Where are microorganisms found in the ocean ecosystem? Describe the different zones of the ocean, their abiotic characteristics (e.g. temperatures, pressures, salt content, pH), and which types of organisms live there.
What will be an ideal response?
The ocean is salty throughout. However, the water column is not uniform throughout.
Diffusion rate of oxygen in water is about 10,000 times less than in air. So, the oxygenated parts of the ocean are usually the top parts (neuston zone and euphotic zone). Photosynthetic microbes (i.e. producers or phytoplankton) that fix half the world's carbon inhabit these zonesThe neuston is the air-water interface (10 microns thick). It contains the highest concentration of microbes. By contrast, the euphotic zone contains the upper 200-300 meters of the open ocean. In this zone, we find phytoplankton, as well as zooplankton (i.e. microbial predators of phytoplankton), as well as decomposers. The coastal shelf can decrease the size of the euphotic zone to a couple of meters. The aphotic zone has no light penetrating, so does not support the growth of phototrophs (only heterotrophs). The benthos zone is where the water column meets the ocean floor, and harbors microorganisms that live near hydrothermal vents, for example.
pH is mostly determined by the dissolution of CO2 in the water, such that pH is low near the top of the ocean (due to CO2 from air dissolving at the surface, creating carbonic acid). In the benthos, hydrothermal vents can emit pH ~10 fluids, increasing the pH of the surrounding water significantly. In the benthos, psychrophiles and barophiles grow, although slowly, because little organic matter is hitting the ocean floor. By contrast, thermophiles grow in black smoker thermal vents. Reduced minerals support lithotrophic bacteria, including mutualists of giant clams and worms. H2S oxidizers fix carbon from the carbonates, generating organic metabolites that feed the animal hosts. The tube worm Riftia is colored bright red by a pigment that carries H2S and O2 through its circulatory fluid. It has evolved such dependence on its microbes that it has lost its own digestive tract.
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Refer to the table above. Because the shark rectal gland functions only when ATP molecules are present, what can you infer about the movement of Na+, K+, and Cl-?
A) Movement of these ions from circulation into the rectal gland is an active process. B) Movement of these ions takes place from a region of higher concentration to a region of lower concentration. C) These ions move into the rectal gland down their concentration gradient. D) The rectal gland is unable to concentrate these ions.
The major problem associated with Luft's Syndrome is
a. insufficient ATP production. b. slow metabolism. c. too few mitochondria. d. excessive ATP production. e. low cellular oxygen consumption
What type of mutation occurred in the following? Normal allele GGAAUGAAACAGGAACCC Mutant allele GGAAUGAAAUCAGGAACCC
A. insertion B. substitution C. deletion D. frameshift
Molting is necessary for:
A) all animals. B) only animals with endoskeletons and scaly skin. C) all animals with exoskeletons. D) all animals with skeletons. E) all animals with endoskeletons.