Impact of Seamounts on Turbulent Mixing in the Mariana Arc

Abstract

Internal tide production leads to increased turbulent mixing when reaching rough topography like seamounts. This leads to upwelling of abyssal waters that contain components like essential nutrients, carbon, and heat. Seamounts are common throughout the Pacific Ocean, specifically in the Western Pacific. The Mariana Arc experiences a westward dominant internal tide production with seamounts located to the west of the arc. Seamounts NW Rota - 1 and Ruby were focused on with CTD casts taken at equal depths around the seamounts. The Thorpe length scale and average dissipation rates were used to quantify turbulent mixing. Mixing was inconsistent from seamount to seamount, with a dissipation rate range approximately 2 magnitudes larger than average. Negligible differences in mixing were found between the northern and southern quadrants. Increased mixing leads to more upwelling from the Meridional Overturning Circulation (MOC). Understanding where upwelling occurs can improve our understanding of what physical influences are on the MOC.