increasing yellow band disease, a bacterial infection that kills reef-building hard corals by fifty percent. Air pollution A study released in April 2013 has shown that air pollution can also stunt the growth of coral reefs; researchers from Australia, Panama and the UK used coral records (between 1880 and 2000) from the western Caribbean to show the threat of factors such as coal-burning coal and volcanic eruptions. The researchers state that the study signifies the first time that the relationship between air pollution and coral reefs has been elucidated, while former chair of the Great Barrier Reef Marine Park Authority Ian McPhail referred to the report as "fascinating" upon the public release of its findings. Marine debris Marine debris is defined as any persistent solid material that is manufactured or processed and directly or indirectly, intentionally or unintentionally, disposed of or abandoned into the marine environment or the Great Lakes. Debris may arrive directly from a ship or indirectly when washed out to sea via rivers, streams, and storm drains. Human-made items tend to be the most harmful such as plastics (from bags to balloons, hard hats to fishing line), glass, metal, rubber (millions of waste tires), and even entire vessels. Plastic debris can kill and harm multiple reef species. Corals and coral reefs are at higher risk because they are immobile, meaning that when the water quality or other changes in their habitat occur, corals cannot move to a different place; they must adapt or they will not survive. There are two different classes of plastics, macro and microplastics and both types can cause damage in a number of ways. For example, macroplastics such as derelict (abandoned) fishing nets and other gear—often called "ghost nets" can still catch fish and other marine life and kill those organisms and break or damage reefs. Large items such as abandoned fishing nets are known as macroplastics whereas microplastics are plastic fragments that are typically less than or equal to 5 mm in length and have primarily been found to cause damage to coral reefs though corals ingesting these plastic fragments.Fig. 1. Video frame sequence of capture and ingestion of a microplastic particle by a polyp of Astroides calycularis. Obtained from Savinelli et al. (2020)]] Some researchers have found that ingestion of microlastics harms coral, and subsequently coral reefs, because ingesting these fragments reduced coral food intake as well as coral fitness since