Cruise report RV Hercules Valletta-Valletta, 1-10.10.2018 MARCAN Project

Abstract

Coastal regions are the most densely populated areas in the world with an average population density nearly 3 times higher than the global average. Freshwater resources in coastal states and island nations are therefore under enormous stress, and their quantities and qualities are rapidly deteriorating. This problem is exacerbated by population growth, pollution, climate change and political conflicts. Problems are especially felt in arid areas, such as Malta, where groundwater is the only source of freshwater and the periods of highest demand (e.g., agricultural and tourist seasons) coincide with the periods of lowest recharge from precipitation. By comparison, Cape Town, South Africa is the first major city in the modern era to face the threat of running out of drinking water, and other large cities like Jakarta, and Beijing are likely to follow suit. Offshore aquifers (OAs) have been proposed as an alternative source of freshwater to cover demand by domestic, agricultural and tourist industries in coastal regions. During the Last Glacial Maximum (19-22,000 years ago), modern shelf areas were sub-aerially exposed, leading to the development of extensive water tables recharged by atmospheric precipitation (meteoric water), rivers, lakes and, in some areas, glacial melt water. In view of the fact that sea level has been much lower than today for 80% of the Quaternary period (last 2.6 million years), and that meteoric groundwater systems migrate landwards more slowly than rising sea levels, remnants of meteoric groundwater occur extensively offshore.