4Ocean Biological Research
The human impact on ecosystems around the world. Areas of high impact are shown in sections B, C, and D. Section E shows an area of low impact off the coast of Northern Australia.
Plastic Pollution
Plastic is ubiquitous around the world, its wide applicability makes it invaluable to almost every industry. Since the 1950’s when plastic become popular, this material has been chosen for durability and because it is lightweight (Villarrubia-Gómez et al., 2017). However, this has been catastrophic for marine ecosystems. Plastic accounts for up to 80% of waste that accumulates on shores and the ocean surface. Areas of high plastic pollution are generally associated with urbanized and densely populated areas, this is shown on the figure to the left. Plastic can last for hundreds of years in terrestrial environments and even longer in marine habitats and in the deep-sea. The highest inputs of plastic debris are from rivers and accumulation hot spots are impacted by tides, currents and wind patterns. This widespread distribution of plastic causes the detrimental impacts to be felt throughout the ecosystem. Plastic pollution can cause marine organisms to become entangled and trapped, often resulting in fatality. Due to the gradual degradation of plastic, it also poses a risk for ingestion and exposure to chemicals (Barnes et al, 2009).
Macroplastic
Macroplastic is a term for plastic debris that is greater than 5mm. This type of plastic pollution is what is most notable, it includes plastic water bottles, nets, straws, and plastic bags. This type of plastic is most associated with entanglement and ingestion of marine life (Barnes et al., 2009). Currently, many remediation efforts are focused on removing these larger pieces of plastic from the oceans and coastlines. Another environmental concern is the chemicals that could be leaching from the plastic material.
Microplastic
Microplastic is plastic debris that is less than 5mm. Pollution at this size is becoming more of a problem as plastic has been persistent in marine environments for over 50 years. Plastic, while durable becomes more unstable when exposed to high salinity and UV radiation. Both chemical and physical degradation causes plastic to fragment into smaller pieces, which pose a high risk for ingestion (Danso et al, 2019). In addition, due to their elevated surface area to volume ratio they can carry environmental pollutants along with the chemicals already present in plastic.
Ingestion & Entanglement
Ingestion and entanglement are the two biggest concerns with macroplastic. Debris like discarded fishing nets and lines can easily entangle a marine mammal or bird, restricting movement which is often fatal. Ingestion of plastic poses a high risk for birds that feed at the ocean’s surface in addition to filter feeders like baleen whales. Ingestion of plastic can cause a marine organism to choke or interfere with normal digestive processes (Thiel et al., 2018)
Chemical Leaching & Toxins
Plastic contains many toxins and are often coated in chemicals that are known to be carcinogenic and endocrine-disrupting (Barnes et al., 2009). These chemicals are not only being leached into the environment but directly into an organism if ingested. Persistent Organic Pollutants (POPs), which already exist in the marine ecosystem are accumulating on the surface of plastics. This concentration and accumulation causes increases toxicity and can impact important cell processes.
Remediation
Remediation and removal of pollution is the focus of many worldwide organizations including 4Ocean. These organizations focus on the removal of macroplastic in the ocean and along the coastlines. This is a vital step in removing these hazards from the marine environment. However, there must all be legislative and societal efforts to target the source of the problem. By reducing the amount of plastic and addressing waste management the amount of plastic reaching the world’s ocean will decrease.