Degradation is accompanied by depletion of aquatic resources based on human exploitation. Relevant statistics about marine and coastal water quality and pollutant concentrations may include, but are not limited to, nutrients and chlorophyll, organic matter, pathogens, metals, organic contaminants, physical and chemical characteristics, and coral bleaching. The most commonly monitored marine pollutants and associated phenomena, such as eutrophication and red tide, can be analysed as relevant in local, national or supranational terms, based on the type of pollution and effect. Data sources for marine water quality statistics are typically either national or international monitoring stations, associated with scientific research or compliance with policy objectives and targets.