Resumen
In the Tablas de Daimiel National Park (TDNP) wetlands, a semi-arid wetland system in Spain that is of international importance, it is believed that pollutants from a variety of sources accumulate. In the study reported here, we evaluated soils from the flooded part of this wetland in an effort to establish relationships between the abundance/structure of microbial communities (mainly cyanobacteria) and certain soil properties (redox potential, dissolved oxygen, organic matter, soil reaction, electrical conductivity, calcium carbonate, total nitrogen, soluble phosphorus and total phosphorus). This objective was achieved by establishing one transect from the entrance to exit of the flood plain, including sampling from potentially polluted sites. Substantial variations between sampling sites were found in soil in terms of salinity, dissolved oxygen (DO), organic matter (OM), total phosphorus (TP) and nitrogen (TN). The presence of primary producers was more evident in contaminated samples. In addition to calcium, high levels of oxidizable organic matter, traces of dissolved oxygen, and considerable amounts of nitrate and phosphates probably stimulated the growth of cyanobacteria, these latter characteristics can be explained as being due to the influence of wastewaters from urban, industrial and agricultural activities that run off directly into this unique wetland. In the future it will be necessary to understand the synergic effects of other soil properties.