Introducing a novel methodological approach to the analysis of long-term phytoplankton changes in the Adriatic Sea

Vlašiček, Ivan (2025) Introducing a novel methodological approach to the analysis of long-term phytoplankton changes in the Adriatic Sea. Doctoral thesis, Prirodoslovno Matematički Fakultet.

PDF - Published Version - article Available under License Creative Commons Attribution. Download (4MB)

Abstract

Phytoplankton, the main primary producer in marine ecosystems, plays a crucial role in global biogeochemical cycles and in the functioning of the environment as a whole. This doctoral dissertation investigates long-term changes in the structure of the phytoplankton community in the northern Adriatic Sea over the period from 2000 to 2024, using traditional light microscopy and advanced pulse-shape recording flow cytometry. Cluster analysis reveals phytoplankton communities of different compositions, some of which exhibit temporal stability, while others appeared sporadically or emerged later during the observation period. The development of these communities is strongly linked to environmental factors, including day length and nutrient availability, especially phosphorus. Over the study period, phytoplankton seasonality became less predictable, likely due to irregular freshwater inflow and increasingly unstable meteorological conditions. Flow cytometry, supported by imaging, proved effective in tracking diversity and abundance trends comparable to those obtained by microscopy, despite a lower number of identified taxa. High-frequency sampling made it possible to detect rapid shifts in community structure, which was particularly evident during the mucilage events of 2024. The optical properties of phytoplankton cells also varied in space and time, reflecting cellular adaptations to environmental conditions rather than changes in taxonomic composition. Although flow cytometry does not replace light microscopy, it provides valuable complementary insights into phytoplankton dynamics. It is proposed that pulse-shape recording flow cytometry and high-frequency sampling be included in long-term monitoring programs to enhance the resolution and ecological relevance of phytoplankton data in coastal systems.

Item Type:	Thesis (Doctoral thesis)
Uncontrolled Keywords:	phytoplankton; light microscopy; long-term changes; flow cytometry; ecology
Subjects:	NATURAL SCIENCES > Interdisciplinary Natural Sciences NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science
Divisions:	Center for Marine Research
Projects:	Project title Project leader Project code Project type Molekularne životne strategije fitoplanktona u Jadranu-Adri LIFE Daniela Marić Pfannkuchen UIP-2020-02-7868 HRZZ Joint European Research Infrastructure of Coastal Observatories: Science, Service, Sustainability-JERICO-S3 Martin Pfannkuchen 871153 EK
Depositing User:	Ivan Vlašiček
Date Deposited:	15 Jan 2026 11:25
URI:	http://fulir.irb.hr/id/eprint/10890

Actions (login required)

View Item