|Challenger Deep internal wave turbulence events|In: Deep-Sea Research, Part I. Oceanographic Research Papers. Elsevier: Oxford. ISSN 0967-0637; e-ISSN 1879-0119, meer
Challenger deep; Long-term mooring; High-resolution temperature measurements; Convective turbulent intrusions; Internal wave driven turbulence
Marine life has been detected in the ocean's trenches at great depths, down to nearly 11 km. Such life is subject to particular environmental conditions of large static pressure exceeding 1000 atm. While current flows are expected to be slow, waters cannot be stagnant with a limited exchange of fresh nutrients needed to support life. For sufficient nutrient supply, the physical process of turbulent exchange is required. However, environmental conditions hamper research in such waters. To study potential turbulent water motions, a string equipped with specially designed high-resolution temperature sensors was moored near the deepest point on Earth, in the Challenger Deep, Mariana Trench for nearly three years. A preliminary analysis of a six-day period when the mooring was still, demonstrates hundreds of meters slanted convection due to internal waves breaking from above. The associated turbulence dissipation rate with peak values hundred times above the background value is considered sufficient to maintain deep-trench life. Turbulence was associated with one-ten thousandth of a degree temperature anomalies of about one hour duration.