The importance of studying marine litter in São Miguel

All the plastic that has been ever made is still around. Every year, more than 8 million tons of plastic are dumped in our oceans. The global trend on plastic production is growing exponentially since 1950’s, when the mass production and consumption started (UNEP, 2016).

If current production and waste management trends continue, by 2050 the amount of plastic in the sea will outweigh the amount of fish (World Economic Forum, Ellen MacArthur Foundation Report, 2016).

Plastic has become ubiquitous. Not only as large items, but as well as tiny pieces smaller than 5 mm, which are called microplastics. They suppose a major threat for the global environment.

They can enter the food chain through the first trophic levels; they can release chemical additives and contaminants harmful for marine biota; or even favour the adsorption of toxic particles to their surface. They are classified in two main groups according to their origin: primary and secondary microplastics (UNEP, 2016). Primary microplastics are microscopic since their origin, like pellets, marine and building paints or microbeads frequently used in cosmetics and personal care products.
Secondary microplastics are derived from degradation of different products through radiation, abrasion, fragmentation or even washing, among which we find building and road paints, textiles and clothing, and vehicle tyre dust (which is by far one of the main sources). Land-based sources, such as packaging or everyday items, represent roughly the 80% of the plastic that ends up in the ocean; while sea-based sources are mostly linked to shipping and fisheries (Eunomia, 2016; UNEP, 2016).

Plastic has been found everywhere in the marine environment, from shores and surface waters, to the seabed and deep ocean trenches with more than 5700m (Fischer et al., 2014). Actually, around 94% of the marine plastic litter end up in the ocean bottom (Eunomia, 2016), with an average concentration of around 70 kg/km2 (Pham et al., 2014). Barely 1% of marine plastic is found floating on the surface or sub-surface waters, with an average concentration of 0.74 kg/km2. According to the general circulation of the oceans, floating marine debris tends to aggregate in higher concentrations in the five subtropical gyres; and so far, the maximum concentration (18 kg/km2) has been measured in the North Pacific Gyre (Eriksen et al., 2014). The rest is washed up on the coast, mainly on the beaches, where an astonishing concentration of more than 1000 kg/km2 (some estimates exceed even 2000 kg/km2) has been reported (Andrady, 2011; Eunomia, 2016).

Due to the remote location of the Azores in the middle of the Atlantic and within the northern edge of the North Atlantic Subtropical Gyre, assessing abundance and composition of the litter found on the Azorean coastlines becomes a great tool to better understand the health status of our ocean. So far, studies about marine debris around those islands are still scarce and have been conducted only recently (Pieper et al, 2015; Pham et al., 2013; Chambault et al., 2018; Ríos et al., 2018). Chambault et al. (2018) have found that floating marine debris around the archipelago is composed mainly by plastic user items, packaging and fishing gear, and its density is higher around the islands of the archipelago than in surrounding waters, particularly around the central group. Pieper et al. (2015) and Rios et al. (2018) analysed the marine litter found in beaches around Faial Island and the entire archipelago respectively, and in both cases, plastic was the most abundant type of trash found. Surprisingly, Pieper reported in the Azores plastic with labels from Canada, Vietnam, and other distant countries, which reinforces the importance of a global concern.

Furthermore, waste production in the archipelago has increased at a rate of 4% last year (which suppose 5600 more tons of waste produced in 2017 than in 2016) partially due to the rise of the floating population (i.e. tourism). In São Miguel, where there is a stronger influence of tourism, this trend is particularly notable. Waste production it has been continuously increasing in the last 3 years, with a rate of 1.7% in 2015, 4.8% in 2016 and 5.4% in 2017; and the average production of waste per person is indeed higher than in other islands (1.62 kg/day in São Miguel; 1.13 kg/day in Santa Maria) (Governo dos Açores – PEPGRA, 2015; Câmara de Comércio de Angra do Heroísmo, 2018).

Within this context, it is unquestionable the importance of monitoring the abundance and composition of marine litter in the Azores, and particularly in São Miguel. Coastlines are the most visibly affected areas; and therefore, beach surveys may provide a good approach to assess the marine litter at a local level.

The potential to identify the main sources of the plastic/trash found on our coasts, as well as to address possible ways to reduce it may be a great tool to influence local management and to raise awareness among the society. Additionally, this kind of long-term monitoring program of marine litter on beaches move forward to meet the Descriptor 10, “Properties and quantities of marine litter do not cause harm to the coastal and marine environment”, of the Marine Strategy Framework Directive (MSFD) to assess a “Good Environmental Status” (European Commission, 2 018).

As a responsible tourism company that operates within the natural environment, Futurismo is concerned about the impact of plastic in our surroundings. The main activity of the company is run in São Miguel Island, and thus, caring about our local environment is a must for us.

On our daily tours we try to minimize our impact, collecting rubbish and trash from the ocean, minimizing the use of plastic and packaging on our picnics, or avoiding singleuse plastic.

However, we recognize that further efforts are needed, not only to change our habits or attitude towards a more sustainable lifestyle, but also to raise awareness among society. We do believe that taking action at local level is a must, and therefore, we aim to develop middle to long term marine litter monitoring program in São Miguel.

Article written by Laura González

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