Penguins, Noah, iron all receive WHOI investigation

 Far-flung research nothing new for Woods Hole Oceanographic Institution

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A pair of researchers at Woods Hole Oceanographic Institution have participated in a paper to that found that melting sea ice is putting at least part of the emperor penguin population at risk.

By James Kinsella

Emperor penguins at serious risk. A legendary flood that was less than advertised. Iron's key role in locking carbon dioxide into the ocean.

Founded in 1930, WHOI is dedicated to research and higher education atthe frontiers of ocean science. The organization is headquartered inWoods Hole, from which its scientists and vessels set out to doresearch around the world.

All are the subject of research conducted by scientists associated with the Woods Hole Oceanographic Institution and recently published.

The research finds that the loss of sea ice through global warming may place some emperor penguins in danger of extinction; that an event that possibly served as the historic basis for Noah's Flood appears smaller that researchers previously thought; and that iron fertilization of the ocean is enhancing the export of iron to the deep ocean.

Founded in 1930, WHOI is dedicated to research and higher education at the frontiers of ocean science. The organization is headquartered in Woods Hole, from which its scientists and vessels set out to do research around the world.

Penguins

The 2005 movie "March of the Penguins," an endearing and poignant look at the epic yet fragile life cycle of emperor penguins, popularized the species around the world.

But a trend has emerged that could spell serious trouble for the species in at least part of its geographic range.

Five researchers, including WHOI biologists Stephanie Jenouvrier and Hal Caswell, examined the situation in a paper published Jan. 26 in Proceedings of the National Academy of Sciences of the United States of America.

The paper uses mathematical models to predict the effect on penguins of climate change and the resulting loss of sea ice.

Melting ice threatens colony

Their research shows that if climate change continues to melt sea ice at the rates published in the latest Intergovernmental Panel on Climate Change, the median population size of a large emperor penguin colony in Terre Adelie, Antarctica, likely will shrink from its present size of 3,000 to only 400 breeding pairs by the end of the century.

The researchers further calculate that the probability of a drastic decline (by 95 percent or more) is at least 40 percent and perhaps as much as 80 percent.

Another question is whether the penguins might adaptto changing conditions, perhaps by changing the timing of theirbreeding cycle. However, this does not seem to be happening.

Such a decline, according to the researchers, would put that population at serious risk of extinction.

Caswell said while the researchers focused on Terre Adelie, given the excellent data available for the region, their findings may have implications for the species throughout the Antarctic.

Yet another question, Jenouvrier said, is whether the penguins might adapt to changing conditions, perhaps by changing the timing of their breeding cycle. However, this does not seem to be happening.

"Unlike some other Antarctic bird species that have altered their life cycles, penguins don't catch on so quickly," she said. "They are long-lived organisms, so they adapt slowly. This is a problem because the climate is changing very fast."

Noah and the Danube

Scientists have suspected that the devastating flood experienced by Noah in the Bible has some basis in historical fact.

A number of researchers have focused on a flood that may have occurred about 9,500 years ago, wiping out settlements on the shore of the Black Sea.

But now Liviu Giusan, a geologist in the WHOI Geology and Geophysics Department, and two Romanian colleagues write in the January issue of Quaternary Science Reviews that a flood, if any occurred, was smaller than previously thought.

"We don't see evidence for a catastrophic flood as others have described," Giosan said.

Geologists and archaeologists have debated what happened to the sill asthe glaciers melted and sea levels rose. Did the sill gradually erodeaway, or did it break suddenly, sending a wall of water to inundatesettlements along the Black Sea's shore?

Ten thousand years ago, according to WHOI, at the end of the last glacial period, the Black Sea was a lake, cut off from the Sea of Marmara and beyond it the Mediterranean by the Bosphorus sill.

Geologists and archaeologists have debated what happened to the sill as the glaciers melted and sea levels rose. Did the sill gradually erode away, or did it break suddenly, sending a wall of water to inundate settlements along the Black Sea's shore?

The level of the Black Sea at the time plays a key role in the possible scenarios.

To conduct their research, Giosan and his colleagues examined sediment cores from the delta ofthe Danube River, which empties into the Black Sea.

They determined sea level was approximately 30 meters below present level, rather than the 80 meters others hypothesized.

Searching for a 'Holy Grail'

The source of the uncertainty fueling the Black Sea flood debate has been the difficulty of finding reliable sea level markers to date the flood.

"Sea level is like the Holy Grail," Giosan has said. "You can't really talk about a flood if you don't know the exact levels of the sea level in both the Black Sea and outside it in the Mediterranean. And that's what we tried to find."

As part of their research, Giosan and his colleagues drilled a new core to 42 meters depth at the mouth of the Danube River, the largest river emptying into the Black Sea. The goal was to reconstruct the history of that part of the delta - before and after the flood - through an examination of the sediments.

In analyzing the delta sediment from the new core as well as others taken in the region, Giosan's team discovered fresh water deposits of the newly forming delta dating back approximately 10,000 years, subsequently overlaid by fine marine sediments, followed by the modern delta deposits.

After reconstructing the long-ago delta plain, the researchers subsequently determined that sea level at time was five or 10 meters above the level of the Black Sea, not 50 or 60 meters as had been hypothesized.

Even if the flood in question wasn't as devastating as some had thought, Giosan has said the event still could have important effects, such as drowning the Danube Delta and putting an area of 2,000 square kilometers of prime agricultural land underwater.

"This has important implications for the archaeology and anthropology of southern Europe, as well as on our understanding of how the unique environment of the Black Sea formed," he said.

Iron and carbon in the ocean

In research published Jan. 29 in Nature, a team that included Matthew Charette, a marine chemist at WHOI, explored the role that iron plays in locking carbon dioxide from the atmosphere into the ocean.

The team focused on the seas around the Crozet Islands and Plateau, about 1,400 miles southeast of South Africa.

According to WHOI, these seas provided a natural laboratory, because each spring the waters north of Crozet experience an enormous bloom containing billions of individual phytoplankton and covering an area of 120,000 square kilometers, the size of Ireland.

These seas provided a natural laboratory, because each spring thewaters north of Crozet experience an enormous bloom containing billionsof individual phytoplankton and covering an area of 120,000 squarekilometers, the size of Ireland.

In contrast, the area south of Crozet experiences only a small, short bloom later in the season.

Iron is an important micronutrient for phytoplankton.

Charette said the team first had to determine where the iron was coming from. Testing revealed its source to be Crozet itself and the shallow waters around the island and plateau.

A second question the team sought to answer was whether the differences in the blooms between the north and south sides of Crozet would result in greater amounts of carbon held in the deep ocean.

Using sediment traps and sediment cores, the researchers uncovered the first evidence that carbon deposited at 3,000 meters and in the sediment was two to three times higher beneath the natural fertilized region than for the nearby iron-poor region.

"This work demonstrated for the first time that Southern Ocean phytoplankton blooms fueled by natural sources of iron have the potential to sequester carbon in the deep ocean," Charette has said.

According to Raymond Pollard of the National Oceanography Centre, Southampton, U.K., the lead author on the study, much less carbon has been detected in the deep ocean than previously suspected.

Purposefully adding iron to the ocean, Pollard has stated, may serve as a way to help counteract climate change.

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Biological productivity in large areas of the Southern Ocean is limited by the supply of iron, an important micronutrient for phytoplankton. The main sources of iron to the bloom area around the Crozet Islands in the Southern Ocean are the atmosphere, deep-sea upwelling (vertical), and the islands, themselves (horizontal).

 

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