How and what turbulent are deep Mariana Trench waters?

To study potentially turbulent water motions near the deepest point on Earth in the Challenger Deep of the Mariana Trench, a 588-m long string equipped with specially designed sensitive temperature sensors was moored for nearly three years. Detailed analysis of one year of good data distinguishes ubiquitous internal tidal waves and hundreds of meters slanted convection turbulent spurs due to internal waves’ breaking from above. The spurs, or intrusions of anomalous waters, can occur on a tidal periodicity. Some tidal wave breaking including 100-m tall turbulent overturns reaching the trench floor is associated with warm waters that push from above, and of which the largest occurred during the passing of a tropical storm. The various turbulence types prevent the hadal, below 6000 m, waters from being stagnant, which is an important necessity for deep-trench life.