Owing in part to their vast size, abyssal plains are believed to be major reservoirs of biodiversity. They also exert significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over time scales of a hundred to a thousand years. The structure of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization have a substantial effect on patterns of primary production in the euphotic zone. There are also amounts of carbon, nitrogen, silica and phosphorus down there, because of the material that shrinks and decomposes. The water is devoid of oxygen and the creatures absorb dissolved oxygen. Oxygen that did exist in this zone came from polar regions that had melted a long time aago, but now since there is pretty much no oxygen, abyssal plains result in a death trap for organisms and creatures that do not have enough time to reach the oxygen-enriched waters above. The only plant-like life that exists in abyssal plains includes deep sea coral reefs, that can very rarely be found at depths bellow 2,000 meters and are geraraly in depths of 3,000 meters and bellow.