Oceanography

The rise in atmospheric CO2 levels has been a talked-about subject for quite some time, but while scientists and politicians are coming to what they call a “solution,” the impact on marine environments is being ignored.

Proposed emission cuts are aiming to significantly lower the amount of CO2 produced within the United States, but what impact does this value have outside the human world? Scientists say that even the lowest proposed percentages aren’t nearly enough to halt oceanic damage.

 

CO2 is a soluble gas that is easily absorbed into the ocean’s waters. When CO2 is combined with H2O, the reaction releases what is known as Carbonic Acid, or H2C03. When the carbonic acid is dissolved, it loses a hydrogen ion resulting in HCO3, leaving the H+ ion to move freely. This process is known as ocean acidification and is ultimately responsible for the rise in seawater acidity.

Observations of ice coverage in the Arctic from space began 30 years ago so it's inflammatory to talk about record lows in such a short period of time but two consecutive years near this 'record' still merit some concern.

Because the extent of ice cover is usually at its lowest about mid-September, this year's minimum could still fall and set another record low.

Envisat observations from mid-August depict that a new record of low sea-ice coverage could be reached in a matter of weeks. The animation above is a series of mosaics of the Arctic Ocean created from images acquired between early June and mid-August 2008 from the Advanced Synthetic Aperture Radar (ASAR) instrument aboard Envisat. The dark grey colour represents ice-free areas while blue represents areas covered with sea ice.

 

It was two years ago that I first wrote about ocean dead zones. These are areas of the ocean that, due to a lack of oxygen, no longer sustain any life. While dead zones can happen naturally, they usually are caused by the results of human activity. A primary cause is nitrogen-rich nutrients from agricultural fertilizers that flow into coastal waters from rivers and streams.

 

Last week there was a report published in the Journal of Science that stated that the number of these ocean dead zones around the world has doubled every decade since the 1960s. There are now some 400 coastal areas that periodically or perpetually become dead due to oxygen starved bottom waters.

Researchers monitoring daily satellite images of Greenland's glaciers have discovered break-ups at two of the largest glaciers in the last month. They expect that part of the Northern hemisphere's longest floating glacier will continue to disintegrate within the next year.

A massive 11-square-mile (29-square-kilometer) piece of the Petermann Glacier in northern Greenland broke away between July 10th and by July 24th. The loss to that glacier is equal to half the size of Manhattan Island. The last major ice loss to Petermann occurred when the glacier lost 33 square miles (86 square kilometers) of floating ice between 2000 and 2001.

Petermann has a floating section of ice 10 miles (16 kilometers) wide and 50 miles (80.4 kilometers) long which covers 500 square miles (1,295 square kilometers).

A revised outlook for the Arctic 2008 summer sea ice minimum shows ice extent will be below the 2005 level but not likely to beat the 2007 record, say researchers with DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies), an integrated ice-atmosphere-ocean monitoring and forecasting system designed for observing, understanding and quantifying climate changes in the Arctic.

DAMOCLES will dispatch eleven research missions into the Arctic this autumn to better understand the future of the sea ice.

Chances that the 2008 ice extent will fall below last year's record minimum is about 8 percent, researchers forecast after having run a number of different models predicting the fate of the Arctic sea ice this summer. But there is still reason for concern; the scientists are almost certain the ice extent will fall below the minimum of 2005, which was the second lowest year on record. With a probability of 80% the minimum ice extent in 2008 will be in the range between 4.16 and 4.70 million km2.

Global climate change could explain the explosion in marine biodiversity that took place 460 million years ago, according to researchers from INSU-CNRS Laboratoire PaléoEnvironnements et PaléobioSphère (CNRS)Université Claude Bernard Lyon and Australian National University in Canberra.

They have found evidence of a progressive ocean cooling of about 15°C over a period of 40 million years during the Ordovician, a geologic period extending from 490 to 440 million years ago. Until now, this geologic period had been associated with a "super greenhouse effect" on our planet. The results from this study were published in the July 25, 2008 issue of Science.

Biogeoscientists show evidence of 90 billion tons of microbial organisms—expressed in terms of carbon mass—living in the deep biosphere, in a research article published online by Nature. This tonnage corresponds to about one-tenth of the amount of carbon stored globally in tropical rainforests. The authors: Kai-Uwe Hinrichs and Julius Lipp of the Center for Marine Environmental Sciences (MARUM) at University of Bremen, Germany; and Fumio Inagaki and Yuki Morono of the Kochi Institute for Core Sample Research at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) concluded that about 87 percent of the deep biosphere consists of Archaea.

University of Alberta scientists contend they have the answer to mass extinction of animals and plants 93 million years ago. The answer, research has uncovered, has been found at the bottom of the sea floor where lava fountains erupted, altering the chemistry of the sea and possibly of the atmosphere.

Earth and Atmospheric Science researchers Steven Turgeon and Robert Creaser found specific isotope levels of the element osmium, an indicator of volcanism in seawater, in black shale—rocks containing high amounts of organic matter—drilled off the coast of South America and in the mountains of central Italy.

Scientists announced today the discovery of reef structures they believe doubles the size of the Southern Atlantic Ocean's largest and richest reef system, the Abrolhos Bank, off the southern coast of Brazil's Bahia state. The newly discovered area is also far more abundant in marine life than the previously known Abrolhos reef system, one of the world's most unique and important reefs.

Researchers from Conservation International (CI), Federal University of Espírito Santo and Federal University of Bahia announced their discovery in a paper presented today at the International Coral Reef Symposium in Fort Lauderdale. "We had some clues from local fishermen that other reefs existed, but not at the scale of what we discovered," says Rodrigo de Moura, Conservation International Brazil marine specialist and co-author of the paper. "It is very exciting and highly unusual to discover a reef structure this large and harboring such an abundance of fish," he adds.

Human emissions of carbon dioxide are loading the atmosphere with heat-trapping greenhouse gases and have also begun to alter the chemistry of the ocean, according to a team of chemical researchers.

The ecological and economic consequences are difficult to predict but possibly calamitous, they say in the July 4 issue of Science, and halting the changes already underway will likely require even steeper cuts in carbon emissions than those currently proposed to curb climate change.

Ken Caldeira of the Carnegie Institution's Department of Global Ecology, writing with lead author Richard Zeebe of the University of Hawaii and two co-authors*, note that the oceans have absorbed about 40% of the carbon dioxide (CO2) emitted by humans over the past two centuries. This has slowed global warming, but at a serious cost: the extra carbon dioxide has caused the ocean's average surface pH (a measure of water's acidity) to shift by about 0.1 unit from pre-industrial levels. Depending on the rate and magnitude of future emissions, the ocean's pH could drop by as much as 0.35 units by the mid-21st century.