Fitoplankton eksremnih staništa, primjer Rogozničkog jezera

undergraduate thesis

• Title (english): Phytoplankton of extreme habitats, example of the Rogoznica Lake
• Author: Ivana Pozojević
• Mentor: Zrinka Ljubešić (mentor)
• 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

Rogozničko jezero je malo, slano, krško jezero 15 m dubine i veličine 5300 četvornih metara. Smješteno u kotlini, zaštićeno je od jakih vjetrova, te u njemu nema strujanja vode. Velike sezonske amplitude saliniteta, temperature i otopljene organske tvari čine ga ekstremnim staništem. Ono je meromiktičko jezero sa anoksičnim dubinskim slojevima. Životna zajednica u njemu sastoji se od malog broja fitoplanktonskih vrsta i beskralježnjaka. Krajem rujna i početkom listopada 1997. godine dolazi do naglog miješanja vodenog stupca i do anoksičnog stanja cijelog jezera. Nakon tog događaja dolazi do odumiranja gotovo cijele jezerske populacije fitoplanktona. Brojnim uzorkovanjima i istraživanjima praćen je oporavak fitoplanktona. Prvi primjerci mikroflagelata javljaju se već nakon dva tjedana na područjima povećane koncentracije amonijaka. Kasnija oksidacija vodenog stupca i stvaranje nitrata pogoduje pojavi većeg fitoplanktona kao dijatomeja i dinoflagelata. Uzorkovanje nakon godinu dana pokazuje kako je jezerska populacija fitoplanktona potpuno oporavljena te je jednaka onoj prije anoksije. U Rogozničkom jezeru nalazimo dvije rijetke vrste: Prorocentrum arcuatum Issel i Hermesium adriaticum Zaharis. Ove morske vrste fitoplanktona su rijetke u cijelom Sredozemlju. Možemo zaključiti kako u ovom malom slanom jezeru postoji specifična mikroklima koja odgovara upravo ovim rijetkim vrstama. Potpuna regeneracija životne zajednice ukazuje i na samoodrživost ove ekstremne mikroklime slanog, krškog Rogozničkog jezera.

Abstract (english)

The Rogoznica Lake is a small, marine, karstic lake 15 m deep and the size of 5300 square meters. There is no fresh water inflow or drifts because it is situated in a valley, protected from strong winds. Large seasonal amplitudes of salinity, temperature and dissolved organic matter make it an extreme habitat. It is a meromictic lake with anoxic deeper layers. The biological community of the lake consists of a small number of phytoplankton species and invertebrates. In late September of 1997 there was a sudden mixing of the water column that caused anoxic conditions in the whole lake. After this event, almost the whole population of the lakes phytoplankton had died. With numerous sampling the recovery of phytoplankton was monitored. The first examples of microflagellates appear already two weeks after the mass mortality in areas of increased concentration of ammonia. Subsequent oxidation of the water column and larger nitrate concentrations favored the creation of larger phytoplankton, such as diatoms and dinoflagellates. Sampling a year after shows that the lake´s phytoplankton populations fully recovered and is the same as before the anoxia. In the Rogoznica Lake there are two rare species: Prorocentrum arcuatum Issel and Hermesinum adriaticum Zaharis. These marine species of phytoplankton are rare throughout the Mediterranean. We can conclude that specific microclimate in the lake favoures the growth of those rare species. The complete regeneration of 14 phytoplankton communities indicates that the Rogoznica Lake, is a selfsustainable environment.

• Keywords: Rogozničko jezero; fitoplankton
• Keywords (english): Rogoznica Lake; phytoplankton
• Language: croatian
• URN:NBN: urn:nbn:hr:217:026064
• Study programme: Title: Ecology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-03-29 09:10:36