Littoral periphyton dynamics in newly established post-mining lakes

Hydric recultivation-flooding of abandoned mining pits-creates a completely new, underexplored habitat for a wide range of aquatic organisms. Periphyton, dominated by algae and cyanobacteria, is frequently a key component of newly established aquatic ecosystems. Periphyton and its response to abiotic factors were studied in the littoral zone of three post-mining lakes with different ages of foundation situated in the Czech Republic. The microbial diversity of phototrophs as a major component of periphyton is largely unknown in such localities. The studied habitat proved to harbour a huge periphytic diversity-25% of diatom species found in the respective watershed (similar to 5500 km(2)) inhabited exlusively the studied lakes. Species composition of phototrophic microorganisms varied significantly (Permutational Multivariate Analysis of Variance) among the studied lakes, seasons, and sampling years. However, the sampling depths and sampling site of the studied lake have not shown a significant impact on the diversity, indicating the homogeneous composition of the littoral periphyton within a particular lake and growing season. The seasonal dynamics of periphyton were unique for each lake, documenting three distinct successional patterns. The proportion of diatoms in the periphytic community decreases with the higher trophic state and flooding age of the post-mining lakes. Cyanobacteria and mobile diatom forms prevailed later in the growing season, suggesting that they could utilise nutrients released from the accumulated periphyton biomass. Calcium ions were one of the best correlates of species data among other abiotic variables tested, offering the intriguing question of the role of calcium in the formation of periphytic mats for future research.

Automated summary

Hydric recultivation by flooding abandoned mining pits creates a new habitat for aquatic organisms. The periphyton in the littoral zone of post-mining lakes showed a high diversity, with different species compositions and successional patterns. Calcium ions were found to be correlated with the periphytic mats and should be investigated further.