This map shows Regional Cabled Array infrastructure at the summit of Southern Hydrate Ridge and the location of MARUM instruments, denoted by a 1 superscript. Credit: University of Washington.

The MARUM CTD-DO instrument was provided by the MARUM Center for Marine Environmental Sciences and the Department of Geosciences, University of Bremen, Germany. The probe was by funded by the German Federal Ministry of Education and Research (BMBF) within the scope of the “M³: Monitoring Marine Methane” projects (grants 03F0765A and 03F0854A). The MARUM CTD-DO instrument measures the pressure near the seafloor, temperature, conductivity and dissolved oxygen every minute at the summit of Southern Hydrate Ridge.

Access CTDPFA110 Data

Instrument Models & Deployed Locations

The MARUM CTD-DO Probe was installed on the Southern Hydrate Ridge summit near the medium-powered junction box MJ01B to which it is connected (Figure 1). It consists of a CTD probe (Sea-Bird Electronics SBE16plusV2 SeaCAT) with a dissolved oxygen optode sensor (Sea-Bird Electronics SBE63) and a flushing pump (Sea-Bird Electronics SBE5T). The CTD probe is installed on a tripod with the water inlet about one foot above the seabed. The sensors are flushed for 40 sec before every sample. Each sample is the average of 20 consecutive measurements (taken at a 4 Hz rate).
Series Make Model
CTDPFA Sea-Bird SBE 16plusV2

Reference Information

Data Format

The data products of the MARUM CTD-DO Probe consist of:
  • Raw sensor data output (.dat files): raw data in engineering units recorded in one file for each day. Raw data lines are formatted as follow:
  1. Temperature (°C, ITS-90) = ttt.tttt
  2. Conductivity (S/m) = cc.ccccc
  3. Internally mounted pressure (decibars) = pppp.ppp
  4. SBE 63 oxygen phase(µsec) =
  5. SBE 63 oxygen temperature voltage = t.tttttt
  6. UTC date, time = dd Mmm yyyy, hh:mm:ss (day month year hour:minute:second)
A complete description of the probe and raw data products can be found in the manufacturer's documentation (16plusV2_rs232_012HighRes.pdf).
  • Timeseries data: text files including all raw data in a column format. The dissolved oxygen (in ml/L) and practical salinity (PSU) calculated from the raw data are also provided.

Data Access

Data for the MARUM CTD-DO Probe can be accessed through at Within the accessed ftp site, a read me text file provides information about data formats and instrument data.