Marine pollution is caused by

A. Sewage

B. Land runoff

C. Oil spills

D.. Ocean mining

Choose the correct code:

Correct option is C

Introduction
· Marine pollution occurs when harmful effects result from the entry into the ocean of chemicals, particles, industrial, agricultural, and residential waste, or the spread of invasive organisms.
· Approximately 80% of marine pollution originates from land-based activities, reaching the ocean through various direct and indirect pathways.
· Understanding these sources is vital for international maritime law and the conservation of coral reefs and marine biodiversity.

Information Booster
· Sewage : Direct discharge of untreated municipal waste leads to nutrient loading (Nitrogen and Phosphorus), causing eutrophication and "dead zones" where oxygen levels are too low to support life.
· Land runoff : This is a non-point source of pollution. It includes agricultural runoff (pesticides and fertilizers) and urban runoff (heavy metals and oils) washed into the sea via rivers or rain.
· Oil spills : While dramatic tanker accidents capture headlines, a large portion of oil pollution comes from routine ship maintenance, illegal tank cleaning, and natural seeps. Oil forms a surface film that prevents oxygen exchange and coats the feathers/fur of marine life.
· Ocean mining : This emerging threat involves the extraction of minerals from the deep sea floor. It causes physical destruction of benthic habitats and creates "sediment plumes" that can smother organisms far from the mining site.

Additional Knowledge
· Plastic pollution is another major component of land runoff and sewage, with microplastics now found in the deepest parts of the ocean, such as the Mariana Trench.
· Thermal pollution from power plants located on coasts can also disrupt local marine life by altering the temperature of the water, affecting the metabolic rates of fish and coral.
· Acoustic pollution (noise from ships and sonar) is an invisible form of marine pollution that interferes with the communication and navigation of marine mammals like whales and dolphins.
· The MARPOL Convention is the main international convention aimed at preventing pollution of the marine environment by ships from operational or accidental causes.