|
|
Reintroduction of a copepod species Cyclops abyssorum (Crustacea) and its impact on zooplankton in Plešné Lake
Křenová, Radka ; Vrba, Jaroslav (referee) ; Sacherová, Veronika (advisor)
Abstract Plešné Lake is a small glacial lake in the Bohemian Forest. In the 1980th, it was heavily influenced by an acification event caused by severe atmospheric pollution. Due to some extreme parameters in the water chemistry (mainly low pH and high concentration of toxic aluminum compounds) several zooplankton species got extinct. Among these, two species important in lakes food web: Daphnia spp. and Cyclops abyssorum. They, however, survived the acidification period in one of the Bohemian Forest Lake: Prášilské. Although recovery of lakes from acidification is usually followed by return of some species or colonization by others, recolonization of Plešné Lake is assumed to be very slow or impossible from external sources thanks to the remote position of the lake. Therefore in the fall of 2004 two zooplankton species (Daphnia longispina and Cyclops abyssorum) were artificially reintroduced into Plešné Lake. In the course of 4 years that followed only Cyclops abyssorum appeared in the lake, Daphnia longispina was not recorded. My thesis focuses on several aims. First, I evaluate the development of C. abyssorum population. Second, I studied the competition between C. abyssorum and another copepod species - Heterocope saliens, acidotolerant species which never disappeared from the lake. Third, I...
|
|
|
Biogeochemické cykly ekologicky významných prvků v měnících se přírodních podmínkách lesních ekosystémů NP Šumava
Správa národního parku Bayerische Wald ; Česká zemědělská univerzita, Fakulta lesnická a environmentální ; Ústav pro hydrodynamiku AV ČR, Praha ; Hydrobiologický ústav AV ČR, České Budějovice ; Česká geologická služba, Praha ; Beudert, Burkhart ; Máca, Petr ; Šír, Miloslav ; Tesař, Miroslav ; Metelka, Václav ; Vrba, Jaroslav ; Kopáček, Jiří ; Oulehle, Filip ; Hofmeister, Jeňýk ; Hruška, Jakub
Zpráva shrnuje poznatky získané v období listopad 2004 - prosinec 2005, které jsou doplněny o předchozí pozorování členů autorského kolektivu. Zaměření je na biogeochemické a hydrologické charakteristiky území na obou stranách Šumavy. Zpráva je rozdělena do částí: Zhodnocení látkových toků v NP Šumava na třech povodích s různým typem managementu; Chemismus půd a jehličí ve studovaných povodích; Modelování dlouhodobého vývoje chemismu vod a půd; Změny chemismu a oživení Rachelsee na Šumavě v důsledku kůrovcové kalamity a zotavování ekosystému z acidifikace; Vyhodnocení vodního režimu půd na lokalitách lišících se vegetačním krytem v Národním parku Šumava; Vliv usazených srážek na vodní a látkovou bilanci malého horského povodí.
|
|
|
Possibilities and specifications of usage of social networks in logistics
Vrba, Jaroslav ; Molnár, Zdeněk (advisor) ; Měsíček, Libor (referee)
The main purpose of this thesis is to examine current most important social networks usable in Czech Republic and evaluate usefulness for logistic companies. The aims of thesis are basics of internet marketing, separation of social networks and evaluation their commercial potential. Author attaches his research in form of questionnaire aimed on current usage social networks in logistic companies and compiles recommendations how use social network for commercial purpose.
|
|
|
The fluorescence assay of aminopeptidase activity as an alterantive indicator of water quality?
Vrba, Jaroslav ; Svoboda, J. ; Fuksa, J. K.
Recent water quality/pollution control uses standard chemical, biological or microbiological indicators that provide information on water status with a delay of several days. Though they characterise direct impact of released compounds on water quality in a recipient, they do not well reflect consequent reaction of the ecosystem on increased pollution. Following the Water Framework Directive 2000/60/EC we focused on such alternative microbial indicators that would allow for instant evaluation of ecological status of running waters and ongoing in-stream processes. Recently, activities of different extracellular enzymes have been suggested as indicators of both trophic status of lakes and organic or faecal pollution of streams. This contribution evaluates an indication potential of the extracellular aminopeptidase assay.
|
|
|
Development of microbial activity in the Vltava River - a longitudinal profile to Podolí and downstream
Svoboda, J. ; Vrba, Jaroslav ; Simanov, L. ; Fuksa, J. K.
Extracellular ß-glucosidase activity, bacterial number (direct counts and MPA colony forming units), chlorophyll .i.a./i. concentration, BOD.sub.5./sub., and COD were measured along the Vltava River and its reservoir cascade in 2000 (April-September;n = 5-8). The study demonstrated an important role of reservoirs in water quality management and, in particular, the dominant role of the microbes in matter transfers, decomposition, and nutrient dynamics in the transient zones of reservoirs.
|
|
| |
|
| |
|
| |
|
| |
|
| |
guest ::
