Introduction
Marine animals, already being susceptible to
the dangers of other man-made processes, must be also confronted by the threat
of plastic debris. The accumulation of anthropogenic debris (in particular
plastic pollution) have resulted in huge threats on marine biota. The plastic threat
is a growing global phenomenon. People have seen the ocean as an inexhaustible
food source as well as a dumping ground without thinking about the consequences
thereof. However, the ocean isn’t limitless and sustainability of our seas
isn’t taking place. Marine litter is degraded at a very slow rate, and coupled
with the exponential pace and quantity of debris that is disposed, ultimately
leads to an unfortunate increase in plastic pollution. Thus, greater awareness
on this significant problem is required.
Defining
marine plastic debris
Marine debris is defined as any persistent
manufactured or processed solid material discarded, disposed of or abandoned in
the marine and coastal environment. It includes items made or lost by people,
and those deliberately discarded into or unintentionally lost in the marine
environment (Gall & Thompson 2015). Glass, metal, paper, and plastic are some
of the most commonly found marine debris materials.
 |
| Source: Ocean Leadership Organisation |
 |
| Source: Ocean Conservancy |
Land-based sources are responsible for
around 80 per cent of all marine pollution. Global production of plastics has
increased considerably over the last few decades from 5 million tonnes per year
in the 1960s to 280 million tonnes per year in 2011. There are estimated to be over
5 trillion plastic pieces weighing over 250,000 tonnes afloat at sea ((UN, 2004
& Eriksen et al., 2014 as cited in WWF Living Blue Planet Report 2015;
Gall &
Thompson 2015).
It is estimated that about 6.4 million
tons of marine litter are disposed in the oceans and seas each year. According
to other estimates and calculations, some 8 million items of marine litter are
dumped in oceans and seas every day, approximately 5 million of which (solid
waste) are thrown overboard or lost from ships. Furthermore, it has been
estimated that over 13,000 pieces of plastic litter are floating on every square
kilometre of ocean today (UNEP. 2005. Marine Litter: An analytical overview).
There are approximately 35,500 tonnes of
microplastics (tiny plastic particles) floating in our ocean (Eriksen et al.,
2014 as cited in WWF Living Blue Planet Report 2015). Even with improved waste
disposal management and recycling initiatives, a large amount of plastics will
be swept into watercourses, which will eventually end up in the oceans. Over
60% of the world population live within 100km. Furthermore, because of rapidly
growing global population, land-based activities it will ultimately lead to
marine pollution taking exponentially place.
Reasons why this phenomenon occurs and its various contributors
Reasons why plastic is utilised
Plastic materials are commercially successful as they are durable and economically affordable. Moreover, because they are low cost, plastic is readily available and utilised as a disposable material source. The very qualities of durability that make plastic convenient to use, however, also make it a persistent, non-degradable, permanent presence in the marine environment. When discarded, lost, or abandoned in the world's seas, plastic debris adversely affects living creatures there. (Joyner & Scot Frew 1991).
Types, sources, and locations of ocean
plastic debris
Plastic pollution poses a serious threat as
it is concentrated in areas where marine life is abundantly found. Marine
debris can travel vast distances. Plastic fragments on beaches are derived
either from inland sources and are transported to coasts by rivers, wind,
man-made drainage systems or human activity, or directly from the oceans where
low density floating varieties accumulate and are transported across great
distance. Marine litter can blow around; remain floating on the water surface;
drift in the water column; get entangled on shallow, tidal bottoms; or sink to
the seabed at various depths. It is found in oceans and seas, in salt marshes
and estuaries, in mangroves, on coral reefs, and on all kinds of shores. Beachgoers
also contribute tremendously when they accidentally lose, carelessly handle, or
leave behind plastic materials. There are major inputs of plastic litter
from land-based sources in densely populated or industrialized areas, most in
the form of packaging. Types and amounts of plastic debris on beaches are
controlled mainly by topography, current and storm activity, proximity to
litter sources and extent of beach use. Deposition and retention of plastics on
beaches however, are largely controlled by the composition and degradation
rates of the plastic particles (Corcoran et al. 2009; Derraik 2002; UNEP Marine
Litter: An analytical overview 2005).
 |
| Source: Denver Post |
Unfortunately, plastic debris into the ocean has become an increasingly growing problem and the density thereof has also taken place at an astronomically fast rate.
Human-related impacts
Undoubtedly knowledge about plastic’s harmful
impacts on marine biota has increased and relates to environmental, economic,
safety, health, and cultural impacts. It also detrimentally impacts human
health, while simultaneously damages people’s livelihoods, as well as spoil the
beaches aesthetically and for people’s enjoyment, it creates navigation
hazards, and negatively affects tourism, too. Therefore it has negative
socio-economic consequences.
Impacts on marine species
Conversely, the marine environment has been
perniciously affected by the plastic revolution which have resulted in a serious
environmental issue. Marine populations have fallen significantly as numerous
important habitats have been destroyed. Importantly, plastic pollution
significantly threatens ecosystems and is harmful to organisms, it increases
the transport of organic and inorganic contaminants, it smothers coral reefs, disturb
habitats from mechanical beach cleaning, and breakdown by chemical weathering
and mechanical erosion is minimal at sea. Marine litter is also a source of
accumulation of toxic substances in the marine environment, and environmental
changes due to the transfer and introduction of invasive species (UNEP Marine
Litter: An analytical overview 2005). The biological and ecological performance
of certain individuals will unfortunately be compromised.
Species of crustaceans, fish, turtles,
marine birds, and mammals are affected and the scope and severity of it varies
according to the species and plastic type. Species listed on the IUCN Red List
are particularly vulnerable as they are at a greater risk of becoming extinct. At
least 17 per cent of species affected by entanglement and ingestion of marine
debris are listed as threatened or near threatened on the IUCN Red List (Gall
and Thompson, 2014; WWF Living Blue Planet Report 2015).
Non-degradable plastic
The greatest threat is the durable
properties of plastic as plastic materials persist in the marine environment
long after disposal and may take up to 400 years to degrade. What is worrisome
is the fact that more and more plastic are disposed of every day, and
accumulate in the oceans at an even faster rate. These non-biodegradable items
attract encrusting organisms as drift plastics. The drifting debris acts as a
kind of oasis, attracting other marine animals in search of prey (Joyner &
Frew 1991). Unfortunately, the durable properties of plastic lead to killing
repeatedly. Another potential danger is the accumulation of plastic debris on
the sea floor as certain seabirds select specific plastic shapes and colours,
mistaking them for prey.  |
| Source: Envirocon.org |
Entanglement
Entanglement in plastic debris, especially
with regards to discarded fishing gear, poses a serious threat to marine
animals. When an animal is entangled, it may drown, or impair its ability to catch
food or to avoid predators, reduce its fitness as it leads to an increase in
energetic costs of travel, or incur wounds from abrasive or cutting action of the
debris. Sea birds with stomachs full of plastic waste and turtles entangled in
plastic bags are a serious marine problem. Lost or abandoned fishing nets pose
a particular great risk. |
| Source: Wikipedia |
Sea birds
Recreational fishermen also contribute to
the problem as they don’t properly discard plastic line and birds dive beneath
the water for their prey but become ensnared in the nearly invisible plastic
monofilament line. It also reduce food consumption, limiting their ability to
lay down fat deposits and thus reduces fitness. |
| Source: Earth Rangers |
Ingested plastic particles regularly remain inside species, leading to harmful effects. Many organisms ingest small plastic particles, working their way up to the food chain. Among seabirds, plastic ingestion is directly correlated to foraging strategies and technique, and diet. The durable properties of plastic prevent species from easily digesting it. Small fish and seabirds who ingest plastic debris lead to a reduction in food uptake, cause internal injury, and, sadly, death following blockage of intestinal tract. While feeding on schools of fish, whales can unintentionally ingest plastic debris. Other species mistake translucent plastic bags for squid. Afflicted animals may be eaten or sink to the sea bottom.
 |
| Source: Shutterhead |
 |
| Source: Wikipedia |
All known species of sea turtle have ingested or become entangled in marine debris. Sea turtle hatchlings, which spend their juvenile stage along ocean fronts, can unintentionally consume plastic pellets. In later life, sea turtles sometimes frequent ocean fronts in search of food. These turtles are known to ingest plastic bags, which are mistaken for jellyfish which can be fatal (Joyner & Frew 1991). Young sea turtles are significantly vulnerable and their survival is at risk.
 |
| Source: Energy Digital |
 |
| Source: Project Aware |
Solutions to the problem
Plastic pollution has severely affected the marine environment. Usage of plastics continues to increase, while simultaneously accelerating the amount of plastics polluting the marine environment. The fact is that marine debris does not belong in the marine environment. The threat of plastics to the marine environment has been ignored for a very long time and its severity and serious have only been recognised recently. However, solutions have so far only been a drop in the ocean and more effective solutions are required. Gall & Thompson (2015) suggest that “finding effective solutions requires a holistic approach, considering the entire life cycle of items that become marine debris including green chemistry and design and manufacturing as well as effective waste management and prevention and removal of marine debris”. Nevertheless, attempts have been made to conserve the world’s oceans by way of international legislation. The biggest challenge here is to enforce it effectively in such a vast area as the world’s oceans.
Education is another valuably powerful
tool and can be particularly effective in schools. Through this way children
can change their own habits while concurrently positively impacting their local
community, too, starting with their family and friends. Thus, they can be a
catalyst for important change which would lead to a community be willing to act
sustainably in order to make also an eco-friendly contribution and foster an enhancement
of ecological consciousness. Derraik (2002) notes that “thinking globally and
acting locally is a fundamental attitude to reduce such an environmental
threat”. He further notes that “the general public and the scientific community
have the responsibility of ensuring that governments and businesses change
their attitudes towards the problem”.
These two aspects can successfully and
effectively be the best way forward to solve such a dire environmental problem.
Conclusion
Beaches across the globe are strewed with
plastic debris and pose an imminent and global threat to marine species. Marine
habitats, including shorelines, estuaries, and the sea surfaces, are negatively
impacted by manmade debris. An ecosystem degraded by pollution and fragmented
by development will recover slower from the effects of overfishing and less
resilient to the impacts of climate change (WWF Living Blue Planet Report
2015). It is axiomatic that plastic debris pollution, being an environmental
hazard that threatens our oceans’ biodiversity, must be urgently addressed.
References:
Derraik, J.G.B. 2002. The Pollution Of The
Marine Environment By Plastic Debris: A Review. Marine Pollution Bulletin 44
842–852.
Corcoran, P.L., Biesinger, M.C., &
Grifi, M. 2009. Plastics And Beaches: A Degrading Relationship. Marine
Pollution Bulletin 58 80–84.
Gall, S.C., & Thompson, R.C. 2015. The
Impact Of Debris On Marine Life. Marine Pollution Bulletin 92 170–179.
Joyner, C.C. & Scot Frew, S. 1991.
Plastic Pollution In The Marine Environment. Ocean Development &
International Law 22:1, 33-69.
WWF. 2015. Living Blue Planet Report: Species,
Habitats And Human Well-Being.
UNEP. 2005. Marine Litter: An Analytical Overview.
