Wednesday, August 24, 2011

The Last Great Global Warming - article in Scientific American Magazine

The July 2011 issue of Scientific American Magazine contains an article describing what is now known about  a period of global warming that occurred about 56 million years ago.
During that period:
"in the course of a few thousand years—a mere instant in geologic time—global temperatures rose five degrees Celsius, marking a planetary fever known to scientists as the Paleocene-Eocene Thermal Maximum, or PETM.
 "Climate zones shifted toward the poles, on land and at sea, forcing plants and animals to migrate, adapt or die. Some of the deepest realms of the ocean became acidified and oxygen-starved, killing off many of the organisms living there. It took nearly 200,000 years for the earth’s natural buffers to bring the fever down."

 Image: Illustration by Ron Miller [from the magazine]
The article's author   describes how the researchers went to the island of Spitsbergen in the Svalbard archipelago within the Arctic circle to retrieve drill core samples saved from earlier exploration work done during commercial mineral exploration. These sediment samples contained material which had been deposited throughout the PETM period and which had since been undisturbed underground until the drillers arrived.

What the deposits revealed, in summary, is that 
  • "Global temperature rose five degrees Celsius 56 million years ago in response to a massive injection of greenhouse gases into the atmosphere.
  • That intense gas release was only 10 percent of the rate at which heat-trapping greenhouse gases are building up in the atmosphere today.
  • The speed of today’s rise is more troubling than the absolute magnitude, because adjusting to rapid climate change is very difficult."
The fossils in the mineral records indicate that absorption of carbon dioxide by the ocean caused significant acidification which happened then much slower than is happening now. Even so, something like 30 percent of all species of ocean flora and fauna die out.
"[the] evidence suggests the pace of Earth's most abrupt prehistoric warm-up paled in comparison with what we face today. The episode has lessons for our future."

Sunday, June 19, 2011

Richard A Feely interview about ocean acidification on ABC Radio National - 'National Interest' program

If you download the whole edition of the "In the National Interest" program, Richard Feely starts at about 29th minute and goes for about 10mins.

Monday, May 30, 2011

Study of ocean acidification using natural volcanic C02 seeps

Another study - reported on the Physorg website - predicting the demise of coral reefs; a longer time-frame here: they say the die off may occur at the end of 21st Century
http://www.physorg.com/news/2011-05-ocean-acidification-diversity-resiliency-coral.html

that article's source listed as:
"Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations," Nature Climate Change, June 2011.

Sunday, May 15, 2011

More bad news for corals

An Australian researcher has found that acidification of the ocean gives some seaweeds an edge over their coral neighbours.
"The new study experimentally confirms this hypothesis using two of the most abundant species co-occurring—and competing—on the Great Barrier Reef. The branching coral Acropora intermedia and the brown fleshy seaweed Lobophora papenfussii were placed in tanks exposed to four different carbon dioxide-dosing regimes, simulating the range of historical and projected ocean acidification conditions: pre-industrial, present-day, mid-century and late-century carbon dioxide levels ...
 "The new study experimentally confirms this hypothesis using two of the most abundant species co-occurring—and competing—on the Great Barrier Reef. The branching coral Acropora intermedia and the brown fleshy seaweed Lobophora papenfussii were placed in tanks exposed to four different carbon dioxide-dosing regimes, simulating the range of historical and projected ocean acidification conditions: pre-industrial, present-day, mid-century and late-century carbon dioxide levels"
Click the link to see the short article on Seaweb.
Their  Source: Diaz-Pulido, G. et al. 2011. High CO2 enhances the competitive strength of seaweeds over corals. Ecology Letters 14(2): 156-162


Monday, March 28, 2011

Upside-down "Hills Hoist" - an idea about growing kelp in equatorial deep ocean

It occurs to me that one way of providing for the needs of kelp in deep ocean at the equator is to make something like an enormous, upside down, "Hills Hoist" circular clothes line and suspend this from a buoy.

Like the Hills Hoist clothes line [see Hills Products for examples of this] in which the central column can be wound up and down to facilitate easy hanging of cloths on the line, the upside down seaweed growing framework would be capable of being raised up at the start of a growing cycle to allow attachment of kelp and other seaweed seeds, and then lowered to the particular depth favoured by that species. Later the framework would be raised to facility harvesting and the seaweed. The buoys would need to be connected by a network of floating ropes or cables of which some would be linked no doubt to the Ocean Cities ice rafts. In order to keep the seaweed growing frameworks in good condition and not let them get damaged, or keep the kelp on them from being overshadowed by seaweed on other frameworks, some nodes of the network would need to be anchored to the sea floor four kilometres below.