Utjecaj biotičkih čimbenika na raspodjelu zooplanktona eutrofnog jezera

master's thesis

• Title (english): Biotic impact on zooplankton distribution in the eutrophic lake
• Author: Ana Pestić
• Mentor: Maria Špoljar (mentor)
• Committee member: Maria Špoljar (predsjednik povjerenstva)
• Committee member: Božena Mitić (član povjerenstva)
• Committee member: Blanka Cvetko Tešović (član povjerenstva)
• Committee member: Neven Bočić (član povjerenstva)
• Committee member: Ines Radanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2015-02-26, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Istraživanje zooplanktona u mrtvaji Škrčev kut je provedeno od svibnja do listopada 2013. godine. Ciljevi ovog rada bili su utvrditi: (i) raznolikost, brojnost, veličinsku i trofičku strukturu zooplanktona u pelagijalu i litoralu; (ii) zooplanktonske vrste u sedimentu; (iii) strukturu taktilnih i vizualnih predatora; (iv) utjecaj predacije i izvora hrane na raspodjelu zooplanktona eutrofnog jezera. Rezultati statističke analize ukazali su na statistički značajne oscilacije fizičko-kemijskih čimbenika tijekom istraţivanog razdoblja, dok njihove razlike kao i strukture zooplanktona između pelagijala i litorala nisu bile statistički značajne. Na porast mutnoće prvenstveno su utjecale suspendirane tvari i fitoplankton, što je uzrokovalo slabu ili nikakvu pokrovnost makrofitima. Rezultati ukazuju da su zooplanktonske skupine manje migrirale u potrazi za zaklonom, jer su ribe kao vizualni predatori zbog velike mutnoće bile manje efikasne u hvatanju plijena. Izostanak makrofita također je smanjio ulogu litoralne zone, iako je ukupna brojnost zooplanktona bila veća u litoralu. Mala brojnost skupine Cladocera u zooplanktonu ukazuje da su zbog većih dimenzija i slabe pokretljivosti oni bili glavni izvor hrane vizualnim predatorima. Uklanjanjem većeg algivornog zooplanktona (Cladocera) od strane predatora veću brojnost postiţu sitniji organizmi (Rotifera) koji imaju manju stopu filtracije te nisu utjecali na smanjenje mutnoće. U veličinskoj strukturi zoplanktona dominirale su sitne jedinke. Najveću brojnost i raznolikost u pelagijalu i litoralu zabiljeţila je skupina Rotifera, sa najvećim udjelom mikrofiltratorskih vrsta, od kojih je najveću brojnost imala vrsta Keratella tecta. Taktilni predatori (ličinke Insecta i rakovi Cyclopidae) iz bentosa su utjecali na smanjenje planktivornih mikrofiltratora. Rezultati rada ukazuju da povećanje trofije jezera smanjuje raznolikost staništa i utječe na promjenu biotičkih odnosa u plitkim jezerima.

Abstract (english)

The research of zooplankton in Oxbow Škrčev kut was carried out from May to October 2013. The goals of this study were to determine: (i) diversity, abundance, a size and trophic structure of zooplankton in the pelagic and littoral; (ii) zooplankton species in the sediment; (iii) structure of tactile and visual predators; (iv) impact of predation and food resources on zooplankton distribution in the eutrophic lake. The results of statistical analysis indicated a statistically significant oscillations of physico-chemical factors during the study period, while their differences as well as the zooplankton structure between the the pelagic and littoral were not statistically significant. The increase of turbidity was primarily driven by suspended solids and phytoplankton, which caused little or no cover of macrophytes. Results indicate that zooplankton migrations were not exhibited because the fish as a visual predators were less efficient due to high turbidity. The absence of macrophytes also reduced the role of the littoral zone, although the total abundance of zooplankton was higher in the littoral area. The small abundance of the group Cladocera in zooplankton indicates that due to larger dimensions and low mobility they were the main source of food for visual predators. Removing of large algivornog zooplankton (Cladocera) by predators causes higher abundance of smaller organisms (Rotifera) that have a lower rate of filtration and didn't affect the reduction of turbidity. The size structure zoplanktona was dominated by small individuals. The greatest abundance and diversity in the pelagic and littoral recorded Rotifera, with the highest share of microfiltrator species, of which the greatest abundance species had Keratella tecta. Tactile predators (Insecta larvae and crustaceans Cyclopidae) in macrozoobenthos with their predation contributed to a reduction of planktivory microfiltrators. Results of this study suggest that increasing of trophic level reduces the diversity of habitats and impacts on changing of biotic interactions in shallow lakes.

• Keywords: mutnoća; taktilni i vizualni predatori; /Rotifera; Cladocera; Copepoda
• Keywords (english): turbidity; tactile and visual predators; Rotifera; Cladocera; Copepoda
• Language: croatian
• URN:NBN: urn:nbn:hr:217:181602
• Study programme: Title: Enviromental Sciences; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra struke znanosti o okolišu (magistar/magistra struke znanosti o okolišu)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-04-24 08:04:38