Abstract Investigations of hydrostatic pressure effects on microbial enzymatic processing are challenging but critical for understanding element cycling in the world's oceans. In this study, we developed and tested a stainless‐steel pressure cell capable of withstanding up to 110 MPa of hydrostatic pressure (equivalent to ~ 11,000 m depth), featuring three sapphire windows that enable real‐time measurements of spectral absorption and fluorescence. The temperature‐controlled system (5–50°C) can be incorporated in standard laboratory spectrofluorophotometers. The hydrostatic pressure of the 2.6 mL sample is regulated using a manually controlled spindle pump. The system was tested with fluorometric enzyme assays and used to evaluate the activity of chitinase enzymes produced by piezophilic and piezosensitive marine bacteria at a constant temperature of 10°C. Experiments on enzymes from three bacterial strains revealed distinct and reproducible differences in pressure responses. This compact system enables precise monitoring of pressure‐sensitive activity of microbial communities and extracellular enzymes and thus provides an avenue for detailed investigations on the importance of hydrostatic pressure in regulating deep‐sea biogeochemical processing.
Papadimitraki et al. (Sat,) studied this question.