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

• Autor(a) principal: Rosas, Eloah Garcia
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15061
• topic: Lixos marinhos flutuantes; Llixo de praia; Algarve; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

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.