Marine debris - the effects

Photograph: Ryan Lawler, Newport Coastal Adventure, 2017.

The threat of marine plastics is no new thing. For decades it’s been overlooked and ignored. In 1974, a member of the Council of the British Plastics Federation and a Fellow of the Plastics Institute stated, “plastics litter is a very small proportion of all litter and causes no harm to the environment except as an eyesore” (1). Fast forward 40 years and we are becoming more aware of just how “harmless” plastic pollution is and how far reaching the detrimental effects of plastic are. But how much of this is fact and how much is hype? Here are the facts.
 
Plastic pollution is ubiquitous throughout the marine environment. In a 7-year study spanning from 2007 – 2013, scientists were able to estimate that 5.25 trillion particles of plastic weighing 268, 940 tonnes existed within the world’s five gyres (2). That doesn’t sound too good, I hear you say. But what exactly does that figure look like? Put into perspective, this is the equivalent of 45,000 African elephants, over 4,000 army tanks, or 2,000 of the world’s largest animal – the blue whale. It’s almost 17,000 fully packed public buses. If that still doesn’t help, imagine those buses lined up end to end and side by side. This would cover the area of almost 1000 AFL footy ovals. Then add to that the exponential increase in plastic production and marine pollution that’s occurred since (this number is expected to reach 250 million tonnes by 2025 (3)). And that’s floating around in one of the most important ecosystems on Earth, one that interacts with the atmosphere to regulate our climate (4), that stores huge amounts of our ever-growing carbon dioxide emissions (5, 6), that creates over half of the world’s oxygen (7), and that is home to a vast amount of Earth’s plants and animals.
 
Much of the debris that pollutes our marine environment is nonpoint source, that is, it cannot be attributed to a specific location or time (8). Whether from land-based sources or those on the seas, intentionally and unintentionally discarded plastic debris makes it into our oceans. Ocean gyres, those great big current systems that span our oceans and are vital for the movement of nutrients among other things across our globe, also shift and concentrate debris in different oceans. They carry our waste – from rubber sandals and toothbrushes to plastic bags and balloons, from one continent to the next and inadvertently marine life gets caught up in the mix. While the impacts of plastic pollution on our ocean’s ecosystems are starting to emerge, there is increasing evidence of the threat to marine life (9). So how exactly does plastic pollution affect the plants and animals of our underwater world?
 
Sadly and all-to-often, we are witnessing the obvious and deleterious effects on marine life. We turn to social media and see emotive images of seahorses clutching cotton buds rather than seagrass and videos of plastic cutlery being removed from turtles’ nostrils as they seem to gasp with relief. But how does this happen?
 
Ingestion and entanglement spans the food web, from the tiny zooplankton at the base of the food chain to the largest fish – the whale shark. Unlike humans that can (generally) distinguish between food and foe, wildlife are unaware of the existence of man’s artificial creations. Plastic can mimic natural prey items in its appearance. Plastic bags when floating in open water can seem jellyfish-like, pieces of faded plastic can look identical to cuttlefish bones. In some species, plastic ingestion has been reported in more than 80% of sampled individuals (10).
 
And like us, animals are curious creatures. You know what they say about curiosity and the cat? The same can be said for marine creatures and interactions with our trash. In 1997, a comprehensive list of marine species known to be impacted by entanglement and ingestion was compiled identifying over 250 species (11). This showed that marine debris doesn’t discriminate. Turtles, seabirds, whales, dolphins, sharks, seals and sea lions, manatees, dugongs, sea otters, fish, crustaceans have all been caught up in our waste. They are either drawn to or accidentally entangled in active or discarded netting, rope and fishing line, which continues to fish as more and more animals are attracted (12). And sadly it’s not just fishing gear that catches marine wildlife. All-too-often animals are becoming trapped by items of convenience – packing loops and bands, bottle rings, plastic bags, rubber bands that strangle, disfigure and tie down our oceans (eg. 12, 13). Not so convenient huh.
 
And like we said, that’s the obvious effects. In addition to these confronting and oh-so-real nasty impacts, many more are lurking in the shadows. Organic pollutants (we’re talking polychlorinated biphenyls or PCBs – toxic man-made chemicals that were manufactured until banned in 1975 (14)) and trace metals like lead are attracted to plastic as it floats around the ocean which, once ingested, can leach into an animal’s bloodstream (15). Sounds pretty nasty, right? And so is the suite of health issues that can ensue. Stomach ulcers, liver damage, neurological and reproductive effects just to name a few (15). But this isn’t just the bigger, charismatic animals we like to spot through binoculars or see porpoising alongside our boats. These chemicals can be consumed by the tiniest of organisms, transferred and magnified throughout the foodweb as they are eaten by ever larger predators (16), many of which we serve our families up for dinner. See where we’re going here?
 
Then there’s the multitude of invasive and pest species – the hangers-on and hitch-hikers that ride on their floating plastic taxis, the debris that no longer wants to float around on currents but sinks to the sea floor and smothers our bottom-dwellers (12), and the effects plastic and its contaminants are having on our planet’s energy makers phyto- and zooplankton (10,17).
 
Basically, plastic pollution isn’t just a harmless eyesore. It’s not something that has just come into existence. And it doesn’t just affect our oceans. It affects us all. From the animals we find ourselves privileged to share our planet with, to the food we eat and the climate and air we rely on for life, the choices we make impact us all. While the solution to this ever-expanding problem seems both out of reach and out of sight, the responsibility is falling on us to make change. Because without it… we don’t even want to imagine that world.
 
What you can do:
Reduce plastic use and choose plastic-free alternatives where available
Reduce waste and dispose of what you do have appropriately
Recycle where possible and compost food waste to reduce CO2 creation from landfill
Stop and pick up that piece of litter

Report entangled/injured marine wildlife:
VIC – https://www.wildlife.vic.gov.au/injured-native-wildlife/wildlife-tool
           Melbourne Zoo’s AGL Marine Response Unit – 1300 245 678
           Whale and Dolphin Emergency Hotline – 1300 136 017
NSW - https://www.environment.nsw.gov.au/questions/injured-sick-marine-animal
             ORRCA (Organisation for the Rescue and Research of Cetaceans in Australia)
             (02) 9415 3333
             Australian Seabird Rescue (02) 6686 2852
QLD - https://www.qld.gov.au/environment/plants-animals/reporting
            RSPCA – 1300 264 625
NT – https://nt.gov.au/environment/animals/report-injured-wildlife-or-rescue
          Parks and Wildlife – (08) 8999 4555 (Darwin)
          Fishwatch – 1800 891 136
          Wildcare Inc – 0408 885 341 (Darwin)
WA – https://www.dpaw.wa.gov.au/management/marine/marine-wildlife
           Wildcare Helpline – (08) 9474 9055
TAS -  https://dpipwe.tas.gov.au/wildlife-management/marine-conservation-program
            Marine Conservation Program (MCP) Hotline – 0427 942 537
 
References
1. Ferguson, W.C. 1974. Summary. J.J.P. Staudinger (Ed.). 1974. Plastics and the environment. Hutchinson and Co., London. p.2.

2. Erikson, M., Lebreton, L.C.M., Carson, H.S., Thiel, M., Moore, C.J., Borerro, J.C., Galgani, F., Ryan, P.G., Reisser, J. 2014. Plastic pollution in the world’s oceans: more than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea. PLoS ONE.
 
3. Jambeck, J.R., Geyer, R., Wilcox, C., Siegler, T.R., Perryman, M., Andrady, A., Narayan, R., Law, K.L. 2015. Palstic waste inputs from land into the ocean. Science. 347, 768-771.
 
4. Webster, P.J. 1994. The role of hydrological processes in ocean-atmosphere interactions. Rev. Geophys.32, 427-476.
 
5. Leung, S., Cabré, A., Marinov, I. 2015. A latitudinally banded phytoplankton response to 21st century climate change in the Southern Ocean across the CMIP5 model suite. Biogeosciences. 12, 5715-5734.
 
6. Sanders, R., Henson, S. 2014. Ecological carbon sequestration in the oceans and climate change. In: Freedman, B. (eds) Global environmental change. Handbook of global environmental pollution, vol. 1. Springer, Dordrecht.
 
7. Morsink, K. 2017. With every breath you take, thank the ocean. Smithsonian Ocean Portal, National Museum of Natural History, Smithsonian Institution, Washington, DC.
 
8. Potters, G. 2013. Marine pollution. In: Clarke, R.B. 2002. Marine pollution (5th ed.), Oxford University Press.
 
9. Derraik, J.G.B. 2002. The pollution of the marine environment by plastic debris: a review. Mar. Pollut. Bull. 44, 842-852.
 
10. Gallo, F., Fossi, C., Weber, R., Santillo, D., Sousa, J., Ingram, I., Nadal, A., Romano, D. 2018. Marine litter plastics and microplastics and their toxic chemicals components: the need for urgent preventative measures. Environ. Sci. Eur. 30, 1-14.
 
11. Laist, D.W. 1997. Impacts of marine debris: entanglement of marine life in marine debris including a comprehensive list of species with entanglement and ingestion records. In: Coe, J.M., Rogers, D.B. (eds) Marine debris. Springer Series on Environmental Management. Springer, New York, NY.
 
12. Gregory, M.R. 2009. Environmental implications of plastic debris in marine settings – entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions. Phil. Trans. R. Soc. B. 364, 2013-2025.
 
13. National Oceanic and Atmospheric Administration (NOAA). 2014. Report on the entanglement of marine species in marine debris with an emphasis on species in the United States. NOAA Marine Debris Program. Silver Spring, MD. 28 pp.
 
14. Department of the Environment and Energy (DEE). 2014. Polychlorinated Biphenyls (PCBs). Australian Government, Commonwealth of Australia. .
 
15. Lavers, J.L., Bond, A.L., Hutton, I. 2014. Plastic ingestion by Flesh-footed shearwaters (Puffinus carneipes): implications for fledgling body condition and the accumulation of plastic-derived chemicals. Environ. Pollut. 187, 124-129.
 
16. Colabuono, F.I., Taniguchi, S., Montone, R.C. 2010. Polychlorinated biphenyls and organochlorine pesticides in plastics ingested by seabirds. Mar. Poll. Bull. 60, 630-634.
 
17. Besseling, E., Wang, B., Lürling, M., Koelmans, A.A. 2014. Nanoplastic affects growth of S. oliquus and reproduction of D. magna. Environ. Sci. Technol. 48, 12336-12343.