Marine Litter, What Is It And What It Does To The Environment

Being based in Brighton and a stone’s throw from the beach, Groundsure is in an envious position to many. However all too often litter can spoil the beauty of our beaches, something it is all too easy to observe being so close to the sea. In this blog post we investigate the phenomenon, where it comes from, its effects and its future management.

Marine litter, also known as marine debris, is human-created waste that has deliberately or accidentally been released in a body of water [1]. The 2018 Ocean Conservancy’s International program of beach cleans recorded the top ten offending articles as; cigarette butts, food wrappers, plastic beverage bottles, plastic bottle caps, plastic grocery bags, other plastic bags, straws and stirrers, plastic take out/away containers, plastic lids, and foam take out/away containers [2]. Of course plastics are often resistant to degradation, persist in the marine environment and often float, making them prominent, both to us and to wildlife.

Marine litter has featured heavily in the media around the world in recent years, for example in the UK, The Independent in 2018 wrote an article entitled “Plastic chemicals changing marine animals’ behaviour and leaving them vulnerable to attack, study suggests” [3]. While in Asia the Asian Correspondent wrote a recent article in 2019 “More plastic bags than fish: East Asia’s new environmental threat” [4]. For an American context CNN wrote an article “Ocean plastic predicted to triple within a decade” [5] while in Australia ABC wrote “Arctic birds, seals and reindeer killed by marine plastics; pollution expected to rise“ [6], and further searches online return thousands of such articles.

On the right is a photo of rubbish on Brighton seafront.

A 2009 United Nations Environment Programme (UNEP) report summarises marine litter as ‘an environmental, economic, health and aesthetic problem’ [7]. Marine debris can enter the ocean environment through a myriad of sources ranging from rivers, streams, open lakes, estuaries, and land-based sources such as waste, run off, and sewage effluent, as well as through ocean-based sources, such as maritime and cruise industries, commercial fisheries, and recreational fishing and boating activities. But what exactly are these impacts and how do they affect the environment?

Ingestion and Entanglement
The two best studied environmental impacts of marine litter are the entanglement of, and ingestion by, marine wildlife. A wide range of species including invertebrates, turtles, fish, seabirds and mammals, have been reported to ingest or become entangled in plastic debris, resulting in impaired movement and feeding, reduced reproductive output, lacerations, ulcers and death [7].

The negative effects of entanglement on individuals are more obvious, with external injuries or death often observed. Determining the effect of ingesting marine debris on an individual can be more difficult, and the consequences of ingestion are still not fully understood [8]. Sub-lethal effects of entanglement and ingestion that alter the biological and ecological performance of individuals are highly likely, and include compromising the ability of a marine animal to capture food or eat, sense hunger, move, escape from predators, migrate and reproduce.

Above shows a seal pup eating plastic debris in Norfolk.

Microplastics
Microplastics, defined as plastic pieces or fragments less than 5 millimetres in diameter [9], have been accumulating in the marine environment (presumably) since the advent of the use and production of plastics, and are at present only likely to increase in abundance given the current dependence of plastics and reluctance to adopt alternatives. Microplastics can be primary (purposefully manufactured) or secondary (derived from the fragmentation of larger plastic items) in origin [10], and are often added to cosmetics. They are a persistent pollutant that is already present in all marine habitats including Antarctic ice [11]. As a result, it is likely that every level of the food web is exposed to microplastics, from primary producers to apex predators and they have the potential to accumulate within organisms and up the food web to humans [12].

Socio-economic impacts of marine debris 
From the above discussion, we can see that marine debris has extensive negative social and economic impacts for society. There have been substantial economic losses for industries such as commercial fishing, shipping, recreation and tourism. There are also widespread social impacts of marine debris such as direct, short-term human health issues (e.g., injuries, and navigational hazards) and indirect issues such as impacts on quality of life, and reduced visitor numbers.

A global assessment on the sources, fates and effects of microplastics in the marine environment, published by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) concluded that the presence of microplastics has negative social and economic impacts, reducing ecosystem services and compromising perceived benefits [13].

The Millennium Ecosystem Assessment, the work of more than 1,360 experts worldwide defined ecosystem services as ‘the benefits people derive from ecosystems’ [14]. Besides provisioning services or goods like food, wood and other raw materials; plants, animals, fungi and micro-organisms provide essential coastal regulating services such as flood and erosion control, climate regulation, the aforementioned recreation and tourism and even carbon sequestration.

Habitat damage 
The degradation of aquatic habitats due to marine debris poses potentially serious threats to the health of marine and coastal ecosystems and living marine resources. Habitat degradation due to marine debris has far-reaching impacts on biodiversity since many critical areas, such as coral reefs, mangroves, marshes, and seagrass also serve as breeding grounds or nurseries for nearly all marine species [15].

Marine debris can not only damage habitats directly via physical and chemical impacts, but it can also lead to reduced recruitment and reproduction for certain species, which may indirectly alter or degrade critical nurseries and other fragile ecosystems [16]. Accelerated species extinctions and declines in global biodiversity are associated with habitat loss, thus making it critical to unravel the ecological consequences associated with marine debris [17].

The impacts of debris on marine habitats vary in scope depending on the type, quantity, and location of the debris, as well as the vulnerability of the habitat. Although direct physical damage to marine habitats such as coral reefs, benthic zones, sandy beaches, and mangroves has been discussed, all habitats in this paper are in need of additional research [15].

So what can be done? The obvious starting point is preventing land-based sources of debris entering the marine environment, but this is a complex and expensive undertaking. It has been calculated that Local Authorities in the UK spend approximately £18 million each year in removing beach litter, which has also seen a 37% increase in cost over the past 10 years [18].

Legal efforts have been made at both international and national levels to address marine pollution. The most important are the 1972 Convention on the Prevention of Marine Pollution by Dumping Wastes and Other Matter (or the London Convention), the 1996 Protocol to the London Convention (the London Protocol), and the 1978 Protocol to the International Convention for the Prevention of Pollution from Ships (MARPOL). However, compliance with these laws is still poor, partly due to limited financial resources to enforce them.

Recycling and reuse of plastic materials are the most effective actions available to reduce the environmental impacts of open landfills and open-air burning that are often practiced to manage domestic waste. Sufficient litter and recycling bins can be placed in cities, and on beaches in coastal areas to accelerate the prevention and reduction of plastic pollution.

Rubbish bin, Brighton seafront

To effectively address the issue of marine plastics, research and innovation should be supported. Knowledge of the full extent of plastic pollution and its impacts would provide policy-makers, manufacturers and consumers with scientific evidence needed to spearhead appropriate technological, behavioural and policy solutions. It would also accelerate the conceptualisation of new technology, materials or products to replace plastics. Therefore, management should consist of a fourfold approach:

• Prevention of further marine debris input to the marine and coastal environment;
• Education of the effects and how simple steps can make a difference;
• Monitoring of marine litter quantities and distribution; and
• Removal of existing marine litter and its proper disposal.

Sources
[1] National Oceanic and Atmospheric Administration (NOAA) (1999). Marine Debris 101, available: https://web.archive.org/web/20090213110801/http://marinedebris.noaa.gov/marinedebris101/

[2] Ocean Conservancy’s International. (2018). Building a Clean Swell, 2018 Report available: https://oceanconservancy.org/wp-content/uploads/2018/07/Building-A-Clean-Swell.pdf
[3] The Independent. (2018). Plastic chemicals changing marine animals’ behaviour and leaving them vulnerable to attack, study suggests. The Independent, available: www.independent.co.uk/environment/plastic-pollution-ocean-animal-behaviour-microplastics-chemicals-study-research-a8654541.html
[4] Asian Correspondent. (2019). More plastic bags than fish: East Asia’s new environmental threat. Asian Correspondent, available: https://asiancorrespondent.com/2019/04/more-plastic-bags-than-fish-east-asias-new-environmental-threat
[5] CNN. (2018). Ocean plastic predicted to triple within a decade. CNN, available: https://edition.cnn.com/2018/03/21/health/ocean-plastic-intl/index.html
[6] ABC. (2018). Arctic birds, seals and reindeer killed by marine plastics; pollution expected to rise. ABC, available: www.abc.net.au/news/2018-02-09/marine-plastics-killing-arctic-creatures/9417270
[7] UNEP. (2009). Accessible analyses of the environmental impacts of marine litter can be found, inter alia, in Derraik (n 4) 844-847; 2155-2156.
[8] Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel – GEF. (2012). Impacts of Marine Debris on Biodiversity: Current status and Potential Solutions, Montreal, Technical Series No.67, 61 pp.
[9] Arthur, C. et al. (2009). Proceedings of the international research workshop on the occurrence, effects and fate of microplastic marine debris. September 9-11, 2008: NOAA Technical Memorandum NOS-OR&R30.
[10] Wright, S.L. et al. (2013). The physical impacts of microplastic on marine organisms. Env. Poll. 178: 483-492.
[11] Green Peace. (2008). Microplastics in the Antarctic. Green Peace, available: www.greenpeace.org/international/publication/16899/microplastics-in-the-antarctic/
[12] Oliviera, M. et al. (2012). Effects of exposure to microplastics and PAHs on microalgae Rhodomonas baltica and Tetraselmis chuii. Comp. Bio-chem. Physiol. A Mol. Integr. Physiol. 163: S19-S20.
[13] Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP). (2015). Sources, fate and effects of microplastics in the marine environment: a global assessment. Rep. Stud. GESAMP No. 90, 65 p.
[14] Millennium Ecosystem Assessment. (2005). Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC.
[15] National Oceanic and Atmospheric Administration (NOAA). (2016). Report on Marine Debris Impacts on Coastal and Benthic Habitats. Silver Spring, MD. 20910 301-713-2989
[16] Gall, S C, and Thompson, R C. (2015). The impact of debris on marine life. Marine Pollution Bulletin, 92(1–2), 170–179. doi: 10.1016/j.marpolbul.2014.12.041
[17] Pimm, S. L et al. (2014). The biodiversity of species and their rates of extinction, distribution, and protection. Science, 344(6187). doi: 10.1126/science.1246752
[18] Mouat, J, J., Lozano, R., Bateson, H. (2010). Economic Impacts of Marine Litter, KIMO available: www.kimointernational.org/wp/wp-content/uploads/2017/09/KIMO_Economic-Impacts-of-Marine-Litter.pdf