Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

This dataset includes temperature, salinity, conductivity, oxygen, depth, sound velocity, chlorophyll fluorescence, and pH measurements from McMurdo Sound, Antarctica.  Data were collected by CTD, fluorescence, and pH sensors during austral years 2012/2013 and 2014/2015

A small hole was drilled in the McMurdo Sound fast ice. The CTD was deployed below the fast ice to ~ 2 m depth. The CTD was then powered on and allowed to sit a few minutes until the pumps turned on and sensors stabilized and equilibrated. The CTD was then lowered using a hand winch to depths between 97 and 175 m.

These data are not quality controlled.  The oxygen sensor failed at some point during both 2012 and 2014. The conductivity sensor calibrations did not show significant drift, however, a bad cable in 2014 likely caused intermittent data spikes.

There are no fluorescence values in these data for 2012 and the beginning of 2014.  The first station with fluorescence is station 108 in 2014.  There are no pH values in the 2014 data.

Raw data were saved as hex files and converted to 1 m bin averaged data using the Sea-Bird Electronics Inc. Data Processing Software v.7.23.1.  For calibration and instrument information please consult the CTD header files (ZIP, 131 files, 440 KB total). The header files contain header lines generated by Sea-Bird processing software for each cast.

The "Parameter" section of this dataset landing page provides the data parameter names currently used in this data version as well as the original name used in the Sea-Bird Data Processing Software.

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values replaced with no data value 'nd'
* data from Jan 02 2013 15:00 had some trailing commas and/or extra values at end of lines (0.0).  Characters after the last comma were removed.
* v0 Voltage 0 was duplicated with same variable name, values, and description.  Removed second instance
* For station 212, austral season 2014 the time was in elapsed seconds so added the time in hh:mm instead to match other files.  Got the time from a date time string column (timeJ) in the original file.
* Date format converted to ISO Date format (source timeJ)
* Data version 2017-05-04 is an update of version 2017-02-08 that includes variable name changes in the data and a timestamp change from local to UTC.  Time and date now called time_local, date_local.  Other variables are now more descriptive for example "depSM" is now "depth."  Added time zone offset parameter.

Extracted from the NSF award abstract:

The research project investigates the importance of top down forcing on pelagic food webs. The relatively pristine Ross Sea includes large populations of upper-level predators such as minke and killer whales, Adélie and Emperor penguins, and Antarctic toothfish. This project focuses on food web interactions of Adélie penguins, minke whales, and the fish-eating Ross Sea killer whales, all of which exert foraging pressure on their main prey, crystal krill (Euphausia cyrstallorophias) and silver fish (Pleuragramma antarcticum) in McMurdo Sound.

The investigators used a video- and acoustic-capable ROV, and standard biological and environmental sensors to quantify the abundance and distribution of phytoplankton, sea ice biota, prey, and relevant habitat data.  The sampling area included 37 stations across an 30 x 15 km section of McMurdo Sound, stratified by distance from the ice edge as a proxy for air-breathing predator access. This study will be among the first to assess top-down forcing in the Ross Sea ecosystem and will form the basis for multidisciplinary studies in the future.

Map sampling stations