Ocean Floor First Readings

1.   Up Close and Personal On the Ocean’s Floor

Marine biologists take up residence

4/1989 washington post

By PhillipliJ.  Hilts

TRITON BAY, St. Croix—Sixty feet below the calm, translucent blue water off the shore of this island paradise, a huge metal cylinder sits on the sandy bottom, perched on four steel legs like a great armored insect. It is called Aquarius, and it is humanity’s only outpost in the hostile and little known undersea realm of the Caribbean.

   The new $5.5 million facility, owned by the National Oceanic and Atmospheric Administration and operated in the U.S. Virgin Islands by Fairleigh Dickinson University, is to marine biology what a giant telescope is to astronomy.

   Under water, the barrier to science is not distance but time. Without such underwater habitats, marine biologists can only hook their objects of study and drag them out of the water, unable or more than a few minutes at a time to watch the animals where they live. Even with scuba gear, researchers have only 15 minutes at 120 feet before they must surface to avoid getting the bends, the curse of divers that makes the blood ‘boil’ as gases forced into it by the pressure bubbles out.

  Facilities such as Aquarius break the time barrier, allowing humans to live for days on the ocean bottom— postponing the long, slow decompression needed to let the gases escape slowly before surfacing. Time in Aquarius offers an experience still so new, that even routine trips produce sights and insights that are fresh to human eyes and minds.

   Recently a group of six and students allowed a reporter to visit several times during their 10-day stay in Aquarius. Their mission was to study the shaggy, bright walls of coral cliffs rising from the bottom off the northwestern coast of St. Croix.

  Over thousands of years, the corals, quarter inch long creatures that seem half rock and half animal, have built vast limestone reefs that protect islands and seashores around the world. Their cathedral like lattices serve as spawning grounds for many important fish, and ultimately, when buried, coral becomes the source of much of the world’s oil.

   In recent years, corals have become a trove of potent drugs and chemicals. Now, researchers suspect, they also may provide crucial clues to the state of global climate change.

   In many ways, corals are the undersea equivalent of the canaries that miners used to take with them below the earth to detect traces of poisonous gas.  When the sensitive birds died, the miners knew it was time to get out of the mine. Similarly, coral reefs are so sensitive to changes in  light and temperature that they may be among the first biological systems to change, or to collapse, if the world warms and the seas rise over the next 50 years, as the "greenhouse effect" theory predicts.

   Currently one of the chief mysteries of reefs is the widespread death of corals and other reef animals.  In the past five years, massive die-offs have swept across the Caribbean and the eastern Pacific, the greatest marine mass deaths ever witnessed.

 Ninety eight percent of the entire population of black urchins died in one season. Few are left here at St. Croix. More than half of the corals on some reefs in Caribbean, and on virtually all of the reefs in one area of the eastern Pacific, died in two epidemics. Sea grasses and fish have also died in sudden epidemics.

It remains unclear whether the dieoffs are connected to a global greenhouse warming, but the possibility has spurred Aquarius biologists to undertake a wide range of basic studies of coral reef ecosystems. According to Richard Rounds of Fairleigh Dickinson, it was only recently that researchers began collecting as basic a form of data as water temperature.

    In life and color, the reefs are as prolific as any acreage on Earth. They are packed with an estimated million species, the whole swarming community creating and burning up energy at a furious rate. Wherever corals can gain a foothold, they build. Their skeletons, instead of being inside their bodies, are on the outside—bony apartments in which they live. The shapes of these apartment complexes are strange and varied, and their names describe them: brain coral as a dome with grooves, the Elkhorn stands like broad antlers, the sea fan is a great lacy leaf and the deadman's fingers reach up from the bottom and undulate like a grasping hand.

    But there is no margin in this life. The corals live at their upper limit of temperature; a warming of 2 degrees can kill them all.  They soak up light hungrily, but a little extra light, as might fall on them if ozone layer decays enough, can scorch them.   And if the sea level rises only slightly faster than it does now, the slow building reef will be unable to keep up. It will slowly die from lack of light.  Leading scientific team on Aquarius was Drew Harvell, a Cornell University biologist.  Also on the mission were two other students, Josh Nowlis and Brian Helmuth, two Northeastern University researchers,  Julia Milesand, George Bruno, and Doug Keslingm from Fairleigh Dickinson.

Twice each day, the divers launched themselves from under the habitat to carry out their experiments, donning double air tanks and swimming among the unearthly shapes and colors of the corals, fish, anemones and worms. They also went out on five (nights, gliding through the  water with lights to make observations.

     "Until a few years ago, ecologists had no information about chemical effects in the ocean. Now we realize that they have more effect than any other single phenomenon in marine says William Fenical of Scripps Institution of Oceanography, who waited ashore to analyze coral specimens.

     From the point of view of small creatures such as reef fish, the apparently placid coral reef on which they depend for sustenance is alive and threatening. "Imaginea Landscape of white rock pockmarked with thousands of holes,’ wrote Eugene Kaplan in his book, “Coral Reefs."  "At night, out of each hole extends a hand… . . . writhing and snapping at anything that passes by…. Visualize the hands covered with hair. To touch these hairs could mean instant death, for some are poisonous."

 In the key experiments, divers collected two species of soft coral from shallow reefs and from reefs 100 feet deep. They transplanted them—shallow to deep and deep to shallow—into little artificial colonies.colonies.

   The experiment is aimed at understanding the puzzling defense mechanisms of soft corals. They l stand upright, prominently displayed on the reef, seemingly a choice morsel (passing predators. Unlike hard corals, they have no stony armor, no piercing projectiles, no nasty barbs. But fish will not go near them. The reason may be important to medicine as well as to science:  The corals produce an array of noxious compounds to defend themselves.

     Biologists want to know whether the production of toxins is fixed at a given rate by evolution or can vary according to environmental factors.   If the chemical production is limited by genes, the corals should not be able to adapt when transplanted to a different environment, such as deeper or shallower water. If, on the other hand, the production is not fixed the animals should be able to adapt. For example, corals that produce few toxins in deep water, where there are few predators, should begin producing the chemicals when moved to shallow waters where fish start nibbling at them. The transplanted corals will rest in the canyon off St. Croix over the next years and will be visited periodically by researchers who will measure their progress.

   The scientists did not have to wait for results of experiment. One night, the team went out with mesh bags to find banded butterfly fish. The fish were unprepared for night visitors, and the researchers found that they could stun them simply by shining a light in their eyes. Back near the Aquarius, Nowlis put each butterfly fish into a 4by4 foot wire cage with some soft corals. What he saw was fascinating: The fish avoided eating soft corals, preferring nearly anything else. But if given nothing else, they nibbled on the less noxious ones from deeper reefs.

     Nowlis other predators— in one cage the orange and black flamingo tongue, in another the bristly red and white fire worm. They too chewed up the deep water corals and avoided the shallow water ones.,

Even Aquarius cannot give the divers enough time underwater to watch as the natural of a coral reef unfolds. The corals reproduce only every few years, and then only for few hours.  In one night, four days after the full moon, they commit their free-swimming larvae to the sea, to seek their own way. The next time the corals reproduce, Drew  Harvell be there to watch, to collect, to study the young and how they join the life of the coral reef.


Coral in Hot Water?

5/1989 Star Bulletin

By Jan TenBruggencate


Hawaii corals have been strained by abnormally hot summer water temperatures that may be linked to the greenhouse effect, according to a University of Hawaii researcher.

If the warming continues, it probably will result in a decline in marine life in Hawaiian waters, the researcher said. 

The temperature sensitive corals could also be an indicator of the larger potential environmental problem said Paul L. Jokki, a coral researcher at the Hawaii Institute of Marine Biology.

Scientists have found that overly warm water is a primary cause of “bleaching” and sometimes the subsequent death of coral communities.

 s, And they have noted more and more of these bleachings in Hawaii and elsewhere when ocean temperatures have been abnormally high. There have already been incidents of bleaching in sensitive Hawaiian corals, and “there is a possibility that we will see bleaching here in late summer this year (1989) or in the next few years if ocean temperatures continue to rise,” said Jokiel

Jokiel and co author L. Coles, with the King University of Petroleum and Minerals Research I in Saudi Arabia, have written an article, “Response of Hawaiian and Other EndoPacific Reef Corals to Elevated Temperatures" tbe published in an upcoming issue of the journal “Coral Reefs".

  The death of reef coral is a concern for a variety of reasons, including the protection such reefs provide to the shoreline. But coral death may be even more important as an indicator of the health of the marine community, Jokiel said.

   Studies show that there tends to he more marine life from shellfish to swimming fish, in areas with healthy coral communities than in areas with unhealthy or dead coral, Jokiel said. The reduction in both the diversity of species and the overall weight of the living things in a given area may be related to the decline in corals as members of the food chain and as shelter. But more, the other species decline for the same reasons that cause the coral to die off, he said.

Corals are long lived and require a high water quality, If the corals are going because of changing water conditions, you can assume other species are impacted also,” he said.

Jokiel did his initial studies in the late 1960's and early 1970's on the effects of heated water on coral communities in the hot water outfalls of electrical power plants.  Much of the work was done on the reefs off the Kahe Point plant on Oahu.  , At the time, there was no indication the research would have broader significance.

Then, 1O years ago, Hawaii began to see a dramatic rise in ocean temperatures. In a review of maximum Hawaii ocean water temperatures, only one year in the past 10 has had late summer temperatures below the average for the previous 24 years. That year, 1983, was only a tenth of a degree lower. (The figures are in degrees centigrade, each of which is a little less than two degrees Fahrenheit.)

    Jokiel said there is still not sufficient information to link the higher water temperature greenhouse effect. Most scientists agree the global warming of the greenhouse effect is coming but they disagree over whether odd worldwide weather patterns and heat of the past few years mean it’s already here. Still, a “prolonged warming trend of this intensity and duration is unprecedented in the long term record,” Jokiel said in their article for “Coral Reefs’ “

"In 1986, 1987 and 1988 Hawaiian corals were perilously close to their bleaching threshold during the summer months, and localized bleaching did occur, " he said.

     Bleaching occurred in some shallow reef areas, but also in waters as much as 60 feet deep the lee sides of the larger islands: off Olowalu, Maui, and Kona, Hawaii.

 “What we’ve had in Hawaii so far is the very beginning.  What they’ve had in the Caribbean and elsewhere is massive bleaching and mortality,’ Jokiel said. It seems strange that Hawaii would have such problems, because Hawaii’s waters, even in late summer, are cooler than those in many other coral growing areas.

     But Jokiel said Hawaii’s corals appear to have adapted to Hawaii’s normal ocean temperatures and lost their ability to handle the higher temperatures their tropical relatives do.  That adaptation to different temperatures might suggest hope, but Jokiel said it appears the adaptation take thousands or even million of years.

“Repeated annual summer bleaching of corals in the thermal (power plume) off Kahe Point did not appear to enhance their thermal resistance. The same corals continued to bleach every summer, suggesting that much longer times are needed for adaptation.

. “The possible rate of warming due to the greenhouse affect would probably occur in less than 50 years, a time frame that appears to be too short for genetic selection in long-lived reef corals,” the authors wrote in the for “Coral Reefs."

 R Jokiel said the studies of the same species of coral in Hawaii and Enewetak, where the water temperatures are generally slightly warmer, show lethal water temperatures for Hawaii corals are about 2 degrees centigrade lower than the warmer water corals.

    Studies of related corals in Hawaii and the Florida Keys showed the Florida coral "has a bleaching threshold that is about 1 degree centigrade higher than for its congener from Hawaii, suggesting adaptation to the higher summer ambient temperatures that occur in Florida.”

  Coral bleaching doesn’t only happen because of heated water. Ultraviolet radiationrcan cause it, as can darkness and lower salinity in water.   But temperature appears to be the cause of recent reports of bleaching off Florida, the Galapagos, Hawaii and elsewhere


.2.  Antarctic Meltdown

At Shackleton Camp just 300 miles from the South Pole, it is hard to imagine Antarctica as anything but a polar desert. Some 95% of this remote continent is covered by a vast, featureless ice sheet that in places runs 3 miles deep. It is the coldest, windiest place on Earth with a recorded low of minus 89.2 degrees C. But Antarctica has not always been so cold and dry. During the last Antarctic field season, which ended in early 1996, scientists staying at Shackleton Camp found mosslike plants and seashells in the nearby Dominion Mountain Range. They say these finds are evidence of a temperate environment that existed only 3 million years ago, which in geological terms means yesterday. This scenario has both startled and perplexed the scientific community. Not only does it fly in the face of conventional wisdom, which says the ice cap has been in place for more than 15 million years, but it also raises questions about the validity of current climate models that are based on a frozen Antarctica.

            The Transantarctic Mountains divide the Antarctic ice cap into two regions. To the west, south of Argentina, an ice sheets sits anchored to bedrock below sea level. Researchers have long worried that this western sheet might one day slip off into the ocean, and there is plenty of evidence that it could. But what really worries people is the possibility that the much larger eastern ice sheet, south of New Zealand, might also melt. This ice sheet rests on land and was, until recently, presumed to be stable. But now there is mounting evidence that the eastern sheet may have shrunk significantly three million years ago during the Pliocene, the world’s most recent warm period.

            If there was a major meltdown during the Pliocene, it could happen again. Antarctica, which is almost twice the size of Australia, contains 90% of the world’s ice and 70% of its freshwater. So even a partial melting could flood coastal cities and swamp fertile farmland. If the entire ice cap were to melt, sea levels could rise as much as 200 feet. This could make Memphis a deep sea port, turn Miami into scuba-diving destination, and create an island out of the Empire State Building.

            So, are we headed for Waterworld ? Should we build our homes in stilts? Scientists are divided on this issue. Once camp, the “dynamists”, believes that the Antarctic ice sheet is dynamic: It has undergone rapid changes in the past and could do it again. The other camp, the “stablists”, believes that the Antarctic ice sheet is stable and unlikely to melt away in the foreseeable future. To see what evidence is being gathered to settle the debate. I flew south last year to visit members of the two factions during their field seasons.

            Getting to Antarctica requires an eight-hour flight to MeMurdo Research State from Christchurch, New Zealand, in the equivalent of a B-52 on skis. You wear full polar gear, including a pair of massive rubber moon boots, two sets of long underwear, polyester overalls, and a fur-trimmed parka. Passengers strap in should-to-shoulder on benches mead from cloth webbing.

            After landing a McMurdo, I took a second flight to Shackleton Camp where the dynamists team had been working for the past two months.Stiff from the long, cold ride, I stood up stretched, and looked through the window for any sign of life in this foreboding, desolate land. I saw six Quonset huts, a handful of tents, and three outhouses perched on a slab of ice in the middle of a mountain valley. Once outside, my parka rippling against the freezing wind. I tried to imagine a land that the dynamists say once looked like the green fjords of Chile. I quickly gave up, and walked as fast as I could toward food and shelter. On the way to the hut, I ran into David Harwood of the University of Nebraska, who was returning to McMurdo to pack off his samples. There on the landing strip, he laid out the details of his story. By the end of the tale, the idea of water in valleys like this one seemed almost plausible.

            It all began in 1983 when Peter Webb, a geologist at Ohio State University, and Harwood, then a graduate student, performed a laboratory analysis of glacial sediment from the Transantarctic Mountains. What they discovered was astonishing: The sediment, known as the Sirius Group, contained diatoms, or marine microfossils, that were only three million years old.

This suggested that the climate during the Pliocene may have been warm enough to melt the ice and allow the ocean that surrounds Antarctica to flood its subglacial basins. Later that year, Harwood left for the frozen continent, where he dug up additional sediment samples from the Reedy Glacier area. They to contained diatoms of three million year old vintage.

            At first the findings were dismissed. The few scientists who gave them any thought said that the diatoms must have somehow blown into the sediment from the sea floor. It was a fluke, they said.

            Back in 1983, it was generally agreed that after Antarctica splintered from the southern continent, Gondwana, over 100 million years ago. It slid into a deep freeze, accumulating an ice cap that has remained about the same size for the past 15 million years. There was no reason to doubt this picture. It was supported by geological studies of Antarctica, as well as deep-sea oxygen isotope measurements that reflect ice volume and temperature changes.

            But in 1985, Webb and Harwood visited Beardmore Glacier, where they found bits of wood later identified as souther beech. This made them think that perhaps small trees once grew there. They confirmed this hypothesis in 1990 by unearthing beech tree leaves and roots. The survival of these plants, they say, indicates a prolonged warm period.

            Three years later, beetle remains turned up in the rubble. With this find, Harwood and Webb's notion of a dynamic ice sheet and climatic shifts finally grabbed the interest of a cadre of experts. "The survival of a bettle during the Pliocene in Antarctica implies that temperatures were significantly warmer than present," say micropaleontologist Allan Ashworth of North Dakota State University in Fargo.

            In the field season that ended in 1996, Harwood and Webb took further steps to investigate their theory. First, they revisited the Dominion Range to collect more fossils. Then, they scoured a new site called Bennett Platform, and studied its geology. Finally, they collected samples form 15 other Sirius sediment sites throughout the Transantarctic Mountians to sift for diatoms. "If they blew in, then there should be a uniform distribution of them," Harwood says. They should also vary in age.

            It will take several years to analyze diatom populations. In the meantime, Harwood and his team are puzzling over a mosslike plant colony found at Bennett platform. Harwood says it probably grew in wetlands that were eventually covered by silt from a nearby river or stream during a glacial advance. The geology of the area, which is part of the Sirius Group, suggests that a lot of water was present when the rock face formed.

            Ashworth also made a fascinating discovery: He found seeds and sea shells in the box of rocks he brought back from the field last year. "They're interesting in their right," he says, because neither fossil group had previously been found on Antarctica. But their true value may be in their ability to date the sediment in which they were found.

            Meanwhile, a variety of other research has beguin to yield supportive evidence. One study suggests that warm-blooded sea creatures, including dolphins, may have migrated closer to Antarctica during the Pliocene, which would have meant warmer water. Other studies have found evidence that, about three million years ago, sea levels were between 25 and 30 meters higher than they are now, perhaps due to ice cap melt.

            "The evidence is quite compelling," says paleontologist Brian Huber of the Smithsonian's Museum Of Natural History. But not to the stablists. A period of climatic warming at a time when other evidence suggests Antarctica was completely covered by ice remains unacceptable to many scientists. Tlo hear the stablists' side of the story, I flew to Antactica's Dry Valloeys to meet with George Denton of the University of Maine and David Marchant of Boston University.

            As I flew by helicopter over McMurdo Sound toward the Dry Valleys, I soon realized that this place was like no other I had seen in Antarctica. There is no ice or snow in the Dry Valleys. Mummified seals lie in heaps. Wind-sculptured rocks decorate the hillsides. This area, which is about 1,260 square miles, has rifts and valleys no less impressive than the Grand Canyon, plus ephemeral streams, leeves, and sand beaches.

            Denton has worked here for more than 20 years, and knows more about this landscape than anyone else in the world. Now, to learn more about the climate during the Pliocene, Denton and Marchant are combining their study of the landscape(geomorphology) with that of ash that flows into the area from offshore volcanoes.

            I land in Bull Pass, a desert pavement 20 miles from Mt. Fleming. It is so flat and so barren that it has been likened to Mars before the big freeze. Indeed, there is no visible sign of life except for a tiny camp consisting of two tents and a portable stove. As we hike over what look like the rounded backs of dinosaurs, Denton tells me that he believes Antarctica's massive ice sheet has remained fairly stable for 10 to 15 million years.

            Marchant then strolls over to a sandy mound where he has been digging for ash with a trowel. He says that he reads the history of climate by examining how rocks weather, and where they are found. Then, for a chronological framework, he looks for nearby volcanic ash. Ash, like rocks, can reveal environmental clues through its content and current condition. And because it is the last thing to land on the surface of a formation, it can pinpoint a minimum age for the rocks.

            Marchant and Denton have collected rock samples from Mt. Fleming and Table Mountain nearby peaks with the same Sirius Group glacial sediments as the area around Shakleton Camp. The two scientists say these rocks have been preserved in dry and cold conditions, and show no sign of erosion. This suggests that the Dry Valleys have remained a cold desert for much longer than three million years.

            The team has also mapped 75 ash deposits, and obtained dates for 50 of them. The samples show that the ash formed in a cold, dry environment, and remained undisturbed. It was found on rocks that are unmarked by any massive ice sheet movement.

            In addition, geologist David Sugden of the University of Edinburgh in Scotland has found an eight-million year-old ice slice in the Dry Valleys that he says could not have survived a warming period. And cores extracted from the ocean floor around Antarctica show no curtailment of sediment from melting icebergs, as would be expected if the continent was partly ice free during the Pliocene.

            Taken together, these results speak volumes in favor of a dry, cold, steady state. They indicate that the Pliocene temperatures were only three to eight degrees Celsius above today's temperatures, and that the ice sheet covering the Transantarctic Mountains overrode the area more than 10 million years ago.

            "We do not deny that Harwood is finding the fossils," says Marchant. In fact, he says, "we'd expect it." Before Antarctica split from Gondwana, it supported many of the same plants and insects that are now found in South America and New Zealand. So these fossils may represent the last vestige of these life forms. "What we disagree with is the timing of it all," Marchant says.

            While Harwood and Webb contend that their miniature forest withered three million years ago, Denton and Marchant argue for at least 23 million years ago, when Antarctica was clenched firmly by the icy grip that still holds it today. "Their entire argument  relies on the diatoms, which we think may have blown in," Marchant says. Meanwhile, Harwood questions the validity fo the Dry Valleys results, saying "that area is anomalous, now, maybe it was then too."

            For now, the argument remains unsettled. Though Harwoods says that both camps may eventually prove to be correct--that there was a long period of cold punctuated by relatively short bursts of heat--Marchant disagrees, say "these are mutually exclusive positions and there is no evidence for an intermediate theory."

            About the only thing both camps agree on is that the key to solving this mystery is to establish, once and for all, the age of the Sirius sediment fossils. Although this will be difficult, because there is no definitive technology on which to rely, an attempt will be amde this year. An independent group of researchers will drill a core from the Sirius Group rocks to determine whether diatoms exist below the surface (and therefore are unlikely to have been windblown), or only near cracks or at the top.

            Both groups recognize the urgency of coming to a firm conclusion. The Antarctic ice sheet affects only only global sea level, but also world climate. So agreement on a clear picture of the past could help to cast a more accurate vision of Earth's future. If the stablists are correct, and the eastern ice sheet remained frozen during the Pliocene, then there is little reason to worry about the fate of our coastal cities. A major temperature increase would be required to have any effect. But if the dynamists are right, and the ice sheet did melt down, then a moderate rise in the mercury could one day bring on the floods. For now, however, the answer lies hidden in Antarctica's frozen landscape.



Short Essays



What about the West?

While the fate of Antarctica's eastern ice sheet is uncertain, scientists have plenty of reasons to believe that the smaller western ice sheet could eventually slip into the ocean. It is the world's only remaining marine ice sheet. The other, which existed in the Northern Hemisphere, disintegrated and melted away during the Pliocene period.

            There are signs that the west Antarctic ice sheet is already breaking up. A huge iceberg broke free of the Larsen ice shelf in 1995. Shortly thereafter, a 40-mile-long crack opened in the adjoining shelf area. Now, ice streams that flow through the sheet are behaving erratically.

            Last year, Stanly Jacobs of Columbia University's Lamont Donerty Earth Observatory made the first oceanographic measurements across a deep channel beneath the leading edge of Pine Island Glacier.His findings show that the west Antarctic ice sheet is losing mass to the oceans. But whether this instability is symptomatic of an impending collapse remains unknown.

To further study the current state of the west Antarctic ice sheet, and to predict its future, the National Science Foundation is sponsoring a variety of Antarctica-based research projects. For example, Cal Tech scientists at Upstream Bravo Camp are sinking ice strings and digging ice cores to study the movement of fast flowing ice streams.

They're also burying seismic monitors in snow fields to listen for "ice quakes" set off by colliding ice sheets.


How Antarctic Ice Affects World Climate

Think of the Antarctic ice sheet as Earth's refrigeration unit: It exerts a major tw0-way control over today's global environment.

First, the ice sheet (along with a raft of ice that surrounds it in the southern ocean) reflects back into space about 80 to 85 percent of the sun that hits it. So icy Antarctica, which records the coldest temperatures on Earth, helps to reduce the world's overall heat budget.

            Second, the near-freezing meltwater that runs off the ice cap, along with the water from melting icebergs, falls to the ocean floor and surges northward. This surge affects deep-sea circulation, which in turn influences climate. So, a major meltdown would not only raise sea level worldwide, but cold also modify weather patterns.

            For a better fix on the details, the National Oceanic and Atmospheric Administration is monitoring weather, ozone depletion, and long-term climate trends at the South Pole. In addition, scientists are refining their models of the oceans and the atmsophere by studying bottom water in Antarctica's Weddell Sea, and satellite images of sea lice.


Alaska glaciers melting at higher rate - study

July 19, 2002 Posted: 5:28 AM EDT (0928 GMT)



Researchers surveyed volume and area changes across Alaska's glacier regions   

 From Natalie PawelskiCNN Sci-Tech

(CNN) -- A new study indicates that glaciers in Alaska are melting faster than previously thought, providing further evidence of global warming, researchers said Thursday.

Scientists have long warned that global warming -- when heat-trapping gases force atmospheric temperatures to rise -- could eventually raise sea levels to a dangerous point by melting ice sheets and glaciers.

"The whole issue of global climate change is important to everyone," said glacier expert Anthony Arendt of the University of Alaska at Fairbanks. "The whole issue of sea-level change affects people who live near the coast quite directly. Just small changes in sea level can cause very large incursions of water up along the coast and can destroy valuable property there. It can move people away from their homes."

Arendt and his colleagues used a technology called laser altimetry to measure volume changes of 67 Alaskan glaciers over four decades.

"Glaciers in Alaska seem to be thinning from the mid-1950s to the mid-1990s," said Arendt, adding that the thinning rate has about doubled between the mid-1990s and 2001.

"We know that the climate has had to change for that to happen," he said. "Whether or not these changes in climate are due to human influences, that's not for us to say, but it's possible that it is linked to a larger-scale change in global climate caused by human activity."

A panel of scientists that regularly reports to the United Nations on global warming issues has projected that sea level will rise between three inches and about two-and-a-half feet during this century. But glaciers melting faster than expected could increase that projection.

The study found that the Alaskan glaciers were thinning enough to produce a sea-level rise of about .14 millimeters per year -- melting almost twice as fast as the Greenland ice sheet, the researchers said.

The survey, published in the journal Science, relied on an airborne laser and a satellite-based global positioning system to plot the glaciers' altitudes and calculate their volume. Comparisons were then made with topographic maps from years before the 1990-technology was developed, to extrapolate melting rates back to the 1950s.

The Environmental Protection Agency says the Earth's temperature has risen about 1 degree Fahrenheit during the past 100 years, most likely because of global warming.

"Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide," says a definition posted on the EPA Web site. "The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how Earth's climate responds to them."




Measuring the meltdown  




Birth of New Hawaiian Island by William Broad  NY Times Science 10/8/1996

Rising from deep within the earth is a jet of molten rock that cuts large holes in the Pacific seabed, forming new volcanoes and eventually whole new islands as well, its brood including Maui and Oahu.  Each year, the jet, the Earth's most intense, spews enough lava to build a road that would circle the earth TWICE.  It has been thundering and exploding and erupting lava for tens of millions of years.

Now, scientists have descended in a submersible to probe an episode of explosive violence at the jet's leading edge accompanying the birth throes of a new Hawaiian island.  Their target, a half mile down, was the summit of Loihi, which has suddenly become one of the worlds most active volcanoes.

"It's nerve-racking" Dr Alexander Malahoff, the expedition's chief scientist, said of his dives into the dark, churning waters. "The top of the volcano is a physical wreck."

In July and August, the site was rocked by thousands of seaquakes, including the strongest ever  recorded around Hawaii.  Since the volcanic seamount is only 17 miles southeast of the big island of Hawaii, disaster officials feared that the deep violence might set off tidal waves at the surface that could devastate the big island as well as more distant shores of Oahu, including Honolulu and Waikiki Beach.

Land was in fact spared. But Dr. Malahoff and other scientists who dove to the craggy recesses of the undersea volcano discovered a riot of landslides, toppled rock formations and a bus-size volcanic boulders strewn over four or five miles.  But this was not the result of a major eruption.  The turmoil at the volcano's top had collapsed its summit, creating a murky crater more than a half-mile wide and 1000 feet deep.

This was a Mt. St. Helens sized volcanic event," Dr Malahoff said at a news conference on Friday at the National Press Club in Washington.  "Pete's Dome, an area on the southern rim of the volcano that previously had been considered very stable had simply vanished."

He made three dives into the volcanic depths in as many days late in Sept. 1996, and the dives continued through October 1996.  The team is diving in a Pisces submersible, which can carry three people down a little more than a mile and therefore is limited to exploring the volcano's summit.  The whole seamount rises almost three miles from the ocean floor.

Dr. Malahoff is a director at the Hawaii Undersea Research Lab at the University of Hawaii, and dives are financed by the National Oceanic and Atmospheric Administration. Diving into the new crater, Dr. Malahoff found vents spewing a mixture of superheated water, dissolved minerals and microbes that thrive in the seabed's rocky substratum.  Churning clouds of particles often limited visibility to about a yard or less.

And tricky currents posed dangers. Waters flowed into the newly formed pit,   percolated through the volcano's hot interior and rushed out over a lip on the volcano's western edge.  The scientists had to avoid getting sucked down by the inrush ton one side and pushed up by the out-rush of the other.  

They say the tumult is part of the volcano's halting upward growth.  Lava flows build it up, and avalanches and collapses and cataclysmic explosions knock it down and widen it, creating a larger base for the next stage of building, Tens of thousands of years are expected to pass before the volcano's fiery summit rises above the waves. The fight is between construction and destruction.” Dr. Malahoff said at the news conference.

Avalanches are well known to have shaken the steep sides of Loihi, but no episode this violent has ever before been studied up close. Scientists say the event sheds important new light on the dynamics of island building as well as a whole range of environmental issues, like the extent to which explosive releases of volcanic gases like carbon dioxide may be contributing to the greenhouse warming of the earth. Such releases, they say, may augment human ones.

And it is aiding overall studies of the Hawaiian jet, the earth's most dynamic zone of volcanic upheaval.  Beneath the big island of Hawaii, it powers the fireworks of both the Kilauea and Mauna Loa volcanoes.

We think it is rather large, as much as 200 kilometers in diameter-or about 125 miles, Dr. James G. Moore, a geologist with the United States Geological Survey in Menlo Park. Calif., said an interview. "Loihi is the first manifestation of volcanic activity on that crust", added Dr. Moore, who has studied the Hawaiian volcanoes. "Its the leading edge.”

The great heat engine within the Earth stirs a sea of hot plastic rock that melts through the crust in places, with the vast majority of the surface action taking place in the hidden darkness of the deep sea.

In places, the interior heat gives birth to jets or plumes of hot material that are stationary in relation to the deep earth but continuously rise toward the surface. Over the eons, the Jets pierce plates that move slowly overhead, much as a blowtorch would melt holes in a steel plate moving by.

The gigantic plates that make up the earth's crust move over the jets at the rate of a few centimeters a year, or about as fast as fingernails grow.

As a result of this SLOW creep, a single jet aver the ages can leave a

Trail of extinct, progressively older volcanoes in the plate above.

Such a trail is seen the Pacific, where the Hawaiian hot spot has

formed not only the Loihi volcano but a chain of extinct ones that  run west-ward

across the Pacific plate from Hawaii and then turns northward to form the Emperor seamount chain., extending to the northwest corner of the ocean. In all, the chain covers thousands of miles and mirrors tens of millions of years of volcanic action.

The bend where the Hawaiian chain turns into the Emperor chain represents a change of plate motion that occurred about 40 million years ago. 

The volcanic islands are slowly pared down by landslides  and sink deeper into the sea, usually leaving only the newer ones at the head of the chain above water — or struggling to break through the waves.

Loihi,  which means “long one” in Hawaiian and is pronounced low-EE-hee,  and is an elongated monster 13 miles wide and 25 miles long.  The `Pacific sea bed on which it rests isl~3.4 miles down at its lowest point.  During eruptions and outbursts over tens of thousands of years. Loihi has grown until the volcano is now more than 2.8 miles tall.  Its stirrings are carefully monitored by several government agencies including the National Oceanic and Atmospheric Administration, an arm of the Commerce Department, and the United States Geological Survey, which maintains a network of seismometers on the big island. Seismometers measure faint vibrations in the ground that tell of distant earthquakes

ear~tLoihi has heaved with seaquakes before, most recently in 1991, but not like this summers torrent of violence. The quakes prompted Harry Kim, the Civil Defense director of Hawaii County. which encompasses the big island, to warn residents to head for higher ground immediately if they felt an earthquake, since there would be no time for sirens or emergency broadcasts before a tidal wave struck.

Island residents are used to coping with threats of tidal waves generated by distant earthquakes far across the ocean, but not local ones. 

To better understand what was happening and, in part, to help develop ways to predict and warn of future dangers, Dr. Malahoff and his team dove into the depths. 

 "Eventually something will happen," he said of disasters on land touched by the deep volcano, " but maybe not in our lifetimes.” 

In trying to unravel the mystery of the deep upheaval, the team early on monitored the violence with microphones suspended from buoys and detected cracklings that sounded like the flow of deep lava.  But submersible probings of the northern Summit in the area of the cracklings revealed no new flows, only old ones.

What the team did discover, based on a comparison with older observations, was that a huge part of the volcanoes summit had collapsed in the frenzy of destruction.  "Nobody," Dr. Malahoff said. “has ever observed the formation of these pitcraters.”

 The collapse of the summit probably look two or three days, he said, and its slowness was a godsend.. A quick collapse would have generated. a huge tsunami, or tidal wave. A likely possibility, he said, is that he slow collapse was provoked when the hot lava from the volcano’s interior oozed out of its flanks at a depth somewhere below the region where the Pisces submersible could explore.

 ex’ 1 In the most dangerous moment of the series of dives, Dr. Malahoff and two  colleagues ventured down to bottom of the new crater past fractured walls of towering rocks that were threatening to fall.. Later, at the crater’s bottom 1,000 feet the summit, the anxious team in the submersible, heard the rumble of a distant landslide.

At the base of the huge cliff, the team found a big vent belching hot water and clouds of microbial snow in the area around the vent painted  with orange and redand flapping lettucelike leaves of bacterial slime.




 Mapping the Ocean Floor4




"We have known more about the topography of Venus, Mars, and the Moon than the bottom of our own oceans - until today," said Dr. Walter Smith of the Commerce Department's National Oceanic and Atmospheric Administration as he introduced a stunning new map of ocean floor structures.   Using satellite sensor data recently declassified by the Navy in combination with data from the European Space Agency, Smith and his colleague, Professor David Sandwell of the Scripps Institution of Oceanography, have generated a computer model of the seafloor in unprecedented detail. The new map, which infers seafloor features from changes in the strength of gravity, provides the first detailed view of ocean floor structures in many remote areas of the Earth.


Marine geologists have been mapping the ocean floors for some time but, because of limited quality and coverage of the available data, they have had to use guesswork. Until now, the most common method of mapping the seafloor has been acoustic echo sounder readings taken by ships; only a small fraction of the sea floor has been charted, and in some remote parts of the oceans there are gaps between charted areas the size of Kansas. Much of the available data is also low tech, and inaccurately navigated. Even using the most advanced technologies available today, it would take over 125 years to chart the ocean basins using acoustic devices on ships.


The newly declassified satellite data have a survey track every three miles, and so scientists can be confident that any feature six miles across will not be missed. Another benefit of mapping the ocean floor via satellite is that the features detected are located with great precision. With this data it may be possible to answer questions like: Is there an uncharted island somewhere where Amelia Earhardt could have landed? Are there uncharted shallow banks that could be rich with marine life and exploitable by commercial fishing? (We already know the answer to that one is Yes.) Are there sedimentary basins that might have petroleum reserves that we haven't mapped yet?


The data used to generate the new map was gathered by the U.S. Navy's GEOSAT spacecraft between March 31, 1985, and October 30, 1986. As the satellite orbited the Earth almost 500 miles up in space, a radar altimeter on board returned readings of the distance from the satellite to the ocean surface accurate to about one inch. The radar waves were reflected by the ocean surface and did not penetrate it, unlike the sound waves of an echosounder, so that the satellite data yield measurements of the shape of the ocean surface, not the ocean floor. However, Smith and his colleagues at NOAA and Scripps have worked out a method for exploring the ocean floors using these data. They first use the satellite data to find tiny changes in the pull of the Earth's gravity field, and then use those gravity anomalies to infer the topography of the ocean floor.


"If I had to choose one thing as being most revolutionary about this map, I would say it is the view it gives us of the fracture zones," said Smith. In the process of seafloor spreading that causes continental drift, scars are made on the ocean floors called fracture zones that record the history of plate motion. These are used to reconstruct the ancient positions of the continents. Such knowledge can be extremely valuable in minerals exploration and in the study of climate change.


The scientific value of these data was anticipated even as the satellite was flying, and many people have worked a long time to get the data declassified. While a senator, Vice President Gore started a group called the Environmental Task Force, to seek answers to this question: are there technologies and data sets which, because of their military value, are classified, but which would have even greater value to the scientific community and the civilian economy if they could be released? This release of data set is one result of this exercise.


Although the work to declassify the data is done, NOAA's work with the data is really only now beginning, as it is now possible to derive data products that can be distributed to scientific, educational and commercial users. The raw data representing the spacecraft's measurement of ocean surface heights is now available from NOAA's National Ocean Data Center in Washington, D.C., on a set of 4 CD ROM discs. Over the coming months, new products, such as marine gravity fields and predicted sea floor topography, will be made available. A picture of what kinds of products will be coming can be had on the Internet at http://www.ngdc.noaa.gov/mgg/announcements/announce_predict.html. Color prints of the draft version of the new world gravity map will be available to qualified news media from the contact above.


Cool Science Facts


  [Mauna Loa]   While the ocean floor does have some canyons and steep slopes, much of it is very flat. The Pacific Basin is the flattest stretch of solid surface on Earth. Even the slopes where the continental shelves drop off into the ocean floor slope at an angle of only about four degrees -- barely steep enough for people to detect they are on a slope. Most maps of the ocean floor distort the height of the mountains so that they will be easier to see. The Hawaiian island of Mauna Loa, the largest mountain on Earth, rises over 10 km above the sea floor (4 km above sea level), but has a typical slope of only ten degrees. Since much of the "land" on the Earth is ocean floor, half of the Earth's surface is 2,000 meters or more below sea level. Less than one tenth of the Earth's surface is 850 meters or more above sea level. What kind of rock is more dense --continental granite, or ocean floor basalt? Could the answer have anything to do with the fact that oceanic basalt forms low plains, while continental granites make mountains?


 Current technology does not allow us to burrow through the Earth.  The rock and metal thousands of kilometers below our feet are so inaccessible that they might as well be on another planet.


Believe it or not, the Earth's solid iron-nickel core helps make life possible. The solid portion of the metal core spins inside the liquid portion, making the planet act like a giant generator. The rotation creates the magnetic field which, among other things, makes compass needles point north and helps create Earth's magnetosphere. The magnetosphere and the lower atmosphere work together to protect us from some of the Sun's most dangerous particles.


Every 2,000 - 10,000 years, the Earth's magnetic field reverses. The field leaves a magnetic "imprint" on crustal rocks, as particles within the rocks align themselves according to the field. Different layers of rocks in a formation will have particles aligned differently, depending on the alignment of the poles when the rocks formed. Many scientists think that the Earth's poles may reverse again within the next one hundred years. Within your lifetime, compass needles may point south instead of north. Although this won't be directly harmful to the human population, it may be confusing for many boy scouts, not to mention navigators in planes and ships. How do yo u think this event will affect your life? Some birds and fish use the Earth's magnetic field to navigate their migration. How do you think they will be affected? 








Readings  1 UP CLOSE...OCEAN FLOOR..............NAME....................................................

1.          How much did Aquarius cost?

2.  How long do divers have to study the bottom at 120 feet?

3.  Why so short a time?

4.  What clues are found in the coral?

5.  What happened to the black urchin population?

6. How does "dead man's fingers" get its name?

7.  What abiotic components can kill coral?

8. What changes on the coral reef at night?

9. What do corals produce for defense?

10.  Which corals did the caged butterfly fish eat?

11.  When do corals reproduce?


12.  What does warm water do to the corals?

13.  Where do these bleachings occur?

14. What does the death of reef coral indicate?

15.  During which year in Hawaii did the temperature drop?

16.  Why, with the lower temperature of the waters of Hawaii, is coral bleaching still occurring?

17.  How much higher is the leeching threshold of Florida coral compared to Hawaii?

18.  Besides temperature, what may be causing coral bleaching?

19. What is the main idea of this article


2 Antarctic Meltdown by Beth Livermore   Popular Science Feb, ‘97

1. What percentage of the Antarctic is covered by an ice sheet?

                          How thick is the ice sheet?

 2. What living organisms have been found on this ice sheet continent?

3. When, in the past, could the Antarctic had a temperate climate?

4. How is the Antarctic ice sheet divided?

5. To what structure is the western ice sheet attached?

6.To what structure is the eastern ice sheet attached?

7. How big is the Antarctic land mass?

8 How much ice and freshwater is there on the continent? 1)

 2// 9. What do the "dynamists" believe?

10. What do the "stabiists" believe?

11. What evidence was found that indicated the Antarctic climate was warmer?

12. What other evidence was found to indicate that the Antarctic was warm in the

last 3 million years?

13. Where is there no ice or snow in the Antarctic?

14. Why do we think that the Antarctic was once connected to South America and New Zealand?

15. What does the Antarctic Ice Sheet affect?

16. What is the main idea of the  article about the Alaskan Ice



3 “Undersea Birth Throes of a New Hawaiian Island    

1. How much lava does the Hawaiian opening(jet) produce each year?

2. How long has the “Hawaiian jet” been producing lava ?

3. What is the name of the new Hawaiian Island, not yet above the water line?

4. The new Hawaiian Island had several eruptions this year and created a crater, under the ocean, how big is it?

5. What happened to “Pete’s Dome’?

6. How high is this new “ to be” island?

7. What two volcanoes are powered by the Hawaiian jet?

8. What is the comparison used in this article about crustal movement and a common similarity?

9. How big is Loihi?

10. Why have recent earthquakes on Loihi caused concern on the big island of Hawaii?

11. What is the main idea of this article



1. What does this new map use to map the ocean floor?

2.  Why is this a better method than echosounding?

3.  How long will it take to map the sea using echosounding?

4.  How small of an area can this new method pinpoint?

5.  Explain how scientists use the radar wave data?

6.  Where is the flattest stretch of solid surface on earth?

7.  What angle do continental slopes usually reach?

8.  How tall is Mauna Loa from the sea floor and what does this height make this mountain?

9.  What causes the earth’s magnetic field?

10.  What happens to this field (9) every 2,000-10,000 years?

11.  How would this (10) effect new layers of rock?

12. What is the main idea of this article