Data from end of the last ice age illuminate the precarious nature of global ocean chemistry

Jun 14, 2013
Data from end of the last ice age illuminate the precarious nature of global ocean chemistry

The ocean the Titanic sailed through just over 100 years ago was very different from the one we swim in today. Global warming is increasing ocean temperatures and harming marine food webs. Nitrogen run-off from fertilizers is causing coastal dead zones. A McGill-led international research team has now completed the first global study of changes that occurred in a crucial component of ocean chemistry, the nitrogen cycle, at the end of the last ice age. The results of their study confirm that oceans are good at balancing the nitrogen cycle on a global scale. But the data also shows that it is a slow process that may take many centuries, or even millennia, raising worries about the effects of the scale and speed of current changes in the ocean.

"For the first time we can quantify how oceans responded to slow, natural climate warming as the world emerged from the last ice age," says Prof. Eric Galbraith from McGill University's Department of Earth and Oceanic Sciences, who led the study. "And what is clear is that there is a strong in the ocean nitrogen cycle."

The nitrogen cycle is a key component of the global ocean metabolism. Like the proteins that are essential to human health, nitrogen is crucial to the health of oceans. And just as proteins are carried by the blood and circulate through the body, the nitrogen in the ocean is kept in balance by through a complicated cycle that keeps the ocean healthy. The phytoplankton ( at the base of the food chain) 'fix' nitrogen in the shallow, sunlit waters of the ocean, and then as they die and sink, nitrogen is eliminated (a process known as 'denitrification') in dark, oxygen-poor pockets of the ocean depths.

Using sediment gathered from the ocean floor in different areas of the world, the researchers were able to confirm that as the ice sheets started melting and the climate warmed up at the end of the last ice age, 18,000 years ago, the marine nitrogen cycle started to accelerate. The ocean had stabilized itself in its new, warmer state, in which the overall nitrogen cycle was running faster, by about 8,000 years ago. Given the current dramatic rate of change in the ocean the researchers are not sure how long it will take for marine ecosystems to adapt.

"We are changing the planet in ways we are not even aware of," says Galbraith. "You wouldn't think that putting carbon dioxide into the atmosphere would change the amount of nitrogen available to fish in the ocean, but it clearly does. It is important to realize just how interconnected everything is."

Explore further: Scientists may be cracking mystery of big 1872 earthquake

More information: www.nature.com/ngeo/journal/va… t/full/ngeo1832.html

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User comments : 7

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verkle
1.7 / 5 (19) Jun 14, 2013
The ocean the Titanic sailed through just over 100 years ago was very different from the one we swim in today.

I beg to differ. Apart from a few local changes, overall, the ocean today is very similar to what it was 100 years ago.

This kind of hype hurts the credibility of alarmists.

Howhot
4.2 / 5 (14) Jun 14, 2013
Only a very dim bulb would say "This kind of hype hurts the credibility of alarmists.". First, it's not hype. You just mis-read the article. Second, you beg to differ, but there is nothing to beg about. It just fact! Facts are the based on observation, measurements, studies, investigations and thorough, rigorous analysis. Your counter proof is what? Hearsay?

No your just another one of the dim-bulb denier class, just one of the minion of dim bulbs that knows nothing of physics or climate.

Global warming is increasing ocean temperatures and harming marine food webs. Nitrogen run-off from fertilizers is causing coastal dead zones.
Sounds about right to me.
Benni
1.3 / 5 (13) Jun 15, 2013
If a cyclical Ice Age period were in the process of sharply winding down in 2013 as what happened about 12,000 years ago to end the last cycle, I wonder if we'd be complaining about "global warming" as our ice covered cities began the thawing out process & we could see our streets again & watched as our lawns spring back to life & countryside wildlife & flowers repopulate the planet.

The Earth's rotational cycle that causes "ice age/warming cycles" is just about halfway through the present cycle to the next "freeze". There is no amount of methane, soot, CO2, forest fire & volcano effluent, or AGW effluent that can spewed into the atmosphere, that will prevent this cycle from repeating itself. I'll take the warming sweet spot we're presently experiencing to what the planet will be will be changing over to 5000 years from now.

Luv it while you still have, it will change like it or not.........

antigoracle
1.6 / 5 (14) Jun 15, 2013
For the first time we can quantify how oceans responded to slow, natural climate warming as the world emerged from the last ice age

The lies and deceit of a desperate AGW Alarmist cult.
If in their judgement, back then the warming was slow and natural, then it's even slower and natural now.
http://upload.wik....svg.png
deepsand
3.6 / 5 (14) Jun 15, 2013
AO and Benni are like insane woodpeckers looking for a grub in a block of concrete.
antigoracle
1 / 5 (11) Jun 16, 2013
AO and Benni are like insane woodpeckers looking for a grub in a block of concrete.

An AGW Alarmist turd with an obsession for wood/pecker.
deepsand
3.3 / 5 (10) Jun 16, 2013
AO and Benni are like insane woodpeckers looking for a grub in a block of concrete.

An AGW Alarmist turd with an obsession for wood/pecker.

You lack the humour to be entertaining, the knowledge to be informative, and have all the charm and attraction of a deceased rat which suffered from leprosy and incontinence.

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