A metabarcode based (species) inventory of the northern Adriatic phytoplankton

The northern Adriatic is characterised as the coldest and most productive marine area of the Mediterranean, which is due to high nutrient levels introduced by river discharges, the largest of which is the Italian Po River (at the same time also the largest freshwater input into the Mediterranean). The northern Adriatic is a very shallow marine ecosystem with ocean current patterns that result in long retention times of plankton in the area. The northern Adriatic phytoplankton biodiversity and abundance are well-studied, through many scientific and long-term monitoring reports. These datasets were based on phytoplankton morphological traits traditionally obtained with light microscopy. The most recent comprehensive eastern Adriatic phytoplankton checklist was published more than 20 years ago and is still valuable today. Since phytoplankton taxonomy and systematics are constantly being reviewed (partly also due to new molecular methods of species identification that complement classical methodologies), checklists need to be updated and complemented. Today, metabarcoding of molecular markers gains more and more importance in biodiversity research and monitoring. Here, we report the use of high throughput sequencing methods to re-examine taxonomic richness and provide updated knowledge of phytoplankton diversity in the eastern northern Adriatic to complement the standardised light microscopy method.This study aimed to report an up-to-date list of the phytoplankton taxonomic richness and phylogenetic relationships in the eastern northern Adriatic, based on sequence variability of barcoding genes resolved with advanced molecular tools, namely metabarcoding. Here, metabarcoding is used to complement standardised light microscopy to advance conventional monitoring and research of phytoplankton communities for the purpose of assessing biodiversity and the status of the marine environments. Monthly two-year net sampling targeted six phytoplankton groups including Bacillariophyceae (diatoms) and Chrysophyceae (golden algae) belonging to Ochrophyta, Dinophyceae (dinoflagellates), Cryptophyceae (cryptophytes), Haptophyta (mostly coccolithophorids) and Chlorophyta with Prasinophyceae (prasinophytes) and Chlorophyceae (protist green algae). Generated sequence data were taxonomically assigned and redistributed in two kingdoms, five classes, 32 orders, 49 families and 67 genera. The most diverse group were dinoflagellates, comprising of 34 found genera (48.3%), following by diatoms with 23 (35.4%) and coccolithophorids with three genera (4.0%). In terms of genetic diversity, results were a bit different: a great majority of sequences with one nucleotide tolerance (ASVs, Amplicon sequence variants) assigned to species or genus level were dinoflagellates (83.8%), 13.7% diatoms and 1.6% Chlorophyta, respectively. Although many taxa have not been detected that have been considered as common in this area, metabarcoding revealed five diatoms and 20 dinoflagellate genera that were not reported in previous checklists, along with a few species from other targeted groups that have been reported previously. We here describe the first comprehensive 18S metabarcode inventory for the northern Adriatic Sea

Microbial community in the sediments of seagrasses Cymodocea nodosa and Zostera noltii in the coastal area of western Istria

U ovom diplomskom radu analizirani su uzorci sedimenta, morskih cvjetnica i algi, te je određena brojnost mikrobne zajednice tijekom proljeća, ljeta i jeseni 2021. g., i to u uvalama Ribnjak, Funtana i Veštar na zapadnoj obali Istre. Karakteristike sedimenta u uvalama odraz su izloženosti taložnog okoliša i različitog donosa materijala s kopna. Stanje livada cvjetnica i s njime povezana brojnost mikrobne zajednice su pod utjecajem čovjeka i karakteristika sedimenta. Uvala Ribnjak je pod manjim antropogenim utjecajem, a sadrži muljevit sediment i očuvanu livadu cvjetnica. U uvali Veštar livada u karbonatnom pijesku je značajnije devastirana, vjerojatno radi turističkih aktivnosti, a mikrobna zajednica je najmanje zastupljena. Na uglavnom muljevitom dnu uvale Funtana livadu cvjetnica degradira utjecaj invazivne alge, a moguć je i utjecaj turističkih aktivnosti.In this thesis sediment, seagrass, and algae together with microbial abundancy were analysed in Ribnjak, Funtana, and Veštar Bays along the western Istrian coast during spring, summer and, autumn 2021. Sediment characteristics in all bays are the result of sedimentary environment exposure together with various inputs of terrigenous material. Seagrass meadow conditions and related microbial abundancies reflect the anthropogenic influence and sediment nature. Ribnjak Bay with muddy sea bottom and seagrass meadow in good condition is the least affected by human activities. Veštar Bay meadow, developed in carbonate sand, is significantly degraded, probably due to the tourism, while its microbial community is of the lowest abundance. Mostly muddy sea bottom of the Funtana Bay is covered by a partially degraded seagrass meadow, probably due to the competition of invasive algae, while touristic activities is not excluded

Microbial community in the sediments of seagrasses Cymodocea nodosa and Zostera noltii in the coastal area of western Istria

U ovom diplomskom radu analizirani su uzorci sedimenta, morskih cvjetnica i algi, te je određena brojnost mikrobne zajednice tijekom proljeća, ljeta i jeseni 2021. g., i to u uvalama Ribnjak, Funtana i Veštar na zapadnoj obali Istre. Karakteristike sedimenta u uvalama odraz su izloženosti taložnog okoliša i različitog donosa materijala s kopna. Stanje livada cvjetnica i s njime povezana brojnost mikrobne zajednice su pod utjecajem čovjeka i karakteristika sedimenta. Uvala Ribnjak je pod manjim antropogenim utjecajem, a sadrži muljevit sediment i očuvanu livadu cvjetnica. U uvali Veštar livada u karbonatnom pijesku je značajnije devastirana, vjerojatno radi turističkih aktivnosti, a mikrobna zajednica je najmanje zastupljena. Na uglavnom muljevitom dnu uvale Funtana livadu cvjetnica degradira utjecaj invazivne alge, a moguć je i utjecaj turističkih aktivnosti.In this thesis sediment, seagrass, and algae together with microbial abundancy were analysed in Ribnjak, Funtana, and Veštar Bays along the western Istrian coast during spring, summer and, autumn 2021. Sediment characteristics in all bays are the result of sedimentary environment exposure together with various inputs of terrigenous material. Seagrass meadow conditions and related microbial abundancies reflect the anthropogenic influence and sediment nature. Ribnjak Bay with muddy sea bottom and seagrass meadow in good condition is the least affected by human activities. Veštar Bay meadow, developed in carbonate sand, is significantly degraded, probably due to the tourism, while its microbial community is of the lowest abundance. Mostly muddy sea bottom of the Funtana Bay is covered by a partially degraded seagrass meadow, probably due to the competition of invasive algae, while touristic activities is not excluded

Microbial community in the sediments of seagrasses Cymodocea nodosa and Zostera noltii in the coastal area of western Istria

U ovom diplomskom radu analizirani su uzorci sedimenta, morskih cvjetnica i algi, te je određena brojnost mikrobne zajednice tijekom proljeća, ljeta i jeseni 2021. g., i to u uvalama Ribnjak, Funtana i Veštar na zapadnoj obali Istre. Karakteristike sedimenta u uvalama odraz su izloženosti taložnog okoliša i različitog donosa materijala s kopna. Stanje livada cvjetnica i s njime povezana brojnost mikrobne zajednice su pod utjecajem čovjeka i karakteristika sedimenta. Uvala Ribnjak je pod manjim antropogenim utjecajem, a sadrži muljevit sediment i očuvanu livadu cvjetnica. U uvali Veštar livada u karbonatnom pijesku je značajnije devastirana, vjerojatno radi turističkih aktivnosti, a mikrobna zajednica je najmanje zastupljena. Na uglavnom muljevitom dnu uvale Funtana livadu cvjetnica degradira utjecaj invazivne alge, a moguć je i utjecaj turističkih aktivnosti.In this thesis sediment, seagrass, and algae together with microbial abundancy were analysed in Ribnjak, Funtana, and Veštar Bays along the western Istrian coast during spring, summer and, autumn 2021. Sediment characteristics in all bays are the result of sedimentary environment exposure together with various inputs of terrigenous material. Seagrass meadow conditions and related microbial abundancies reflect the anthropogenic influence and sediment nature. Ribnjak Bay with muddy sea bottom and seagrass meadow in good condition is the least affected by human activities. Veštar Bay meadow, developed in carbonate sand, is significantly degraded, probably due to the tourism, while its microbial community is of the lowest abundance. Mostly muddy sea bottom of the Funtana Bay is covered by a partially degraded seagrass meadow, probably due to the competition of invasive algae, while touristic activities is not excluded

Supplementary material 1 from: Grižančić L, Baričević A, Smodlaka Tanković M, Vlašiček I, Knjaz M, Podolšak I, Kogovšek T, Pfannkuchen MA, Marić Pfannkuchen D (2023) A metabarcode based (species) inventory of the northern Adriatic phytoplankton. Biodiversity Data Journal 11: e106947. https://doi.org/10.3897/BDJ.11.e106947

List of taxa retrived in this study, during 2 years monthly samplin