Trofička struktura zooplanktona u rukavcu rijeke Krapine

master's thesis

• Title (english): Trophic structure of zooplankton community in the oxbow lake of Krapina river
• Author: Zlatko Grčić
• Mentor: Maria Špoljar (mentor)
• Committee member: Branka Pevalek-Kozlina (predsjednik povjerenstva)
• Committee member: Vesna Benković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2010, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Istraživanje zooplanktona u rukavcu rijeke Krapine provedeno je u razdoblju od siječnja do lipnja 2008. godine na dvije postaje. Postaja P je bila smještena u zoni slobodne vode, a postaja L u litoralnoj zoni. Sezonske i prostorne promjene trofičke strukture zooplanktona razmatrane su na organizmima iz skupina kolnjaka (Rotifera), rašljoticalaca (Cladocera) i veslonožaca (Copepoda). Istraživanje je provedeno u zimskom razdoblju bez emerzne vegetacije te u proljetnom razdoblju s razvijenom emerznom vegetacijom. Osnovna hipoteza u ovom radu bila je da prozirnost vode i morfometrijska obilježja litoralne zone te raznolikost makrofita utječu na trofičku strukturu zooplanktona u plitkim eutrofnim jezerima. Ciljevi istraživanja bili su sljedeći: 1. analizirati i utvrditi utjecaj hranjivih tvari i izvora hrane na brojnost i biomasu trofičkih skupina zooplanktona; 2. utvrditi utjecaj prozirnosti vode i riblje predacije na veličinske kategorije zooplanktona u litoralnoj zoni i zoni slobodne vode; 3. analizirati fizičko-kemijske čimbenike i njihov utjecaj na trofičku strukturu zooplanktona u zoni slobodne vode i u litoralnoj zoni. U litoralnoj zoni zabilježen je veći broj svojti (postaja P 25, postaja L 36), ali manja brojnost jedinki (srednja vrijednost: P 650±383 jed/L, L 354±169 jed/L) i biomasa suhe tvari (P 216±260 μg/L, L 203±214 μg/L) zooplanktona u odnosu na zonu slobodne vode. U trofičkoj strukturi kolnjaci su prevladavali na obje postaje, čemu je brojnošću najviše pridonijela mikrofiltratorska vrsta Keratella cochlearis. Fizičko-kemijski čimbenici nisu se statistički značajno razlikovali između istraživanih postaja (p > 0,05). Prozirnost i temperatura vode, konduktivitet te koncentracije otopljene i suspendirane organske tvari statistički su značajno pozitivno korelirali s ukupnom biomasom zooplanktona i indeksa raznolikosti vrsta (H’). Utjecaj predacije riba očitovao se u dominantnoj biomasi veslonožaca u zoni slobodne vode koji dobro izbjegavaju predatorski pritisak (veličina tijela 1000 - 1500 μm, veličinska kategorija VII) te dominantnoj biomasi rašljoticalaca u litoralnoj zoni koji su osjetljiviji na predaciju te nalaze zaštitu u zoni vodenih makrofita (veličina tijela 500 – 1000 μm, veličinska kategorija VI). Rezultati ovog rada ukazuju da stupanj prekrivenosti litoralne zone makrofitima te prozirnost vode imaju značajan utjecaj na primarnu produkciju, a time i trofičku strukturu i prostorni raspored veličinskih kategorija zooplanktona.

Abstract (english)

Research in the oxbow lake of Krapina river was provided from January untill June 2008 on two study sites, marked as P (in the open-water zone) and L (in littoral zone). Spatial and temporal variations in the trophic structure of zooplankton community were examined on Rotifera, Cladocera and Copepoda. Research was conducted during winter period without emergent vegetation and spring period with emergent vegetation. Main hypothesis in this study was that water transparency and morphometrical characteristics of littoral zone and diversity of macrophytes effect trophic structure of zooplankton community in shallow eutrophic lakes. Aims of this study were 1. to analyse an establish effect of food resources and nutrients on abundance and biomass of trophic structure of zooplankton community; 2. to establish effect of water transparency and fish predation on body size groups of zooplankton in littoral zone and i open-water zone; 3. to analyse physico-chemical factors on trophic structure of zooplankton community in open-water zone and littoral zone. Higher species richness was recorded in littoral zone (station P 25, station L 36), but lower abundance (average: P 650±383 jed/L, L 354±169 jed/L), and biomass dry weight (P 216±260 μg/L, L 203±214 μg/L) of zooplankton in comparison to the open-water zone. In trophic structure, rotifers were most abundant on both stations, with the most dominant microfilter-feeder species Keratella cochlearis. Differences in physico-chemical factors between station were not statistically significant (p > 0,05). Water transparency, conductivity, water temperature and concentrations of dissolved and suspended organic matter significant positively corelated (p < 0,05) with total zooplankton biomass and species diversity index (H’). Effect of fish predation manifested in dominant biomass of copepods in open-water zone (body size 1000 – 1500 μm, size category VII), and dominant biomass of cladocerans in littoral zone (body size 500 – 1000 μm, size category VI). The results of this study suggest that the percentage of macrophyte covered area and water transpareny have a significant influence on primary production, and therefore on trophic structure and size categories distribution of zooplankton.

• Keywords: zooplankton; prozirnost vode; trofičke skupine; veličina tijela; predacija riba
• Keywords (english): zooplankton; water transparency; trophic groups; body size; fish predation
• Language: croatian
• URN:NBN: urn:nbn:hr:217:657152
• Study programme: Title: Biology; specializations in: Ecology; Course: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra biologije (magistar/magistra biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-03-23 11:06:46