification in the mixed layer. In contrast, at the end of the mixing period associated with the bloom total nitrogen reaches the highest concentrations. During the well-established stratification, total nitrogen reaches the lowest concentrations in the mixed layer. In the mixing period, the high total nitrogen values favor the winter diatom bloom. Lake Alchichica is notably low in silicate concentration (5.1 ± 4.8 µmol/L). Major epilimnetic concentration precedes the first deep chlorophyll maximum due to Cyclotella alchichicana in the stratification period. Nitrogen and silicates co-limited the phytoplankton growth in Lake Alchichica. Most of the fixed nitrogen and silicates in Alchichica are exported below the thermocline instead of recycled in the mixed layer, sustaining an apparent nitrogen deficiency at surface waters while increasing the lake?s trophic status over time. Dissolved inorganic carbon (422.3 ± 38.4 mg/L) composed the main fraction and type (98-99%) in Lake Alchichica, associated with its watershed lithology, groundwater supply, and alkaline pH. Dissolved organic carbon is mainly autochthonous; therefore, it has low values (4.5 ± 0.4 mg/L); it increases in the mixed layer at the end of the mixing period. Particulate carbon is mostly organic (0.38 ± 0.19 mg/L); it increases in the mixed layer during the winter circulation associated with the diatom bloom and in the well-established stratification associated with the deep chlorophyll maximum. Particulate inorganic carbon (0.24 ± 0.22 mg/L) represents the minor type and fraction (0.001-0.01%); it increases during the winter circulation. It must be noted, electrical conductivity, pH and ionic composition of Lake Alchichica?s water is discussed in Chap. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.
Entidades citadas de la UNAM:
ISBN:
9783030790967
Editorial:
Springer International Publishing Nombre de la publicación:
Physicochemical Characteristics
Página inicial:
101
Página final:
142
