|
|
Recovery of zooplankton community from the acidification in mountain lakes
Bartošíková, Martina ; Sacherová, Veronika (advisor) ; Šorf, Michal (referee)
Mountain Lakes in Bohemian forest are currently undergoing a process of acidification. In spite of the rapid improvement of chemistry, the biological recovery is considerably delayed. This state may be due to a number of factors, such as persistent periodic pH fluctuations and hence increased aluminum leaching, phosphorus limitation, resistance of acid-tolerant communities, or limited opportunities for spreading from surrounding sites or damage to the egg bank. With the delay in improving the chemical composition of water gradually comes the improvement of the biological state, which manifests in the first phase by increasing the abundance of the existing species, in the second by increasing the number of species. In addition to the fish, it seems that the largest filtering dwarfs of the genus Daphnia are returned. In spite of their efforts to accelerate their return in the natural experiment by repatriating the species Cyclops abyssorum and Daphnia longispina to Plešné Lake in 2004, the wildebeests did not enjoy the new locality. Still, after almost ten years, individual individuals of this kind were found in lake litoral. This diploma thesis builds on the research of the Bohemian forest lakes, which is going on for almost 150 years. The zooplankton's response to changes in chemistry was studied...
|
|
|
Zooplankton response to a change of water chemistry and amount of food during the recovery of lakes from acidification
Bartošíková, Martina ; Stuchlík, Evžen (advisor) ; Šorf, Michal (referee)
Anthropogenic acidification has affected assemblages in thousands of lakes in North America and Europe. It turned out that, during the acidification, the number of zooplankton changed and also the species composition of their assemblages, at some sites there was also the total disappearance. The main reason was a decrease of pH, wash out toxic aluminium and a change of trophic status. The rate and extent of biological recovery after restoring the pH in acidified lakes varies considerably across regions. Recovery of aquatic communities is significantly lagging behind the recovery in chemistry. Some zooplankton species are nonetheless able to quickly colonize recuperating ecosystems and in many acidified lakes again started to appear native species that have disappeared during acidification. The return of indigenous species, however, can be blocked acid-tolerant occurrence of species after species extinct occupied empty niches. Zooplankton can be affected by water chemistry directly, but also indirectly by the quality and quantity of food. An important factor is the possible spread of colonizing species. However, the relative roles of these factors in regulating recovery may be difficult to determine. Key words: zooplankton, acidification, water chemistry, aluminium toxicity, phytoplankton
|
guest ::
