ABSTRACT A benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate ( ε ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f –5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10 –3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate ( w s ) scaled with the friction velocity ( u * ) in the form w s / u * = D * /8. The median size of resuspended aggregates ( d f ) scaled inversely with dissipation ( ε ) in the form d f = 5 × 10 –6 ε –0.24 m , which is close to the relationship found in the literature.

ABSTRACT Sutherland, T.F.; Sterling, A.M.; Shaw, K.L.; Blasco, N.N.J., and Bradford, M.J., 2019. Detecting indicator taxa associated with benthic organic enrichment using different video camera orientations. Journal of Coastal Research, 35(2), 467–479. Coconut Creek (Florida), ISSN 0749-0208. Two video cameras mounted on a remotely operated vehicle (ROV) were used to generate paired forward-facing (FF) and downward-facing (DF) observations of benthic epifauna along 10 single transects at eight marine finfish aquaculture sites in British Columbia, Canada. The abundance of mat-forming primary indicators of organic enrichment, such as sulphide-oxidizing bacteria and opportunistic polychaete complexes (OPC), were quantified through percentage coverage estimates. Coverage estimates for sulphide-oxidizing bacteria were strongly correlated between the FF and DF orientations across all substrate types. The occurrence of OPC was limited to a single mixed-substrate site, which provided the strongest FF vs . DF relationship within this study. In contrast to sulphide-oxidizing bacteria, epifaunal abundance (count data) revealed strong relationships between camera orientations for fine sediments and mixed sediments and a weaker relationship observed for vertical rock wall environments. Similar observations occurred for estimates of both sessile (dominated by plumose anemones) and motile taxa guilds comprising the total epifaunal community. Weaker relationships associated with the rock wall substrate are likely due to alternating blackout periods experienced by each camera orientation as the ROV passes vertical or ledge habitat zones. Overall, a combination of FF and DF video orientations may provide more robust abundance estimates for settings that are characterized by various substrate grades and structural and/or mat-forming taxa.

ABSTRACT Amos, C.L.; Martino, S.; Sutherland, T.F., and Al Rashidi, T., 2015. Sea surface temperature trends in the coastal zone of British Columbia, Canada. Coastal sea surface temperature (SST), measured daily at the British Columbia (BC) Lighthouse network of stations, has been analyzed in this paper. A network of 14 of the 27 stations had (near) continuous data sets. These stations were clustered previously into exposed (northern/outer) and sheltered (southern/inner) sites. SST trends, evaluated between 1973 and 2010, show that the temperature contrast between these clusters is becoming greater: The northern/exposed stations are strongly influenced by interdecadal (Pacific Decadal oscillation [PDO]) and multidecadal oscillations in the north Pacific that are coherent with HadISST1.1 data for the region. There is no statistically significant warming trend for this region. The stations in the Strait of Georgia are much less influenced by the PDO and show a statistically significant mean increase in SST of up to 0.56°C/decade (Anomaly 1). This is higher than the global average and contrasts markedly with the trends from the northern stations. The warming trends of the southern stations are significant at all months of the year but are most evident during summer (July–September). The summertime anomalies in temperature at Active Pass are significantly correlated ( p < 0.001) with the temperature of the Fraser River water. Temperature differences between the Strait of Georgia and the outer shelf (Anomaly 2) are increasing in time; this is particularly evident since 2000. Monthly averaged MODIS satellite data (4×4-km resolution) show that trends in SST at two selected sites in the Strait of Georgia are very similar to the BC Lighthouse measurements and support the spatial extrapolation of the Lighthouse measurements. At present rates of SST rise, the southern coastal waters of BC will be about 3°C warmer by the end of the 21st century.