Impacts of agricultural used substances on the bacterial community structure in groundwater ecosystems

Groundwater is an essential renewable resource for industrial, agricultural and municipal purposes. However, groundwater is not only an important resource but also an ecosystem that contains a variety of species that have adapted to the specific conditions in the groundwater and react very sensible to changes of environmental conditions. These organisms provide ecosystem services which play an important role for the quality of groundwater. It is therefore important to maintain and protect the groundwater ecosystems from pollution or other disturbing factors, because alteration of environmental conditions can lead to a shift in the community composition and therefore also in the functional structure of these biocenoses. One of the main reasons for changes in environmental conditions is anthropogenic activities, especially in the field of agricultural land use. The influence of intensive agricultural land use on the abiotic conditions of the groundwater has been revealed by chemical surveys and is well known. However, and importantly, assessment of groundwater ecosystems on the basis of abiotic parameters is insufficient to detect impacts on the biocenoses of groundwater ecosystems. The aim of our study is to analyse the spatial and temporal impact of agricultural induced substances on the microbial community structure and to identify specific operational taxonomic units which reflect these impacts.