RESEARCH ARTICLE Comparative Study of Physical Factors and Microbial Diversity of Four Man-Made Extreme Ecosystems Imran Ali 1,2,3 • Ali Akbar 3 • Muhammad Aslam 4 • Sami Ullah 5 • Muhammad Anwar 2 • Hunsa Punnapayak 1 • Pongtharin Lotrakul 1 • Sehanat Prasongsuk 1 • Benjawan Yanwisetpakdee 1 • Ponlada Permpornsakul 1 • Sudip K. Rakshit 6 Received: 6 May 2014 / Revised: 26 December 2014 / Accepted: 5 March 2015 Ó The National Academy of Sciences, India 2015 Abstract Ten soil samples were collected from four man- made extreme ecosystems, located adjacent to each other, at Ban Laem district, Phetchaburi province, Thailand. The area is used for sea salt extraction produced in artificial solar salterns. Soil analysis was performed which revealed the extreme conditions in terms of salinity, moisture content, organic matter and nitrogen content. Selective medium was provided for the isolation of microorganisms. Bacteria were found to be the most dominating group of microorganisms followed by fungi, actinomycetes and algae. Morphological and biochemical identification were performed to determine the genus of each microorganism. An actinomycete genus: Streptomyces, an algal genus: Dunaliella, three bacterial genera: Halobacillus, Halobacterium and Halomonas, and a fungal genus: Aspergillus, were the most frequently found microbes in these extreme man-made ecosystems. Interest- ing inter and intra relationships were observed between physical factors and microbial diversity. Except pH and salinity all physical factors were found to have positive correlation effect on microbial numbers. Actinomycetes was found to favor the fungal populations in man-made extreme ecosystems. Keywords Biodiversity Á Extremophiles Á Halophiles Á Hypersaline environments Introduction Microorganisms that can survive extreme physical condi- tions such as pH, pressure, temperature and salinity [sodium chloride (NaCl)] are known as extremophiles. Organisms surviving in different salt concentrations are called halotolerants, while the organisms requiring NaCl for their growth are called as halophiles. According to Kushner [1], halophiles can be divided into five groups on the basis of salt required for their growth: (1) non-halo- philes, requiring approximately 1 % NaCl, (2) mild halo- philes, requiring approximately 1–3 % NaCl, (3) moderate halophiles, requiring approximately 3–15 % NaCl, (4) borderline extreme halophiles, requiring approximately 9–23 % NaCl and (5) extreme halophiles, requiring ap- proximately 15–32 % NaCl. Hypersaline environments are extreme habitats, which in addition to having high salt concentrations also have low oxygen concentrations, invariable pH and high or low temperatures. These extreme conditions limit their biodi- versity. Some other factors that also influence their biodi- versity are the low nutrient availability, solar radiation, Electronic supplementary material The online version of this article (doi:10.1007/s40011-015-0519-8) contains supplementary material, which is available to authorized users. & Imran Ali imranalisheik@gmail.com 1 Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand 2 Institute of Biochemistry, University of Balochistan, Quetta 87300, Pakistan 3 Food Engineering and Bioprocess Technology, School of Environment, Resources and Development, Asian Institute of Technology, Klong Luang, Pathumthani 12120, Thailand 4 Faculty of Marine Sciences, Lasbella University of Agriculture, Water and Marine Sciences, Uthal, Pakistan 5 Department of Chemistry, University of Balochistan, Quetta 87300, Pakistan 6 Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay ONP7B5E1, Canada 123 Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. DOI 10.1007/s40011-015-0519-8