Resumen
Environmental impacts, such as earthquakes, chemical pollution and anthropogenic factors can affect the stability and sustainability of an ecosystem. In this study, a long-term (3.7 years) investigation experiment was conducted to estimate the sustainability of a constructed wetland (CW) under the impact of aquatic organisms overloading. The situation of aquatic organisms overloading in this study meant that around 27,000 kg of fishes had to be moved and accommodated in a 4 ha water area of wetland for six months. Experimental results indicated that the pH value of CW water was slightly acidic and the Dissolved Oxygen (DO) level decreased under the impact. On the other hand, the levels of Electrical Conductivity (EC), Suspended Solids (SS), Chemical Oxygen Demand (COD), and Total Kjeldahl Nitrogen (TKN) of CW water were increased under the impact. The pathogen analysis revealed that total coliforms, Salmonella spp., Enterococcus spp., and Escherichia coli, in the wetland water increased under the impact. The analyzed factors of water quality and amount of pathogens were all returned to their original statuses soon after the impact ended. Eventually, the results of microbial community structure analysis showed that overloading of aquatic organisms slightly increased the specific richness (R) of wetland bacteria, whereas higher structural biodiversity (H) of CW could stabilize the whole microbial community and prevent the pathogens or other bacteria from increasing to become the dominant strains. These results were novel and could be possible to conclude that a CW environment could not only stabilize the water quality and amount of pathogens resulting from the impact of aquatic organisms overloading, but also they could stabilize the microbial community structures, allowing the biogeochemical cycles of the CW to function. They could provide the useful information for wetland sustainability.