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Sea die-out blamed on volcanoes
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rockin robin tweet
User ID: 153222
7/16/2008 11:40 PM
Report abusive post | Sea die-out blamed on volcanoes
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Sea die-out blamed on volcanoes
Contessa quarry, Italy (Steve Turgeon)
Different colour sediments represent oxygenated versus anoxic conditions
Undersea volcanic activity has been blamed for a mass extinction in the seas 93 million years ago.
In the so-called "anoxic event" of the late Cretaceous Period, the ocean depths became starved of oxygen, wiping out swathes of marine organisms.
Researchers from the University of Alberta, Canada, found a tell-tale signature of underwater volcanism in rocks dating to the period.
Their findings have been published in the journal Nature.
At the time of the anoxic event, the average temperature was nearly twice that of today, researchers say.
Palm trees grew in what would later become Alaska and large reptiles roamed northern Canada. The Arctic Ocean was ice-free and scientists think it would have had a temperature we might describe today as lukewarm.
However, the oceans were also hit by a mass extinction which wiped out a type of large clam common at the time as well as tiny ocean creatures known as foraminifera, which live on the sea floor.
Ocean chemistry
Helped by a sudden sluggish shift in ocean circulation, the remains of these minuscule organisms littered the sea bed in thick layers, and over geological time became transformed into oil.
After the extinction, levels of greenhouse gases in the atmosphere dropped and Earth lurched into a sudden, but short-lived, period of cooling.
Geologists have pondered for years as to the cause of this extraordinary event.
Inoceramid (USGS)
Giant clams were among the organisms killed off
According to Steve Turgeon and Robert Creaser from Alberta's department of Earth and atmospheric sciences, the answer to the cataclysm lies in volcanic eruptions which took place on the ocean floor.
These appear to have altered the chemistry of the sea and possibly of the atmosphere also.
The clue can be found in levels of two forms, or isotopes, of osmium found in black shale rocks.
The sedimentary rocks they analysed came from cores drilled from the sea bed off the coast of South America, and from mountains in Italy.
Future warming
The bed of the present-day Caribbean was formed by the huge lava flows thought to have been involved. However, the researchers say the flows would have preceded the extinction by up to 23,000 years.
Two theories, which are not mutually exclusive, have emerged to explain the chemistry of what happened next, says Tim Bralower, a geologist at Pennsylvania State University, US, who reviewed the paper.
One possibility is that the volcanoes spewed out metal-rich fluids that seeded the upper level of the ocean with micronutrients, he says.
Tiny life forms on the sea surface, called phytoplankton, gorged on the food, and storing up carbon as they grew. They then sank to the sea floor and decayed, stripping the ocean of oxygen.
The other is that the volcanoes disgorged clouds of CO2 to the atmosphere, warming the climate to the extent that Earth's ocean circulation system ground to a near-halt.
Beyond the surface layers, water was no longer turned over and anoxia (lack of oxygen) was the result.
Dr Bralower says that figuring out the post-volcanism scenario could help scientists wrestling with some of the unknowns of climate change today.
These include the impact of higher temperatures on marine circulation and whether controversial schemes to sow the ocean with iron filings, to spur phytoplankton growth and thus soak up CO2 from the atmosphere, would ease warming or cause oxygen starvation in the ocean depths.
[link to news.bbc.co.uk] |
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Anonymous Coward
User ID: 469490
7/16/2008 11:49 PM | | Re: Sea die-out blamed on volcanoes | Quote |
Thanks, OP, very informative. There are many volcanoes in the ocean that the scientists don't know about. I read one account that for every underwater volcano that they know about that they estimate that there are from 4 to 10 that they do not know about. |
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Rusty the Rooster
User ID: 153222 (OP)
7/17/2008 12:09 AM | | Re: Sea die-out blamed on volcanoes | Quote |
Thanks, OP, very informative. There are many volcanoes in the ocean that the scientists don't know about. I read one account that for every underwater volcano that they know about that they estimate that there are from 4 to 10 that they do not know about. Quoting: Anonymous Coward 469490
Yes thank you it's hard to make a distinction to then and now and the information we are feed. Keep it coming |
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Anonymous Coward
User ID: 452866
7/17/2008 12:26 AM | |
Anonymous Coward
User ID: 469495
7/17/2008 12:26 AM | | Re: Sea die-out blamed on volcanoes | Quote |
Sheep believe everything they are told.
What is killing the marine life, and has been for sometime, is the United States' submarine and warship's new sonar devices.
The 'new' frequencies are causing the fish's frequencies to be disrupted enough to die. |
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* <-----Kingdom of Heaven
User ID: 418811
7/17/2008 12:30 AM | | Re: Sea die-out blamed on volcanoes | Quote |
Thanks, OP, very informative. There are many volcanoes in the ocean that the scientists don't know about. I read one account that for every underwater volcano that they know about that they estimate that there are from 4 to 10 that they do not know about.
Yes thank you it's hard to make a distinction to then and now and the information we are feed. Keep it coming
IMPOSSIBLE!! Only man can cause the seas to die.    Hey...wait a sec.   hehe
By your thinking we cant destroy life so therefore we should never try to improve ourselves or live with life in balance and harmony because we dont make any difference at all. |
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Big Bird
User ID: 153222 (OP)
7/17/2008 12:47 AM | | Re: Sea die-out blamed on volcanoes | Quote |
Thanks, OP, very informative. There are many volcanoes in the ocean that the scientists don't know about. I read one account that for every underwater volcano that they know about that they estimate that there are from 4 to 10 that they do not know about.
Yes thank you it's hard to make a distinction to then and now and the information we are feed. Keep it coming
IMPOSSIBLE!! Only man can cause the seas to die. Hey...wait a sec. hehe
I know what you mean..conventional wisdom...only a mile size rock can cause upheavals
other C wisdom today it's heavier than air gases than can cause changes |
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Clyde the Seagull
User ID: 153222 (OP)
7/17/2008 12:56 AM | | Re: Sea die-out blamed on volcanoes | Quote |
Funny CO2 gas was responsible way back then
And CO2 gas now.
there may be a message here |
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Anonymous Coward
User ID: 435072
7/17/2008 1:06 AM | | Re: Sea die-out blamed on volcanoes | Quote |
This too, is in the Bible prophecy..
And the SEA became as blood, and all life died.
Just keep watch, and don't think to do anything, like repent, and get right with JESUS..
It just makes me so happy to see you a freak out |
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Francis the Finch
User ID: 142594
7/17/2008 1:17 AM | | Re: Sea die-out blamed on volcanoes | Quote |
didn't even finch a muscle
Cause I know Jesus doesn't like those kinda remarks |
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GraftedPromise U$ofA
User ID: 469736
7/17/2008 12:05 PM | | Re: Sea die-out blamed on volcanoes | Quote |
But ... but ... but ... according to AlGore we humans are to blame. Not!
So glad the TRUTH is coming out!! |
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Anonymous Coward
User ID: 258519
7/17/2008 12:26 PM | | Re: Sea die-out blamed on volcanoes | Quote |
Volcanic eruptions reshape Arctic ocean floor: study
Wed Jun 25
PARIS (AFP) - Recent massive volcanoes have risen from the ocean floor deep under the Arctic ice cap, spewing plumes of fragmented magma into the sea, scientists who filmed the aftermath reported Wednesday.
The eruptions — as big as the one that buried Pompei — took place in 1999 along the Gakkel Ridge, an underwater mountain chain snaking 1,800 kilometres (1,100 miles) from the northern tip of Greenland to Siberia.
Scientists suspected even at the time that a simultaneous series of earthquakes were linked to these volcanic spasms.
But when a team led of scientists led by Robert Sohn of the Woods Hole Oceanographic Institution in Massachusetts finally got a first-ever glimpse of the ocean floor 4,000 meters (13,000 feet) beneath the Arctic pack ice, they were astonished.
What they saw was unmistakable evidence of explosive eruptions rather than the gradual secretion of lava bubbling up from Earth’s mantle onto the ocean floor…
The mid-ocean ridge runs 84,000 kilometres (52,000 miles) beneath all the world’s major seas except the Southern Ocean, and marks the boundary between many of the tectonic plates that make up the surface of the Earth.
When continental plates collide into each other, they can thrust up mountain ranges such as the Himalayas.
But along most of the mid-ocean ridge — including the Gakkal Ridge — the plates are pulling apart, allowing molten magna and gases trapped beneath the crust to escape…
Both sonar and visual images showed an ocean valley filled with flat-topped volcanos up to two kilometres (1.2 miles) wide and several hundred metres high.
Er, is it not possible that these volcanic eruptions — going back to at least 1999 — may have played a part in whatever melting there has been of the Greenland and Arctic ice sheets?
If there has even been any... scientists at
NOAA’s Geophysical Fluid Dynamics Laboratory, the amount in ice began to decline precipitously in around 1999, which is when these volcanoes began their eruption. |
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Prof_Rabbit
User ID: 148352
7/17/2008 12:36 PM | | Re: Sea die-out blamed on volcanoes | Quote |
Volcanic eruptions reshape Arctic ocean floor: study
Wed Jun 25
But when a team led of scientists led by Robert Sohn of the Woods Hole Oceanographic Institution in Massachusetts finally got a first-ever glimpse of the ocean floor 4,000 meters (13,000 feet) beneath the Arctic pack ice, they were astonished. Quoting: Anonymous Coward 258519
Lots more here.
[link to www.whoi.edu]
"Anger is a wind that blows out the lamp of your mind" |
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Anonymous Coward
User ID: 469495
7/17/2008 12:42 PM | | Re: Sea die-out blamed on volcanoes | Quote |
Sheep also tend to not respond to things that are true or doesn't fit in with their BS.
---------------------------------------
Sheep believe everything they are told.
What is killing the marine life, and has been for sometime, is the United States' submarine and warship's new sonar devices.
The 'new' frequencies are causing the fish's frequencies to be disrupted enough to die. |
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