Figure 5
From: Holocene life and microbiome profiling in ancient tropical Lake Chalco, Mexico
Climate and limnological inferences for the three Holocene zones in the Lake Chalco sediment core: (1) cool, freshwater lake, (2) warm, hyposaline lake, and (3) temperate, subsaline lake, determined using metagenomic, diatom, and geochemical analyses. The horizontal bar represents the time range of each zone, determined during this study and by previous studies cited in the text. The right bar shows the microbiota and enzyme pathways found in each paleoenvironmental zone. Si/Ti and P/Ti values in zone 1 (cool, freshwater lake) suggest high lacustrine productivity. The most abundant Eukarya families (algae) are associated with freshwater conditions. Values of Ca/Ti and TOC in zone 2 (warm, hyposaline lake) suggest periods of intense evaporation and high productivity. Highest TOC values suggest eutrophic conditions. Mn/Fe values in zones 1 and 2 suggest periods of anoxic bottom waters in the lake. Zone 3 (temperate, subsaline) is characterized by a slight increase in lake depth and a decrease in salinity. Geochemical variables Ti and Ti/Fe suggest greater rainfall and runoff. High diversity of fungal pathogens of crops, and highest abundance of Poaceae (grasses), suggest environmental perturbation, probably related to human settlement. Image was made in Inkscape 1.0.
