Spatial heterogeneity is one of the fundamental characteristics of organisms from microbes, animals, plants, to human beings. We humans do not distribute randomly on the earth, and microbes in hot springs do not neither. We aggregate or distribute unevenly on the earth and so our spatial distribution is aggregated or heterogeneous. The study revealed that hot spring microbiomes are distributed heterogeneously and further we discovered that the heterogeneity parameter is invariant with major environmental factors, particularly the hot spring water temperature and acidity (pH-value). This finding indicates that the spatial distribution of hot spring microbiomes is primarily determined by evolutionary forces and is little influenced by environmental factors.
Using an analogy, the heterogeneity scaling parameter for the hot-spring microbiome is similar to the gravitational acceleration constant (g=9.8), which is constant on the earth except for slightly variations on different latitudes but is different on the moon. In the case of the heterogeneity scaling parameter (b), the parameter is constant for the hot spring and is invariant with the water temperature and acidity of the hot spring. However, similar to that earth and moon have different gravitational acceleration constants, the hot spring microbiome and human microbiome exhibited different heterogeneity scaling parameter values (b=1.6 for hot spring microbiome and b=2.0 for the human gut microbiome).
The above findings are reported in a paper titled “Comparative Power Law Analysis for the Spatial Heterogeneity Scaling of the Hot‐Spring Microbiomes” published in Molecular Ecology, and authored by Lianwei Li and his PhD adviser Sam Ma. The comparative study was performed based on the extensions of the classic Taylor’s power law [Nature: 1961(vol. 189, 732-735); 1977(vol. 265, 415–421); 1983 (vol. 303,801–804)] from population to community ecology by Ma (2015) “Power law analysis of the human microbiome”, also published in Molecular Ecology. – Sam Ma, CAS Center for Excellence in Animal Evolution and Genetics