DOI: 10.5061/dryad.0k6djhb7w
title: Data from: Isotopic composition of particulate black carbon in the northern Indian Ocean

description: The dataset contains the concentration and stable isotopic composition of
 particulate black carbon (PBC) in the surface waters of the northern
 Indian Ocean. Samples were collected during multiple cruises to the
 Northern Indian Ocean (locations, date and time are provided in the
 datasheet) along with end member sampling of riverine particulate. Surface
 water samples were filtered onto 0.7 micron GF/F filters (precombusted at
 400 degree Celsius) and oven-dried. Particulate black carbon was estimated
 following the chemothermal oxidation (CTO - 375) method. Briefly, samples
 were treated using HCl fumes to remove inorganic carbon fractions followed
 by heating at 400 degree celsius for 24 hours in active airflow to remove
 the organic carbon fraction. The residual carbon (BC in micromoles per
 litre) and its isotopic composition (represented by delta notation in
 permil) was measured using an elemental analyzer (EA: Flash 2000, Thermo
 Scientific) connected to an isotope ratio mass spectrometer (IRMS: Delta
 V, Thermo Scientific). The precision of measurement by repeated analysis
 of standards was better than 10 % for PBC concentration and 0.1 permil for
 its isotopic composition. The data is associated with the manuscript
 accepted in Geophysical Research Letters titled, 'Isotopic evidence
 for degradation of particulate black carbon in the ocean.
description: Samples were collected during multiple cruises to the Northern
 Indian Ocean (locations, date and time are provided in the data sheet)
 along with end member sampling of riverine particulate. Surface water
 samples were filtered onto 0.7 micron GF/F filters (precombusted at 400
 degree celcius) and oven dried. Particulate black carbon was estimated
 following the chemothermal oxidation (CTO - 375) method. Briefly samples
 were treated using HCl fumes to remove inorganic carbon fractions foloowed
 by heating at 400 degree celcius for 24 hours in active airflow to remove
 the organic carbon fraction. The residual carbon (BC in micro moles per
 litre) and its isotopic composition (represented by delta notation in
 permil) was measured using an elemental analyzer (EA: Flash 2000, Thermo
 Scientific) connected to an isotope ratio mass spectrometer (IRMS: Delta
 V, Thermo Scientific). The precision of measurement by repeated analysis
 of standards was better than 10 % for PBC concentration and 0.1 permil for
 its isotopic composition.
description: # Data from: Isotopic composition of particulate black carbon in the
 northern Indian Ocean
 [https://doi.org/10.5061/dryad.0k6djhb7w](https://doi.org/10.5061/dryad.0k6djhb7w) The dataset contains the concentration and stable isotopic composition of particulate black carbon (PBC) in the surface waters of the northern Indian Ocean. Samples were collected during multiple cruises to the Northern Indian Ocean (locations, date and time are provided in the datasheet) along with end member sampling of riverine particulate. Surface water samples were filtered onto 0.7 micron GF/F filters (precombusted at 400 degree celsius) and oven-dried. Particulate black carbon was estimated following the chemothermal oxidation (CTO - 375) method. Briefly, samples were treated using HCl fumes to remove inorganic carbon fractions followed by heating at 400 degree celsius for 24 hours in active airflow to remove the organic carbon fraction. The residual carbon (BC in micromoles per litre) and its isotopic composition (represented by delta notation in permil) was measured using an elemental analyzer (EA: Flash 2000, Thermo Scientific) connected to an isotope ratio mass spectrometer (IRMS: Delta V, Thermo Scientific). The precision of measurement by repeated analysis of standards was better than 10 % for PBC concentration and 0.1 permil for its isotopic composition. The data is associated with the manuscript accepted in Geophysical Research Letters titled, 'Isotopic evidence for degradation of particulate black carbon in the ocean.' ## Description of the data and file structure The file contains latitude, longitude, date and time of sampling at each sampling locations in the Arabian Sea, Bay of Bengal, Andaman Sea, Andaman Creeks, Mahanadi Estuary, Sabarmati, Mahi and Ambika River along with the respective concentration and isotopic composition of particulate black carbon (PBC), total particulate organic carbon (PBC+POC) and particulate organic carbon (POC). Missing data code- "NA"