干旱区生态环境知识资源中心

It has been claimed that free-living ciliated protozoa are cosmopolitan microbes that thrive anywhere in the world where their preferred habitats are realised. A simple test of this proposition would include searching for marine ciliates in NaCl-dominated inland saline aquatic environments that are not directly connected to a coastal marine environment, and that are located at a substantial distance from the sea. There are many reasons why marine ciliates may not be found at inland sites (e.g. their vital habitat requirements may not be realised), but if typical marine ciliates can be found at inland sites with suitable habitat types, the idea of dispersal at large geographical scales would be lent further support. Here we describe our observations of typical marine ciliate morphospecies living in four inland evaporation salt pans in Central Spain, roughly 300 km from the nearest marine coastal environment, and roughly equidistant from the Atlantic Ocean and the Mediterranean Sea. We found ciliate communities typical of marine and hypersaline environments, and we identified 38 ciliate species. One of the ciliate species found was Trimyema marinum, a small anaerobic ciliate that has not been reported for at least 50 years. We consistently found similar communities of marine ciliates in the different salt pans. This indicates two things - that ubiquitous dispersal of at least some marine ciliates operates across wide geographical areas, and that specific habitat types select for specific ciliate taxa. We also report some observations of Trimyema marinum.