Pacific Ocean width at about 5°N latitude, where it stretches approximately from Indonesia to the coast of Colombia—halfway around the world, and more than five times the diameter of the Moon. The lowest known point on Earth—the Mariana Trench—lies below sea level. Its average depth is , putting the total water volume at roughly . Due to the effects of plate tectonics, the Pacific Ocean is currently shrinking by roughly per year on three sides, roughly averaging a year. By contrast, the Atlantic Ocean is increasing in size. Along the Pacific Ocean's irregular western margins lie many seas, the largest of which
Ocean acidification in the Arctic Ocean is thought that because of this, additional stressors such as ocean acidification, will cause ocean acidification effects on marine organisms to appear first in the Arctic. There exists a significant variation in the sensitivity of marine organisms to increased ocean acidification. Calcifying organisms generally exhibit larger negative responses from ocean acidification than non‐calcifying organisms across numerous response variables, with the exception of crustaceans, which calcify but were not negatively affected. The acidification of the Arctic ocean will impact these marine calcifiers in several different ways. The uptake of CO₂ by seawater increases the concentration of hydrogen ions, which lowers pH