Water temperature, salinity, beam attenuation, and other parameters from CTD from the research vessel Knorr in the Western North Atlantic from 1979-09-09 to 1979-10-01 (NCEI Accession 0189618)

This dataset contains water temperature, salinity, beam attenuation, and other parameters taken by CTD/transmissometer collected in 1979 during the High-Energy Benthic Boundary-Layer Experiment (HEBBLE, https://darchive.mblwhoilibrary.org/handle/1912/10611), a program designed to test the hypothesis that seabed modifications can result from contemporary local erosion and deposition. We observed several 'benthic storms' that re-suspended record-high concentrations of particulate matter – filtered samples showed up to 12,700 µg/l.

As part of HEBBLE activities, full water column CTD/Transmissometer/Nephelometer data were collected at 44 stations during R/V Knorr cruise KN74 (09/09/1979-10/01/1979). Beam attenuation data were acquired with a 1-m path-length red LED (660 nm wavelength) SeaTech transmissometer interfaced with the CTD. A Lamont nephelometer (Gardner et al., 1985) was attached to the wire above the CTD (nephelometer data not included in this data submission).

Although many papers were published based on HEBBLE data (including Gardner et al., 1985, which made the first and only evaluation of particle concentrations from a transmissometer and a Lamont nephelometer using simultaneous profiles through the water column and a three-month time series on a bottom tripod) no electronic copies of the KN74 CTD/Transmissometer data were preserved. The data survived only as tabular printouts made in the late 1970’s from now lost magnetic tape.

Because of the uniqueness of the record-high particulate matter concentrations, with ambient current velocities of up to 70 cm/sec near the seafloor, it was important to rescue and preserve these data.

Attempts to scan and apply OCR to the data with standard copying/scanning machines proved futile. Texas A&M University Library Digital Service Center (https://library.tamu.edu/services/print_scan_copy.html) scanned our 685 pages of tables using an advanced Supra Scan Quartz A00-Cam Quartz HD scanner, utilizing ABBYY Fine Reader OCR and PDF software (https://www.abbyy.com/en-us/finereader/), which is more frequently used in the humanities for digital preservation and conservation. Final scans were markedly better, but still contained many errors because of low quality originals.

Two students (Rebecca Gray Thomas and Kenna Nolen) performed QA/QC of the 685 pages of data. Through tedious effort, they successfully corrected the data, thus making it possible to load data into a database management system to visualize and analyze data profiles, make maps and sections, perform and publish further scientific analyses, and submit data to publicly accessible archives for preservation and use by future generations. Data are in text format.