Potential effects of climate changes on the marine ecosystem stability: assessment of the water quality.

JORGE E. MARCOVECCHIO; NATALIA BUZZI; MATIAS N. TARTARA; CARLA V. SPETTER; PIA SIMMONETTI

Marine Ecology in a Changing World

Science Publisher/CRC Press/Taylor&Francis

Lugar: Boca Ratón; Año: 2014; p. 1 - 42

Climate extreme conditions strongly affect life development and distribution on the planet. Considering not only the intensity and duration of the climatic anomaly but also the characteristics of the considered ecosystem (i.e. coastal, oceanic), the corresponding impacts can range from imperceptible to catastrophic ones. Changes in the environmental conditions lead to potential variations in their both physico-chemical and oceanographic scenarios, determining modifications in the distribution and behavior of different populations, and eventually in fisheries and exploitation of resources. A possible manifestation of these changing conditions within marine ecosystems as a function of climate anomalies is the loss of stability of the water column, which leads to changes in their physical, chemical and / or oceanographic variables, thereby affecting water quality. In this regard it is highlighted that both the coastal and oceanic systems are dominated by hydrological and physical processes governing the transport of materials and energy regimes. The major climatic changes that may affect marine ecosystems (i.e. Sea level rise; changes in seawater temperature; changes in precipitation regimes; changes in the path, frequency and intensity of storms; etc. ) determine different phenomena on coastal and/or oceanic systems. In coastal areas a wide range of effects can be produced at different scales, from local (i.e. Increased turbidity due to continental runoff overdischarge; overload of nutrients linked to increased rainfall; drastic changes in salinity during periods of drought or flood; etc.) and up to the regional or even global ones (i.e. changes in ocean surface circulation patterns due to freshwater over-discharge; changes in CO2 levels that determine significant variations in pH / alkalinity; etc.). These kinds of phenomena could strongly influence aquatic communities on the global scale, affecting plankton dynamics and leading to regime shifts in the pelagic realm. In addition, these types of changes might drive severe problems on the coastal ecosystems as eutrophication; erosion; or, saline intrusion / salinization of aquifers; while on the oceanic ones the main problems which have been identified are oceanic acidification; potential collapse of the great processes of the planet´s climatic regulation (i.e. Thermohaline circulation -THC- ; South Asia monsoon -SAM- ; Circum Antarctic low pressure belt -CALPB- ; among others); or, increase/decrease of upwelling ? downwelling processes, which regulate the fertilization of the oceans. Keeping in mind the described scenarios, different local and global study cases are fully considered in order to offer a significant contribution to the understanding of this environmental crisis.