Ecosystem effects of the Atlantic Multidecadal Oscillation

Multidecadal variability in the Atlantic Ocean and its importance to the Earth's climate system has been the subject of study in the physical oceanography field for decades. Only recently, however, has the importance of this variability, termed the Atlantic Multidecadal Oscillation or AMO, been recognized by ecologists as an important factor influencing ecosystem state. A growing body of literature suggests that AMO-related fluctuations are associated with shifts in ecological boundaries, primary productivity, and a number of ecologically and economically important coastal and marine populations across the Atlantic basin. Although the AMO is a basin-wide index of SST, the drivers of ecosystem change encompass more than temperature anomalies and the mode of action differs within each ecosystem. A common theme in assessing ecosystem change indicates that fluctuations in water masses and circulation patterns drive shifts in ecosystem states, but the magnitude and rate of change is dependent on the physical characteristics of the region. Because of the wide ranging geographic effects of the AMO, and considering its multidecadal nature, a more complete understanding of its causes and effects would allow scientists and managers to more effectively inform ecosystem-based management across the Atlantic Basin.

► The AMO affects all levels of taxa and is a major influence on ecosystem state in the North Atlantic. ► Although frequently represented as a time series, the AMO and its ecosystem effects vary spatially. ► Correlations between the AMO and ecosystem state should be further examined to identify mechanisms. ► The AMO can and has been used to inform both single-species and ecosystem-based management. ► Coordinated monitoring of physical and ecological endpoints is necessary to understand the AMO.