Then again, you may soon come to rest upon an endless heap of parrotfish poop. You may be about to comfortably nestle down in the remains of million-year-old rocks. So the next time you unfurl your beach towel down by the shore, ponder the sand beneath you, which, as Rachel Carson said, is telling you a story about the Earth. At the same time that it helps to maintain a diverse coral-reef ecosystem, parrotfish can produce hundreds of pounds of white sand each year! The red, firm flesh is also delicious as sashimi or sushi. Usually served grilled, a yellowfin tuna can weigh up to 300 pounds. The fish bite and scrape algae off of rocks and dead corals with their parrot-like beaks, grind up the inedible calcium-carbonate reef material (made mostly of coral skeletons) in their guts, and then excrete it as sand. AHI Here’s one Hawaiian fish that has made it onto Mainland restaurant menus, along with mahi mahi. Traps are culturally almost universal and seem to have been independently invented many times. The famous white-sand beaches of Hawaii, for example, actually come from the poop of parrotfish. Fish traps include fishing weirs, lobster traps, and some fishing nets such as fyke nets. Less common but no less inviting beaches, devoid of quartz as a source of sand, rely on an entirely different ecologic process. Bermuda's preponderance of pleasantly pink beaches results from the perpetual decay of single-celled, shelled organisms called foraminifera. The by-products of living things also play an important part in creating sandy beaches. Black-sand beaches are common in Hawaii, the Canary Islands, and the Aleutians. Black sand comes from eroded volcanic material such as lava, basalt rocks, and other dark-colored rocks and minerals, and is typically found on beaches near volcanic activity. The tan color of most sand beaches is the result of iron oxide, which tints quartz a light brown, and feldspar, which is brown to tan in its original form. Once they make it to the ocean, they further erode from the constant action of waves and tides. Often starting thousands of miles from the ocean, rocks slowly travel down rivers and streams, constantly breaking down along the way. Rocks take time to decompose, especially quartz (silica) and feldspar. Sand forms when rocks break down from weathering and eroding over thousands and even millions of years. Sand comes from many locations, sources, and environments. The environmentalist Rachel Carson wrote, "In every curving beach, in every grain of sand, there is a story of the Earth."
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