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Supplement to: Hatton, Jade Elizabeth; Hendry, Katharine R; Hawkings, Jonathan; Wadham, Jemma; Opfergelt, Sophie; Kohler, Tyler; Yde, Jacob; Stibal, Marek; Žárský, Jakub (2019): Silicon isotopes in Arctic and sub-Arctic glacial meltwaters: the role of the subglacial weathering in the silicon cycle. Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences, 475(2228) This data product contains dissolved and amorphous particulate silicon concentrations and isotopic compositions, and ancillary data (discharge, conductivity, suspended particulate matter, pH, major ion data) for glacial meltwaters collected from Pan Arctic and Subarctic glacial catchments.

Abundance data of the epibenthic fauna annotated on each photograph taken with the ROV Isis (NOC, UK) at a deep-sea wall located offshore the West coast of Greenland (Labrador Sea, [63°51.9'N, 53°16.9'W, depth: 703 to 803 m]). Abundances were standardized to 1 m² using the images' total area. Screenshots of the morphospecies are presented in the morphospecies guide pdf. These data were used to assess for differences in community composition analysis pooled in 20 m² samples defined according to high-resolution terrain abiotic clusters computed in an unsupervised way.

Description and NotesDescription: Methane concentration from the Greenland NEEM-2011-S1 Ice Core from 71 to 408m depth (~270-1961 CE). Methane concentrations analysed online by laser spectrometer (SARA, Spectroscopy by Amplified Resonant Absorption, developed at Laboratoire Interdisciplinaire de Physique, Grenoble, France) on gas extracted from an ice core processed using a continuous melter system (Desert Research Institute). Methane data have a 5 second integration time (raw data acquisition rate 0.6 Hz). Analytical precision, from Allan Variance test, is 0.9 ppb (2 sigma). Long-term reproducibility is 2.6% (2 sigma). Gaps in the record are due to problems during online analysis. Online analysis conducted August-September 2011.Note: Lat-Long provided is for main NEEM borehole. The NEEM-2011-S1 core was drilled 200 m distance away in 2011 to 410 m depth.Methane concentrations are reported on NOAA2004 scale (instrument calibrated on dry synthetic air standards).A correction factor of 1.079 has been applied to all data to correct for methane dissolution in melted ice core sample prior to gas extraction. Correction factor calculated using empirical data (concentrations not aligned/tied to existing discrete methane measurements).Additional methods description provided in:* Stowasser, C., Buizert, C., Gkinis, V., Chappellaz, J., Schupbach, S., Bigler, M., Fain, X., Sperlich, P., Baumgartner, M., Schilt, A., Blunier, T., 2012. Continuous measurements of methane mixing ratios from ice cores. Atmos. Meas. Tech. 5, 999-1013.* Morville, J., Kassi, S., Chenevier, M., Romanini, D., 2005. Fast, low-noise, mode bymode, cavity-enhanced absorption spectroscopy by diode-laser self-locking. Appl. Phys. B Lasers Opt. 80, 1027-01038.* NEEM (North Greenland Eemian Ice Drilling) project information http://neem.dk/ NEEM-2011-S1 CH4 outliers.Data points removed from dataset according to specified cut-off value.Please refer to Rhodes et al. (2013) for full discussion of origins outlying data points. Briefly, these high frequency features are not artifacts of the continuous method and have been replicated by traditional discrete analyses. Comparison to chemistry measurements suggests they are related to biological in situ production of methane.

We used a multibeam echosounder (Reson7125) front-mounted onto the ROV Isis (Dive D333, DY081 expedition) to map the terrain of a vertical feature marking the edge of a deep-sea glacial trough (Labrador Sea, [63°51.9'N, 53°16.9'W, depth: 650 to 800 m]). After correction of the ROV navigation (i.e. merging of USBL and DVL), bathymetry [m] and backscatter [nominal unit] were extracted at a resolution of 0.3 m and different terrain descriptors were computed: Slope, Bathymetric Position Index (BPI), Terrain Ruggedness Index, Roughness, Mean and Gaussian curvatures and orientations (Northness and Eastness), at scales of 0.9, 3 and 9 m. Using a Principal Component Analysis (PCA), the terrain descriptors enabled to retrieve 4 terrain clusters and their associated confusion index, to investigate the spatial heterogeneity of the terrain. This approach also underlined the presence of geomorphic features in the wall terrain. The extraction of the backscatter intensity for the first time considering vertical terrains, opens space for further acquisition and processing development. Using photographs collected by the ROV Isis (Dive D334, DY081 expedition), epibenthic fauna was annotated. Each image was linked to a terrain cluster in the 3D space and pooled into 20-m² bins of images. A Bray-Curtis dissimilarity matrix was constructed from morphospecies abundances. This enabled to test for differences of assemblage composition among clusters. Few species appeared more abundant in particular clusters such as L. pertusa in high-roughness cluster. However, nMDS suggested differences in assemblage composition but these dissimilarities were not strongly delineated. Whereas the design of this study may have limited distinctive differences among assemblages, this shows the potential of this cost-effective method of top-down habitat mapping to be applied in undersampled benthic habitat in order to provide a priori knwoledge for defining appropriate sampling design.

The data compilation includes the first occurrence of G. huxleyi and other species of Gephyrocapsa as revealed by Quaternary sediment samples from the world oceans. This new synthesis includes previously published data, all with rigorous relationships of their emergence events with marine isotope stages based on good quality oxygen isotope stratigraphy and/or astronomical tuning from each sediment core.

Description and NotesDescription: Methane concentration from the Greenland NEEM-2011-S1 Ice Core from 71 to 408m depth (~270-1961 CE). Methane concentrations analysed online by laser spectrometer (SARA, Spectroscopy by Amplified Resonant Absorption, developed at Laboratoire Interdisciplinaire de Physique, Grenoble, France) on gas extracted from an ice core processed using a continuous melter system (Desert Research Institute). Methane data have a 5 second integration time (raw data acquisition rate 0.6 Hz). Analytical precision, from Allan Variance test, is 0.9 ppb (2 sigma). Long-term reproducibility is 2.6% (2 sigma). Gaps in the record are due to problems during online analysis. Online analysis conducted August-September 2011.Note: Lat-Long provided is for main NEEM borehole. The NEEM-2011-S1 core was drilled 200 m distance away in 2011 to 410 m depth.Methane concentrations are reported on NOAA2004 scale (instrument calibrated on dry synthetic air standards).A correction factor of 1.079 has been applied to all data to correct for methane dissolution in melted ice core sample prior to gas extraction. Correction factor calculated using empirical data (concentrations not aligned/tied to existing discrete methane measurements).Additional methods description provided in:* Stowasser, C., Buizert, C., Gkinis, V., Chappellaz, J., Schupbach, S., Bigler, M., Fain, X., Sperlich, P., Baumgartner, M., Schilt, A., Blunier, T., 2012. Continuous measurements of methane mixing ratios from ice cores. Atmos. Meas. Tech. 5, 999-1013.* Morville, J., Kassi, S., Chenevier, M., Romanini, D., 2005. Fast, low-noise, mode bymode, cavity-enhanced absorption spectroscopy by diode-laser self-locking. Appl. Phys. B Lasers Opt. 80, 1027-01038.* NEEM (North Greenland Eemian Ice Drilling) project information http://neem.dk/ NEEM-2011-S1 CH4 no outliers.Data minus data points exceeding cut-off value. Cut-off value is 2*median absolute deviation (MAD)> 15 yr running median. Different MAD values used for 250-1000 AD and 1100-1835 AD sections of record.