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Darwin's Paradise Awash
New Scientist 10 Jan 98

WEIRD weather in the Galspagos Islands is threatening to alter forever the ecosysNinotems that support the archipelago's unique plants and animals. The high temperatures and rainfall brought by the El Nino event currently gripping the Pacific could cause populations of several species living in the archipelago to crash, biologists warn. They fear that alien species which have invaded the islands will then establish such a foothold that native species won't bounce back. "It's going to be a catastrophe," predicts JenNinonifer Stone of the Galapagos Conservation Trust, a British charity. The current El Nino is shaping up to be at least as severe as the devastating event of 1982-83. Fifteen years ago, the GalApagos had 2770 millimetres of rain-almost six times as much as normal. When the El Nino reached its peak, the sea temperature was 3 'C higher than average for the time of year. The outlook is grim, says Michael Bliemrieder of the Charles Darwin Research Station on the island of Santa Cruz. In 1982-83, the number of flightless cormorants, which are unique to the Galapagos, fell by 45 per cent, while 78 per cent of the rare Galapagos penguins died. Waved albatrosses failed to breed. In the sea, green algae eaten by marine iguanas-were replaced by inedible red algae. On some islands, 70 per cent of iguanas starved. The heavy rains of 1982-83 also triggered an explosion of plant growth on the islands. This encouraged the spread of introduced pests, such as fire ants and rats. Under the current El Nino, the cool misty season, known as garua, which is supposed to arrive in June, never materialised, and the climate remains hot and sticky. "It feels more like the tropical jungles of the Amazon than the and Galapagos Islands," says Bliemsrieder. The rains, which in a normal year don't start until February, began with a vengeance in November, which saw 147 millimetres. Biologists working on the normally dry island of Espanola reported 204 millimetres of rain in just two days in mid-December. Rain is forecast to continue until El Nino reaches its peak in March. There are already signs that the wildlife catastrophe of 1982-83 may be about to repeat itself. Many seabirds have failed to nest, including the waved albatrosses. A shift from green to red algae is in progress, and hammerhead sharks have moved into deeper, cooler waters. On land, meanwhile, normally dry and barren islands are once again blooming with luxuriant vegetation. "Even the most and islands are covered with a green carpet," says Bliemsrieder. In the past, native species eventually recovered. But since 1983, alien species have become further established, and biologists fear that they could now stop native animals making a comeback. "Introduced species are by far the most serious threat to the biodiversity of the Galapagos," says Robert Bensted-Smith, director of the Darwin research station. Conservationists have been battling against rats, cats and goats for years. More recent arrivals include two species of fire ants and an unpleasant biting fly "Some islands are now completely infested with fire ants," says Charlotte Causton, an entomologist at the Darwin research station. "And the fly breeds in running water, so you would expect it to increase when there is more rain." Stephanie Pain


Surface Tension Brett Phibbs NZ Listener May 20 1998
The Hammerheads are leaving the Galapagos

El Nino Tightens its Grip New Scientist 25 Apr 98

HAMMERHEAD sharks have fled, corals have turned white and giant barnacles are dead. The overheated water around the Galapagos Islands, caused by El Nino in the Pacific, is beginning to take a toll of the archipelago's unique wildlife, as ecologists predicted (This Week, 10 January, p 4). In Brussels last week, a meeting of the Charles Darwin Foundation heard that the next few weeks will be crucial. Climate experts originally predicted that the current disruption of Pacific Ocean cur- rents would tail off by May. But it now looks likely to drag on. Marine species have been hardest hit so far, faced with waters 5 'C warmer than usual for several months. During diving surveys in February, Ken Collins, a marine biologist from Southampton University, saw many fishes from warmer regions but no hammerhead sharks, which prefer cooler waters. "What was startling was the almost total death of large barnacles and the extensive bleaching of corals in shallow water," he adds. This happens when the green algae that live in the tissues of corals become stressed and desert their hosts. Marine iguanas, unique to the Galipagos, are also in trouble because the seaweeds they feed on have been replaced by inedible species. "They have been getting thinner and in the past few weeks we have been seeing significant mortality," says Robert Bensted- Smith, director of the Charles Darwin Re- search Station on the island of Santa Cruz. Most of the islands' seabirds have also failed to breed, including the endemic blue-footed booby. Some GalApagos natives are thriving, however. "El Nino's really good for the giant tortoises," says Tom Fritts of the National Museum of Natural History in Washington DC. Increased rainfall provides them with an abundance of vegetation to eat. Annual rings laid down in the tortoises' shells reveal growth spurts corresponding to El Nino years, says Frits. Stephanie Pain, Brussels

El Nino puts a damper on Star Gazing New Scientist 10 Jan 98

THE scourge of farmers around the globe, El Nino can upset astronomers' observations as well. Its dramatic warming effect in the Pacific may draw enough water into the atmosPhere to dim views of the cosmos at infrared wavelengths, even on the clearest nights. Astronomer Jay Frogel of Ohio State University in Columbus studied data from nearly 200 nights of observations at the Cerro Tololo Inter-American Observatory in Chile, spanning 1978 to 1992. Each time, he monitored about a dozen "standard" stars of known brightness. Changes in the apparent brightness of these stars betrayed hourly and daily fluctuations in the clarity of Earth's atmosphere. Over longer timescales, several patterns emerged in the measurements for near-infrared wavelengths. Most notably, the standard stars appeared slightly dimmer during the southern hemisphere summer, from December to February. That was no surprise-warm air holds more water vapour, which absorbs infrared radiation. But Frogel also found a link with episodes of El Nino. Strong El Ninos draped a moist veil above the observatory, dulling stars by as much as 2 per cent compared with "normal" years. The analysis will appear in Publications Of the Astronomical Society of the Pacific. Frogel suspects that observers more distant from El Nino's warm water pool would see a similar influence especially now, during the century's strongest El Niho. "For observational programmes that require an accuracy of 1 per cent or better, this effect Must be taken into account," he says.