Flow-through bio-optical system This system operates semi-continuously with water from the ship’s non-toxic supply. The water is first debubbled with a vortex debubbler. Approximately every 4 minutes it measures temperature, salinity, chlorophyll fluorescence, total backscattering at 532nm (bbptot), acidified backscattering (bbpacid; backscattering of the seawater suspension after the pH has been lowered to dissolve calcium carbonate), acid-labile backscattering (bb’; the difference between the bbptot and bbpacid), absorption and attenuation at 9 visible wavelengths (made every 2 minutes), absorption and attenuation at 9 visible wavelengths after water was routed serially through a 1.0um then a 0.2um cartridge filter (during intervening 2 minute segments). Above-Water Radiance Measurements In order to check ocean color algorithm performance, free of atmospheric error, water-leaving radiance, sky radiance and downwelling irradiance were measured from the bow of the ship using a Satlantic SeaWiFS Aircraft Simulator (SAS or MicroSAS). The system consists of a down-looking radiance sensor and a sky-viewing radiance sensor, both mounted on the bow. A downwelling irradiance sensor was mounted far from any potentially shading structures, on the tallest mast of the ship. These data were then used to estimate normalized water-leaving radiance as a function of wavelength. The radiance detector was set to view the water at 40o from nadir as recommended by Mueller et al. (2003b). Sensors were rinsed regularly with Milli-Q water in order to remove salt deposits and any dust. The water radiance sensor was able to view over an azimuth range of ~180o across the ship’s heading with no contamination from the ship's wake. The direction of the sensor was adjusted constantly to view the water 120o from the sun's azimuth, to minimize sun glint. This was done using a computer-based system that calculated the sun's azimuth angle relative to the ship's heading and elevation constantly. The system used the ships gyro-compass to determine the heading of the ship. The computer controlled a stepping motor that turned the sensors to the proper viewing angle depending on the ship’s course. Protocols for operation and calibration were performed according to Mueller (Mueller et al. 2003a; Mueller et al. 2003b; Mueller et al. 2003c). Before 1000h and after 1400h local time, data quality was poorer as the solar elevation decreased. The 6Hz data were filtered to remove as much residual white cap and glint as possible (we accept the lowest 5% of the data). When the ship was stopped on station, measurements were also made. A plaque calibration was performed every several days (using a 2% spectralon plaque) to check for instrument drift. Description of measurements made During cruise underway samples were collected about every 3-6 hrs for particulate inorganic carbon and biogenic silica, particulate organic carbon/nitrogen and chlorophyll a. Water-column samples were taking from CTD casts during the cruise for PIC, POC, PON, BSi and Chlorophyll. Samples were taken from 6 light depths (between 50% and 0.1%) and 2 other depts. down to 500m with occasional samples taken from 1000+m if available. Coccolith counts were performed using the technique of Haidar and Thierstein (2000; 2001) except optical adhesive was substituted for Canada Balsam. Instrument models and serial numbers Instrument models and serial numbers are denoted in the calibration file list provided in the metadata headers of individual files. For example, ac90194.dev is the calibration file for an ac9, serial number 0264, vsf-061g.txt is a Wetlabs VSF, serial # 061g, and WS3S-1048P is a Wetlabs Wetstar Fluorometer, serial # 1048P. BSi samples were processed on a Hitachi U-3010 spectrophotometer. Please see the metadata and calibration files to determine the specific instruments. References: Haidar A.T., Thierstein H.R., Deuser W.G. 2000. Calcareous phytoplankton standing stocks, fluxes and accumulation in Holocene sediments off Bermuda (N. Atlantic). Deep Sea Research 47(9-11), 1907-1938. Haidar A.T., Thierstein H.R. 2001. Coccolithophore dynamics off Bermuda (N. Atlantic). Deep Sea Research 48(8-9), 1925-1956. Mueller J.L., Austin R.W., Morel A., Fargion G.S., McClain C.R. 2003a. Ocean optics protocols for satellite ocean color sensor validation, Revision 4, Volume I: Introduction, background, and conventions. Greenbelt, MD: Goddard Space Flight Center. 50 p. Mueller J.L., Morel A., Frouin R., Davis C., Arnone R., Carder K., Lee Z.P., Steward R.G., Hooker S.B., Mobley C.D., McLean S., Holben B., Miller M., Pietras C., Knobelspiesse K.D., Fargion G.S., Porter J., Voss K. 2003b. Ocean optics protocols for satellite ocean color sensor validation, Revision 4, Volume III: Radiometric measurements and data analysis protocols. Greenbelt, MD: Goddard Space Flight Center. 78 p. Mueller J.L., Pietras C., Hooker S.B., Austin R.W., Miller M., Knobelspiesse K.D., Frouin R., Holben B., Voss K. 2003c. Ocean optics protocols for satellite ocean color sensor validation, Revision 4, Volume II: Instrument specifications, characterisation and calibration. Greenbelt, MD: Goddard Space Flight Center.