Comparative study of mesozooplankton ecology in the marine ecosystems of Central Greece

Η παρούσα διατριβή αφορά στη μελέτη του ζωοπλαγκτού (πιο συγκεκριμένα στην κατηγορία του μεσοζωοπλαγκτού) στα παράκτια και πελαγικά νερά της Κεντρικής Ελλάδας σε σχέση με περιβαλλοντικά χαρακτηριστικά των επί μέρους περιοχών. Η περιοχή μελέτης διακρίθηκε με βάση τον Ισθμό της Κορίνθου σε δυτικό και ανατολικό τμήμα. Το ζωπλαγκτό στη συνολική περιοχή μελετήθηκε κατά τον Ιούλιο 1998 (περίοδος θερμοστρωμάτωσης) σε 124 σταθμούς δειγματοληψίας, σε βάθος 0-200m, ενώ κατά το Μάρτιο και Σεπτέμβριο 2000 (περίοδος ανάμιξης και θερμοστρωμάτωσης αντίστοιχα) μελετήθηκε μόνο στο δυτικό τμήμα σε 23 σταθμούς τόσο οριζόντια όσο και κατακόρυφα σε τρεις στρώσεις βάθους (0-50, 50-100 και 100-200m). Εκτιμήθηκε η αφθονία και η βιομάζα καθώς και η σύνθεση σε ομάδες και είδη του ζωοπλαγκτού μεταξύ των διαφόρων περιοχών, εποχών και στρώσεων βάθους και συσχετίσθηκαν με τους περιβαλλοντικούς παράγοντες

Istraživanje dužinsko-masenih odnosa za 10 komercijalnih vrsta riba kao mogućih indeksa trofičkih stanja obalnih laguna

Length-weight (L-W) relationships were estimated and compared for 10 commercially important fish species caught during September-December 2004 from two lagoons in the Ionian Sea based on similar length ranges. The median value of the exponent b of the L-W relationships was 3.091 and ranged from 2.444 to 3.536. The larger specimens of the mid-trophic level species (i.e. Sparus aurata, Diplodus annularis and D. sargus) were heavier at the same length in the less eutrophic lagoon. In contrast, most of the low-trophic level species (i.e. Mugilidae) did not show significant (P>0.05) differences of the L-W parameters between the studied lagoons. The estimated parameters of the L-W relationships for each species between the two lagoons in relation to their trophic state are also discussed. Our findings indicated that the L-W relationships of the mid-trophic level species may be possibly used as an index of the trophic state in lagoons.Dužinsko-maseni (LW) odnosi su procijenjeni i uspoređeni za 10 komercijalno važnih vrsta riba ulovljenih tijekom razdoblja rujan-prosinac 2004. godine iz dvije lagune u Jonskom moru na temelju raspona sličnih dužina. Medijan vrijednosti eksponenta b dužinsko-masenog odnosa je iznosio 3,091, a kretao se od 2,444 do 3,536. Veće jedinke, srednjeg trofičkog nivoa, vrsta Sparus aurata, Diplodus annularis i D. sargus su bile teže za istu duljinu ali u manje eutrofnim lagunama. Nasuprot tome, većina vrsta niskog trofičkog nivoa (tj. Mugilidae) nisu pokazali značajne razlike (P> 0,05) između parametara dužinsko masenog odnosa u istaživanim lagunama. Izračunati parametri dužinsko masenog odnosa za svaku vrstu između dviju laguna u odnosu na njihov trofički status se također raspravlja u ovom radu. Naši rezultati pokazuju da dužinsko maseni odnosi vrsta srednjeg trofičkog nivoa mogu eventualno poslužiti kao indeks trofičkog statusa u lagunama

From Shell to Sequence: Optimizing DNA Extraction and PCR for Pen Shell Identification

Pinna nobilis, an ecologically significant and critically endangered bivalve endemic to the Mediterranean Sea, has been classified as “Critically Endangered” by IUCN due to habitat degradation, climate change, and mass mortality events caused by the protozoan parasite Haplosporidium pinnae. Effective conservation efforts require robust molecular tools for species identification and genetic monitoring, necessitating the development of optimized DNA extraction and amplification protocols for a non-invasive sampling protocol. In this study, we evaluated multiple DNA extraction methods—Chelex-100, the sodium chloride (NaCl) method, a modified CTAB protocol, and a commercial kit, NucleoSpin Tissue Kit—using minute shell fragments from both ethanol-preserved and air-dried (dead) samples. We optimized key parameters, including incubation times, temperatures, and sample preparation, to determine the most effective protocol for obtaining high-quality DNA suitable for downstream applications. Additionally, we assessed different PCR strategies, including nested and semi-nested approaches targeting the COI gene marker, to enhance species identification. To further refine the methodology, we evaluated novel specific primers for nested PCR, improving sensitivity and specificity in detecting P. nobilis DNA from minute and degraded samples. Our results provide an optimized, cost-effective, and time-efficient workflow for non-invasive molecular identification of P. nobilis, with broad implications for conservation genetics, biodiversity monitoring, and species recovery programs

An intercalibration exercise for benthic macrophyte indices across the Mediterranean Sea coastal lagoons

Within the transitional waters macrophyte Mediterranean Geographical Intercalibration Group (MEDGIG) of the Water Framework Directive intercalibration, three countries (France, Greece, and Italy) compared their methodologies (Exclame, EEI-c, R-MaQI, respectively) for coastal lagoons. All methods classified soft bottom benthic macrophytes (angiosperms, seaweeds) in several sensitivity groups following the concept that “anthropogenic pressure” (stress) drives the ecosystem from a pristine state, where seagrasses are dominant, to a degraded state, where opportunistic species and phytoplankton are dominant. While Greece and Italy assessed the species abundance as coverage (%) in the laboratory, France assessed the species abundance as cover (%) in the field. A database consisting of 105 taxa abundance and pressure data from 55 shallow (depth=1-3m) and vegetated (cover >10%) sites (14 in France, 20 in Greece, 20 in Italy) belonging to meso-, poly- and euhaline (salinity >5‰) coastal lagoons, either confined or not confined, has been created. The 3 methods used a similar scale at biological (species), spatial (site) and temporal (one sampling per year during spring-summer) level, enabling a direct comparison of the 3 indices at biological community level. A common pressure index based on expert judgment was calculated. Multivariate analyses (MDS, Cluster) indicated no biogeographical differences across the Mediterranean Sea. SIMPER analyses confirmed that reference “benchmark” sites communities (pressure index ≤ 6) were characterized by the dominance of angiosperm species (Cymodocea nodosa=49.9%, Ruppia cirrhosa=35.67%, Zostera noltii=10%), while “borderline” communities between good and moderate ecological status were dominated by macroalgae-cyanobacteria in coexistence with angiosperms. Due to ecosystems high natural variability and to relative low number of benchmark sites provided, it was decided to use continuous benchmarking to determine the differences between the countries. Greece appeared more precautious and adjusted its quality class boundaries by lowering both High/Good and Good/Moderate boundaries to 0.7 and 0.4, respectively (France, and Italy: H/G=0.8, G/M=0.6).JRC.H.1-Water Resource