Sampling and Analytical Methodology:

Samples were obtained during the drift phase (13 August- 1 September 2008) of the international ASCOS field campaign to the high Arctic Ocean. Surface microlayer samples were obtained with battery-operated catamaran-type vessels fitted with a rotating drum covered with a thin sheet of sodium-in-liquid-ammonia-edged (hydrophilic) Teflon film (Matrai et al. 2008). The depth of the SML sampled ranged from 2 to 41 μm. We performed SSWW sampling with acid-cleaned bottles rinsed in distilled deionised water (18 M?) at < 30 cm below the surface microlayer.

DMS and DMSP were measured with cryotrapping and gas chromatography with flame photometric detection. The dissolved fraction was obtained by gravity filtration and low volume sampling, through a Whatman GF/F filter that retained the particulate fraction (Matrai and Keller 1993).

Chlorophylls were determined according to Holm-Hansen et al. (1965).

Bulk carbohydrates (d-MCHO, d-PCHO) were quantified with the TPTZ protocol (Hung et al. 2001, 2003).

Total organic carbon samples were collected in acid-cleaned containers and stored frozen, until analysis by high temperature combustion (Knap et al. 1996), calibrated with DOC Certified Reference standards.

Particulate organic carbon and nitrogen were quantified in material collected on Whatman GF/F glass fiber filters stored frozen until laboratory analysis (Knap et al. 1996).
Individual amino acids were determined on 0.2 µm-filtered samples, with acid hydrolysis and separation achieved by using reverse phase HPLC with precolumn OPA derivitization (Mopper & Dawson 1986, Keil and Kirchman 1991).

Proteins were determined in the particulate phase, after filtration with a Whatman GF/F glass filber filter (Dortch et al. 1984, Clayton et al. 1988).

Phytoplankton and bacterioplankton were enumerated with flow cytometry (Sieracki et al. 1999), after fixation with 0.5% paraformaldehyde, flash-freezing in liquid nitrogen, and storage at -80oC.

Clayton J J, Dortch Q, Thoresen S, Ahmed S (1988) Evaluation of methods for the separation and analysis of proteins and free amino acids in phytoplankton samples. J Plankton Res 10: 341-358. [proteins]

Dortch Q, Clayton J R J, Thoresen S S, Ahmed S I (1984) Species differences in accumulation of nitrogen pools in phytoplankton. Mar Biol 81: 237-250. [proteins]

Holm-Hansen O, CJ Lorenzen, RW Holmes and JDH. Strickland. 1965. Fluorometric determination of chlorophyll. Journal du Conseil. Conseil International pour l'Exploration de la Mer 30 : 3-15.
Hung C-C et al. (2003) Distributions of carbohydrate species in the Gulf ofMexico. Mar Chem 81: 119-135. [polysacharides]

Hung C-C, Tang D, Warnken K, Santschi P H (2001) Distributions of carbohydrates, including uronic acids, in estuarine waters of Galveston Bay. Mar Chem 73: 305- 318. [mono, polysacharides]

Keil R, Kirchman D (1991) Dissolved combined aminoacids in marine waters as determined by a vapor-phase hydrolysis method. Mar Chem 33: 243-259. [aminoacids]

Knap A et al. (1996) Protocols for the Joint Global Ocean Flux Study (JGOFS) Core Measurements. [POC, PON, TOC, TN]

Matrai P A, Keller M D (1993) Dimethylsulfide in a large-scale coccolithophore bloom in the Gulf of Maine. Cont Shelf Res 13: 831-843. [DMS, DMSP]

Matrai, P. A., Tranvik, L., Leck, C. & Knulst, J. Are high Arctic microlayers a potential source of aerosol organic precursors? Mar. Chem. 108, 109-122 (2008). [microlayer sampling]

Mopper K, Dawson R (1986) Determination of amino acids in seawater - Recent chromatographic developments and future directions. Sci Total Environ 49: 115-131. [amino acids]

Sieracki, M., T. Cucci, and J. Nicinskihttp://aem.asm.org/content/65/6/2409.abstract - aff-1 (1999). "Flow cytometric analysis of 5-cyano-2,3-ditolyl tetrazolium chloride activity of marine bacterioplankton in dilution cultures." Applied and Environmental Microbiology 65(6): 2409-2417. [phytoplankton and bacterial counts]

Biology.csv