The BATS time-series demonstrates a regular pattern of mixing with mixed layer depths (white line) extending as deep as 200 - 300 m throughout the BATS record. There is significant interannual variability, nonetheless these annual deep convective overturn events are extremely important to the biogeochemistry at BATS.

Convective overturn provides a mechanism for nutrient to be entrained into the surface waters. This nutrient entrainment into the euphotic zone sets the stage for phytoplankton blooms. At BATS there is annual spring bloom followed by summer low
The regular annual pattern of PP and mixing also generates a regular annual pattern of DOC production, accumulation and export out of the euphotic zone. The interaction between DOC and microbial processes, as well as the role microbial community structure has on DOC remineralization patterns, is one of the major research focuses of this Microbial Observatory.

For more details on the biogeochemical patterns at BATS see:

Carlson et al. 1994

Hansell and Carlson 2001

Steinberg et al. 2001