Supervisors info:
Διονύσης Ραΐτσος-Εξαρχόπουλος, Αναπληρωτής Καθηγητής, Τμήμα Βιολογίας, ΕΚΠΑ
Μαρία Σαλωμίδη, Ερευνήτρια Β’, Τμήμα Θαλάσσιας Οικολογίας, Ινστιτούτο Ωκεανογραφίας ΕΛ.ΚΕ.Θ.Ε
Αθηνά Οικονόμου – Αμίλλη, Ομότιμη Καθηγήτρια, Τμήμα Βιολογίας, ΕΚΠΑ
Summary:
Phytobenthic communities, particularly macroalgae and seagrasses, are fundamental for the coastal zone, mainly by providing food and shelter to associated species. Their presence and distribution, naturally depends on substrate and nutrient availability, temperature, light penetration, and various biotic factors, and are being increasingly affected by various human pressures. Macroalgae, particularly and seagrasses such as Posidonia oceanica, provide shelter and feeding grounds for many marine organisms, as also multiple ecosystem services to human communities. Marine phytobenthos is threatened worldwide, and there is limited knowledge about their response and consequent impacts on coastal ecosystems. This master thesis aims to describe the present status of phytobenthos within global warming in the Mediterranean and especially the Eastern part. Sea surface temperature data for the period 1948-2023 were analyzed to extract seasonal variability, climatology, mean SST (annually), and histogram characteristics of the study area (Aegean Sea). Analysis of sea surface temperature (SST) data from 1983 to 2023 reveals an increasing trend in annual mean SST, along with changes in climatology and the frequency of high temperatures, with both maximum and minimum SST values closely linked to extreme weather events. The data from 1948 to 2023 indicate long-term warming, with a clear upward shift in temperatures over recent decades, particularly from the late 1990s and afterwards. Climatology analysis highlights a consistent increase in SST during the summer months, especially in July and August, with a rise of at least 1°C in the past 25 years. Seasonal variability from 1998 to 2023 further demonstrates an accelerating increase in SST, particularly in February, September, and November, with temperature differences reaching up to 0.95°C. Climate warming directly impacts recruitment and indirectly promotes antagonistic species, jeopardizing the long-term survival of phytobenthic communities. Temperature rise seems to increase the overall stress and therefore the vulnerability of these communities, especially when other stress factors act synergistically. As a conclusion, the decline of marine habitat-forming species still remains poorly understood, and largely hindered by limited awareness, research and funding.
Keywords:
phytobenthic communities, Posidonia oceanica, canopy forming species, Aegean, climate warming, sea surface temperature.
