Description: Hyperspectral image (HSI) scanning of the composite record from Holzmaar (HZM19) was measured using a Specim PFD-CL-65-V10 E line scan camera (University of Bern, Switzerland). Data were processed using the ENVI software following the workflow of Butz et al. (2015, doi10.1117/1.JRS.9.096031): data were white-corrected, masked for cracks in the sediment surface and Relative Absorption Band Depths (RABDs) were computed for 2mm wide subsets. RABD671 (band depths from 640 to 702 nm) for Total Chloropigments-a (TChl-a), RABD845 (790 - 900 nm) for Bacteriopheopigments-a (Bphe-a), and RABD620 (600 - 640 nm) for Phycocyanin (PhyCy). To translate HSI indices into absolute concentrations, a pigment extraction was performed at the University of Bern using 23 samples covering the full range of RABD671 and RABD845 index values. Ca 1 g of wet sediment was treated with 100 % acetone following the method of Lami et al. (1994, doi:10.1007/BF00684032) and extractions were measured using a Shimadzu UV-1800 spectrophotometer to obtain bulk concentrations of TChl-a and Bphe-a in µg/g dry sediment using a molar extinction coefficient for TChl-a and Bphe-a. A proxy-proxy calibration was carried out using an ordinary least square regression. After all, only 1.42 % and 0.77 % of datapoints are outside of the calibration ranges for Chl-a (calibration range: 12.75 – 1202.68 µg/g, intercept = -4799.52, slope= 4756,45, r² = 0.8, p-val = 0.00, RMSEP 10-fold = 169.03, RMSEP % = 14.05) and Bphe-a (calibration range 0.38 – 345.12 µg/g, intercept = -1295,8, slope= 1319,7, r² = 0.94, p-val = 0.00, RMSEP 10-fold = 25.26, RMSEP % = 7.32). Ages refer to Birlo et al. (2023) and the related dataset is Model D available via doi:10.1594/PANGAEA.949292.
Global identifier:
Doi(
"10.1594/PANGAEA.965927",
)
Measurements {
domain: Unspecified,
station: None,
measured_variables: [
"Core section label",
"Section position",
"Depth, composite",
"Calendar age, mean",
"Calendar age, minimum/young",
"Calendar age, maximum/old",
"Relative absorption band depth, 620 nm",
"Relative absorption band depth, 671 nm",
"Relative absorption band depth, 845 nm",
"Chloropigments, per unit sediment mass",
"Bacteriopheopigments, per unit sediment mass",
],
methods: [
"Calculated, based on VT22 (Birlo et al., 2023)",
"Calculated, based on VT22 (Birlo et al., 2023)",
"Calculated, based on VT22 (Birlo et al., 2023)",
"Measured",
"Measured",
"Measured",
"HSI index, calibrated",
],
}
Dataset
Origins: /Wissenschaft/PANGAEA
Tags: Kalibrierung ? Pigment ? Software ? Eifel ? Daten ? Sediment ? Hyperspektrale Fernerkundung ? HSI ? Holzmaar ? XRF ?
Region: Holzmaar
Bounding boxes: 6.883333° .. 6.883333° x 50.11667° .. 50.11667° 6.87847° .. 6.87847° x 50.11924° .. 50.11924°
License: cc-by/4.0
Language: Englisch/English
Issued: 2024-11-14
Modified: 2024-11-14
Time ranges: 2019-08-11 - 2019-08-17
Accessed 1 times.