Sutherland, T.F.; Garcia-Hoyos, L.M.; Poon, P.; Krassovski, M.V.; Foreman, M.G.G.; Martin, A.J., and Amos, C.L., 2018. Seabed attributes and meiofaunal abundance associated with a hydrodynamic gradient in Baynes Sound, British Columbia, Canada.
The distribution of seabed geotechnical, biochemical, and meiofauna attributes was examined in Baynes Sound, British Columbia, between 2009 and 2014. Among attributes measured were sediment porosity, organic carbon and nitrogen, and trace element concentrations (e.g., zinc, copper), which increased with increasing sediment fines content toward the head of the Sound. A ternary plot (sand-silt-clay percentages) revealed a constant clay/silt ratio across a range of sand proportions with textures ranging from well-sorted sand at the high-energy SE entrance to silt-dominated mud in the depositional basin. These sediment textures were related to modeled maximum velocity values within 5 m of the seabed (Umax,5), with highest values (restricted entrance) and lowest values (deep basin) representing sand depositional and mud depositional facies. Sediment porewater sulfide fell into an oxic category (0–700 μM), exhibiting a lack of variation and organic enrichment within the Sound. The first principal component analysis (PCA) factor described the alignment between fine sediments, organics, Cu and Zn, and meiofauna attributes and accounted for 49% of the total variance. The second PCA factor (19% of total variance) described the relationship between Umax,5 and sediment grain size fractions >0.5 mm and an indirect association with water depth and fine sand (0.105–0.250 mm). Meiofauna were associated with a medium sand fraction (0.25 mm) characterized by low-porosity and low-organic sand loam textures. Although the range in abundance was relatively greater for nematodes, harpacticoid copepods revealed a stronger response to changes in sediment geotechnical and organic attributes, suggesting these taxa may be used to describe seabed variations or potential perturbations.