Discover Top Posts Tagged with #deoxygenation

The Science Research Notebooks of Satyendra Sunkavally. Page.1A

#origin of life #clay #deoxygenation #glauconite #potassium #biogenesis #sodium #mica #abiogenesis #transmembrane potential #marine life

The International Union for Conservation of Nature (IUCN) released the largest report of its kind — combining the efforts of 67 scientists from 17 countries — at the global climate summit in Madrid on Saturday. It found that the oxygen level of the ocean has declined by about 2% since the 1950s, and the volume of water completely depleted of oxygen has quadrupled since the 1960s. Sixty years ago, only 45 ocean sites suffered from low oxygen levels. That number skyrocketed to 700 in 2011. According to the study, about 50% of oxygen loss in the upper part of the ocean is a result of temperature increase. "With this report, the scale of damage climate change is wreaking upon the ocean comes into stark focus," Dr. Grethel Aguilar, IUCN acting director general, said in a statement. "As the warming ocean loses oxygen, the delicate balance of marine life is thrown into disarray." A combination of climate change and increased nutrient discharge will cause a 3%-4% decrease in ocean oxygen levels on average by 2100 if business continues as usual, scientists predict.

Climate Change: World's oceans are losing oxygen at a dangerous, unprecedented rate as temperatures rise - CBS News

#climate change #ocean #deoxygenation #environment #marine life

Widespread and sometimes drastic marine oxygen declines are stressing sensitive species—a trend that will continue with climate change

Climate change already poses serious problems for marine life, such as ocean acidification, but deoxygenation is the most pressing issue facing sea animals today, Andreas Oschlies.

After all, he says, “they all have to breathe.”

For Republicans

As oxygen-rich regions become scarcer, current fish habitats will also shrink and force economically important species—such as tuna, which globally generate an estimated $42 billion annually—into new ranges. In the northeastern tropical Atlantic researchers have found habitat for tuna as well as billfish fisheries shrank by 15 percent from 1960 to 2010 (pdf) due to oxygen loss.

“Oxygen levels in some tropical regions have dropped by a startling 40 percent in the last 50 years”

In the past decade ocean oxygen levels have taken a dive—an alarming trend that is linked to climate change, says Andreas Oschlies , an oceanographer at the Helmholtz Center for Ocean Research Kiel in Germany, whose team tracks ocean oxygen levels worldwide. “We were surprised by the intensity of the changes we saw, how rapidly oxygen is going down in the ocean and how large the effects on marine ecosystems are,” he says.

It is no surprise to scientists that warming oceans are losing oxygen, but the scale of the dip calls for urgent attention, Oschlies says.

Levels have dropped more subtly elsewhere, with an average loss of 2 percent globally.

To address the overall deoxygenation problem, Oschlies helped organize an international conference on the subject in Kiel last September. Attendees drafted an impromptu declaration called the Kiel Declaration on Ocean Deoxygenation to raise awareness among international governments, the United Nations and the public as well as to call for immediate action. They want governments and international groups to make more serious strides to slow climate change and cut back on the coastal runoff pollution that exacerbates oxygen decline. The researchers modeled the new declaration after the Monaco Declaration (pdf), which Oschlies thinks successfully helped raise international awareness around ocean acidification in 2008.

“It’s really intended to be an alert to both the public and the various governmental and international agencies that this is a significant issue,” says Wishner, one of the more than 300 scientists from more than 30 countries who signed the declaration.

Brad Seibel, also a signatory, minces no words on the matter: “I think it’s potentially very dire.”

Scientists have just detected a major change to the Earth’s oceans linked to a warming climate

A large research synthesis, published in one of the world’s most influential scientific journals, has detected a decline in the amount of dissolved oxygen in oceans around the world — a long-predicted result of climate change that could have severe consequences for marine organisms if it continues.

The paper, published Wednesday in the journal Nature by oceanographer Sunke Schmidtko and two colleagues from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, found a decline of more than 2 percent in ocean oxygen content worldwide between 1960 and 2010. The loss, however, showed up in some ocean basins more than others. The largest overall volume of oxygen was lost in the largest ocean — the Pacific — but as a percentage, the decline was sharpest in the Arctic Ocean, a region facing Earth’s most stark climate change.

The loss of ocean oxygen “has been assumed from models, and there have been lots of regional analysis that have shown local decline, but it has never been shown on the global scale, and never for the deep ocean,” said Schmidtko, who conducted the research with Lothar Stramma and Martin Visbeck, also of GEOMAR.

Ocean oxygen is vital to marine organisms, but also very delicate — unlike in the atmosphere, where gases mix together thoroughly, in the ocean that is far harder to accomplish, Schmidtko explained. Moreover, he added, just 1 percent of all the Earth’s available oxygen mixes into the ocean; the vast majority remains in the air.

Climate change models predict the oceans will lose oxygen because of several factors. Most obvious is simply that warmer water holds less dissolved gases, including oxygen. “It’s the same reason we keep our sparkling drinks pretty cold,” Schmidtko said.

But another factor is the growing stratification of ocean waters. Oxygen enters the ocean at its surface, from the atmosphere and from the photosynthetic activity of marine microorganisms. But as that upper layer warms up, the oxygen-rich waters are less likely to mix down into cooler layers of the ocean because the warm waters are less dense and do not sink as readily.

#deoxygenation

Trending Tags

Recently Viewed Tags

#deoxygenation