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The ecology of anthropogenic litter (AL) (i.e., trash) in marine ecosystems is a growing field of research. Freshwater and marine ecosystems have similar AL densities, but research on the assemblage and accumulation rates of AL in freshwater environments is less common. We studied AL accumulation at Pratt beach, located on Lake Michigan in Chicago, IL, USA. The beach has a concrete pier at the south end, with two areas of grass bisected by a walking path. Pratt beach receives many daily visitors, but unlike other urban beaches, it has no daily municipal beach grooming. We established five 60 m transects parallel to the shoreline, with increasing distance to the shoreline. Each transect was divided into four habitat zones (i.e., pier, south vegetation, path, and north vegetation). All AL within 1 m of each transect was collected biweekly from March‐November 2015. AL density (No. m−2) and input rate (No. m−2 day−1) were highest at the pier, regardless of distance from the shoreline. Fall had the highest AL density relative to spring or summer. We concluded AL inputs at the pier were dominated by direct littering and the retention of wind‐ and wave‐blown AL at the pier's wall. The study beach had much higher AL than adjacent beaches which received municipal AL cleaning, suggesting cleaning is effective at reducing AL density. This study suggests that, given the mobile nature of AL by natural processes, infrequent sampling may underestimate total AL abundance. Management efforts for AL should be directed towards the greatest AL accumulation sites within a beach, and at prevention of direct littering from visitors.

High-frequency water quality measurements in streams and rivers have expanded in scope and sophistication during the last two decades. Existing technology allows in situ automated measurements of water quality constituents, including both solutes and particulates, at unprecedented frequencies from seconds to subdaily sampling intervals. This detailed chemical information can be combined with measurements of hydrological and biogeochemical processes, bringing new insights into the sources, transport pathways, and transformation processes of solutes and particulates in complex catchments and along the aquatic continuum. Here, we summarize established and emerging high-frequency water quality technologies, outline key high-frequency hydrochemical data sets, and review scientific advances in key focus areas enabled by the rapid development of high-frequency water quality measurements in streams and rivers. Finally, we discuss future directions and challenges for using high-frequency water quality measurements to bridge scientific and management gaps by promoting a holistic understanding of freshwater systems and catchment status, health, and function.

No abstract

Anthropogenic litter (i.e., trash, AL) on beaches has negative ecological and economic impacts. Beach AL is likely moved together with coarse particulate organic matter (CPOM, algae, leaves), but no previous studies have assessed AL and CPOM co-distribution. We measured AL and CPOM on four urban beaches in Chicago, Illinois, USA, along two transect types (pier-adjacent, non-pier adjacent) in which each has three habitats (upland, beach, strand line). As expected, AL and CPOM density were positively related across all transects. AL and CPOM were significantly higher adjacent to piers, and variable among habitats. Wood, leaves, and smoking-related AL were most abundant in beach and upland zones while glass and algal detritus were abundant at the strandline. Overall, AL and CPOM show ‘patchy’ distribution attributed to wind and wave movement toward accumulation sites. Beach CPOM is a hot spot of biological activity (e.g., microbes, invertebrates, birds). Therefore, mixing of AL and CPOM suggests organisms may be more likely to encounter AL in mixed accumulations. Efforts to reduce the abundance and biological impacts of beach AL will benefit from emphasizing organic matter accumulation sites.