DOI: 10.5285/d8369a2f-8b50-4711-b492-ae773bfafd95
title: Dissolved nutrient, carbon and algal abundance in the Dark Zone (Greenland Ice Sheet), July-August 2016

description: Dissolved inorganic and organic nutrient concentrations, dissolved organic carbon concentrations and glacier algal cell abundance are quantified for supraglacial environments in the Dark Zone of the Greenland Ice Sheet during July and August 2016. Samples include surface ice with varying degrees of visible impurities, cryoconite hole water and supraglacial stream water. Surface ice samples are comprised of the top 2 cm of a 1x1 m ice surface area. Dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON), dissolved inorganic phosphorus (DIP), dissolved organic phosphorus (DOP) and dissolved organic carbon (DOC) were quantified for all ice surface, supraglacial stream and cryoconite hole water samples collected. Glacier algae abundance was quantified for ice surface samples. Field blank corrections were conducted for all DIN, DON, DIP, DOP and DOC data. Any values resulting below the instrument limit of detection were considered to be 0. Funding was provided by the NERC 'Black and Bloom' grant NE/M021025/1 and the Marie Sklodowska-Curie grant agreement No 675546.
description: Data was gathered on the 2016 Black and Bloom field campaign and processed in LowTex Laboratory at the University of Bristol. Detailed sampling collection, processing and analysis can be found in the referenced publication. Spatial coverage: The main camp was located approximately 30 km inland from the ice margin, near to the 'S6' weather station on the K- transect. Samples were collected from a nearby designated area of approximately 500 x 500 m.
description: Instrumentation: Dissolved organic carbon was quantified using a Shimadzu TOC-L Organic Carbon Analyzer, with a high sensitivity catalyst. Dissolved nutrients were quantified using a Lachat QuickChem 8500 Series 2 Flow Injector Analyzer (FIA; QuickChem Method 31-107-06-1-I) and a Gallery Plus Automated Photometric Analyzer (Thermo Fisher Scientific, UK). Algal cell abundance was quantified using a Fuchs-Rosenthal haemocytometer (Lancing, UK) on a Leica DM 2000 epifluorescence microscope with attached MC120 HD microscope camera (Leica, Germany).
description: The LoD (limit of detection) for dissolved organic carbon (DOC) was 9.5 µM. Precision was +/-2.4% and accuracy was -5.9%. LoD were 0.14 µM for nitrite (NO2-), 0.64 µM for total oxidized nitrogen (TON) and 0.87 µM for total dissolved nitrogen/dissolved organic nitrogen (TDN/DON). Precision was +/-0.87% (NO2-), +/-1.17% (NO3-) and +/-0.63% (TDN/DON), and accuracy was - 4.04% (NO2-), -8.07% (NO3-) and -5.7% (TDN/DON). The LoD was 0.02 µM for phosphate and total dissolved phosphorus/dissolved organic phosphorus (PO43- and TDP/DOP). Precision was +/-1.6% (PO43-) and +/-3.1% (TDP/DOP), and accuracy was +2.3% (PO43-) and +5.0% (TDP/DOP). All measurements below the LoD were considered to be 0 for all statistical analyses. All dissolved inorganic nitrogen (DIN), DON, dissolved inorganic phosphorus (DIP), DOP and DOC data were water blank-corrected using values from the respective field procedural blanks. Additionally, all blank corrected values that were negative were assumed to be 0 for all statistical analyses.