National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Hawaiian Archipelago in 2013 (NCEI Accession 0161327)

Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for water masses and local sea water chemistry changes. These surveys were conducted to characterize the spatial structure of the physical and chemical properties of the ocean environment influencing the living coral reef resources observed during REA and towed-diver surveys. Water samples were collected at the shallow water CTD sites to examine near-shore water quality. Shallow CTD casts are vertical profiles (max 30 meter depth, downcast only) of water column conductivity, temperature, and pressure (Sea-Bird Electronics, SBE19-plus; accuracy of 0.005 S m-1 in conductivity, 0.0002C in temperature, and 0.1% in pressure). A transmissometer (Wetlabs Inc; provides profiles of beam transmittance, related to turbidity) and a dissolved oxygen sensor (Sea-Bird Electronics, SBE43; accuracy of 2% of saturation) are also attached. Data are collected by lowering the CTD in a profiling mode from a small boat at a descent rate of approximately 0.5 to 0.75m s-1 to a maximum depth of 30m. Data processing was performed using Seabird Instrument's SeaSoft SBE Data Processing Software (http://www.seabird.com/software/SBEDataProcforWindows.htm).