Spatio-temporal distribution of floating objects in the German Bight (North Sea)

Abstract

Floating objects facilitate the dispersal of marine and terrestrial species but also represent a major environmental hazard in the case of anthropogenic plastic litter. They can be found throughout the world's oceans but information on their abundance and the spatio-temporal dynamics is scarce for many regions of the world. This information, however, is essential to evaluate the ecological role of floating objects. Herein, we report the results from a ship-based visual survey on the abundance and composition of flotsam in the German Bight (North Sea) during the years 2006 to 2008. The aim of this study was to identify potential sources of floating objects and to relate spatio-temporal density variations to environmental conditions. Three major flotsam categories were identified: buoyant seaweed (mainly fucoid brown algae), natural wood and anthropogenic debris. Densities of these floating objects in the German Bight were similar to those reported from other coastal regions of the world. Temporal variations in flotsam densities are probably the result of seasonal growth cycles of seaweeds and fluctuating river runoff (wood). Higher abundances were often found in areas where coastal fronts and eddies develop during calm weather conditions. Accordingly, flotsam densities were often higher in the inner German Bight than in areas farther offshore. Import of floating objects and retention times in the German Bight are influenced by wind force and direction. Our results indicate that a substantial amount of floating objects is of coastal origin or introduced into the German Bight from western source areas such as the British Channel. Rapid transport of floating objects through the German Bight is driven by strong westerly winds and likely facilitates dispersal of associated organisms and gene flow among distant populations.

Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles

“…Thus it could be suggested that most of the collected microplastics were exposed long enough to the marine environment to get brittle and be transported over long distances. Thiel et al (2011) reported hotspots of accumulating microplastics in the North Sea and a rapid transport through the German Bight due to strong westerly winds. In contrast, based on the relationship between litter accumulation on Helgoland beaches and southerly winds, Vauk and Schrey (1987) suggested that these winds might push anthropogenic debris from source regions which results in accumulation on local beaches.…”

Microplastics Baseline Surveys at the Water Surface and in Sediments of the North-East Atlantic

“…It seems that for the floating microplastic particles there is a potential influence from rivers. Rivers are both pathways and producers of microplastics (Thiel et al, 2011;Rech et al, 2014). A study on microplastics in European rivers indeed found that fragments (Po and Rhine) and fibers (Danube and Dalålven) were the largest part of the microplastics found (van der Wal et al, 2015).…”

Latitudinal and seasonal effects on short-term acclimation of floating kelp species from the South-East Pacific

“…Floating patches of various seaweed species occur throughout the world´s oceans, although they are most abundant in temperate and cold waters of both hemispheres (30°-60°) (Kingsford, 1992;Hinojosa et al, 2010Hinojosa et al, , 2011Thiel et al, 2011;Rothäusler et al, 2012). Longdistance rafting of buoyant, brown seaweeds contributes to the dispersal of marine biota (Edgar, 1987;Thiel and Gutow, 2005;Fraser et al, 2011).…”