Utjecaj različitih izvora otopljenog organskog ugljika na kolnjake (Rotifera) plitkih jezera

master's thesis

• Title (english): Impact of different sources of dissolved organic carbon on rotifers in shallow lakes
• Author: Anamarija Žavrljan
• Mentor: Maria Špoljar (mentor)
• Committee member: Maria Špoljar (predsjednik povjerenstva)
• Committee member: Sanja Gottstein (član povjerenstva)
• Committee member: Neven Bočić (član povjerenstva)
• Committee member: Vlasta Ćosović (član povjerenstva)
• Committee member: Kristina Pikelj (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2022-02-18, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Klimatske promjene uzrokuju povećan unos otopljenog organskog ugljika (eng. Dissolved
Organic Carbon, DOC) u jezerske ekosustave što dovodi do promjene fizikalno-kemijskih
čimbenika, sastava zooplanktona te odnosa u hranidbenim mrežama. Kolnjaci, kao važna
komponenta zooplanktona slatkovodnih stajaćica, značajno doprinose prijenosu ugljika s nižih
na više trofičke razine. U sklopu ovog rada razmatran je utjecaj labilnijeg i teže razgradivog
organskog ugljika na jezerske ekosustave koristeći mezokozmose (konstruirane in situ pokuse).
Stoga su ciljevi ovog rada bili utvrditi i procijeniti: (i) utjecaj različitih izvora DOC-a na
strukturalna i funkcionalna obilježja kolnjaka; (ii) utjecaj abiotičkih i biotičkih čimbenika na
sastav kolnjaka; te (iii) oporavak ekosustava. Veća raznolikost, abundancija i biomasa kolnjaka
zabilježene su u mezokozmosu s dodatkom labilnijeg ugljika u odnosu na mezokozmos s
dodatkom teže razgradivog ugljika. Tijekom pokusa došlo je do izmjene funkcionalnih
hranidbenih i ekoloških skupina kolnjaka, gdje su planktonske nanoalgivorne vrste kolnjaka
(Keratella cochlearis), dominantne na početku, zamijenjene sa semiplanktonskim detritivornim
vrstama (Lecane spp. i Lepadella patella) dominantnim na kraju pokusa. Nastale biocenološke
promjene odgovor su na veće koncentracije klorofila a na početku te većih koncentracija DOCa i hranjivih tvari na kraju pokusa. Rezultati ovog rada ukazuju na mogućnost oporavka
ekosustava i važnost kolnjaka kao indikatora u procjeni promjena ekološkog stanja plitkih
vodenih tijela.

Abstract (english)

Climate changes cause increased input of dissolved organic carbon (DOC) in shallow lake
ecosystems, leading to alterations in physico-chemical factors, composition of zooplankton and
food web interactions. Rotifers as an important component of freshwater plankton significantly
contribute to the carbon transfer from lower to higher trophic levels. In this study in situ
mesocosms were used to determine the impact of labile and recalcitrant carbon on lake
ecosystems. The main objectives of this study were to determine and assess: (i) the impact of
different sources of DOC on the structural and functional traits of rotifers; (ii) the influence of
abiotic and biotic factors on composition of rotifers; and (iii) ecosystem recovery. Higher
diversity, abundance and biomass of rotifers were observed in the mesocosm with labile carbon
compared to the mesocosm with recalcitrant carbon. During the experiment, planktonic
nanoalgivor species of rotifers (Keratella cochlearis), dominant at the beginning, were replaced
by semiplankton detritivore species (Lecane spp. and Lepadella patella) dominant at the end of
the experiment. The biocenological changes were caused by higher concentrations of
chlorophyll a at the beginning and higher concentrations of DOC and nutrients at the end of the
experiment. The results of this study indicate the possibility of ecosystem recovery and the
importance of rotifers as indicators in assessing changes in the ecological status of shallow
water bodies.

• Keywords: zooplankton; alohtoni izvori otopljenog organskog ugljika; klimatske promjene; mezokozmos; oporavak ekosustava
• Keywords (english): zooplankton; allochthonous sources of dissolved organic carbon; climate changes; mesocosm; ecosystem recovery
• Language: croatian
• URN:NBN: urn:nbn:hr:217:902680
• 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: 2022-03-23 11:48:35