文档介绍：486 marine microbiology
Marine anisms play a significant role in cycling Earth’s carbon. Photosynthetic algae and cyanobacteria take in more
atmospheric carbon than all bined. The assimilated carbon, then, feeds marine and terrestrial food chains.
At this depth, water produces intense pressures that anisms may additionally incorporate extra
anisms cannot withstand. Barometric pres- processes whereby they can quickly repair damage
sure increases gradually with depth, which in turn to the cell due to the high pressures. Researchers
affects the types of anisms living at different have found specific genes in barophiles that turn
depths. The ocean surface where sunlight rates on or off, depending on the barometric pressure
is called the photic zone and contains anisms of the surroundings. The anisms that live
that do not tolerate high pressures. Greater depths in marine waters as well as anisms living
increase the barometric pressure to a maximum of inside marine animal digestive tracts both must tol-
about 1,100 atmospheres, at the deepest places. The erate elevated pressures of the deep sea.
following types of anisms live at differ- Temperature in most of the ocean surface ranges
ent depths based on the barometric pressures they from 59°F to 86°F (15–30°C). Less than 30 percent
tolerate: of Earth’s ocean surface waters have temperature
below 50°F (10°C). At depths greater than 3,280 feet
• barotolerant—33–13,123 feet (10–4,000 m) (1,000 m), temperatures reach a range of 41–29°F
(5 to −°C), where psychrophiles grow best. Many
• moderate barophilc—4,921–18,450 feet (1,500– hydrothermal vents also dot regions of the Pacific
5,500 m) Ocean floor, releasing pressurized water from the
earth’s core. The anisms living in areas
• extreme barophilic—16,404–36,089 feet (5,000– near vents are hyperthermophiles, which withstand
11,000 m) temperatures up to 750°F (400°C).
Temperature varies in gradients in the ocean,
Several pr