Beach debris in the Azores (NE Atlantic): Faial Island as a first case study
Introduction
Marine debris is an issue of global concern since they can be found everywhere in the ocean and coastal areas. When compared to polar regions, higher concentrations have been reported in tropical and mid-latitudes (Thompson et al., 2009, Maximenko et al., 2012), particularly in shipping lanes around fishing areas and in oceanic gyre systems (Allsopp et al., 2006). They are also evident near anthropogenic waste inputs in the vicinity of densely populated places, or even in remote areas (Widmer and Hennemann, 2010), far away from any evident origin (e.g. oceanic islands and polar regions) (Ryan et al., 2009, Barnes et al., 2010, Eriksson et al., 2013).
In the last 30 to 40 years, the nature of debris ending up in the marine environment has suffered a great change due to the upturn in the use of plastics and synthetics (Leite et al., 2014). A large fraction of marine waste (60–80%) consists of plastics (Setälä et al., 2014), whose industries have globally increased from 1.5 million tonnes (1950s) to 299 million tonnes (2013) (PlasticsEurope, 2015). Consisting of long polymeric chains created from organic and inorganic raw materials, plastics are generally obtained from oil, coal and natural gas (Ivar do Sul and Costa, 2013). These result in products that are inexpensive, lightweight, durable and non-corrosive (Wright et al., 2013), but nevertheless, have strong resistance to physical/biological degradation processes (Hidalgo-Ruz et al., 2012). The environmental fate of the debris is understood to be influenced by human activities and hydrogeological factors that eventually lead to accumulation in coastal and open-ocean areas (Kukulka et al., 2012, Eriksen et al., 2013).
Marine pollution has been fairly studied in the Atlantic Ocean since the first researches in the 70s (Law et al., 2010) were predominantly done in the NW Atlantic region (e.g. Ribic et al., 2010, Ribic et al., 2011). However, there is limited information regarding plastic quantification and distribution east of the Gulf Stream (Morét-Ferguson et al., 2010), particularly around oceanic islands (Thompson et al., 2009). The Azores Islands (NE Atlantic) are located at the northern edge of the North Atlantic Subtropical Gyre (SG) – the rotor of the North Atlantic circulation. These islands are subject to very different types of ocean/atmosphere variability and ocean dynamics at diverse scales (Martins et al., 2007, Bashmachnikov et al., 2009). Therefore, near-coast circulation variability around the islands can be quite complex at times.
Although the significance of plastic marine pollution is relatively recent (Cózar et al., 2014), basic understanding about the classification, distribution, variation and fate of these debris still remains uncertain. Despite its recognised geostrategic position, in the Azores there is still very limited knowledge about the presence and quantification of marine debris in the ocean and coastal areas. Therefore, the main objectives of this pioneer study comprehended the monitoring of two sandy beaches of Faial Island (Azores, NE Atlantic) characterised by two different geographical orientations. There have been many attempts to quantify debris on shores, sea floor, water column, and on the sea surface (e.g. van Cauwenberghe et al., 2013, Hong et al., 2014), and most of the acquired knowledge (i.e. abundance, distribution and origin) initially came from surveys of stranded waste on coastlines (Ryan et al., 2009). Beach surveys are considered a key-instrument for measuring loads of marine debris in coastal and marine systems (Cheshire et al., 2009). The surveying technique applied in this research is designed as “standing-stock” assessment (Opfer et al., 2012), and is used to measure loads/concentrations of debris at a shoreline site over time. Each sampling event reflects a snapshot of the concentration of debris at the study site, and continuing snapshots over time allow information on changes in the baseline concentration of debris (Lippiatt et al., 2013). The acquired information reveals the balance between inputs (e.g. land, sea based) and removal (e.g. export, burial, degradation), and also allows for analyses of changes in debris abundances according to drivers of deposition (e.g. weather, beachgoers) (Lippiatt et al., 2013). A first analysis of the abundance, density and temporal variability of marine waste is therefore, documented for these two remote areas of the NE Atlantic.
Section snippets
Study sites
The present research took place in two beaches of the Faial Island (Azores Archipelago, Portugal). The Archipelago is located in the central northeast Atlantic (36–40°N, 24–32°W) and consists of nine islands, clustered into three groups (oriental — two islands, central — five islands, and occidental — two islands), the island of Faial being a part of the central group. Monitoring locations were chosen to have similar features (e.g. sandy sediment, type of access, user profile, closeness to
Composition and temporal variability of marine debris
In total, 28,261 items of debris were found on the monitored beaches. The debris items were composed of plastics (26,321 items, 93.14%), glass (1388 items, 4.91%), rubber (235 items, 0.83%), cloths/fabric (93 items, 0.33%), metal (72 items, 0.25%), processed lumber (58 items, 0.21%), and others (65 items, 0.23%). The category large was considered nearly absent, since only 29 items (0.10%) were counted throughout the survey period (Table 1). We recorded 5756 counts at Conceição and 22,505 counts
Discussion
This research represents the first assessment of beached marine debris in the Azores Archipelago. It is of particular interest to study how marine pollution affects these remote oceanic islands, since plastic items were permanently present.
Acknowledgements
The authors would like to thank professors and colleagues at both Departments (Oceanography and Fisheries and Biology) at the University of the Azores for helpful discussions during the development of this research. Special thanks go to Ricardo Medeiros from ImagDOP for generating the study area map. The comments and suggestions of the editor and two anonymous referees are also greatly appreciated. Computer logistics and facilities were provided by Department of Oceanography and Fisheries at
References (55)
Microplastics in the marine environment
Mar. Pollut. Bull.
(2011)- et al.
Macroplastics at sea around Antarctica
Mar. Environ. Res.
(2010) - et al.
Anthropogenic debris on beaches in the SE Pacific (Chile): results from a national survey supported by volunteers
Mar. Pollut. Bull.
(2009) - et al.
Tracking the sources and sinks of local marine debris in Hawaii
Mar. Environ. Res.
(2013) - et al.
Plastics and beaches: a degrading relationship
Mar. Pollut. Bull.
(2009) - et al.
Ideal width of transects for monitoring source-related categories of plastics on beaches
Mar. Pollut. Bull.
(2006) - et al.
Amount and distribution of neustonic micro-plastic off the western Sardinian coast (central-western Mediterranean Sea)
Mar. Environ. Res.
(2014) - et al.
Plastic pollution in the South Pacific subtropical gyre
Mar. Pollut. Bull.
(2013) - et al.
Daily accumulation rates of marine debris on sub-Antarctic island beaches
Mar. Pollut. Bull.
(2013) - et al.
Strategy for mitigation of marine debris: analysis of sources and composition of marine debris in northern Taiwan
Mar. Pollut. Bull.
(2014)
Macrodebris and microplastics from beaches in Slovenia
Mar. Pollut. Bull.
Influence of proximity to an urban center in the pattern of contamination by marine debris
Mar. Pollut. Bull.
Pathways of marine debris derived from trajectories of Lagrangian drifters
Mar. Pollut. Bull.
The size, mass, and composition of plastic debris in the western North Atlantic Ocean
Mar. Pollut. Bull.
Baseline study of submerged marine debris at beaches in Curaçao, West Indies
Mar. Pollut. Bull.
Marine litter in Mediterranean sandy littorals: spatial distribution patterns along central Italy coastal dunes
Mar. Pollut. Bull.
Trends and drivers of marine debris on the Atlantic coast of the United States 1997–2007
Mar. Pollut. Bull.
Baseline for beached marine debris on Sand Island, Midway Atoll
Mar. Pollut. Bull.
Ingestion and transfer of microplastics in the planktonic food web
Environ. Pollut.
Patterns of marine debris distribution on the beaches of Rottnest Island, Western Australia
Mar. Pullt. Bull
Anthropogenic marine debris in the coastal environment: a multi-year comparison between coastal waters and local shores
Mar. Pollut. Bull.
Origin and abundance of marine litter along sandy beaches of the Turkish Western Black Sea Coast
Mar. Environ. Res.
Microplastic pollution in deep-sea sediments
Environ. Pollut.
The physical impacts of microplastics on marine organisms: a review
Environ. Pollut.
The abundance, composition and sources of marine debris in coastal seawaters or beaches around the northern South China Sea (China)
Mar. Pollut. Bull.
Plastic Debris in the World's Oceans
Remote islands reveal rapid rise of Southern Hemisphere, sea debris
Sci. World J.
Cited by (45)
Understanding the sources of marine litter in remote islands: The Galapagos islands as a case study
2024, Environmental PollutionTracing beach litter sources: Drink lids tell a different story from their bottles
2024, Marine Pollution BulletinIllegal dumping from ships is responsible for most drink bottle litter even far from shipping lanes
2023, Marine Pollution BulletinSocio-economic factors affecting the distribution of marine litter: The Portuguese case study
2023, Marine Pollution BulletinRelationships between marine litter and type of coastal area, in Northeast Atlantic sandy beaches
2023, Marine Environmental ResearchCitation Excerpt :Considering that the most effective measure to reduce this problem is to identify its origin and reduce it (Araújo et al., 2006), linking the marine debris to their origin is an extremely difficult task that can only be achieved by monitoring programmes. Surveys conducted in Portugal have assessed submarine canyons (Mordecai et al., 2011), seamounts (Pham et al., 2013), floating litter (Sá et al., 2016), microplastics (Pequeno et al., 2021), and beaches (Frias et al., 2011; Pieper et al., 2015). The vulnerability of the coast of Portugal to the accumulation of plastic on beaches (both from land and sea origins) has been highlighted (Martins and Sobral, 2011).
Synthetic microplastic abundance and composition along a longitudinal gradient traversing the subtropical gyre in the North Atlantic Ocean
2022, Marine Pollution BulletinCitation Excerpt :Effectively addressing the issue of marine plastic pollution requires information on the abundance, distribution and composition of plastic. While some of the earliest accounts of plastic within the ocean are from the North Atlantic (Carpenter and Smith, 1972; Wilber, 1987), over the subsequent decades, while studies examining beach litter have increased (Edo et al., 2019; Pieper et al., 2015) there have been limited studies published examining and quantifying the geographic range of oceanic plastic pollution (Eriksen et al., 2014; Law et al., 2010; Pham et al., 2020; Reisser et al., 2015) when compared to other ocean basins, such as the North Pacific (Desforges et al., 2014; Egger et al., 2020; Goldstein et al., 2013; Law et al., 2014; Lebreton et al., 2018; Martinez et al., 2009; Rios Mendoza and Jones, 2015). The lack of continued monitoring within the North Atlantic Ocean presents challenges when trying to assess trends in the quantity and distribution of marine plastic pollution in relation to global emissions, and the reduction strategies and regional management plans implemented (Karasik et al., 2020; OSPAR Commission, 2014; Wilcox et al., 2020; Xanthos and Walker, 2017).