The Plastic Whale

‘Joy cometh in the morning’ scripture tells us, I hope so, I truly do. However, sometimes joy doesn’t always arrive. This rainy Saturday morning is an atypical case of this, in which I awakened to the distressing news story of the stranded ‘plastic whale’ which had died from the ingestion of plastic debris. After sombrely drinking some coffee and getting ready, while staring at the rainy clouds representing archetypal pathetic fallacy, I thought it would be wise to spend the day learning about the role of plastic pollutants within our marine environments. This week’s blog therefore, is centred around the negative implications of plastic within our global marine environments.  

I hear you ask, what is marine plastic pollution?

The presence of plastic pollution within our marine environments has become an internationally recognised environmental issue since the early 1970s, following the emergence of seminal research from Carpenter and Smith (1972). The findings indicated the presence of high plastic concentrations among sea surfaces and the ingestion of plastic among fish species. The seminal text offered a future prediction at the time, implicating the relationship between disposability and production would result in increased plastic pollution across marine environments (do Sul and Costa, 2014). Global plastic abundance today stands at 5.25 trillion pieces, equivalent to 720 items for each member of the entire global population (Worm et al., 2017). Controversy remains across the empirical literature regarding the exact volume of plastic that will enter marine environments in the foreseeable future (do Sul and Costa, 2014; Li et al., 2016; Wang et al., 2016). Nonetheless, there is recognition that plastic debris has entered and contaminated global marine ecosystems, providing sustained and long-term damage (Wang et al., 2016). A comprehensive study from Gall and Thompson (2015) found 92% of ingested and entanglement incidents for marine organisms, from over 340 publications, was solely linked with plastic debris causes.

Plastic sources though?

Land and ocean-based sources contribute towards the source of plastic within our marine environments (Li et al., 2016). Plastic debris derived from land-based sources has accounted for 80% of the total plastic debris located within marine environments (Jambeck et al., 2015). These land-based sources often involve coastal urban centres and industrialised areas which are paradigmatically linked with high disposability of plastic products, notably plastic bag usage (Li et al., 2016). The transport routes of plastic debris to marine environments involve passages though river systems and following treatment at wastewater processing centres (Cole et al., 2011). Moreover, land-sourced plastic debris is often transported following the occurrence of weather events, including extreme flooding, which helps to dispose plastic debris towards the sea (Naidoo et al., 2015). Inversely, ocean-based sources make up the remaining 20% of plastic debris within global marine environments (Li et al., 2016). Ocean-based sources are focused around commercial fishing, in which discarding of plastic netting and fishing equipment contributes towards marine environment contamination (Worm et al., 2017). Conservative economic estimates indicate financial damage of plastic debris within global marine environments is potentially $13 billion annually (Nairobi, 2014; Wang et al., 2016).

The temporal accumulation of plastics within marine environments involves contributions from macro-plastic and micro-plastic sources (Wang et al., 2016). Smaller plastic sizes, involving micro-plastics debris, are able to infiltrate environments more effectively, while inversely macro-plastic debris have to undergo a process of fragmentation before successfully infiltrating environments (Barnes et al., 2009). Previous blogposts have helped to address varying definitions of plastic debris.

Distribution:

The distribution of plastic globally remains idiosyncratic and uneven, with plastic debris being collated within Arctic sea ice and the equator regions (Jambeck et al., 2015). A concentration of plastic pollution has been noted around coastlines and urban centres globally (Wang et al., 2016; Worm et al., 2017). Open ocean gyres have also been indicated as hotspots of plastic debris (Lebreton et al., 2012). Oceanographic models have observed that plastic debris can rapidly be transported on a global scale, with research suggesting debris from the East Coast of the United States can be transported and relocated to the North Atlantic Subtropical Gyre in a time-span of less than 60 days (Law et al., 2010).

Figure 1:  A manta ray and a green sea turtle at Oahu beach, surrounded by various macro-plastic and micro-plastic debris (Source: Photographer: John Johnson, National Geographic).

Macro-plastic pollution:

Macro-plastic debris within marine environments, including freshwater lakes and oceans, poses various physical hazard implications for marine organisms (Li et al., 2016). Macro-plastic debris is documented to pose negative implications for marine organisms following the risk from entanglement and ingestion of plastic debris (Worm et al., 2017). A study examining the regions of Australia, Indonesia, and Papua New Guinea found commercial fishing nets resulted in over 15,000 turtle species being entangled annually (Wilcox et al., 2015; Worm et al., 2017). Entanglement from plastic debris can induce hindered movement, disrupted feeding patterns and death in extreme cases for marine species (Gall and Thompson, 2015).

The risk of ingestion is one the most prevalent environmental implications derived from macro-plastic debris (Fendall and Sewell, 2009). The rate of plastic ingestion has been found in some species to have increased over the last 30 years, with the review from Schuyler et al., (2014) implicating plastic ingestion among green turtles has proportionally increased by 20% between the years of 1985 to 2012. Macro-plastic ingestion among marine organisms has been recognised to cause internal blockages of the intestines and the inability of species to reproduce (Nelms et al., 2015). Moreover, macro-plastic debris ingestion has been indicated to seldom induce lowered food consumption among marine organisms (Li et al., 2016). Future blogs will examine the repercussions of micro-plastic debris pollution on marine organisms.

Figure 2: Distribution of marine plastics (Source: Eriksen et al., 2014)

Solutions:

Building from last week’s blog, which highlighted the need for an economic paradigm shift towards ‘doughnut economics’ (Raworth, 2017), interesting solutions are examined from Li et al., (2016) regarding the emergence de novo tailored solutions to tackle plastic pollution within our marine environments. One such policy solution debated was the establishment of an international protocol, in which collective governments become signatories to constrain and mitigate plastic pollution within our marine environments (Worm et al., 2017). Nonetheless, similarly to the COP21 climate agreement, there are obvious debates regarding asymmetrical merits and impacts of such a policy imposition for developing countries. Developing countries, including China and Vietnam, have been recognised as integral sources of plastic debris for marine environments, contributing an estimated 50% of global pollution (Tibbetts, 2015). The asymmetrical nature is heightened when examining that developing countries often mismanage plastic waste compared to developed countries, highlighted with India mismanaging 88% of plastic waste compared with the United States whereby only 2% is mismanaged (Worm et al., 2017).

Careful consideration is therefore, needed towards an international protocol policy which seeks to avoid Western impositions on developing countries but equally provides a comprehensive agreement to mitigate against plastic pollution within our marine environments.  

Figure 3: Diagram for resolving the plastic crisis (Source: Worm et al., 2017).

Finally, if you want to become involved in the protection of marine environments or want to receive regular updates, I highly recommend joining the Sky Campaign Appeal!

That’s all folks, hope you have a brilliant reading week!