Shoreline sensitivity to oil spills, the Mediterranean coast of Israel: Assessment and analysis
Abstract This study, which was carried out during 1999–2002, deals with the identification of the environmental sensitivity of the Mediterranean coastline of Israel to marine oil spills. It includes GIS sensitivity mapping and an analysis of the environmental vulnerability of Israel's shoreline resources. The study analyses the main sources of risk for maritime accidents in the southeastern Mediterranean and develops scenarios for possible oil spills incidents, including an analysis of the priorities for protection of the various coastal ecosystems, in an event of a large spill. It describes the morphology of the coastline of Israel, as well as the main hydrographic and meteorological patterns that dominate and control the dynamics of the shorelines, and of potential major oil spills. The study also discusses the different ways in which oil spills may affect natural ecosystems and socio-economic resources along the coastline of Israel. The basic research question of the study was how different geomorphic and land-use types of the Mediterranean shoreline would be affected by large quantities of spilled oil washing ashore from the sea. The study aims at determining the relative sensitivity of different types of shoreline and ‘prioritizing’ the different types of shoreline and coastal resources to be protected following a large oil spill. The study also aims at presenting the data collected and analyzed to both the scientific and environmental communities, and to the operational national authorities responsible for oil spill preparedness and response, in a clear and useful way. One of the main conclusions of the study is that generally, the sensitivity of the Israeli Mediterranean coastline to oil spills could be considered moderate, compared with other fragile ecosystems. This is mainly because of the morphology of the sandy beaches and the high exposure of most types of beaches to energetic natural cleanup processes. Still, along the southeastern Mediterranean coastline there are ecosystems, habitats, shoreline types and coastal resources that are sensitive to oil spills.
A three-step model to assess shoreline and offshore susceptibility to oil spills: the South Aegean (Crete) as an analogue for confined marine basins.
This study combines bathymetric, geomorphological, geological data and oil spill predictions to model the impact of oil spills in two accident scenarios from offshore Crete, Eastern Mediterranean. The aim is to present a new three-step method of use by emergency teams and local authorities in the assessment of shoreline and offshore susceptibility to oil spills. The three-step method comprises: (1) real-time analyses of bathymetric, geomorphological, geological and oceanographic data; (2) oil dispersion simulations under known wind and sea current conditions; and (3) the compilation of final hazard maps based on information from (1) and (2) and on shoreline susceptibility data. The results in this paper show that zones of high to very-high susceptibility around the island of Crete are related to: (a) offshore bathymetric features, including the presence of offshore scarps and seamounts; (b) shoreline geology, and (c) the presence near the shore of sedimentary basins filled with unconsolidated deposits of high permeability. Oil spills, under particular weather and oceanographic conditions, may quickly spread and reach the shoreline 5-96 h after the initial accident. As a corollary of this work, we present the South Aegean region around Crete as a valid case-study for confined marine basins, narrow seaways, or interior seas around island groups.
Sand Beach Energetics: An Ecosystem Approach Towards a High Energy Interface
General results of a study of energetics on open sandy beaches in South Africa are presented. These sand beaches are considered to interact with adjacent terrestrial environments via the sand dune system and with the sea via the surf zone. A food web is given for the macrofauna showing all known interactions from the supply of food material to the beach, mainly from the sea, to the removal of the macrofauna by birds and fishes. An energy circuit diagram is presented quantifying the main energy flows through this system of filter feeders and scavengers. The interstitial biota of these beaches is considered separate from the macrofauna and consists of bacteria, protozoa and meiofauna feeding on dissolved and particulate organics flushed into the beaches by wave and tide action. Interstitial energy flow and nutrient cycling rates are quantified in an energy circuit diagram. It is suggested that nutrients regenerated by this latter system in the intertidal and surf zone, as well as by the activities of the macrofauna, have sufficient residence times in the surf zone to cause blooms of surf zone phytoplankton which in turn are the main food for the intertidal filter feeders. In this respect the beach and surf zone may represent a more closed system than previously thought. A combined energy circuit diagram is given depicting the beach and surf zone as an ecosystem with the surf zone phytoplankton the producers, the macrofauna the consumers and the interstitial fauna the decomposers. Main imports and exports as well as the consequences of this ecosystem approach are discussed.