“Hot spot” (hot spot) for sea heat waves, that is for periods of unusually high seawater temperatures compared to standard temperatures, with consequences for marine richness, constitutes the Gulf of Thessaloniki, according to oceanographic research published a few days ago in the scientific magazine “Journal of Marine Science and Engineering”.

In the research, which reviewed the relevant data over the last five decades, the eleven researchers, including the Aristotle University of Thessaloniki professors Yiannis Androulidakis, Christos Makris and Yiannis Krestenitis, as well as Katerina Kobiadou, from the University of the Algarve, find that marine heat events in the Thermaikos “not only occur near the sea surface, but also extend throughout the water column, especially in the shallower interior.”

As indicated, the highest temperatures in Thermaikos were observed in 2021 and 2023 while the summers of these two years were the hottest of the entire period, affecting several environmental and socioeconomic factors in the area, such as mussel farming.

Furthermore, according to the survey, marine heat waves have significant biochemical effects, affecting the marine environment and causing mass mortality events of important living organisms with significant impacts on aquaculture, fisheries, tourism and human health.

Increase in salinity

An increase has also been observeds in salinitywhich reached the highest level measured since 2020, an event associated with high temperatures and possible changes in rainfall rates and river discharges.

It is typical that changes in salinity can also affect species diversity, resource use efficiency and productivity, especially in the context of climate change, where short-term temperature changes during heat waves are expected to increase in frequency and magnitude during the 21st century.

On the occasion of the research, the biologist and Postdoctoral researcher at the Institute of Applied Biosciences of EKETA, Dr. Konstantinos Koukaras, points out to APE – MBE that “in general, at a global level, the Mediterranean basin is considered a hot spot for the effects of climate change all over the world, which means that the region that faces the first and most intense consequences of of climate change is the Mediterranean. In particular, in the Mediterranean region, the hot spot seems to be the Thermaikos Gulf, although the truth is that the characteristics it displays, such as the rise in temperature, are also present elsewhere.”

“In general, the areas and closed bays where rivers flow, but also the ecosystems that are close to agricultural areas are somewhat burdened,” he notes, adding to this situation “the red tides and the slimy masses that have been suffering for the last five years, maybe and a little more, many areas from the Thermaic Gulf to the northeastern Aegean”.

“The slime masses are a type of gel, created essentially from polysaccharides secreted by various types of microalgae and polymerized in seawater. As this gel moves, various substances stick to it, turning it green, brown, or transparent and causing problems for fishermen when it is in their nets. Then the nets are impossible to lift out of the water, with the consequence that the fishermen cut them and fall into the sea. This happens every year from April to July, however so far it seems the weather has delayed ithe comments. At the same time he emphasizes that “Thermaikos is greatly influenced by the water masses of the Black Sea which are rich in certain nutrients and when they move towards the coasts of Thrace and Macedonia they create such phenomena”.

Mr. Koukaras referred to the issue while speaking yesterday at the second working meeting on maritime spatial planning organized by the Aristotle University of Thessaloniki (AUTH) in the context of the REGINA – MSP research program, in which the Department of Spatial Planning and Development Engineering participates AUTH, with the region of Central Macedonia as a study area. The meeting was held under the auspices of the Region.

Recommendations from the researchers

Back in the research published in the “Journal of Marine Science and Engineering”, the experts point out that “there was a serious deterioration in the environmental quality of Thermaic Gulf during the 1970s and 1980s when urban sewage treatment was completely absent.

After the 1990s a steady recovery trend was observed. However, so far, the goal of a ‘good environmental status’ imposed by national legislation and European directives has not been achieved.” At the same time, it is stated that the Thermaic Gulf is “a resilient but fragile coastal ecosystem, facing intense pressures from the natural environment and anthropogenic activities”.

The scientists’ key recommendations include the creation of a wide monitoring network of Thermaikos with permanent and new stations, the identification and observation of anthropogenic stressors, enhanced protection measures and the integration of advanced technologies. An oversight body is proposed to assist governance and action on sustainable solutions to mitigate anthropogenic impacts and promote environmentally friendly practices that are paramount to the resilience of the region and the maintenance of ecosystem services into the future .

“We have to decide as a country what we want for the region and then set the criteria for what will happen,” Koukaras emphasized. At the same time, he announced that the Region of Central Macedonia, in collaboration with Aristotle and Democritus universities, are trying to implement new technological applications with mechanisms and artificial intelligence so that such extraordinary phenomena can be predicted and the information received is immediately directed to the administration so that the appropriate decisions”.

The assurance that the Region is starting with the right steps in order to bring to the table the appropriate proposals that will then be implemented was given by the Deputy Regional Governor for Development and Environment of Central Macedonia, Stathis Avramidis, who spoke at the working meeting on maritime spatial planning.

“We as a region, on the initiative of the Regional Governor, Apostolos Tzizikostas, are helping so that the region, the university community and the common citizen can intervene in these meetings that we hold that precede the planning. The whole effort concerns on the one hand the marine photovoltaic parks and on the other hand the zoning of the sea. We are pioneers and in this we are putting it in consultation in order to proceed with spatial planning for the marine environment” he pointed out in APE – BEE.