BryLog

Global warming conjures images of rising seas that threaten coastal areas. But in Juneau, as almost nowhere else in the world, climate change is having the opposite effect: As the glaciers here melt, the land is rising, causing the sea to retreat….

The geology is complex, but it boils down to this: Relieved of billions of tons of glacial weight, the land has risen much as a cushion regains its shape after someone gets up from a couch. The land is ascending so fast that the rising seas — a ubiquitous byproduct of global warming — cannot keep pace. As a result, the relative sea level is falling, at a rate “among the highest ever recorded,” according to a 2007 report by a panel of experts convened by Mayor Bruce Botelho of Juneau.

Greenland and a few other places have experienced similar effects from widespread glacial melting that began more than 200 years ago, geologists say. But, they say, the effects are more noticeable in and near Juneau, where most glaciers are retreating 30 feet a year or more.

As a result, the region faces unusual environmental challenges. As the sea level falls relative to the land, water tables fall, too, and streams and wetlands dry out. Land is emerging from the water to replace the lost wetlands, shifting property boundaries and causing people to argue about who owns the acreage and how it should be used. And meltwater carries the sediment scoured long ago by the glaciers to the coast, where it clouds the water and silts up once-navigable channels…. (more @ NYTimes)

Experts have warned that the richly diverse coral reefs of the Coral Triangle around southeast Asia will disappear by the end of the century if action is not taken against climate change.

As well as the loss of one of the world’s most diverse underwater ecosystems, the knock on effect would be the collapse of coastal economies that supports around 100 million people, according to the WWF- commissioned study outlined at the World Ocean Conference this week.

The Coral Triangle includes 30 percent of the world’s reefs, 76 percent of global reef building coral species and more than 35 percent of coral reef fish…. (continues @ CNN)

A new study describes a novel technique for reattaching large sponges that have been dislodged from coral reefs. The findings could be generally applied to the restoration of other large sponge species removed by human activities or storms…. (continues @ ScienceDaily)

Evidence from fossil coral reefs in Mexico underlines the potential for a sudden jump in sea levels because of global warming, scientists report in a new study.

The study, published in the journal Nature, suggests that a sudden rise of 6.5 feet to 10 feet occurred within a span of 50 to 100 years about 121,000 years ago, at the end of the last warm interval between ice ages.  “The potential for sustained rapid ice loss and catastrophic sea-level rise in the near future is confirmed by our discovery of sea-level instability” in that period, the authors write….

What is their evidence?

The study focuses on a set of fossil reef remains exposed in excavations for channels at a resort and water park, Xcaret, about 40 miles south of Cancún on the east coast of the Yucatan peninsula in Mexico….

Dr. Blanchon calculated the ages of coral samples by measuring isotopes of thorium in the fossils and then confirmed the ages by comparing the Mexican reefs to coral reefs in the Bahamas whose ages have been thoroughly studied.

The team says it found that two Mexican reefs grew during the last “interglacial,” or warm interval between ice ages.

To determine the pace of sea-level rise in that period, Dr. Blanchon charted patterns of coral revealed in excavations at the resort. He said his work revealed a clear point where an existing reef died as the sea rose too fast for coral organisms to build their foundation up toward the sea surface. Once the sea level stabilized again, the same group of corals grew once more, but farther inland and up to 10 feet higher in elevation, a process known to geologists as backstepping.

Such an abrupt change from stable coral growth to death and a sudden upward and inland shift of a reef could only happen because of a sudden change in sea level…. (more @ NY Times)

One Antarctic ice shelf has quickly vanished, another is disappearing and glaciers are melting faster than anyone thought due to climate change, U.S. and British government researchers reported on Friday.

They said the Wordie Ice Shelf, which had been disintegrating since the 1960s, is gone and the northern part of the Larsen Ice Shelf no longer exists. More than 3,200 square miles (8,300 square km) have broken off from the Larsen shelf since 1986…. (continues @ Reuters)

In the future, natural gas derived from chunks of ice that workers collect from beneath the ocean floor and beneath the arctic permafrost may fuel cars, heat homes, and power factories. Government researchers are reporting that these so-called “gas hydrates,” a frozen form of natural gas that bursts into flames at the touch of a match, show increasing promise as an abundant, untapped source of clean, sustainable energy.

The biggest ever investigation into “ocean fertilisation” as a climate change fix has brought modest results.  The idea is that putting iron filings in the ocean will stimulate growth of algae, which will absorb CO2 from air. ….

Previous experiments, which have been going on for at least a decade, had indicated that iron particles could stimulate the growth of phytoplankton - algae - and that when the phytoplankton died, they fell to the sea floor, meaning that carbon taken from the air was effectively locked away on the bottom of the ocean.

Following fertilisation of a 300 sq km patch of ocean, Lohafex, too, saw a burst of algal growth.

But within two weeks, the algae were being eaten by tiny creatures called copepods, which were then in turn eaten by amphipods, a larger type of crustacean.

The net result was that far less carbon dioxide was absorbed and sent to the sea floor than scientists had anticipated.