The scope of the research project is to investigate the consequences of climate change on deltaic plains, as one of the most vulnerable coastal and wealth-producing ecosystems. The Pinios river delta, located in the region of Thessaly (Greece) has been selected as a case study, as one of the largest Greek rivers with very limited flow controls. But, despite the fact that deltaic plain is part of the NATURA network, human intervention continuous to occur at an increasing rate. The main objectives of the project are to: (i) study the relative contribution of fluvial fluxes (water/sediment), nearshore hydrodyanmics and climate conditions in the formation and evolution of deltas; (ii) evaluate the impact of human activities in the evolution of the River Pinios delta (e.g., alteration of riverine fluxes, agricultural pollution, over-pumping of the aquifer); (iii) assess and to evaluate quantitatively changes in the deltaic environment for different climate change scenarios, i.e. water balance, issues of water quality, desertification, coastal erosion, inundation; (iv) investigate the interaction between natural processes and parameters associated with socio-economic development and use; (v) develop Sustainable Development Strategies for the natural deltaic system, in order to mitigate the consequences of the climate change, towards a better management of the wealth- producing resources (i.e. fresh water yield); (vi) contribute to the training of young scientists in environmental issues, related to the impact of the climate change on coastal environments; and (vii) disseminate science based management strategies to the local and scientific communities. During the first phase of project implementation, the study of the surface and ground water and their interrelationship is investigated through: (i) the climatological conditions of the deltaic plain and the drainage basin; (ii) the determination of the subsurface geological/stratigraphical information provided by geophysical data; (iii) surface and water fluxes estimated on monthly measurements (quantitative and qualitative) of river flow and phreatic water table.

The present work investigates the decadal morphological evolution of a microtidal, perched beach and the effect that beach rock formations can have on coastal morphology. Using historical and recent morphological observations from Ammoudara Beach on the island of Crete, Greece, and numerical modeling, the interaction of beach rock formation and retreating coastline are investigated. The principal feature of the morphological evolution of the coastal zone under investigation has been the transformation of a beach rock formation, initially attached to the shoreface (1950s), to a submerged reef that is aligned subparallel to the present-day shoreline. At present, the beach rock is attached to the shoreface at sea level at the western part of the beach, but it has evolved to a submerged reef toward the east, being approximately 40moff the shoreline at the central part and \~{}70moff the coastline at the eastern part of the beach. This kind of beach evolution is attributed to the interplay of natural hydrodynamic and sediment transport processes (that have been changing as the beach rock formation evolved to an offshore submerged reef) and to human intervention. The latter is exhibited mainly as changes in the sediment supply to the coastal zone (e.g., reduction in terrestrial freshwater/ sediment influx, deterioration of sand dune field, and arbitrary abstraction of beach material). After a period of readjustment of the nearshore hydrodynamics to the changing morphology and vice versa, it seems that, at present, Ammoudara Beach has attained a new morphodynamic equilibrium where the shore-parallel reef acts as a submerged breakwater.

The Aegean Sea covers an area of some 160??103 km2 and receives the water/sediment fluxes from a mountainous drainage basin of >200??103 km2. On the basis of its morphodynamic characteristics, the Aegean Basin could be divided into: (1) the North Aegean Sea, an elongated region (trending between N50?? and N70??) including the extensive northern shelves and the Deep Aegean Trough; (2) the Central Aegean, which includes: the Cyclades Plateau, a relatively shallow (average depth <350 m) submerged platform, surrounded by small basins (up to 1000 m depth), including also the relatively extended eastern shelf of Asia Minor, and (3) the Southern Aegean Sea, located southwards of the Hellenic volcanic arc, which presents the characteristics of a true back-arc basin (the Cretan Sea). The surficial unconsolidated sediments of the north Aegean floor are dominated by the terrigenous component (from 50% up to >90%) due to the large terrigenous riverine fluxes. The South Aegean presents high percentages (>50%) of biogenic material, due to the small terrigenous inputs and despite the fact that it is more oligotrophic than the North Aegean. The Central Aegean presents a transitional character with the terrigenous influxes being imported along its eastern part and quantitatively being in between those of the North and South Aegean Sea sub-regions. The coarse-grained materials in shallow (shelf) areas are attributed to 'relict' deposits, while those in large water depths are almost exclusively biogenic products. The offshore distribution of the fine-grained terrigenous material is dominated by the overall circulation pattern, while meso-scale eddies may, locally, either enhance (anticyclones) or reduce (cyclones) settling rates. Moreover, the spatial distribution of the predominant clay minerals (illite and smectite) and of kaolinite and chlorite is governed by the lithology and proximity to land source areas, the water circulation and the processes of differential settling and flocculation. Overall, the North Aegean is characterised by sedimentation processes similar to those of a 'continental margin', primarily neritic and secondarily hemipelagic, the Central Aegean region mostly by hemipelagic and the South Aegean, behaving more like an 'oceanic margin', mostly by pelagic processes. ?? 2009 Elsevier Ltd. All rights reserved.

In the current paper are presented the results of a multidisciplinary study (stratigraphical, sedimentological, geophysical and geochemical) combined with modern techniques (G.I.S. and remote sensing). This study aims at integrating the natural and anthropogenic factors affecting the Korissia lagoon. It is a shallow coastal lagoon, communicating with the sea via an artificial channel. The area around the lagoon consists of alluvial sediments hosting, in places, newly formed and/or “old” (pre – Holocene) sand-dunes. The broader area constitutes a post- alpine sedimentary basin characterised by smooth morphological relief. The lower stratigraphic unit of the post-alpine sequence is a Pleistocene marly formation, which was detected as the basement (5-15 hm.m) by the geophysical survey. The resistivity-based basement map implies the existence of a “palaeo-gulf” trending E- W. These marls constitute the impermeable basement of a shallow aquifer hosted in the area. The salinity of the lagoon is very high during summer (>40psu) but it does not affect significantly the wells around it. The lagoon is well oxygenated, while the wells have lower D.O. values. Ammonia and nitrates are the main inorganic Nitrogen forms, in the lagoon and the wells, respectively. Phosphorus is the limiting factor for phytoplankton growth. Human activities affect the area that is in need of an environmental management plan in order to prevent ecological degradation.

The morphological characteristics of a coastal reef that is observed along the Ammoudara beach (6 km to the west of the city of Heraklion, Crete) are investigated in relation to the sedimentology and modern evolution of the adjacent beach zone. The reef has a length close to 4 km, a mean width close to 35m and is located at a distance of 60 m from the shoreline at an average water depth of 2.6m, while the seaward water depth exceeds 3m. Its height above the seafloor, exceeds 80 cm, reaching in places less than 0.5 m from the sea surface. It has two layers; the lower one which consists of fine grained (sandy) material and is approximately 40 cm thick and the upper layer, around 30 cm thick, consisting of relatively coarse,grained material (gravel and sand). Moreover, on the surface of the upper layer, runnels are observed, whilst distinguished cross bedding, similar to that observed in aeolian deposits, exists within the bottom layer. The reef is not present in front of the active mouths of the rivers Gazanos and Xiropotamos which debouch in the coastal area of Ammoudara. The western end of this submerged reef is attached to the beach face, exhibiting the characteristics of a typical beach,rock formation. On the basis of the above, it is concluded that the reef under investigation it is a submerged beach rock which indicates the position of a former coastline that is now submerged due to a relative sea level rise of approximately 0,5m.

This work is a description of the water masses and circulation in the site of the CINCS (Pelagic–Benthic Coupling IN the Oligotrophic Cretan Sea) experiment in the southern boundary of the Cretan Sea, a region of recently renewed interest with respect to the hydrology of the Eastern Mediterranean Basin. Analysis of hydrological data from the study area reveals the presence of five water masses: local surface water and remotely advected Modified Atlantic Water (MAW) share the surface layers below them are Cretan Intermediate Water (CIW), between 50 and 150 dbar, Transition Mediterranean Waters (TMW) with its core located between 300–400 dbar, and the Cretan Deep Waters (CDW) occupying the depths below 800 dbar. The circulation over the coastal shelf and slope is dictated by the offshore semi-permanent mesoscale features that dominated the Cretan Sea in 1994–1995, forcing locally a shoreward flow. The hydrographic observations are verified by current-meter measurements from a mooring in the sampling area. The recorded velocity is generally towards the SE direction, seasonally modulated, reaching maximum speeds of 27 cm s−1. Analysis of the new data set has revealed a previously unobserved feature of the oceanographic characteristics of the region. Over the base of the Cretan Slope there occur lenses of water that are warmer and more saline than their surroundings. These lenses probably form on the shelf seasonally; their waters are rich in oxygen, and have a density that is higher than historical Cretan Deep Water values.

The Cretan Basin can be characterized as a back-arc basin of the Hellenic Trench System, that is related to the subduction zone of the African Plate under the Eurasia Plate. The study area includes the narrow and relatively steep (gradient 1.5°) continental shelf of the island of Crete followed by the steep slope (2°–4°) and the rather flat deeper part of the Cretan basin (water depths >1700 m). Surficial sediments of the coastal zone are coarser and of terrigenous origin, while in deeper waters finer sediments, of biogenic origin, are more abundant. Sand-sized calcareous sediment accumulations, identified in middle-lower slope, may be attributed to the aggregation of seabed biogenic material related to the near bed current activity. High resolution profiles (3.5 kHz) taken from the inner shelf shows a typical sigmoid-oblique progradational configuration, implying prodelta sediment accumulation during the Holocene. In the upper-middle slope, sub-bottom reflectors indicate continuous sedimentation of alternating fine and/or coarse grained material. Small-scale gravity induced synsedimentary faults appeared, locally. In contrast, a series of gravity induced faults, identified in the lower slope, are associated with sediment instabilities due to seismotectonic activity. Sediment cores taken from the shelf-break consists of calcareous muddy sand with small amounts of terrigenous silt and fine sand, while the cores recovered from the middle slope has revealed a more homogeneous fine sediment texture of hemipelagic deposition. The prevailing accumulation processes in the southern margin of the Cretan basin are: (i) prodelta deposition in the inner-middle shelf; (ii) settling from bottom nepheloid layers in the shelf and upper slope; (iii) calcareous sediment formation due to settling from suspension and post accumulation aggregation (middle-lower slope); (iv) long-term episodic sediment gravity processes in the lower slope; and (v) to a lesser extent, redeposition from resuspension due to gravity processes and bottom currents.

Seasonal variability and the spatial distribution of sea surface temperatures (SST) and salinities (SSS) are reviewed, in relation to the prevailing climatological conditions, heat fluxes, water budget and general water circulation patterns. Within this context, consideration is given to: sea surface temperatures; air temperatures; precipitation; evaporation; wind speeds and directions; freshwater (mainly riverine) discharges throughout the Aegean; and the exchange of water masses with the Black Sea and eastern Mediterranean Sea. The investigation of satellite images, covering a 6-yr period (1988–1994), has enabled a synthesis of the monthly sea surface thermal distribution to be established. The climate of the Aegean Sea is characterised by annual air temperatures of 16–19.5°C, precipitation of about 500 mm yr−1 and evaporation of some 4 mm d−1. The Aegean has a negative heat budget (approximately −25 W m−2) and positive water balance (+ 1.0 m yr−1), when inflow from the Black Sea is considered. During the summer, the (northerly) Etesians are the dominant winds over the Sea. Mean monthly sea surface temperatures (SST) vary from 8°C in the north during winter, up to 26°C in the south during summer. SST depends mainly upon air temperature; there is a month's delay between the former and latter maxima. The sea surface salinity (SSS) varies also spatially and seasonally, ranging from less than 31 psu, in the north, to more than 39 psu, in the southeast; lower values (< 25 psu) occur adjacent to the river mouths. SSSs present their maximum differences during summer, whilst during winter and autumn the distribution of SSS is more uniform. The overall spatial SST and SSS distribution pattern is controlled by: distribution of the (colder) Black Sea Waters; advection of the (warmer) Levantine Waters, from the southeastern part of the Aegean; upwelling and downwelling; and, to a lesser extent, but locally important, freshwater riverine inflows.