V. Grammar 5%
Sixty miles north of Guam and more than 1,700 feet under the ocean's surface is thesummit of NW Rota-l, an undersea volcano discovered in 2003. At that depth, water pressuresuppresses the explosive force of the volcano's eruptions, allowing scientists to watch themup close via remotely operated vehicles. Surprisingly, the volcano appears to have beencontinuously active； it even grew 130 feet in height between 2006 and 2009. Yet, despite thehostile environment created by the constant volcanic activity, life is thriving there. Specialadaptations are the key to survival.
NW Rota-1 is far below the ocean's photic zone where sunlight drives photosynthesis；(41) nevertheless, bacteria supporting a unique food web have adapted to this perpetuallydark environment. The bacteria have evolved to use hydrogen sulfide instead of sunlight forthe energy that drives their metabolic processes, and hydrothermal venting is the source of thechemical soup necessary to support them. Seawater seeping into fissures in the ocean floor isated by underlying magma, and the heat drives chemical reactions that remosulfates, and other chemicals from the water. Once the superheated water (up to 750°F ) risesthrough vents in the ocean floor, additional reactions cause mincrals and compounds toprecipitate onto the seafloor, where bacteria feed on them.
Loihi shrimp—originally thought to exist only around an undersea volcano near 6Hawaii-survive by using tiny, shear-like claws to harvest rapidly growing bacterial filamentscovering rocks ncar NW Rota-I's hydrothermal vents. The Loihi shrimp spend most of theirtime grazing on the bacteria and evading another, previously unknown, species of shrimp.rimp of that species also graze on bacterial filaments as juveniles, (42) resultintheir ability to cope with the noxious environment around the volcano. They feed on theLoiti shrimp and other organisms that are overcome by the toxic plumes of volcanic gas andash.
During an underwater eruption, steam quickly condenses and leaves only carbon dioxidebubbles and droplets of molten sulfur. This means that the water near Nw Rota-1 is moreacidic than (43) that of stomach acid, presenting yet another challenge to life-forms livingnearby. As the carbon dioxide level in Earth's atmosphere rises, the [44) worlds' ocean'sabsorb more carbon (45) dioxide. Organisms flourishing near the volcano may help biologistsunderstand how life adjusts to very acidic conditions. In addition, NW Rota-I is a naturallaboratory where scientists can study conditions that may be similar to those that gave rise tolife on Earth and perhaps even other worlds.