Microbes and their use as Indicators of Pollution

Abstract

Two thirds of the Earth is covered by water and about 99.7% of water found on this planet is contained in the oceans and seas. Marine ecosystems are an important resource not only for the extraordinary variety of life they host but also for the multiple activities that occur in them (i.e. recreational and productive activities like tourism, aquaculture and fimaritime shipping and traffi c; exploitation of energy resources like oil and gas extraction; pipelines and submarine cables location; uses for military activities, and others). Th e anthropic impacts on the marine environment are particularly evident in coastal areas, which are the most vulnerable to pressures [1], and are exposed to urban, agriculture runoff and industrial discharges - with their load of organic and inorganic particles, xenobiotics and other contaminants, oil spill, heavy metals, etc - with consequent impairment of water quality and alterations of ecosystem functioning. Th e awareness of the increasing threats caused by the anthropic pressure over marine ecosystem explains the growing interest towards the protection of marine environments, which has recently been shown by the issue of the European Marine Strategy Framework Directive (2008/56/EC) [2]. Th is Directive deals with the set up of monitoring plans and the adoption of measures for the achievement of Good Environmental Status (GES) by 2020. Th e GES is the environmental status of marine waters under which the ecological diversity and viability of the seas and oceans are preserved, in order to keep them clean, healthy and productive; the use of the marine environment must be in a sustainable way, safeguarding its potential for uses and activities for present and future generations. Th e defi nition of GES varies according to the diff erent sub-regions (i.e. for the Mediterranean Sea, the Western Mediterranean Sea, the Adriatic Sea and the Ionian and Central Mediterranean Sea). Specifi c criteria and indicators are set to achieve qualitative and quantitative targets, acting on the pressures and in order to reduce the impacts. Th e Marine Strategy is based on an integrated “ecosystem” approach and aims at becoming the environmental pillar of the future Maritime Policy of the European Union. Preservation of the Mediterranean waters from contamination is particularly needed due to the central role of this basin for most of the European, African and Middle East Countries. Th e use of natural resources must match with the maintenance of optimal productivity levels and health status. To achieve such an objective, it is needed to identify some sustainability limits of marine ecosystems, which must be respected in all human activities. Safeguard and protection of areas at risk must rely on the continuous observation of parameters describing the health status of each marine ecosystem. In this context, monitoring of biological indicators is suggested, as they play a fundamental role in the description and prediction of environmental changes. Particularly, the use of marine microorganisms is recommended to assess the quality of marine ecosystems, in parallel with physical and chemical parameters, due to their ubiquitous distribution in seawaters, high biomass turnover and quick response to environmental variations [3]. Bacteria or their antigens, genes or metabolic pathways can be used as suitable markers of contamination [4].