The specimens are arranged in three rows that read: Bottom R…
The specimens are arranged in three rows that read: Bottom Row: Mussels, Giant Tubeworms, and Shrimp. Middle Row: Zoarcid Fish and Dandelion Siphonophores. Top Row: Octopuses and Blind Crabs. In the bottom row, there is one arrow from Mussels to Octopuses; there is one arrow from Giant Tubeworms to Zoarcid Fish; and there are three arrows from Shrimp to Zoarcid Fish, Dandelion Siphonophores, and Blind Crabs. In the middle row, there is one arrow from Zoarcid Fish to Octopuses; and there is one arrow from Dandelion Siphonophores to Blind Crabs. In the top row, there is one horizontal arrow from Blind Crabs to Octopuses. The food web above represents feeding relationships in a biological community near a deep-sea hydrothermal vent. Hydrothermal vents are geysers on the seafloor that gush super-heated, mineral-rich water. The seawater surrounding hydrothermal vents typically contains carbon dioxide (CO2), molecular hydrogen (H2), hydrogen sulfide (H2S), and methane (CH4). Sunlight, however, fails to reach the seafloor where deep-sea hydrothermal vents are located. As part of an investigation, researchers collected living specimens from an area near a deep-sea hydrothermal vent. Mussels in the collection were found to be dependent on molecular hydrogen in seawater. Also, the researchers discovered multiple species of bacteria living in the gills of the mussels. Mussels use gills for filter-feeding and gas exchange with the surrounding seawater. On the basis of their experimental results, the researchers hypothesized that some bacteria living in the gills of the mussels are capable of chemosynthesis. Which of the following best explains how biological communities near deep-sea hydrothermal vents can exist in a habitat lacking sunlight?