The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027)

Taylor Caps are distinctive dynamical features of seamounts and serve as critical conduits for the exchange of materials and energy between the abyssal ocean and the upper ocean. However, the upwelling processes of Taylor Caps over deep seamounts, especially their three-dimensional structures, remain poorly characterized. Here, using in-situ observations from a deep Pacific seamount, we identify a three-dimensional Taylor Cap structure that extends across the pycnocline, characterized by a horizontally annular pattern and a vertical structure tilted westward. This structure is controlled by the east-west asymmetry in Taylor Cap intensity and the associated vertical secondary circulation, which is further shown to be a widespread dynamical feature of seamounts worldwide based on Argo observations and reanalysis products. Theoretical estimates indicate that approximately 14.8% of global seamounts support pycnocline-penetrating Taylor Caps, influencing a total area of up to 8.6 million km², nearly eight times the combined spatial extent of the four major Eastern Boundary Upwelling Systems. Enhanced chlorophyll-a concentrations are observed within these regions, highlighting the significant role of deep-seamount Taylor Caps in cross-layer transport and their broader implications for global marine ecosystems.