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The organisms responsible for primary production are called primary producers or autotrophs. Most marine primary production is generated by a diverse collection of marine microorganisms called algae and cyanobacteria. Together these form the principal primary producers at the base of the ocean food chain and produce half of the world's oxygen ...
Fish do not use energy to keep warm, eliminating some carbohydrates and fats in the diet, required to provide this energy. This may be offset, though, by the lower land costs and the higher production which can be obtained due to the high level of input control. Aeration of the water is essential, as fish need a sufficient oxygen level for ...
At the beginning of the 20th century California kelp beds were harvested for their potash. [1] [5] [6] Commercial interest increased during the 1970s and the 1980s due to the production of alginates, and also for biomass production for animal feed due to the energy crisis.
Water is very effective at absorbing incoming light, so the amount of light penetrating the ocean declines rapidly (is attenuated) with depth. At one metre depth only 45% of the solar energy that falls on the ocean surface remains. At 10 metres depth only 16% of the light is still present, and only 1% of the original light is left at 100 metres.
Benthic communities around methane seeps rely on methane-oxidizing microorganisms to supply energy to other microorganisms. [8] In some rare cases, bacteria use chemical energy sources such as sulfides and methane. Many of the animals in the aphotic zone are bioluminescent, meaning they can produce their light.
Another impact aquaculture production can have on wild fish is the risk of fish escaping from coastal pens, where they can interbreed with their wild counterparts, diluting wild genetic stocks. [108] Escaped fish can become invasive , out-competing native species.
Records of bioluminescence due to bacteria have existed for thousands of years. [4] They appear in the folklore of many regions, including Scandinavia and the Indian subcontinent. Both Aristotle and Charles Darwin have described the phenomenon of the glowing oceans which is most likely due to these light-producing organisms. [4]
It covers 11.4 million square kilometres (4.38 million sq mi), which is the second largest zone in the world, exceeding the land area of the United States. [5] According to the FAO, in 2005, the United States harvested 4,888,621 tonnes of fish from wild fisheries, and another 471,958 tonnes from aquaculture. This made the United States the ...