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lunes, 8 de junio de 2015

DÍA MUNDIAL DE LOS OCÉANOS : nsf.gov - National Science Foundation - Warmer, lower-oxygen oceans will shift marine habitats .- Océanos más cálidos con más baja en oxígeno desplazará hábitats marinos

Hola amigos: A VUELO DE UN QUINDE EL BLOG,, en nuestro Blog, estamos a la expectativa en cuanto a los acontecimientos del cambio climático, justamente las Naciones Unidos en su Asamblea del 5 de diciembre del 2008, aprueba la Resolución 63/111, y se resuelve que a partir del 2009, se designe el 8 de junio como Día Mundial de los Océanos; justo con ese suceso hemos recibido información de la Fundación Nacional de Ciencias de los Estados Unidos, en la cual según sus investigaciones  los océanos se vuelven más cálidos con evidente bajo de oxígeno que originará el desplazamiento de los Hábitats marinos.
Para comparación y poder entender:
Modernos alpinistas suelen llevar los tanques de oxígeno para ayudar a alcanzar la cumbre. La combinación de ejercicio físico y la falta de oxígeno a gran altura crea un gran desafío para los alpinistas.
Ahora, justo a tiempo para el Día Mundial de los Océanos el lunes 8 de junio de investigadores han encontrado que el mismo principio se aplica a las especies marinas durante el cambio climático.
La temperatura del agua más cálidas acelerarán necesidad metabólica de los animales para el oxígeno, como también ocurre durante el ejercicio, pero el agua más caliente sostendrán menos del oxígeno necesario para alimentar sus cuerpos, similar a lo que sucede en las altas altitudes.
 Los resultados del estudio se publican en la edición de esta semana de la revista Science.
"Este trabajo es importante porque vincula limitaciones metabólicas a los cambios en las temperaturas marinas y suministro de oxígeno", dijo Irwin Forseth, director del programa en la División de la Fundación Nacional de Ciencia (NSF) de Integradora de Organismos Systems, que financió la investigación junto con la División de Océano de la NSF Ciencias.
"La comprensión de las conexiones, como esto es esencial para permitirnos predecir los efectos de los cambios ambientales sobre la distribución y diversidad de la vida marina."

Animales marinos empujados lejos de ecuador:
 Los científicos encontraron que estos cambios pueden actuar para empujar animales marinos lejos del ecuador. Alrededor de dos tercios de la presión respiratoria debido al cambio climático es causado por las temperaturas más cálidas, mientras que el resto se debe a que el agua más caliente sostiene menos gases disueltos tales como oxígeno.
"Si su metabolismo aumenta, usted necesita más alimentos y que a la vez  necesita más oxígeno", dijo el autor principal papel Curtis Deutsch de la Universidad de Washington.
"Los animales acuáticos podrían convertirse  en hambrientos de oxígeno en un futuro más cálido falta de oxígeno, incluso si el oxígeno no cambia. Sabemos que los niveles de oxígeno en el océano están bajando ahora y disminuirán más con el calentamiento climático."
More information.....
http://www.nsf.gov/news/news_summ.jsp?cntn_id=135248&WT.mc_id=USNSF_51&WT.mc_ev=click
Changes will result in marine animals moving away from equator
An Atlantic rock crab
Scientists studied Atlantic rock crabs to see how they would fare in a warmer climate.
Credit and Larger Version
June 4, 2015

Modern mountain climbers usually carry tanks of oxygen to help them reach the summit. The combination of physical exertion and lack of oxygen at high altitudes creates a major challenge for mountaineers.
Now, just in time for World Oceans Day on Monday, June 8, researchers have found that the same principle applies to marine species during climate change.
Warmer water temperatures will speed up the animals' metabolic need for oxygen, as also happens during exercise, but the warmer water will hold less of the oxygen needed to fuel their bodies, similar to what happens at high altitudes.
Results of the study are published in this week's issue of the journal Science.
"This work is important because it links metabolic constraints to changes in marine temperatures and oxygen supply," said Irwin Forseth, program director in the National Science Foundation's (NSF) Division of Integrative Organismal Systems, which funded the research along with NSF's Division of Ocean Sciences.
"Understanding connections such as this is essential to allow us to predict the effects of environmental changes on the distribution and diversity of marine life.”

Marine animals pushed away from equator

The scientists found that these changes will act to push marine animals away from the equator. About two thirds of the respiratory stress due to climate change is caused by warmer temperatures, while the rest is because warmer water holds less dissolved gases such as oxygen.
"If your metabolism goes up, you need more food and you need more oxygen," said lead paper author Curtis Deutsch of the University of Washington.
"Aquatic animals could become oxygen-starved in a warmer future, even if oxygen doesn't change. We know that oxygen levels in the ocean are going down now and will decrease more with climate warming."

Four Atlantic Ocean species studied

The study centered on four Atlantic Ocean species whose temperature and oxygen requirements are well known from lab tests: Atlantic cod in the open ocean; Atlantic rock crab in coastal waters; sharp snout seabream in the sub-tropical Atlantic; and common eelpout, a bottom-dwelling fish in shallow waters in high northern latitudes.
Deutsch and colleagues used climate models to see how projected temperature and oxygen levels by 2100 would affect the four species ability to meet their future energy needs.
The near-surface ocean is projected to warm by several degrees Celsius by the end of this century. Seawater at that temperature would hold 5-10 percent less oxygen than it does now.
Results show that future rock crab habitat, for example, would be restricted to shallower water, hugging the more oxygenated surface.

Equatorial part of animals' ranges uninhabitable 

For all four species, the equatorial part of their ranges would become uninhabitable because peak oxygen demand would be greater than the supply.
Viable habitats would shift away from the equator, displacing from 14 percent to 26 percent of the current ranges.
The authors believe the results are relevant for all marine species that rely on aquatic oxygen as an energy source.
"The Atlantic Ocean is relatively well-oxygenated," Deutsch said. "If there's oxygen restriction in the Atlantic Ocean marine habitat, then it should be everywhere."
Climate models predict that the northern Pacific Ocean's relatively low oxygen levels will decline even more, making it the most vulnerable part of the seas to habitat loss.
"For aquatic animals that are breathing water, warming temperatures create a problem of limited oxygen supply versus higher demand," said co-author Raymond Huey, a University of Washington biologist who has studied metabolism in land animals and in human mountain climbers.
"This simple metabolic index seems to correlate with the current distributions of marine organisms," he said. "That means that it gives us the power to predict how range limits are going to shift with warming."

A day-to-day "dead zone"

Previously, marine scientists thought about oxygen more in terms of extreme events that could cause regional die-offs of marine animals, also known as dead zones.
"We found that oxygen is also a day-to-day restriction on where species will live," Deutsch said.
"The effect we're describing will be part of what's pushing species around in the future."
Other co-authors are Hans Otto-Portner of the Alfred Wegener Institute in Germany; Aaron Ferrel of the University of California, Los Angeles; and Brad Seibel at the University of Rhode Island.
The Gordon and Betty Moore Foundation and the Alfred Wegener Institute also funded the research.
-NSF-
Media Contacts
Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov
Hannah Hickey, University of Washington, (206) 543-2580, hickeyh@uw.edu

Related WebsitesNSF Grant: Collaborative Research: LiT: Vulnerability of Tropical Ectotherms to Climate Warming: http://www.nsf.gov/awardsearch/showAward?AWD_ID=1038016&HistoricalAwards=false
NSF Grant: Collaborative Research: A metabolic index to predict the consequences of expanding oxygen minimum zones for midwater ecosystems:
 http://www.nsf.gov/awardsearch/showAward?AWD_ID=1458967&HistoricalAwards=false

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2015, its budget is $7.3 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 48,000 competitive proposals for funding, and makes about 11,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.
Useful NSF Web Sites:
NSF Home Page:
 http://www.nsf.gov
NSF News:
 http://www.nsf.gov/news/
For the News Media:
 http://www.nsf.gov/news/newsroom.jsp
Science and Engineering Statistics:
http://www.nsf.gov/statistics/
Awards Searches:
http://www.nsf.gov/awardsearch/
The carapace of an Atlantic rock crab
The carapace of an Atlantic rock crab; the crabs may need to change locations in a warmer world.
Credit and Larger Version
Atlantic cod under a shipwreck off Massachusetts
Atlantic cod, here under a shipwreck off Massachusetts, may soon need to move to cooler waters.
Credit and Larger Version
a school of cod fish swimming
Declining cod stocks may be further threatened by ever-warmer waters.
Credit and Larger Version
Common eelpout next to a ruler
Common eelpout, bottom-dwelling fish in northern latitudes, may head yet farther north.
Credit and Larger Version
The Awa people of the Brazilian Amazon
The researchers' findings are described in the June 5, 2015, issue of Science magazine.
Credit and Larger Version

The National Science Foundation (NSF)
Artículos relacionados

http://www.un.org/es/events/oceansday/
  Resolución 63/111

 http://es.wikipedia.org/wiki/D%C3%ADa_Mundial_de_los_Oc%C3%A9anos

Días, Años y Decenios

Día Mundial de los Océanos
8 de junio.

 

Día Mundial de los Océanos - 8 de junio

www.un.org/es/events/oceansday/
Sitio oficial relativo al Día Mundial de los Océanos de las Naciones Unidas. Aquí encontrará información y enlaces relacionados.
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The Ocean's Carbon Balance
by Holli Riebeek • design by Robert Simmon • June 30, 2008
The idea seemed simple enough: the more carbon dioxide that people pumped into the atmosphere by burning fossil fuels, the more the oceans would absorb. The ocean would continue to soak up more and more carbon dioxide until global warming heated the ocean enough to slow down ocean circulation. Water trapped at the surface would become saturated, at which point, the ocean would slow its carbon uptake. To oceanographers of 30 years ago, the question was less, how will human emissions change the ocean carbon cycle, and more, is the ocean carbon cycle changing yet?




Photograph of mid-ocean waves.
The question matters because if the ocean starts to take up less carbon because of global warming, more is left in the atmosphere where it can contribute to additional warming. Scientists wanted to understand how the ocean carbon cycle might change so that they could make more accurate predictions about global warming. Thus motivated, oceanographers began a series of research cruises, trolling across the Pacific from Japan to California, from Alaska to Hawaii, and through the North Atlantic from Europe to North America. On shore, others developed computer models.

One of the largest unknowns
in our understanding of the greenhouse effect is the role of the oceans as a carbon sink. Much of the carbon dioxide released into the atmosphere by the burning of fossil fuels is soaked up by the oceans, but changes in the climate are altering this absorption in surprising ways. (Photograph ©2007 *Fede*.)











Map of carbon sampling cruise tracks.
After 30 years of research, the question itself hasn’t changed, but the reasoning behind it couldn’t be more different. Oceanographers started out wanting to know if the ocean was keeping up with the amount of carbon dioxide people are putting into the atmosphere. Instead, they found that people aren’t the only players changing the ocean carbon cycle. Over decades, natural cycles in weather and ocean currents alter the rate at which the ocean soaks up and vents carbon dioxide. What’s more, scientists are beginning to find evidence that human-induced changes in the atmosphere also change the rate at which the ocean takes up carbon. In other words, it turns out that the world is not a simple place.

The Measured Ocean

The group surrounds a circular cluster of instruments and 36 three-foot-tall PVC (plastic) bottles, taking turns extracting sea water from the bottles, assembly-line style. It is a deliberate, well-ordered procedure. The glass sample bottles set aside for oxygen samples are filled first, followed by the massive syringe meant for chlorofluorocarbon (freon) samples, and so on, until 10 to 15 different samples have come out of each bottle. Everyone has a task and a place. It’s a social event, a break from the lonely hours each will spend in his or her lab analyzing the samples before the next batch is hauled out of the ocean. It might even be fun. Except that it’s late winter. In the North Pacific. And they are on the deck of a ship, looking at the same faces that they’ve seen day after day for four weeks or more, and they’ll be repeating this procedure again in another 30 nautical miles.

 For more than 30 years, research ships have cruised the world’s oceans, measuring carbon dioxide concentrations, ocean temperatures, winds, and other properties. The map shows the paths of research cruises conducted as part of the World Climate Research Programme’s Climate Variability and Predictability project. Cruise measurements—along with those from buoys, drifting floats, orbiting satellites, and land-based weather stations—are beginning to reveal long-term trends to ocean researchers. (Map by Robert Simmon, based on data from Dana Greeley, NOAA.)

Photograph of the recovery of a sampling rosette aboard the R/V Roger Revelle in the Southern Ocean, February 2008.
“It’s pretty brutal,” says Richard Feely, with the air of a veteran who thoroughly enjoys his work. An oceanographer who studies the ocean carbon cycle at the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory, he’s been at this sort of thing for almost forty years. Feely is one of a community of oceanographers who have been monitoring Earth’s oceans for decades, trying to figure out how much human-released carbon dioxide the ocean has been soaking up.
For eons, the world’s oceans have been sucking carbon dioxide out of the atmosphere and releasing it again in a steady inhale and exhale. The ocean takes up carbon dioxide through photosynthesis by plant-like organisms (phytoplankton), as well as by simple chemistry: carbon dioxide dissolves in water. It reacts with seawater, creating carbonic acid. Carbonic acid releases hydrogen ions, which combine with carbonate in seawater to form bicarbonate, a form of carbon that doesn’t escape the ocean easily.
 Crew members aboard the R/V Roger Revelle retrieve a CTD rosette from the frigid waters of the Southern Ocean. As the device is lowered into the ocean, electronic instruments measure salinity, temperature, and depth. Each of the white bottles collects seawater at different depths for detailed analysis. (Photograph ©2008 Brett longworth.)






Graph of carbon dioxide concentration in water versus temperature at 3 different atmospheric concentrations.
As we burn fossil fuels and atmospheric carbon dioxide levels go up, the ocean absorbs more carbon dioxide to stay in balance. But this absorption has a price: these reactions lower the water’s pH, meaning it’s more acidic. And the ocean has its limits. As temperatures rise, carbon dioxide leaks out of the ocean like a glass of root beer going flat on a warm day. Carbonate gets used up and has to be re-stocked by upwelling of deeper waters, which are rich in carbonate dissolved from limestone and other rocks.
In the center of the ocean, wind-driven currents bring cool waters and fresh carbonate to the surface. The new water takes up yet more carbon to match the atmosphere, while the old water carries the carbon it has captured into the ocean.

 The concentration of carbon dioxide (CO2) in ocean water (y axis) depends on the amount of CO2 in the atmosphere (shaded curves) and the temperature of the water (x axis). This simplified graph shows that as atmospheric CO2 increases from pre-industrial levels (blue) to double (2X) the pre-industrial amounts (light green), the ocean CO2 concentration increases as well. However, as water temperature increases, its ability dissolve CO2 decreases. Global warming is expected to reduce the ocean’s ability to absorb CO2, leaving more in the atmosphere…which will lead to even higher temperatures. (Graph by Robert Simmon.)

Diagram of carbon dioxide exchange in the ocean's mixed layer.

In the short term, the ocean absorbs atmospheric carbon dioxide into the mixed layer, a thin layer of water with nearly uniform temperature, salinity, and dissolved gases. Wind-driven turbulence maintains the mixed layer by stirring the water near the ocean’s surface. Over the long term, carbon dioxide slowly enters the deep ocean at the bottom of the mixed layer as well in in regions near the poles where cold, salty water sinks to the ocean depths. (NASA illustration by Robert Simmon.)
The warmer the surface water becomes, the harder it is for winds to mix the surface layers with the deeper layers. The ocean settles into layers, or stratifies. Without an infusion of fresh carbonate-rich water from below, the surface water saturates with carbon dioxide. The stagnant water also supports fewer phytoplankton, and carbon dioxide uptake from photosynthesis slows. In short, stratification cuts down the amount of carbon the ocean can take up.

Defying Expectations

To try to understand the ocean’s carbon limits, Feely and the rest of the oceanography community measure dissolved carbon and the ocean’s pH. They probe its temperature, alkalinity, salinity, and record the presence of tracers like chlorofluorocarbons or helium to find out when the water was last exposed to the atmosphere. By the end of a typical cruise, they will have collected 50,000 or more measurements. And then they go out the next year to repeat it all again, and they have done this for more than three decades.

http://earthobservatory.nasa.gov/Features/OceanCarbon/



Guillermo Gonzalo Sánchez Achutegui
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