Description: We present data set on the concentrations of various phytoplankton pigments (unit: mg/m³) from discrete samples measured using High Pressure Liquid Chromatography (HPLC) during the cruises PS99.1 on R/V POLARSTERN in the Fram Strait.

Description: We present a data set on particulate absorption line height at 676 and surface Chl-a concentration using underway spectrophotometry (Wetlabs AC-s instrument) and collocated discrete water sampling (measured by High Pressure Liquid Chromatography, HPLC, and Quantitative Filtration Technique) during two summer cruises PS93.2 and PS99.2 in the Fram Strait. Additionally we present for the discrete water samples the fraction of different phytoplankton groups on the total biomass, approximated by the chl-a concentration, which are derived from phytoplankton marker pigments also measured by HPLC.

Description: We present data sets on: 1) the concentrations of various phytoplankton pigments (unit: mg/m³) from discrete samples measured using High Pressure Liquid Chromatography (HPLC); 2) the concentrations of various phytoplankton pigments (unit: mg/m³) estimated from underway AC-S particulate absorption data (Fucoxanthin, 19'-hexanoyloxyfucoxanthin and Diadinoxanthin are estimated using SVD-NNLS-9 matrix inversion method; total Chlorophyll a, b, Chlorophyll c1+2, photosynthetic and photoprotective carotenoids are estimated using Gaussian decomposition); and 3) the spectral particulate absorption and attenuation coefficients and their standard deviation (unit: 1/m) derived from underway AC-S measurements during the cruises PS93.2, PS99.2 and PS107 on R/V POLARSTERN in the Fram Strait.

Description: Absorption coefficients (abs) and optical density (OD) by total particles, phytoplankton and non-algal particles (NAP) were measured with standard deviation (sd) estimated on water samples collected from underway AC-S flow-through system outflow and CTD. Measurements were performed using QFT-ICAM (Röttgers et al., 2016) as described in Liu et al. (2018) and Liu et al. (2019). 1. About sampling: a) underway samples were collected from unfiltered AC-S outflow (depth: 11m); CTD samples with 5-6 depths were collected on upcast. b) vacuum pressure for filtration: maximum 200 hPa c) samples were measured fresh (not preserved). d) blank filters were collected by soaking them in 0.2um filtered seawater. e) replicates were not collected. 2. About measurements: a) Instrument: light source: UV-VIS lamp (CF-1000- HC lamp, Illumination Technology, USA); absorption meter: Quantitative Filter Technique - Integrating Cavity Absorption Meter (QFT-ICAM) (Röttgers et al., 2016) with 80 mm- diameter integrating sphere; detector: photodiode array spectrometer (AVASPEC-ULS2048-RS-USB2, Avantes, the Netherlands). b) wavelength range of scan and resolution: 313.5-875.7 nm, 0.3 nm. c) slit band width: 2 nm. d) sample filters were bleached with 10% sodium hypochlorite (NaClO) solution for the OD measurement of NAP. e) samples were measured for four times and bleached samples were measured twice. f) dark current and blank filters were measured and subtracted. 3. About data analysis: a) interpolated wavelength range and resolution: 320-844 nm, 2nm. b) wavelength range for fluorescence correction: 670:800 nm. c) diameter of sample patch on GF/F filter: 2.133 cm. d) pathlength amplification factor (beta correction factor): 4.06 (Röttgers et al., 2016). e) no scattering correction for total particle absorption is applied; NAP absorption was adjusted with an offset in the range of 710-750 nm so that the median value of NAP absorption equals the median value of in total particle absorption in this spectral range. This adjustment is based on the assumption that phytoplankton pigments do not absorb in near-infrared (Neeley et al., 2018). This adjustment was not applied to NAP OD data. f) NAP absorption data from underway samples collected during 2017-07-28T16:46 and 2017-08-10T18:21 were missing. To calculate the corresponding phytoplankton absorption, the missing NAP data were taken the same as the ones from 2017-07-28T19:04 and 2017-08-10T15:00, respectively. However, this was not applied to NAP OD data. References: 1) Liu, Y., et al., 2018, doi:10.1364/OE.26.00A678 2) Liu, Y., et al., 2019, doi:10.3390/rs11030318 3) Neeley, A.R., et al., 2018. Ocean Optics & Biogeochemistry Protocols for Satellite Ocean Colour Sensor Validation: Absorption Coefficient. 4) Röttgers, R., et al., 2016, doi:10.1364/OE.24.0000A1

Description: Absorption coefficients by total particles (ap), phytoplankton (aph) and non-algal particles (aNAP) were measured on water samples collected from underway AC-S flow-through system outflow and CTD. Measurements were performed using a dual-beam UV/VIS spectrophotometer as described in Liu et al. (2018) and Liu et al. (2019). 1. About sampling: a) underway samples were collected from unfiltered AC-S outflow (depth: 11m); CTD samples with 5-6 depths were collected on upcast. b) vacuum pressure for filtration: maximum 200 hPa c) samples were shock frozen in liquid nitrogen and then stored in -80°C until measurement after cruise. d) blank filters were collected by soaking them in 0.2um filtered seawater. e) replicates were not collected. 2. About measurements: a) Instrument: dual-beam UV/VIS Spectrophotometer (Cary 4000, Varian Inc., Palo Alto, CA, USA) equipped with a 150 mm integrating sphere (external DRA-900, Varian, Inc. and Labsphere Inc., made from Spectralon (TM)). b) wavelength range of scan and resolution: 300-850 nm, 1 nm. c) slit band width: 2 nm. d) scan speed: 150 nm min−1 e) Sample filters were extracted with 95% methanol for the absorption measurement of NAP. f) The baseline of the spectrophotometer was set with a dry piece of a blank filter. Filters were wetted with purified water and measured regularly after every fifth sample filter served as references. 3. About data analysis: a) interpolated wavelength range and resolution: 350-750 nm, 1nm. b) pathlength amplification factor (beta correction factor): 4.5 (Röttgers and Gehnke 2012; Röttgers et al., 2014). c) Null-point scattering correction at 750 nm is applied.

Description: Absorption coefficients (abs) and optical density (OD) by total particles, phytoplankton and non-algal particles (NAP) were measured with standard deviation (sd) estimated on water samples collected from underway AC-S flow-through system outflow and CTD. Measurements were performed using QFT-ICAM (Röttgers et al., 2016) as described in Liu et al. (2018) and Liu et al. (2019). 1. About sampling: a) underway samples were collected from unfiltered AC-S outflow (depth: 11m); CTD samples with 5-6 depths were collected on upcast. b) vacuum pressure for filtration: maximum 200 hPa c) samples were measured fresh (not preserved). d) blank filters were collected by soaking them in 0.2um filtered seawater. e) replicates were not collected. 2. About measurements: a) Instrument: light source: UV-VIS lamp (CF-1000- HC lamp, Illumination Technology, USA); absorption meter: Quantitative Filter Technique - Integrating Cavity Absorption Meter (QFT-ICAM) (Röttgers et al., 2016) with 80 mm- diameter integrating sphere; detector: photodiode array spectrometer (AVASPEC-ULS2048-RS-USB2, Avantes, the Netherlands). b) wavelength range of scan and resolution: 313.5-875.7 nm, 0.3 nm. c) slit band width: 2 nm. d) sample filters were bleached with 10% sodium hypochlorite (NaClO) solution for the OD measurement of NAP. e) samples were measured for four times and bleached samples were measured twice. f) dark current and blank filters were measured and subtracted. 3. About data analysis: a) interpolated wavelength range and resolution: 320-844 nm, 2nm. b) wavelength range for fluorescence correction: 670:800 nm. c) diameter of sample patch on GF/F filter: 2.133 cm. d) pathlength amplification factor (beta correction factor): 4.06 (Röttgers et al., 2016). e) no scattering correction for total particle absorption is applied; NAP absorption was adjusted with an offset in the range of 710-750 nm so that the median value of NAP absorption equals the median value of in total particle absorption in this spectral range. This adjustment is based on the assumption that phytoplankton pigments do not absorb in near-infrared (Neeley et al., 2018). This adjustment was not applied to NAP OD data. f) NAP absorption data from underway samples collected during 2016-06-17T21:20, 2016-06-18T00:26, 2016-06-18T03:19, 2016-06-18T06:38, 2016-06-15T12:12, and 2016-06-15T15:09 were missing. To calculate the corresponding phytoplankton absorption, the missing NAP data were taken the same as the ones from 2016-06-17T18:13, 2016-06-18T18:09, 2016-06-18T18:09, 2016-06-18T18:09, 2016-06-15T09:15, and 2016-06-15T09:15, respectively. However, this was not applied to NAP OD data.