In this work, samples were collected from the Argentinean continental shelf –including a Marine Protected Area (MPA) - to assess the occurrence and distribution of synthetic microfibers (MFs), a widespread type of microplastic. MFs were present at 100% of the samples showing an average concentration of 182.85 ± 115.14 particles per Kg of dry sediment and 0.14 ± 0.08 items per m3 of marine water. MFs less than 1 mm were the most abundant (56.4% and 63%, for sediment and surface seawater respectively), followed by 1–2 mm and then 2–3 mm. In regards to the colour, both sediments and water had the major percentage of black MFs (25.6% and 28%, respectively) and the lowest one of green MFs (2.5% and 3%, respectively). Finally, MFs content in sediments was inversely correlated with depth (r = -0.93, p < 0.05). These findings provide the first evidence of microplastic contamination at the Argentinean continental shelf.
Pollution and Marine Debris
Human activities lead to several impacts on marine ecosystems, among which a massive input of plastic entering the marine environment. This scenario has the potential to threaten ecosystem health and integrity, also reducing the ability of marine ecosystems to provide good and services on which human well-being relies. In this study, the global scientific literature on marine microplastics was explored by combining social network analysis and bibliometrics. Network maps displayed the relationships among keywords, authors, countries, and journals dealing with the issue of microplastics in marine ecosystems. The citation analysis of journals showed that “Marine Pollution Bulletin” resulted the first among the scientific journals publishing articles on this subject. The results also highlighted that most research on the subject is focused on toxicology and environmental chemistry, while ecological studies focusing on the impact of microplastics at ecosystem level are still limited.
On the Colombian continental shelf, 12 km SW of the municipality of Galerazamba, Department of Bolívar, is the northern-most island of the Colombian Caribbean: Isla Arena. Despite being remote and uninhabited, this island is being affected by one of the most persistent problems in the marine environment: Marine Anthropogenic Litter (MAL). In this first Colombian insular MAL study, a total of 1436 MAL items were collected along Isla Arena, equivalent to an average abundance of 2.87 items/m2. MAL items belong to 54 categories that are grouped in nine material typologies. These typologies include plastic (36 categories), metal (6), glass (3), medical waste (3), machined wood (2), pottery (1), sanitary waste (1), rubber (1) and cloth (1). Isla Arena now is considered as an “Extremely dirty” site in terms of the Clean Coast Index. Hazardous litter items (sharp and toxic) occur in percentages as high as 10.2% (146 items, Avg: 0.29 items/m2). Along the island, current MAL amounts are so elevated that simple clean-up operations are an insufficient solution, and restoration measures are needed. MAL mainly comes from land-based sources, primarily generated by activities in the adjacent mainland river basins and coastal urban developments, particularly in the area of beaches. Marine anthropogenic litter found on Isla Arena reflects a strong influence from longshore-current transport. Management solutions need to begin at the same litter sources, and must include analytics, policy reforms and enforcement, and private and public investments.
The oil spill accidents may drastically impact the environment and ecosystem at intertidal zones. The spilled oil will penetrate the sediments and accumulate to cause lethal or sublethal effects on the benthic invertebrates. An M-BACI experiment was manipulated in situ to assess the ecological responses of benthic macrofauna to different degrees of diesel oil spill. Both biotic and abiotic parameters were studied for 126 days, subjected to both “pulse” and “press” oil contaminations. The content of aliphatic hydrocarbons (displayed as ratios of n-C17/Pr and n-C18/Ph) slightly dropped then continuously existed in the sediment during the experiment time. The macrofaunal assemblage structures were dramatically altered in species number, abundance and biomass. In general, it takes longer time for the macrofauna assemblages to recover under high concentration oil spill than that under low concentration. Our results highlight the diversified strategies for survival and recolonization among dominant species, which distinguish themselves between: i) tolerant species, ii) opportunistic species, and iii) equilibrium species.
In this study, we assessed plastic accumulation in marine sediments due to finfish aquaculture using floating net-pens. We studied plastic concentrations around three fish farms located at the Mediterranean coastline of Spain. The macroplastic categories and abundances were determined by video monitoring, detecting the majority of elements (78%), including ropes, nets and fibres, a basket trap and a cable tie, close to the facilities, which were not exclusively linked to fish farming but also to fishing activities. Concentrations of microplastics (<5 mm) ranged from 0 to 213 particles/kg dry weight sediment with higher values in sites directly under the influence of the fish farms. Most particles (27.8%) were within the size fraction from 1.1 to 2.0 mm and fibre was the most common shape with 62.2%. The Infrared spectroscopy analysis showed that PE and PP were the predominant types of polymers analysed. In addition, changes in the enthalpy of melting (ΔHm (J/g)) and the degree of crystallinity indicate degradation of the microplastics analysed. This study shows that, in the studied fish farms, levels of microplastic pollution can be one order of magnitude lower compared to other areas suffering other anthropogenic pressures from the same or similar regions. Nevertheless, more research effort is needed to get concluding results.
Rivers transport land-based plastic waste into the ocean. Current efforts to quantify riverine plastic emission come with uncertainty as field observations are scarce. One of the challenging aspects is the lack of consistent measurement methods that allow for comparing rivers over space and time. Recent studies have shown that simple visual observations provide a robust first-order characterization of floating and superficially suspended plastic transport, both in quantity, spatiotemporal distribution and composition. For this study, we applied this method to the river Seine, France, to provide new insights in the spatiotemporal variation in riverine plastic transport. First, we studied the response of plastic flow to increased river discharge by comparing measurements taken during low flow and high flow periods. Second, we investigated the variation of riverine plastic transport over the river length to improve our understanding of the origin and fate of riverine plastics. We demonstrate that during a period with higher river discharge, plastic transport increased up to a factor ten at the observation point closest to the river mouth. This suggests that the plastic emission into the ocean from the Seine may also be considerably higher during increased discharge. Upstream of Paris plastic transport increased only with a factor 1.5, suggesting that most plastics originate from Paris or areas further downstream. With this paper we aim to shed additional light on the seasonal variation in riverine plastic transport and its distribution along the river length, which may benefit future long-term monitoring efforts and plastic pollution mitigation strategies.
Marine litter is a worldwide problem. It impacts negatively marine environment, organisms, human health and coastal communities. In this research, abundance, composition and sources of marine litter (macro-debris > 2.5 cm) and beach cleanliness were assessed for three beaches in the central Croatian Adriatic Sea. Mean abundance for the studied region was 3.35 items/m2 and the highest recorded CCI value was 150. Most of the collected litter was made of artificial polymer material (93.86%), and main sources of litter were shoreline activities representing (31.68% of the total sample) and fishing and aquaculture representing (12.66% of the total sample). Land-based and sea-based sources accounted for 32.76% and 15.16%, respectively. Results from the present study provide another evidence of marine litter problem and high presence of plastic items in the marine environment of the Adriatic Sea. Presence of litter from different countries shows the internationality of marine litter problem which can only be solved by international collaborations and partnerships as well as by taking individual responsibility of all. Presence of the short-life single-use plastic items and the problems associated with them have been recognized in this study as most of the items collected were single-use items. High abundance of these items indicates not only their large use in everyday life, but also the lack of awareness of the general public about the environmental problem they cause. Moreover, the results obtained in this research imply the need for better waste management systems.
Designing effective policy interventions to motivate mitigation actions requires more realistic assumptions about human decision-making based on empirical evidence from the behavioural sciences. We therefore need to consider behavioural rather than only economic costs and benefits in policy intervention designs.
Microplastic pollution is a growing cause of concern for the marine environment, particularly in the Mediterranean Sea, which is considered to be one of the most polluted seas worldwide. In this study, the gastrointestinal tracts of 102 bogues (Boops boops), sampled from three areas off the Catalan coast (Spain) subject to different degrees of industrialization, were analysed to assess microplastic ingestion and thus estimate local levels of microplastic pollution. Microplastics were detected in 46% of samples analysed. As expected, the abundance and frequency of occurrence of ingested microplastics were higher off the most anthropized area of Barcelona. The majority of ingested microplastics were blue fragments ranging 0.1–0.5 mm, and the most common polymer type was polypropylene. The results of this study indicate the area off Barcelona as a possible area of concentration for microplastics, further supporting the use of B. boops as a bioindicator to assess microplastic pollution.
Marine debris is distributed worldwide and constitutes an increasing threat to our environment. The exponential increase of plastic debris raises numerous concerns and has led to an intensification in plastic monitoring and research. However, global spatial and temporal patterns and knowledge gaps in debris distribution, both on land and at sea, are relatively poorly understood, mainly due to a lack of comprehensive datasets. Here we critically review the quality of the available information on beach plastic debris worldwide to highlight where the most urgent actions are required, and to promote the standardization of reporting metrics and sampling methods among researchers. From a total of 174 studies evaluated, 27.0% reported marine debris densities in metrics that were not comparable. Some studies failed to report basic parameters, such as the date of the sampling (9.8%) or the size of the collected debris (19.5%). Our findings show that current research regarding beach debris requires significant improvement and standardization and would benefit from the adoption of a common reporting framework to promote consensus within the scientific community.