Seasonal dynamics of marine litter along the Bulgarian Black Sea coast

Spatial trends and drivers of marine debris accumulation on shorelines in South Eleuthera, The Bahamas using citizen science

This study measured spatial distribution of marine debris stranded on beaches in South Eleuthera, The Bahamas. Citizen science, fetch modeling, relative exposure index and predictive mapping were used to determine marine debris source and abundance. Citizen scientists quantified debris type and abundance on 16 beaches within three coastal exposures (The Atlantic Ocean, Great Bahama Bank and The Exuma Sound) in South Eleuthera. Marine debris, (~2.5 cm or larger) on each beach was monitored twice between March-May and September-November 2013 at the same locations using GPS. Approximately, 93% of all debris items were plastic with plastic fragments (≤2.5 cm) being the most common. There were spatial differences (p ≤ 0.0001) in plastic debris abundance between coastal exposures. Atlantic Ocean beaches had larger quantities of plastic debris by weight and by meter (m) of shoreline. Stranded plastic may be associated with Atlantic Ocean currents associated with leakage from the North Atlantic sub-tropical gyre.

Marine litter accumulation along the Bulgarian Black Sea coast: Categories and predominance

Quantitative assessment of marine litter (ML) along the Bulgarian Black Sea coastline was presented. ML surveys were conducted every season in a total of 8 beach monitoring sites during 2015-2016. Eight main categories of material were determined, based on standard OSPAR monitoring protocol. Annual accumulation of 19,805 nos. was recorded. The highest was the quantity of items related to artificial polymer materials category - 16,690 nos. The most dominant in this category were cigarette butts and filters - 4496 nos., followed by plastic caps/lids drinks - 1413 nos. and cups and cup lids - 1194 nos. The highest was the abundance of most of the litter during the summer period, related to the increased number of beach visitors, numerous temporarily working fast - food eateries, some big and small restaurants and cafes in close proximity to the beaches, as well as fishing, wild camping, etc. The contribution of ML types to the coastal pollution, presented by number and weight of items was determined. The highest was the contribution (by number) of cigarette butts and filters - 29.7%, followed by plastic caps/lids of beverages - 9.4%; plastic cups and cup lids - 7.9%, etc. According to the weight drink bottles > 5 L exhibited highest percentage - 30.7%, followed by shopping bags incl. pieces - 15.5% and drink bottles ≤ 0.5 L - 13.2%. The ML accumulation, presented by number and weight gives more detailed information about litter characteristics, the levels of coastal pollution and improves ML management.

A novel GIS-based tool for predicting coastal litter accumulation and optimising coastal cleanup actions

Effective site selection is a key component of maximising debris removal during coastal cleanup actions. We tested a GIS-based predictive model to identify marine litter hotspots in Lofoten, Norway based on shoreline gradient and shape. Litter density was recorded at 27 randomly selected locations with 5 transects sampled in each. Shoreline gradient was a limiting factor to litter accumulation when >35%. The curvature of the coastline correlated differently with litter density at different spatial scales. The greatest litter concentrations were in small coves located on larger headlands. A parsimonious model scoring sites on a scale of 1-5 based on shoreline slope and shape had the highest validation success. Sites unlikely to have high litter concentrations were successfully identified and could be avoided. The accuracy of hotspot identifications was more variable, and presumably more parameters influencing litter deposition, such as shoreline aspect relative to prevailing winds, should be incorporated.

How microplastics quantities increase with flood events? An example from Mersin Bay NE Levantine coast of Turkey

Floods caused by heavy rain carry significant amounts of pollutants into marine environments. This study evaluates the effect of multiple floods that occurred in the northeastern Mediterranean region in Turkey between December 2016 and January 2017 on the microplastic pollution in the Mersin Bay. Sampling was repeated in four different stations both before and after the flood period, and it was determined that in the four stations, there was an average of 539,189 MPs/km² before the flood, and 7,699,716 MPs/km² afterwards, representing a 14-fold increase. Fourteen different polymer types were detected in an ATR FT-IR analysis, eight of which were not found in samples collected before the floods. The most common polymer type was identified as polyethylene both pre- and post-flood. The mean particle size, which was 2.37 mm in the pre-flood period, decreased to 1.13 mm in the post-flood period. A hydrodynamic modeling study was implemented to hindcast the current structure and the spatial and temporal distributions of microplastics within the study area. In conclusion, heavy rain and severe floods can dramatically increase the microplastic levels in the sea.

A modeling approach for reposition dynamics of litter composition in coastal areas of the city of Santos, Sao Paulo, Brazil

Given the complexity of the dynamics in litter reposition, our objective was modeling the possible main and interaction effects of tidal oscillations, seasons of the year and the moon phases over the solid waste in Santos beaches. A total of 80 collections were carried out using quadrat sampling, from which we classified, counted and weighed all residue items. We fitted mixed Hurdle models to the output datasets and performed hypotheses tests based on this framework. We found plastic to be the most abundant residue in all seasons, moon phases and tides, followed by Styrofoam and wood. Our models suggest the strongest effect was due to seasonal variations, which, in turn, may be related to different human activities. Although the dynamics of different components showed independency of all interaction structures, plastics depended on the interaction of tide and season, whose impact over estuarine life and ecosystem services shall be further investigated.