Coupled benthic and pelagic oxygen, nutrient and trace metal cycling, ventilation and carbon degradation in the oxygen minimum zone of the Peruvian continental margin (SFB 754): Cruise No. M 13611.04. – 03.05.2017Callao (Peru) – CallaoSolute-Flux Peru I

Abstract

The magnitude of nutrient and trace metal cycling in oxygen minimum zones (OMZ) and the involved loss of fixed nitrogen is crucial for the ocean’s nutrient budget, particularly in light of the ongoing expansion of OMZs. The major focus of the measurement program that was carried out in the frame of the DFG Collaborative Research Centre (SFB) 754 „Climate-biogeochemical interactions in the tropical ocean“, was to advance interdisciplinary understanding of benthic and pelagic nutrient and trace metal cycling processes in the OMZ off Peru and to quantify loss of nitrogen nutrients. Further objectives were to determine ventilation rates by submesoscale processes, quantify export fluxes of particulate organic matter, determine production and decay rates of dissolved organic material, and investigate mechanisms of iron stabilization, removal and cycling. The physical-biogeochemical measurement program focused on a transect perpendicular to the coastline at 12°S. Additionally, a transect at 14°S was completed and a submesoscale process study in an upwelling filament structure was carried out in the region of 15°S, 77°W. The coordinated sampling scheme included CTD profiling and water sampling stations, shipboard turbulence and velocity observations, a glider swarm experiment, moored velocity and hydrography observations, in situ benthic flux measurements using landers, sediment retrieval with a multiple corer, drifting sediment trap deployments and recovery and in situ pump deployments. The measurement program that was closely linked to the follow-up cruise M137 was successfully completed and all data sets were acquired as planned