Processed, smoothed on-bottom navigation tracks and conductivity–temperature–depth (CTD) and dissolved oxygen water-column profiles from ROV SuBastian dives during 2025 R/V Falkor (too) expedition FKt250712 in the Mar del Plata Canyon, SW Atlantic

This data set provides processed seafloor navigation tracks for the remotely-operated vehicle (ROV) SuBastian dives during 2025 R/V Falkor (too) expedition FKt250712. Each file records the vehicle position (latitude and longitude in decimal degrees), depth, altitude above the seafloor, and heading during the on-bottom phase of a dive, together with co-located CTD and dissolved-oxygen measurements. Navigation originated from the ROV SPRINT navigation system, with depth and altitude from the SBE49 CTD and altimeter. Per-sensor streams were time-stamped to one-second resolution, merged onto the navigation time base by nearest-neighbor matching (±2 s), resampled to a uniform 0.1 Hz grid (one sample every 10 s), and trimmed to the logged on-bottom interval; records with invalid (0°, 0°) GPS fixes or depths shallower than 20 m were discarded. Position, depth, and altitude were then de-noised with a two-stage filter: an 11-point rolling median to remove acoustic outliers, followed by a Savitzky-Golay filter to suppress high-frequency jitter while preserving track geometry. Files are provided in ASCII CSV format, with the smoothed variables given as additional columns alongside the original CTD and dissolved-oxygen values.