Aristomenis P. Karageorgis

Evidence on the efficacy of impacts from real-world experiments in triggering transformative processes is still scarce. This study evaluates multi-actor labs to provide examples of direct impacts of real-world experiments in tackling long-standing, local, sustainability challenges. Multi-actor labs (MALs), a form of real-world social experiments, were implemented in three coastal-rural regions in France (Charente River Basin), Spain (Mar Menor), and Greece (South-West Messinia) to better assess and tackle coastal-rural interactions that govern local sustainability challenges, such as water use conflicts and biodiversity degradation. The MALs used participative methodologies based on systems thinking and transition management. Stakeholders were continuously engaged in a series of workshops to co-produce knowledge, reach a common understanding of the sustainability challenges and issues at stake, and co-design solutions in the form of a roadmap for sustainable transitions in coastal-rural regions. This paper evaluates MALs to provide examples of successful sustainability transition experiments based on the outputs produced, outcomes achieved, and processes used in the three coastal, rural regions.

Coccolithophores are an important component of phytoplankton abundance and biomass in the brackish environments of the Black Sea. Here, the abundance, composition, and distribution of coccolithophores were investigated in water samples taken from the first 50 m at 18 stations in the western Black Sea during a coccolithophore bloom, in June 2016. The total cell abundances ranged from 2 to 763 × 10⁴ coccospheres L⁻¹; Emiliania huxleyi was the most dominant species, but also Syracosphaera spp. (S. dilatata and S. molischii), Acanthoica (A. acanthifera and A. quattrospina), and Algirosphaera robusta displayed remarkably high concentrations. The formation of the seasonal thermocline significantly affects the vertical distribution of coccolithophores. Emiliania huxleyi, Syracosphaera spp., and Acanthoica spp. were restricted to the upper part of the water column, whereas high abundances of Algirosphaera robusta occurred below the thermocline. Overall, our results show significant differences in the vertical (ANOSIM R = 0.50, p = 0.0001) and spatial (ANOSIM R = 0.18, p = 0.0006) distribution of coccolithophores. Higher abundances of E. huxleyi and Syracosphaera spp. were recorded in the northwestern inner shelf region when compared to the open-sea samples. The observed coccolithophore spatial distribution is suggested to be mostly associated with the influx of less saline river water with high nutrient concentrations.

The Saronikos Gulf, including the industrial zone of Elefsis Bay, is subjected to a variety of urban and industrial impacts that significantly contribute to environmental degradation. Benthic foraminifera comprise a significant component of meiobenthic communities and they are widely used as reliable indicators for the determination of the natural environmental and anthropogenic impact in shallow coastal systems. The present study analyses the living benthic foraminifera composition and its relation to environmental parameters such as grain size, organic carbon content, and heavy metal concentrations, from the surficial sediment layer collected in the Elefsis Bay and the Inner Saronikos Gulf in February 2016. Canonical correspondence analysis and Spearman’s rho correlation show that the foraminiferal species composition is significantly influenced by the increase of organic carbon and Cu, Pb, Zn content. In particular, a relatively low diversity fauna dominated by the stress-tolerant species Ammonia tepida, Bulimina elongata, Bulimina marginata, and Nonionella turgida occurs in the restricted environment of the Elefsis Bay, demonstrating the negative environmental impact caused by the relatively elevated organic carbon and heavy metal contents.