Sea life's importance to the climate
Does the marine biosphere mix the ocean? A group of oceanographers led by W.K. Dewar of Florida State University argue that the swimming action of fish and other marine organisms may play a critical role in driving ocean currents. If true, large-scale over-fishing or the collapse of the marine food chain due to pollution or ocean acidification may cause significant changes in ocean currents--and Earth's climate.
Figure 1. Rainbow made From a sperm whale using his blowhole. Image taken June 17, 2006 in Kaikora, New Zealand by wunderphotographer jhfelder.
The Meridional Overturning Circulation (MOC) or Thermohaline Circulation is a well-known feature of the ocean circulation. In the Atlantic, the Gulf Stream current forms a portion of the MOC. Gulf Stream waters flow to the region near Greenland, where an input of fresh, denser water from melting ice and river run-off creates a downward flow of water that then moves southward along the ocean bottom towards the Equator. This deep water eventually returns to the surface in the mid-Atlantic to complete a cell of the MOC. Scientists have long thought that the energy needed to drive the MOC came from winds and tides--about two terrawatts of energy (Munk and Wunsch, 1998). However, Dewar et al. show that the mechanical energy added to the ocean by the swimming action of whales is about 1% of this total, and the swimming action of other marine organisms (primarily zooplankton) adds up to 50% of this total--one terrawatt of energy. While the authors admit that their calculations may have large errors, this research shows that marine life may have a heretofore unappreciated large impact on Earth's climate. Our climate is intimately connected to the sun, life on land, life in the ocean, and human activities in an incredibly complex web of interconnections. It is our challenge to understand this system, even as we change it and it changes of its own accord.
My next blog will be Thursday afternoon, when the new Dr. Bill Gray/Phil Klotzbach Atlantic hurricane season forecast will be released.
Jeff Masters
Dewar, W.K., R.J. Bingham, R.L. Iverson, D.P. Nowacek, L.C. St. Laurent, and P.H. Wiebe, 2006, "Does the marine biosphere mix the ocean?", Journal of Marine Research, 64, 541-561.
Munk, W., and C. Wunsch, 1998, "Abyssal recipes II: Energetics of tidal and wind mixing", Deep-Sea Res., 45, 1976-2009.
Reader Comments
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polite correction: The Pine Bark beetles are destroying millions of acres of Rockies Pine not because of forestry mismanagement, but because the winters are no longer cold enough in those regions to kill off the majority of the eggs as it used to. This is one of the more easily visible impacts of climate change (a more accurate term than GW as it encompasses localized instability). as the winters get milder, the beetle is also migrating northward, and westward..it is expected to cover most of NA within ten years. Very hard to "manage" infestations of such insane magnitudes without significant enviromental toxicity and cost.
Well, I am familiar with California... in this part of the world, densities of Ponderosa Pine, Jeffrey Pine, White Fir, etc, are believed to be many, many times higher than what was the original state. Old photos, drawings, and journal entries show an open woodland with scattered pines and an understory of duff, herbs, and small bushes. Huge (200+ year old) pines were in the forests as well as an even mix of younger pines. Now, the forests are nearly impenetrable, a condition that may be sustainable for a few decades when the trees are small... however, when they mature, there is NOT enough water for them. Pines kill bark beetles by pushing them out with sap, and when they are water stressed, they can not do this as effectively.
Why are the trees so dense now? Well, most people believe it is because of fire suppression (most ponderosa pine forests probably burned through the understory at least every 10 years and now almost never burn with low intensity fires) and because of large scale clear cutting which led to a flush of many trees germinating at the same time. So, in California, this is a major cause of the bark beetle problem.
Is climate change an issue too? It is very likely that it is. The 'drought' the southwest is in is a routine drought of the sort we have every hundred years or so. However, snow levels are on average higher than they have been in the historic past (and maybe the last 100,000 years depending on who you ask), giving the drought a bigger impact. I do also believe the lack of freezes to kill the beetles is a factor here as well.
Also, pine bark beetles are a natural occurrence and definitely have killed large areas of forest in the past. However, this infestation, stretching across a huge area of the continent, is much larger than what you would see in 'normal' natural conditions. It probably happened in the past during other times of climate change, such as the end of the last ice age... Ponderosa Pine and other pines covered a much larger of low elevation in California during the ice age, and as the climate dried and warmed, something killed the trees.. probably bark beetles.
I completely disagree, this is Florida, and although we have been dry, the chance of this system being a big soaker is just as high as it just being a decent rain maker.
This is Florida, arguably the wettest state or one of the wettest on average depending on your source. So if a pattern change is coming, and we a have a low moving out of the tropics, I think NWS here in the Tampa Bay area is being a little too conservative, I have lived here a while and seen tons of rain out of even very weak systems here.
What they should say is: GFS is painting a lot of rain for our area which is a good sign but we will keep rain chances low for now untill we see more consistency and when we get a better idea what will happen as we get closer to this event.
Thats a good way to be conservative, I think calling it convective feedback seems rather overdone, because that could easily be very wrong.
Afternoon all!
And if you look at climotology, its obious the best solution would be to expect pretty good rains out of this because its typical by June, where as 2 weeks ago it wasn't very typical, and it did exactly that, never materialized.
I thought that the water from melting ice and river runoff (fresh water) was less dense??
Well, I believe it is asinine to dismiss any activity for the next month. Pattern is changing. Shear is dropping, albeit slowly. The pattern we are currently in is normal for May. Let's not forget last year, which was coined a "dud" by many spawned a TS in the Gulf which came over the Tampa area in the second week of June. I was in Dallas at the time on vacation, but my wife was keeping me informed about the copious amounts of hard driving rain that was flooding our property.
Here's the point..... It is foolish to make a long term forecast. I do not do this for good reason. The EPAC situation right now has no bearing on the long term ATL season. None. Zero. We are still in a neutral ENSO. Not going back to El Nino. The pattern is changing. The subtropical jet is retreating northward. Do not let your guard down.
Is there any chance of the caribbean blob to develop into a tropical storm?
It could develope but most likely it would be non-tropical in nature.
What are the SST's off of Africa this time of year?
But as we saw in 04 and 05, either one can be equally dangerous.
why would it be non tropical?
I think to an extent most of us became a little jaded after '04 and especially '05 in terms of when is the season going to get rocking....
valid point
By Timothy Gardner
Wed May 23, 8:42 PM ET
NEW YORK (Reuters) - Hurricanes over the past 5,000 years appear to have been controlled more by El Nino and an African monsoon than warm sea surface temperatures, such as those caused by global warming, researchers said on Wednesday.
The study, published in the journal Nature, adds to the debate on whether seas warmed by greenhouse gas emissions lead to more hurricanes, such as those that bashed the Gulf of Mexico in 2005.
Some researchers say warmer seas appear to have contributed to more intense hurricanes, while others disagree. The U.N. International Panel on Climate Change said this year it was more likely than not that humans contribute to a trend of increasingly intense hurricanes.
Frequent strong hurricanes thrived in the Western Atlantic during times of weak El Ninos, or warming of surface waters of the Eastern Pacific Ocean, and strong West African monsoons even when local seas were cooler than now, the study said.
"Tropical sea surface temperatures as warm as at present are apparently not a requisite condition for increased intense hurricane activity," Jeffrey Donnelly, the lead author and researcher at the Woods Hole Oceanographic Institution, said in the study.
Intense hurricanes made landfall during the latter half of the Little Ice Age, a period of cooling that occurred approximately from the 14th to mid-19th centuries, he said.
Donnelly took core sediment samples from coastal lagoons in Puerto Rico to determine the frequency and strength of hurricanes that hit the Caribbean island over thousands of years. The storms whipped up sand and other coarse grains that were deposited in the lagoons.
He compared the deposits with historic paleoclimatology records to determine that the storms hit during periods when El Ninos were weak and when Western African monsoons were strong.
Intense hurricanes hit when local sea surface temperatures were warm or cool. In fact, "the Caribbean experienced a relatively active interval of intense hurricanes for more than a millennium when local sea surface temperatures were on average cooler than modern," the study said.
Changes in intense hurricane activity should be better predicted with more study of the Eastern Pacific and West African climate patterns, it said.
Nothing wrong with it at all. Passion is what drives desire. Desire drives research. Research drives new technologies to learn more about hurricanes. New technology can possibly save more lives.
And, with Aaron's new system, those assclowns will be history shortly after their post:-)
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