Promjena sastava fitoplanktonskih lipida kao odgovor na okolišni stres

doctoral thesis

• Title (english): Changes in phytoplankton lipid composition as a response to environmental stress
• Author: Tihana Novak
• Mentor: Blaženka Gašparović (mentor)
• Committee member: Zrinka Ljubešić (predsjednik povjerenstva)
• Committee member: Tea Mišić Radić (član povjerenstva)
• Committee member: Petar Žutinić (član povjerenstva)
• Committee member: Jelena Godrijan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geology); Zagreb
• Defense date and country: 2021-02-04, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Interdisciplinary Natural Sciences; Marine Science
• Universal decimal classification (UDC): 55 - Geology. Meteorology. Hydrology

Abstract

Cilj ovog doktorskog rada je ispitati kako promjene u okolišu utječu na sastav i kvantitetu proizvedene organske tvari fitoplanktona. Po prvi puta su sistematski ispitane lipidne klase kao markeri stresa u laboratorijski uzgojenim kulturama dijatomeje Chaetoceros pseudocurvisetus te okolišnim uzorcima vode različitih trofičkih statusa, Jadranskog mora i estuarija rijeka Wengchang, Kina, i Krke, Hrvatska. Od okolišnih čimbenika stresa istraženi su utjecaji promjene temperature i saliniteta te nedostatak hranjivih soli. Za analizu lipida korištene su metode tankoslojne kromatografije i masene spektrometrije. Dobiveni rezultati laboratorijskog uzgoja i terenskih uzoraka uspoređeni su te su pokazali da se u stresnim uvjetima stanice fitoplanktona sporije dijele, nakupljaju više lipida i izlučuju više otopljene organske tvari uključujući lipide. Zamijećena je promjena omjera fosfolipida i glikolipida u nedostatku fosfata, te nakupljanje triglicerida u nedostatku nitrata. Promjena saliniteta dovela je do promjena u sastavu masnih kiselina fosfolipida. Rod dijatomeja Chaetoceros pokazao se kao dobar modelni organizam za razumijevanje prilagodbe fitoplanktona na globalne promjene.

Abstract (english)

The aim of this dissertation is to examine how changes in the environment affect phytoplankton in terms of the quality and quantity of produced organic matter. For the first time, lipid classes were systematically examined as stress markers in cultures of diatoms Chaetoceros pseudocurvisetus and environmental water samples of different trophic statuses, the Adriatic Sea, the Wengchang River, China, and the Krka River, Croatia, estuaries. Among the environmental stress parameters, the effects of temperature and salinity changes and lack of nutrients were investigated. Thin layer chromatography and mass spectrometry methods were used for lipid analysis. The results obtained from cultivation experiments and field samples were compared and showed that under stressful conditions there is reduced phytoplankton growth, phytoplankton accumulate more lipids and excrete more dissolved organic matter including lipids. Remodeling of lipids occurs as a change in the ratio of phospholipids and glycolipids as a response to phosphate deficiency and the accumulation of triglycerides in the absence of nitrates in the growth medium. The change in salinity leads to changes in the fatty acid composition of phospholipids. The diatoms genus Chaetoceros has proven to be a good model organism for understanding the adaptation of phytoplankton to global changes.

• Keywords: Chaetoceros pseudocurvisetus; estuarij; hranjive soli; metabolizam lipida; salinitet; sjeverni Jadran; temperatura
• Keywords (english): Chaetoceros pseudocurvisetus; estuaries; lipid metabolism; Northern Adriatic Sea; nutrients; temperature; salinity
• Language: croatian
• URN:NBN: urn:nbn:hr:217:358826
• Promotion: 2021
• Study programme: Title: Interdisciplinary doctoral study in Oceanology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje interdisciplinarne prirodne znanosti (znanost o moru) (doktor/doktorica znanosti, područje prirodnih znanosti, polje interdisciplinarne prirodne znanosti (znanost o moru))
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-03-09 12:35:52