DOI: 10.5285/260b15b1-f814-4941-84cd-9cd94f386f33
title: Vertical luminophore particle tracer profiles expressed as relative counts for replicate macrofaunal communities from the Western Barents Sea in summer 2017 and 2018

description: Macrofaunal mediated redistribution of optically distinct particulate tracers (luminophores) for intact communities from the western Barents Sea after 12 days incubation. Tracer profiles are quantified from stitched composite images of all four sides of each aquarium taken using a digital SLR camera housed within a UV illuminated imaging box. Counts are expressed as relative counts (proportion of the total). Samples were collected on cruises JR16006 and JR17007. Funding was provided by 'The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems' project (NE/N015894/1 and NE/P006426/1, 2017-2021), part of the NERC funded Changing Arctic Ocean programme.
description: Data were collected from each of 5 stations in 2017 (B13-B17) and 6 stations in 2018 (B13-B17 and Xs) during two consecutive cruises (RRS James Clark Ross: JR16006, 30th June to 8th August, 2017; JR17007: 10th July to 5th August, 2018) following a transect along the 30°E meridian. At each station four replicate intact sediment cores (LWH: 20 x 20 x 12 cm) were obtained from replicate 0.1m2 USNL (Unites States Naval Laboratory) box cores using a core extruder, transferred to transparent acrylic aquaria (internal dimensions, LWH: 20 x 20 x 34 cm) and overlain with ~8 L (20cm depth) surface seawater (salinity, ~34). Aquaria (2017, n = 20; 2018, n = 24) were randomly transferred to one of two insulated fibreglass seawater baths (LWH: 1.2 x 1.2 x 0.8m, Tanks Direct, UK) and maintained at a representative ambient bottom temperature in the dark. Faunal mediated sediment particle reworking was estimated by establishing the redistribution of optically distinct particulate tracers (luminophores: 215g aquaria-1, fluorescent green, &lt;200µm silica sand, density 2.35 kg dm-3; Glass Pebbles Ltd., UK). Luminophores were evenly distributed across the sediment surface immediately after the partial seawater change. After 12 days, the redistribution of luminophores was quantified from stitched composite images (RGB colour, JPEG compression) of all four sides of each aquarium taken using a digital SLR camera (Canon 400D: 2017, 10 s exposure, f5.6 aperture, ISO 400, 83 µm pixel-1; 2018, 10 s exposure, f5.6 aperture, ISO 800, 74 µm pixel-1) housed within a UV illuminated imaging box. Extracted profile data was obtained using a custom-made semi-automated macro that runs in ImageJ (version 1.47s, released 3rd June, 2013), a java-based public domain program developed at the US National Institutes of Health (http://rsb.info.nih.gov/ij/index.html). Resolution: Counts were extracted from digital images, realised camera resolution of 83 µm pixel-1 in 2017 and 74 µm pixel-1 in 2018.
description: Software: ImageJ (version 1.47s)
description: Counts were extracted from digital images with a resolution of 83 µm pixel-1 in 2017 and 74 µm pixel-1 in 2018. Images were cleaned using Adobe Photoshop CS6 to remove highly reflective dust particles, cloth filaments or other non-luminophore pixels. Relative counts are calculated from stitched images of 4 sides of an aquarium except for stations B13 (aquarium #2), B14 (aquarium #4) and B15 (aquarium #3) in 2017 which were calculated from 3 sides of an aquarium following an unrecoverable file corruption on a subset of images during transfer.