The Day 1 will be a welcome day, an introduction to several discussion points. Environments classified as extreme are such called because they are characterized by environmental conditions almost incompatible with life, which can be represented by the total absence of light, high pressures, temperatures that are too hot or too cold. But in recent times, there are numerous signals that the environment sends us, especially the sensitive aquatic environments. There are many factors that are perhaps making the living conditions extreme in a precipitous manner. Phenomena such as global warming, ocean acidification processes, the dispersion of more or less persistent contaminants, the accumulation of waste and plastics in the seas, rivers and lakes of the Earth are increasingly alarming. Researchers try to interpret the effects of these events, and to identify appropriate mitigation measures.

Deep sea represents a peculiar ecosystem characterized by a series of environmental parameters difficult to find in other environments. Deep sea organisms usually face a range of environmental and ecological conditions (light scarcity or absence, high pressures, low oxygen levels, low temperatures, absence of phytoplankton, food scarcity of food, interspecific competition), which over time have adaptively shaped behaviors and the species themselves.

In the morning of Day 2, a first session “Deep-sea organisms: challenges and adaptations” will start with a lecture on the ecology and adaptations of deep sea-fish, followed by a practical section, devoted to the analysis of deep-fish samples and their observation in laboratory. In the afternoon, a second lecture will be focused on the ecology of deep -sea cephalopods, a taxonomic group that plays a key role in the marine trophic web and is of great interest because of the multiple adaptations and still limited knowledge about these species. The importance of zooplankton in mesopelagic waters, in terms of diversity, migratory movements and role will be discussed in another dedicated lecture. The last lecture will be focused on the description of new technological tools and scientific methods for sampling and investigating deepsea organisms in their environment.

On the Day 3 it will be possible to explore issues related to the cold environments, including the Polar ones. The polar environments constitute a reality as remote as it is fascinating. Both the Arctic and Antarctica, due to the peculiar conditions (i.e. low temperatures, dryness, solar radiation) are the subject of numerous researches focused on the exploration of less known environments, on enriching the knowledge of the adaptations of cold-loving organisms, on the possibility of new discoveries useful in biotechnological fields.

A special section will be devoted to deal with various modeling techniques used to study the distribution of marine organisms in extreme environments. The geographic distribution modeling, preference modeling, diversity modeling, and population dynamics modeling will be discussed, examples of how these methods have been applied in different extreme marine environments will be provided. The students will learn how the potential applications of modeling approaches for the conservation and management of these delicate ecosystems.

The final day is devoted to the exploration of further extreme environments, all characterized by very different conditions, but with intriguing research ideas. Special focus will be addressed to the marine hydrothermal systems, which have attracted the interest of researchers due to their enormous ecological and biotechnological relevance. From ecological perspective, these acidified habitats are useful natural laboratories to predict the effects of global environmental changes, such as ocean acidification at ecosystem level, through the observation of the marine organism responses to environmental extremes. In addition, hydrothermal vents are known as optimal sources for isolation of thermophilic and hyperthermophilic microbes, with biotechnological potential. These environments will be treated together with other underexplored ecosystems, such as anoxic basins and meromictic lakes. The Lake Faro, a unique ecosystem located in the Capo Peloro area in Messina, will be taken as an example to describe the peculiarities of these habitats.