Eutrophication of Estuarine and Coastal Marine Environments: An Emerging Climatic-Driven Paradigm Shift

Estuaries and coastal marine waters are complex dynamic environments that are susceptible to the stresses and vagaries of climatic and non-climatic drivers of change. Climate change is an increasingly important factor in the development of eutrophication in estuarine and coastal marine environments. The additive, synergistic, and antagonistic interactions of climatic drivers of change and non-climatic anthropogenic and natural stressors create deleterious conditions that degrade these environments and their biotic communities. Climate-change mediated increases in precipitation, land runoff, river discharges, and temperature result in greater nutrient and organic matter loading, biogeochemical fluxes, enhanced thermal and salinity stratification, altered water circulation, harmful algal blooms, water column light attenuation, and deteriorated sediment and water quality in many estuarine and coastal marine ecosystems. The frequency, intensity, and extent of hypoxia are increasing in these ecosystems as well, where climate change amplifies the effects of eutrophication, leading to deoxygenation and extensive mortality of benthic organisms, a decline of fisheries, and damage to essential habitats. As temperature, nutrient enrichment, and organic matter supply continue to increase in many coastal regions worldwide, there are greater costs incurred for mitigation, adaptation, and resilience programs needed to deal with their adverse effects to improve the viability and sustainability of estuarine and coastal marine ecosystems, especially in urbanized areas. Coastal ecosystems are in a state of flux driven by climatic forcings that are causing a paradigm shift in their assessment and management. To this end, coastal managers are implementing ecosystem-based management programs using holistic, multidisciplinary integrated and unifying frameworks that link ecological, physical, and socio-economic elements to address the causes, consequences, and responses of anthropogenic impacts to maintain estuarine and coastal marine ecosystems in a healthy, productive, and resilient condition.