Marine Litter Thematic Assessment

Benefits and services affected

A regional breakdown of the Impact on ecosystem services changes is currently not appropriate.

In addition to its ecological consequences (see previous section) marine litter also exerts a pressure on ecosystem services (ES), with important implications for human welfare, by impacting negatively on economic sectors such as tourism, fisheries, aquaculture, navigation, and energy and inflicting economic losses on individuals, enterprises, and communities. Figure I.1 presents an overview of the linkages between 'State changes/Environmental impacts’ and ‘Impacts on ES’ for the Marine Litter thematic assessment (Federico Cornacchia, 2022; report includes in-depth assessment of linkages).

As shown schematically, each state change / environmental impact associated with marine litter affects a different marine ecosystem service. The following describes how marine litter can impact ecosystem services.

Wild fish and other natural aquatic biomass and related raw materials:

Marine litter, by impacting on marine ecological components through physical entanglement and other types of damage related to ingestion, smothering and damage of habitats, diffusion of invasive species and transmission of viruses, pathogens and various pollutants, damages wild stocks of fish and other marine organisms and consequently reduces biomass provision.

Nursery population and habitat maintenance:

Marine litter presents mainly negative impacts on the provision of this service. The generation of artificial hardgrounds can degrade pre-existing habitats favourable to native species by altering the structure of habitat components (corals, biogenic reefs, microphytobenthos, etc.), leading to changes in the assemblages of such species (e.g., more short-lived species). Moreover, it increases the range of habitats available for colonisation, including by invasive species.

Water quality regulation:

The illustrated lethal and/or sub-lethal effects related to marine litter can impair to varying degrees the ability of marine ecosystem components to provide water quality regulation, for example through the death of components such as reefs, and the death of or adverse effects on invertebrate organisms such as mussels, given their contribution to water filtration.

Coastal protection:

Considering the contribution of biotic elements such as coral reefs, microphytobenthos, kelp forests and infauna to processes such as erosion control and thus to coastal protection, their degradation (and possible death) as a result of smothering or ingestion can more or less compromise the provision of this ecosystem service.

Pest control:

The environmental impacts associated with marine litter, such as its role as a vector for invasive species, non-invasive proliferating species, nuisance algae and other agents, affect the normal pest control service provided by the marine ecosystem by increasing the presence and range of non-indigenous species. Other negative effects of marine litter, such as increased mortality of species as a result of ingestion, disease, and other factors, also have a negative impact on this ecosystem service if the affected species naturally contribute to pest control.

Biomass and raw materials from in-situ aquaculture:

Marine litter, by impacting on marine ecological components through ingestion, diffusion of invasive species, transmission of viruses, pathogens and various pollutants damages marine organisms reared in aquaculture processes and consequently reduces biomass provision.

Recreation-related services and visual amenity services:

Visible pollution by marine litter (on beaches, on the seabed, entangled with species) can have a significant negative impact on experiential recreation. It is known that people deplore this, given its negative effect on the sense of place associated with the marine location, on sensory enjoyment and consequently on recreational activities. The presence of litter on organisms can reduce or disrupt the ability of such biotic components to underpin activities such as diving, wildlife-watching, and others. The detrimental effect on people's mood and mental wellbeing following time spent on coastlines affected by litter pollution has been documented.

Ecosystem and species appreciation:

Charismatic marine organisms such as birds, turtles and cetaceans are of cultural and/or emotional importance to individuals. Direct sightings and / or images and articles shared through the media of stranded cetaceans and of seabirds with their stomachs full of plastic have a negative effect on human wellbeing in relation to their awareness of the damage and / or loss of these charismatic species. Furthermore, in respect of this ecosystem service, it should be mentioned that marine litter can have negative effects on marine animal welfare, causing them avoidable suffering (Werner et al., 2016). From an ecosystem service perspective, it could be argued that marine animal welfare can benefit humans, in the sense that they derive satisfaction from seeing animal welfare maintained. However, the direct beneficiaries are the marine organisms, and the issue of animal welfare may go beyond the concept of ecosystem services.