D7

7.1 Spatial characterisation of permanent alterations

7.1.1 Extent of area affected

7.2 Impact of permanent hydrographical changes

7.2.1 Extent of habitats affected

7.2.2 Change in habitats

MAL-EL-MS-AL: For descriptors 3, 5, 6, 8 and 9 it is attempted to approach GES quantitatively using environmental thresholds/limits to describe the desired state of GES. For descriptors 1, 2, 4,7 and 10 a qualitative description of what GES will be like is provided.

• Hellenic Republic's marine waters part of the Aegean-Levantine subregion
• It constitutes the assessment area South Aegean Sea belonging in the subregion Mediterranean sea:Aegean-Levantine sea

• ChangeHydrology
• Current velocity
• LBathRock
• LBathSed
• MarineCoast
• MarineOceanic
• MarineShelf
• Mixing
• RedSalinity
• Residence time
• Salinity
• SeaBottomTemperature
• SeaSurfaceTemperature
• ShallMud
• ShallMxdSed
• ShallRock
• ShallSand
• ShelfCoarseSed
• ShelfMud
• ShelfRock
• ShelfSand
• Transparency
• Turbidity (silt/sediment loads)
• UBathRock
• UBathSed
• Upwelling
• VarSalinity
• WaveExposure

D7

7.1

7.1.1

7.2

7.2.1

7.2.2

Human activity causes the Mediterranean Sea to exhibit long-term increasing trends in temperature and salinity, although the shorter, decadal scale variability may temporarily alter the rising trends. The above trends have the following two consequences, which can potentially alter the good environmental status of the region. The first process is the progressive warming of the surface and near-bed layers. The warming trends are depended on the estimation period and are often hidden behind large multiannual variability. The impact of this warming is the Mediterranean tropicalization, providing suitable environment for the propagation of Lessepsian species entering through the Suez canal. A Good Environmental Status descriptor for this process is the mean summer, winter or annual water temperatures within the euphotic zone. A preliminary data analysis has shown that the current sea-surface temperature fields in the Aegean are comparable to the 1970s temperatures in the southeast Levantine Sea. Such analyses could be used to assess the degree of deviation from a more ‘pristine’ period, and thus the succeptibility of the physical system to the introduction of warm-living species. Salinity measurements should be complementing the temperature ones. The second significant process is the vertical stratification, a Good Environmental Status descriptor regarding the ability of the water column to mix and ventilate. Current future projections predict –with little confidence- a deceleration of the overturning in the Mediterranean, thus a lower ventilation rate.