Bioluminescent Organisms, Japan Photograph by Paul A. Zahl The transparent shells of tiny Cypridina hilgendorfii, found in the coastal waters and sands of Japan, hold a creature that emits a luminous blue substance when disturbed. During World War II, the Japanese harvested these creatures for soldiers to use when reading maps and messages at night. (Photo shot on assignment for “Nature’s Night Lights—Probing the Secrets of Bioluminescence,” July 1971, National Geographic magazine)
An aerial view captures the sweep of sea and sky surrounding Japan’s Ogasawara Islands, also known as the Bonin Islands—and now one of the newest World Heritage natural properties. The archipelago is home to nearly 200 endangered bird species and at least one critically endangered bat—the Bonin flying fox. (See pictures of a new volcanic island forming in the Bonin Islands.) More than 400 native plants grow here at an evolutionary crossroads, where species from both southeast and northwest Asia coexist alongside others found nowhere else in the world. “The remoteness of the Ogasawara Islands has allowed animals and plants to evolve practically undisturbed, making it a living evolutionary laboratory,” Peter Shadie, deputy head of IUCN’s World Heritage delegation, told the press.
China’s monopoly over rare-earth metals could be challenged by the discovery of massive deposits in mud on the Pacific floor, a study suggests. China accounts for 97 per cent of the world’s production of 17 rare-earth elements, which are essential for electric cars, flat-screen TVs, iPods, superconducting magnets, lasers, missiles, night-vision goggles, wind turbines and many other advanced products. These elements carry exotic names such as neodymium, promethium and yttrium but in spite of their ‘rare-earth’ tag are in fact abundant in the planet’s crust. The problem, though, is that land deposits of them are thin and scattered around, so sites which are commercially exploitable or not subject to tough environment restrictions are few. As a result, the 17 elements have sometimes been dubbed ’21st-century gold’ for their rarity and value. Production of them is almost entirely centred on China, which also has a third of the world’s reserves. Another third is held together by former Soviet republics, the United States and Australia. But a new study, published in the journal Nature Geoscience , points to an extraordinary concentration of rare-earth elements in thick mud at great depths on the Pacific floor. Japanese geologists studied samples from 78 sites covering a major portion of the centre-eastern Pacific between 120 and 180 degrees longitude. Drills extracted sedimentary cores to depths that in place were more than 50 metres below the sea bed. More than 2000 of these cores were chemically tested for content in rare-earth elements. The scientists found rich deposits in samples taken more than 2000 kilometres from the Pacific’s mid-ocean ridges. The material had taken hundreds of millions of years to accumulate, depositing at the rate of less than half a centimetre per thousand years. They were probably snared by action with a hydrothermal mineral called phillipsite.
