Marine Litter in the Algarve Coast: main sources and distribution using a modelling approach

Anthropogenic litter, mainly plastic, can be found in all the oceans -since the most populated coastline to the most remote - it impacts on marine habitats, fauna and sea ongoing economic activities such as tourism, fishing and aquaculture, are negative. Qualitative and quantitative information about marine litter in our seas and oceans is required for policy development aiming to reduce marine litter and/or to assess effectiveness of existing programmes of measures. This work provided an overview of the Algarve beaches monitoring using OSPAR standardize guidelines for the 2013-2017 period, available by DGRM. Analysis of the two beaches litter surveyed data was performed using the tool Litter Analyst. The data shows an increasing trend in average item counts per year for all beaches aggregated of 11 items per year. In the period 2013-2017, plastic/polystyrene accounts for 37.3 % of all litter items found. The top-80% shows that most of the items that are included in the paper category are cigarettes buts which have a high probability to originate from the tourism sector, whilst most of the items that are included on plastic and polyester categories are plastic pieces less than 50 cm, nets and ropes. Also, the data showed increasing trends for all source categories, except for ‘others’ and shipping where decreasing trends were found. The largest increasing trend in average item counts per year is from tourism (17 counts/year). Numerical modelling is also one of the key tools with which it can gain insight into the distribution of marine litter. Over the past decade, a series of numerical simulations have been constructed that specifically target floating marine litter, based on ocean models of various complexity. This project provided an initial step in identifying available information on litter and developing preliminary analysis of its sources and distribution at the Algarve coast, using the Algarve Operational Modelling and Monitoring System (SOMA). Results showed the coastal circulation plays a fundamental role in the dynamic of floating marine litter and its accumulations on the Algarve beaches, which showed be higher during winter scenario and lower during the upwelling scenario. Also, the simulations indicate that both particle velocity and the rate of floating marine litter accumulation along the Algarve coast increase when an extra wind force is assumed. Accumulations of beached floating marine litter were fond mostly on beaches located at the southwestern region of Algarve, as well as Faro beach.Lixos antropogénicos, principalmente plásticos, podem ser encontrados em todo o mundo - desde os litorais mais populosos até os mais remotos - e seu impacto no habitat, na fauna e nas atividades econômicas costeiras e marítimas como turismo, pescas, aquacultura, são negativas. A região do Algarve apresenta uma economia regional completamente ligada ao mar, e também abrange importantes parques naturais, e atualmente, informações sobre as principais fontes, distribuição e acumulação de lixos são desconhecidas para esta região. Informações qualitativas e quantitativas sobre o lixo marinho são fundamentais para o desenvolvimento de políticas que visam reduzir o lixo marinho e/ou avaliar a eficácia dos programas existentes. Neste trabalho foi apresentado uma visão geral do monitoramento de praias do Algarve usando as diretrizes padronizadas da OSPAR para o período 2013-2017, disponíveis pela DGRM. As análises dos dados levantados sobre as duas praias Algarvias foram realizadas utilizando a ferramenta Litter Analyst. Os dados mostram uma tendência crescente na contagem média de itens por ano para todas as praias agregadas de 11 itens por ano. No período 2013-2017, plástico/poliestireno foi responsável por 37,3% de todos os itens coletados. Método Top 80% (principais lixos) mostrou maioria dos itens incluídos na categoria de papel são cigarros, mas com alta probabilidade de originar-se no setor de turismo, enquanto a maioria dos itens incluídos nas categorias de plástico e poliéster são peças de plástico com menos de 50 cm, redes e cordas. Também, os dados mostraram tendências crescentes para todas as categorias de origem, exceto "outras" e navegação onde foram encontradas tendências decrescentes. A maior tendência crescente na contagem média de itens por ano é do turismo (17 contagens /ano). A modelagem numérica também é uma das principais ferramentas com as quais pode obter informações sobre a distribuição de lixo marinho. Na última década, uma série de simulações numéricas foram construídas visando especificamente lixo marinho flutuante, com base em modelos oceânicos de várias complexidades. Neste projeto, utilizou-se a modelagem hidrodinâmica e Lagrangiana para prever pela primeira vez o destino de lixo marinho flutuante originados de fontes terrestres e marítimas na costa do Algarve em diferentes cenários oceanográficos. Utilizou-se o Sistema Operacional de Modelagem e Monitorização do Algarve (SOMA) e acrescentou um coeficiente de deriva do vento e um fator de encalhe (beaching). Os resultados também indicaram que a velocidade das partículas e a taxa de acumulação de lixo marinho na costa do Algarve aumentam quando uma força extra do vento é adicionada na simulação. Altas concentrações de lixos foram encontradas depositados principalmente na parte sudoeste da costa do Algarve, conhecida como barlavento, e nas praias de Faro

Marine litter on the coast of the Algarve: Main sources and distribution using a modeling approach

The accumulation of floating marine litter poses a serious threat to the global environment and the economy all over the world, particularly of coastal municipalities that rely on tourism and recreational activities. Data of marine litter is thus crucial, but is usually limited, and can be complemented with modelling results. In this study, the operational modelling system of Algarve (SOMA) was combined with a Lagrangian particle-tracking model and blended with scarce litter monitoring data, to provide first insights into the distribution and accumulation of floating marine litter on the Algarve coast. Different meteo-oceanographic conditions, sources regions and wind drift behaviors were considered. Field data and model results show a considerable concentration of marine litter along the beaches and coastal regions. The model also suggests that oceanographic conditions and wind drift have a great influence on the transport and accumulation rate of the floating marine litter on the coast, with the highest rates of accumulation during the winter and the counter current period, concentrated mostly on the south-western coast of the Algarve.Funded by OCASO, grant number Interreg POCTEP project GA0223_OCASO_5_E, and Interreg POCTEP project GA 0754_CIU3A_5_E.info:eu-repo/semantics/publishedVersio

Pathways and hot spots of floating and submerged microplastics in Atlantic Iberian marine waters: a modelling approach

Plastic pollution has been observed in many marine environments surrounding the Iberian Peninsula, from the surface water to deeper waters, yet studies on their pathways and accumulation areas are still limited. In this study, a global ocean reanalysis model was combined with a particle-tracking Lagrangian model to provide insights into the pathways and accumulation patterns of microplastics originating in southern Portuguese coastal waters (SW Iberian). The study investigates microplastics floating on the surface as well as submerged at different water depths. Model results suggest that the North Atlantic Gyre is the main pathway for microplastics in surface and subsurface waters, transporting the microplastics southwards and eastwards towards the Mediterranean Sea and the Canary Islands. Currents flowing out of the Mediterranean Sea act as the main pathway for microplastics in deep waters, transporting the microplastics along western Iberia. An average residence time of twenty days in the coastal waters suggests that microplastics do not accumulate close to their sources due to their relatively fast transport to adjacent ocean areas. Notably, a significant proportion of microplastics leave the model domain at all depths, implying that SW Iberia may act as a source of microplastics for the adjacent areas, including the Mediterranean Sea, Morocco, the Canary Islands, Western Iberia, and the Bay of Biscay.info:eu-repo/semantics/publishedVersio