Impacts of Plastic Waste on the Biota of the Aquatic Ecosystem

The properties that make plastics such desirable materials for modern society can make them lethal for wildlife when introduced into the environment [4]. Numerous species are affected by plastic pollution, primarily because organisms become entangled in plastic nets, or plastic objects are ingested when organisms mistake plastic debris for food [54]. Another problem of plastics pollution is that it facilitates the transport of species to other regions, alien species hitchhike on floating debris and invade new ecosystems, thereby causing a shift in species composition or even extinction of other species [55]. Plastics also transfer contaminants to the environment or, when ingested, to organisms [56]. A technical report considering the impacts of marine debris on biodiversity revealed that over 80% of reported incidents between organisms and marine debris were associated with plastic while 11% of all reported encounters were with microplastics [57]. Although plastic is often buoyant, it can sink to the bottom of the sea, pulled down by certain “bottom-hugging” currents, oceanic fronts or rapid and heavy fouling. Sediment may

TABLE 2.3 Proportion of Plastics among Marine Debris Worldwide (per no. of items)

Locality

Litter Type

Percentage of Debris Items Represented by Plastics (%)

Source

1992 International Coastal Cleanups

Shoreline

59

[26]

St. Lucia, Caribbean

Beach

51

[27]

Dominica, Caribbean

Beach

36

[27]

Curacao, Caribbean

Beach

40/64

[28]

Bay of Biscay, NE Atlantic

Seabed

92

[29]

NW Mediterranean

Seabed

77

[30]

French Mediterranean Coast

Deep sea floor

>70

[31]

European coasts

Sea floor

>70

[32]

Caribbean coast of Panama

Shoreline

82

[33]

Georgia, US

Beach

57

[34|

5 Mediterranean beaches

Beach

60-80

[35]

50 South African beaches

Beach

>90

[24|

88 sites in Tasmania

Beach

65

[24]

Argentina

Beach

37-72

[24|

9 Sub-Antarctic islands

Beach

51-88

[24|

South Australia

Beach

62

[24|

Kodiak Is., Alaska

Seabed

47-56

[36]

Tokyo Bay, Japan

Seabed

80-85

[37]

North Pacific Ocean

Surface waters

86

[38]

Mexico

Beach

60

[39]

Transkei, South Africa

Beach

83

[40]

National Parks in US

Beach

88

|41]

Mediterranean Sea

Surface waters

60-70

[42]

Cape Cod, US

Beach/harbor

90

[43]

4 North Atlantic harbors, US

Harbor

73-92

[43]

Is. Beach State Park, New Jersey, US

Beach

73

|44]

Halifax Harbor, Canada

Beach

54

[45]

Prince Edward Is., Southern Ocean

Beach

88

[46]

Gough Is., Southern Ocean

Beach

84

[46]

Heard Is., Southern Ocean

Beach

51

[47]

Macquarie Is., Southern Ocean

Beach

71

[47]

New Zealand

Beach

75

[48]

Two gulfs in W. Greece

Seabed

79-83

[49]

South German Bight

Beach

75

[50]

Bird Is., South Georgia, Southern Ocean

Beach

88

[51]

Fog Bay, N. Australia

Beach

32

[52]

South Wales, UK

Beach

63

[53]

Source: From Derraik JGB. Mar Pollut Bull 2002, 44(9), 842-852. Abbreviation: Is., Island.

Marine organisms ingesting plastic debris

FIGURE 2.4 Marine organisms ingesting plastic debris: From left to right, recovering plastic debris from carcass of an albatross, plastic debris retrieved from a filleted fish and a turtle eating plastics (polyethylene sachet film). (From Lytle GM. When the mermaids cry: The great plastic tide. Available on: http://www.plastic-pollution.org, accessed on January 4, 2018.)

Entanglement effect of plastic debris on seals

FIGURE 2.5 Entanglement effect of plastic debris on seals: From left to right, seal trapped by a discarded fishing net and seal entangled by ghost fishing lines. (From Lytle GM. When the mermaids cry: The great plastic tide. Available on: http://www.plastic- pollution.org, accessed on January 4, 2018.)

also help keep plastic on the seafloor [5]. It is likely that once on the seafloor, plastic will change the workings of the ecosystem. Goldberg [58] has suggested the plastic sheets could act like a blanket, inhibiting gas exchange and leading to anoxia or hypoxia (low oxygen levels). Plastic waste could also create artificial sand grounds [59] and cause problems, especially for burying creatures.

There is still relatively little information on the impact of plastics pollution on ocean ecosystems [60,61]. There is, however, an increasing knowledge about their deleterious impacts on marine biota [58]. The threats to marine life are primarily mechanical and are due to ingestion of plastic debris and entanglement in packaging bands synthetic ropes and lines or drift nets [38,54,60]; see Figures 2.4 and 2.5. Since the use of plastics continues to increase, so does the amount of plastics polluting the marine environment. In addition to the impact on marine environment and life, plastic debris can also damage the marine industry (entangling propellers and blocking cooling systems). It has been estimated that marine debris damage to the marine industry in the Asia-Pacific region coasts $1.26 billion annually [62].

 
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