Description: In western Greece, the Ionian and pre-Apulian zones represent, respectively, the basin and the transitional zone (slope) to the Apulian platform. The Apulian platform constitutes the weakly deformed foreland of the external Hellenides. The pre-Apulian zone appears in the Ionian Islands and the eastern Ionian Sea, whereas the Apulian platform is exclusively found in the Ionian Sea. The Ionian zone consists of Triassic evaporites, Jurassic– upper Eocene (mostly pelagic carbonates, minor cherts, and shales), overlain by the Oligocene flysch. Organic-rich source rocks occur within Triassic evaporites and Jurassic–Cretaceous pelagic argillaceous-siliceous rocks. The pre-Apulian zone consists of Triassic to Miocene deposits, mainly mixed neritic-pelagic carbonates. Hydrocarbon source rocks include pelagic and hemipelagic deposits rich in marine organic material, although terrigenous organic matter is also found in siliciclastic layers. Apulian platform source rocks are mainly the organic-rich shaleswithin the Triassic Burano evaporites. Western Greece contains major petroleum systems, which extend into the Ionian Sea. Ionian, pre-Apulian, and Apulian petroleum systems contribute to the probable hydrocarbon accumulations within the big offshore (Ionian Sea) anticlines. Western Greece contains important oil and gas shale reservoirs with a potential of unconventional exploration. Promising areas for hydrocarbons need systematic and detailed threedimensional seismic data. Exploration for conventional petroleum reservoirs, through the interpretation of seismic profiles and the abundant surface geologic data, will provide the subsurface geometric characteristics of the unconventional reservoirs. Their exploitation should follow that of conventional hydrocarbons to benefit from the anticipated technological advances, eliminating environmental repercussions.

Description: Experiments and models reveal that moderate dispersal rates between local communities can increase diversity by alleviating local competitive exclusion; in contrast, high dispersal rates can decrease diversity by amplifying regional competition. However, hitherto experimental tests on how dispersal affects diversity in the presence and absence of environmental heterogeneity are largely missing, although it is known that environmental heterogeneity influences diversity. For the first time we experimentally show that the interaction between dispersal rate and the presence of an environmental gradient with on-average lower resource availability than the homogeneous control treatment affects diversity. In metacommunities of nine co-occurring species of marine benthic microalgae we factorially manipulated dispersal rate and the presence and absence of a light intensity gradient across local patches to test effects on local, regional, and beta diversity and to compare results to predictions from monoculture experiments. Although species in this experiment did not show resource partitioning along the light gradient as assumed by source–sink models, dispersal limitation maintained diversity in metacommunities with light gradients but not without. Local diversity and evenness were high under low light intensities when dispersal was limited and decreased with both increasing light intensities and dispersal rates. These diversity changes can be explained by the reduction of growth of the regional superior competitor at low light intensities alleviating its competitive strength. Increasing dispersal rate in turn compensated for the superior competitor's slow growth in those local patches with rather unfavorable light conditions and thus led to decreasing diversity and evenness. In contrast, diversity in the metacommunities without a light gradient was constantly low. Here, the superior competitor contributed 90% to total community biomass in all patches. High dominance, however, likely resulted from on-average higher resource availability (i.e., higher light intensities) compared to metacommunities with light gradient and not from patch homogeneity in itself.