National Coral Reef Monitoring Program: Shallow water conductivity-temperature-depth (CTD) profiles for selected locations across American Samoa

Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided in this collection were conducted at selected sites around American Samoa as part of the ongoing National Coral Reef Monitoring Program (NCRMP). Shallow water CTD surveys provide vertical profiles of temperature, salinity, and turbidity providing indications for water masses and local sea water chemistry changes. These surveys are conducted to characterize the spatial structure of the physical and chemical properties of the ocean environment influencing the living coral reef resources observed during Rapid Ecological Assessments (REA) and towed-diver surveys, both of which are archived separately.

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 is performed using Seabird Instrument's SeaSoft SBE Data Processing Software.