Beach wrack communities within a commercially harvested coastline of the Salish Sea

Accumulations of beach-cast seaweeds and other matter, collectively known as wrack, are a common and ecologically important occurrence along coastal regions worldwide. Between the unincorporated communities of Deep Bay and Bowser, on the east coast of Vancouver Island, beach wrack is primarily composed of an introduced species of red algae called Mazzaella japonica, which became the target of a commercial beach-cast harvest in 2007. Little is known, however, about the ecological role of M. japonica in this recipient system. Furthermore, literature on the effects of harvesting beach-cast seaweed is limited. The goal of this research was therefore threefold: 1) To quantify the contribution of M. japonica to wrack inputs within the harvest region; 2) to explore how wrack characteristics influence macrofauna communities; and 3) to determine if the commercial removal of beach-cast seaweeds has a detectable effect on wrack characteristics and macrofauna community structure. To answer these questions we monitored a series of permanent transects at six sites across the harvest region, from November 2014 until March 2015. We recorded as much as 853 kg (±99.8 SE) of wrack per meter of shoreline, 63 % to 82% of which was identified as M. japonica across sites. Despite the removal of 674.5 tonnes of beach-cast seaweeds, we found that the trends in wrack biomass were similar between both harvested and unharvested locations. Macrofauna communities differed significantly between study sites, as well as with the age class, depth, and total biomass of the wrack from which they were sampled

Uptake, Whole-Body Distribution, and Depuration of Nanoplastics by the Scallop Pecten maximus at Environmentally Realistic Concentrations

Previous studies of uptake and effects of nanoplastics by marine organisms have been conducted at what may be unrealistically high concentrations. This is a consequence of the analytical challenges in tracking plastic particles in organisms at environmentally relevant concentrations and highlights the need for new approaches. Here, we present pulse exposures of 14C-radiolabeled nanopolystyrene to a commercially important mollusk, Pecten maximus, at what have been predicted to be environmentally relevant concentrations (–1). Uptake was rapid and was greater for 24 nm than for 250 nm particles. After 6 h, autoradiography showed accumulation of 250 nm nanoplastics in the intestine, while 24 nm particles were dispersed throughout the whole-body, possibly indicating some translocation across epithelial membranes. However, depuration was also relatively rapid for both sizes; 24 nm particles were no longer detectable after 14 days, although some 250 nm particles were still detectable after 48 days. Particle size thus apparently influenced the biokinetics and suggests a need for chronic exposure studies. Modeling extrapolations indicated that it could take 300 days of continued environmental exposure for uptake to reach equilibrium in scallop body tissues although the concentrations would still below 2.7 mg g–1. Comparison with previous work in which scallops were exposed to nonplastic (silver) nanomaterials of similar size (20 nm), suggests that nanoparticle composition may also influence the uptake tissue distributions somewhat