Oceans face 'deadly trio' of threats, study says

A whale dives into sea off the coast of Greenland's capital Nuuk October 17, 2012.

Credit: Reuters/Alistair Scrutton

By Environment Correspondent Alister Doyle

OSLO | Thu Oct 3, 2013 4:56am EDT

OSLO (Reuters) - The world's oceans are under greater threat than previously believed from a "deadly trio" of global warming, declining oxygen levels and acidification, an international study said on Thursday.

The oceans have continued to warm, pushing many commercial fish stocks towards the poles and raising the risk of extinction for some marine species, despite a slower pace of temperature rises in the atmosphere this century, it said.

"Risks to the ocean and the ecosystems it supports have been significantly underestimated," according to the International Programme on the State of the Ocean (IPSO), a non-governmental group of leading scientists.

"The scale and rate of the present day carbon perturbation, and resulting ocean acidification, is unprecedented in Earth's known history," according to the report, made with the International Union for Conservation of Nature.

The oceans are warming because of heat from a build-up of greenhouse gases in the atmosphere. Fertilizers and sewage that wash into the oceans can cause blooms of algae that reduce oxygen levels in the waters. And carbon dioxide in the air can form a weak acid when it reacts with sea water.

"The ‘deadly trio' of ... acidification, warming and deoxygenation is seriously affecting how productive and efficient the ocean is," the study said.

Alex Rogers of Oxford University, scientific director of IPSO, told Reuters scientists were finding that threats to the oceans, from the impacts of carbon to over-fishing, were compounding one another.

"We are seeing impacts throughout the world," he said.

EXTINCTIONS

Current conditions in the oceans were similar to those 55 million years ago, known as the Paleocene-Eocene thermal maximum, that led to wide extinctions. And the current pace of change was much faster and meant greater stresses, Rogers said.

Acidification, for instance, threatens marine organisms that use calcium carbonate to build their skeletons - such as reef-forming corals, crabs, oysters and some plankton vital to marine food webs.

Corals might cease to grow if temperatures rose by 2 degrees Celsius (3.6F) and start to dissolve at 3 degrees (5.4F), the study said.

Scientists said the findings added urgency to a plan by almost 200 governments to work out a deal by the end of 2015 to limit a rise in average world temperatures to less than 2 degrees Celsius (3.6F) above pre-industrial times.

Temperatures have already risen by about 0.8 degree Celsius (1.4F). The report also urged tougher management of fish stocks including a ban on destructive bottom trawlers and granting more power to local communities in developing nations to set quotas.

Last week, a report by the U.N.'s Intergovernmental Panel on Climate Change (IPCC) raised the probability that mankind was the culprit for most global warming to 95 percent, from 90 in a report in 2007.

The Global Ocean Commission, a group of politicians working to advise governments, urged stronger action.

"If the IPCC report was a wake-up call on climate change, IPSO is a deafening alarm bell on humanity's wider impacts on the global ocean," said Trevor Manuel, co-chair of the Commission and minister in the South African Presidency.

(Reporting By Alister Doyle, editing by Elizabeth Piper)

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Mouse body clock study offers clues to possible jet lag cure

LONDON | Thu Aug 29, 2013 12:22pm EDT

LONDON (Reuters) - Scientists have found a genetic mechanism in mice that hampers their body clock's ability to adjust to changes in patterns of light and dark, and say their results could someday lead to the development of drugs to combat jet lag.

Researchers from Britain's Oxford University and from the Swiss drug firm Roche used mice to analyze patterns of genes in an area of the brain called the suprachiasmatic nuclei (SCN) - which in mammals pulls every cell in the body into the same biological rhythm.

They found that one molecule, called SIK1, is key to how the mice responded to changes in light cycles.

When the scientists blocked the activity of SIK1, the mice recovered faster from disturbances in their daily light and dark cycle that had been designed to induce a form of mouse jet lag.

If the corresponding mechanism can be found and similarly blocked in humans, jet lag may become a thing of the past, the researchers said in their study, published online in the journal Cell on Thursday.

"We're still several years away from a cure for jet lag, but understanding the mechanisms that generate and regulate our circadian clock gives us targets to develop drugs to help bring our bodies in tune with the solar cycle," said Russell Foster, director of Oxford's sleep and circadian neuroscience institute.

He said such drugs could also have broader potential value, including for people with mental illnesses where sleep disturbances are common.

(Reporting by Kate Kelland; Editing by Sonya Hepinstall)

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NEW: Cholera Treatment Workshop: Case Study Questions in Spanish

1. ¿Cuáles son las señales de deshidratación que se presentan, si hubiera alguna?

2. ¿Cuál es el grado de deshidratación?: ninguno, moderado o grave

3. Describa su plan de tratamiento para las primeras cuatro horas.

4. ¿Qué haría si este niño comenzara a vomitar?

5. ¿Qué evidencia buscaría de que este niño está bien hidratado?

6. ¿Cuándo alimentaría a este niño?  ¿Qué le daría?

7. ¿Qué antibiótico utilizaría?  ¿Cuándo lo administraría?

8. ¿Qué haría una vez que el niño esté bien hidratado?

9. ¿Cómo haría un diagnóstico de cólera en este niño?

1. ¿Cuáles son las señales de deshidratación que se presentan, si hubiera alguna?

2. ¿Cuál es el grado de deshidratación?: ninguno, moderado o grave

3. Describa su plan de tratamiento para las primeras cuatro horas.

4. ¿Qué evidencia buscaría de que este hombre está bien hidratado?

5. ¿Cuándo interrumpiría la terapia intravenosa?

6. ¿Qué antibiótico utilizaría?  ¿Cuándo lo administraría?

7. ¿Cuáles son las complicaciones a tener en cuenta en pacientes de este tipo?

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NEW: Cholera Treatment Workshop: Case Study (Questions) in English and French

1. What signs of dehydration are present, if any?

2. What is the degree of dehydration: none, some, or severe?

3. Outline your treatment plan for the first four hours.

4. What would you do if this child started vomiting?

5. What evidence would you look for that this child was adequately hydrated?

6. When would you feed this child? What would you give?

7. What antibiotic would you use? When would you give it?

8. What would you do once the child has adequate hydration?

9. How would you make a diagnosis of cholera in this child?

1. What signs of dehydration are present, if any?

2. What is the degree of dehydration: none, some, or severe?

3. Outline your treatment plan for the first four hours.

4. What evidence would you look for that this man was adequately hydrated?

5. When would you stop IV therapy?

6. What antibiotic would you use? When would you give it?

7. What complications do you need to watch for in patients like this?

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NEW: Cholera Treatment Workshop - Case Study (Answers) in English and French

Sunken eyesAbsent tears IrritabilityDepressed fontanelles (when palpating head)Dry mouthDrinks EagerlyModerate skin tenting

SOME, because the child is awake but irritable, has moderate skin tenting, and is able to drink. (Note that the scenes repeat once)

Because the child has SOME dehydration and is able to drink, he can be treated with oral rehydration solution. He needs observation and can be monitored in the observation area.

The child weighs 7 kg. Based on the guidelines table, he should receive 400 to 600 ml of ORS in the first four hours. The volume of ORS to be given in the first four hours can also be calculated by multiplying 7 kg by 75, which equals 525 ml. He should be reassessed after 1 hour of therapy, and then every 1-2 hours until rehydration is complete. Remember that these ORS amounts are guidelines, and that the quantity of ORS given can vary based on patient’s situation.

The child should also receive zinc supplementation (10-20 mg zinc per day by mouth) if available. This can reduce the severity and duration of diarrhea.

If he has been breast-fed, he should continue to receive breast-feeding.

As soon as the vomiting pauses, he should continue to receive oral rehydration solution. If the child continues to vomit and cannot drink sufficient ORS, he will need intravenous fluids.

Less irritabilityEyes no longer sunkenDrinks less eagerly, or is less thirstyStrong radial pulseUrine has been passedSkin pinch goes back quicklyMouth is moist

Feed the patient when vomiting has stopped. If he has been breast-fed, he should continue to receive breast-feeding.

Because the child has moderate dehydration, antibiotics should be considered if he is still passing large volumes of stool or if he is hospitalized.See the antibiotic table in the CDC/PAHO guidelines to choose an antibiotic. First choices in children <12 months old are Azithromycin, Erythromycin, and Doxycycline oral suspensions.A second choice is tetracycline oral suspension.After each loose stool, give 100 ml of ORS (for children less than 24 months old), though this amount can vary based on the amount of stool.Continue to reassess the patient for signs of dehydration at least every 4 hours to ensure that ORS solution is being taken appropriately, and to detect patients with profuse ongoing diarrhea who will require closer monitoring.Urine output decreases as dehydration develops, and may cease. It usually resumes within 6-8 hours after starting rehydration. Regular urinary output (every 3-4 hours) is a good sign that enough fluid is being given.Keep the patient under observation, if possible, until diarrhea stops, or is infrequent and little in volume. This is especially important for any patient who presented with severe dehydration.If a patient must be discharged before diarrhea has stopped, show the caretaker how to prepare and give ORS solution, and instruct the caretaker to continue to give ORS solution, as above. Also instruct the caretaker to bring the patient back if any signs of dehydration develop.

Assume that any patient with acute watery diarrhea has cholera in an area where there is an outbreak of cholera. If in an area here cholera has not been confirmed, can seek microbiological diagnosis with rapid diagnostic kit and culture.

Severe lethargy, near unconsciousWeak radial pulse (though note the nurse is checking the brachial pulse)Low blood pressureVery sunken eyesSkin pinch goes back very slowly (>3 seconds)Rapid breathing (from acidosis)Shriveled "washerwoman" hands

SEVERE, because of the severe lethargy, weak pulse, inability to drink.

The patient needs immediate intravenous (IV) hydration. Use Ringer’s lactate if available. Use Normal Saline if no Ringer’s Lactate available (though this will not help the acidosis)If he is able to drink, give ORS solution by mouth while the IV drip is set upStart with 1800 ml (30 ml/kg) IV fluid in the first 30 minutes. Repeat this step if the patient’s radial pulse is still weakThen give 4200 ml (70 ml/kg) IV fluids over the next 2.5 hours.Reassess the patient at least every 1-2 hoursThe patient may need 12,000 ml (200 ml/kg) or more in the first 24 hours of treatmentAlso give the patient ORS solution (5 ml/kg per hour) as soon as the patient can drinkPerform a full reassessment at 3 hours. Switch to ORS solution if hydration is improved and the patient can drinkBecomes more alertEyes no longer sunkenStrong radial pulseDrinks normallySkin pinch goes back quicklyUrine has been passed

When the patient is adequately hydrated and can drink ORS.

Because he has severe dehydration, he should receive an antibiotic. See antibiotic table from CDC/PAHO. For adults:
•   First choice is Doxycycline 300mg by mouth in one dose.
•   Second choices are azithromyin, tetracycline, ciprofloxacin, and erythromycin.
Give it after rehydration has begun, when able to take fluids by mouth

Hypoglycemia: This can occur after severe diarrhea. The best way to prevent this is to start feeding the patient as soon as possible.

Renal Failure (anuria): This rare complication occurs when shock is not rapidly corrected. Urine output normally resumes within 6 to 8 hours after starting rehydration. All patients should be urinating before discharge from a CTC.

Pulmonary Edema: Fluid in the lungs from overhydration due to excessive IV fluids. Young children, the elderly, and severely anemic patients are at highest risk. Signs of pulmonary edema include shortness of breath, dry cough, and crepitations or crackles on auscultation. Reduce the IV fluid rate, and sit the patient up.

Hypokalemia (low potassium): Suspect low potassium if repeated episodes of painful cramps occur. This may happen after the first 24 hours of IV rehydration if patients do not eat or drink ORS (ORS provides enough potassium).

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NEW: Cholera Treatment Workshop: Case Study Answers in Spanish

1. ¿Cuáles son las señales de deshidratación que se presentan, si hubiera alguna?

Ojos hundidosAusencia de lágrimasIrritabilidadFontanelas hundidas (al palpar la cabeza)Sequedad bucalBeber con ansiedadPliegue moderado de la piel

2. ¿Cuál es el grado de deshidratación?: ninguno, moderado o grave
MODERADO, porque el niño está despierto pero está irritable, presenta un pliegue moderado de la piel y es capaz de beber. (Tenga en cuenta que las escenas se repiten una vez)

3. Describa su plan de tratamiento para las primeras cuatro horas.
Debido a que el niño sufre una deshidratación MODERADA y es capaz de beber, puede ser tratado con una solución de rehidratación oral. Necesita observación y, para ello, se lo puede controlar en el área de observación.

El niño pesa 7 kg. Según la tabla de pautas, debe recibir de 400 a 600 ml de una solución de sales de rehidratación oral (oral rehydration salts, ORS) en las primeras cuatro horas. El volumen de las ORS que se administrarán en las primeras cuatro horas también se puede calcular al multiplicar 7 kg por 75, que equivale a 525 ml. Se debe realizar otra evaluación después de una hora de tratamiento y, posteriormente, cada 1 ó 2 horas hasta completar el proceso de rehidratación. Recuerde que estas cantidades de ORS son orientativas; la cantidad de ORS administrada puede variar según la situación del paciente.

Además, el niño debe recibir suplementos de zinc (de 10 a 20 mg de zinc por día por vía oral), si está disponible. Esto puede reducir la gravedad y la duración de la diarrea.
Si se amamantó al niño, éste debe continuar con la lactancia.

4. ¿Qué haría si este niño comenzara a vomitar?
Tan pronto como se detengan los vómitos, debe continuar recibiendo la solución de rehidratación oral. Si el niño continúa con vómitos y no puede beber suficiente ORS, será necesario administrarle líquido por vía intravenosa.

5. ¿Qué evidencia buscaría de que este niño está bien hidratado?

Está menos irritableLos ojos ya no están hundidosBebe con menos ansiedad, o tiene menos sedEl pulso radial es marcadoOrina con normalidadLa piel vuelve lentamente a su lugar al plegarlaTiene la boca húmeda

6. ¿Cuándo alimentaría a este niño?  ¿Qué le daría?
Alimente al paciente cuando los vómitos hayan cesado. Si se amamantó al niño, éste debe continuar con la lactancia.

7. ¿Qué antibiótico utilizaría? ¿Cuándo lo administraría?

Debido a que el niño sufre una deshidratación moderada, es necesario considerar los antibióticos especialmente si continúa evacuando grandes cantidades de materia fecal durante el tratamiento de rehidratación, o si es hospitalizado. Consulte la tabla de antibióticos en las pautas de los Centros para el Control y la Prevención de Enfermedades (Centers for Disease Control and Prevention, CDC)/la Organización Panamericana de la Salud (Pan American Health Organization, PAHO) para seleccionar un antibiótico.Las principales opciones para los niños <12 meses son las suspensiones orales de azitromicina, eritromicina y doxiciclina. Las opción secundaria esuna suspensión oral de tetraciclina.

8. ¿Qué haría una vez que el niño esté bien hidratado?

Después de cada deposición blanda, administre 100 ml de ORS (para los niños menores de 24 meses), aunque esta cantidad puede variar según el volumen de la deposición.Continúe evaluando al paciente para detectar señales de deshidratación al menos cada 4 horas a fin de asegurarse de que la solución de ORS se está administrando correctamente, y para determinar si hay pacientes con diarrea continua intensa que requieran un mayor control.La excreción de orina disminuye a medida que crece la deshidratación, e incluso podría interrumpirse. Con frecuencia, se reanuda dentro de 6 a 8 horas de comenzada la rehidratación. La excreción de orina regular (cada 3 ó 4 horas) es una buena señal de que se está administrando suficiente líquido.Mantenga al paciente en observación, si es posible, hasta que cese la diarrea o si ésta es poco frecuente y de volumen reducido. Esto es especialmente importante para cualquier paciente que se presente con una deshidratación grave.Si se debe dar de alta al paciente antes de que cese la diarrea, muéstrele al cuidador cómo preparar y administrar la solución de ORS y explíquele que debe continuar con la administración de esta solución como se indicó anteriormente. También indíquele al cuidador que debe traer de regreso al paciente si presenta alguna señal de deshidratación.

9. ¿Cómo haría un diagnóstico de cólera en este niño?
Suponga que cualquier paciente con diarrea acuosa aguda tiene cólera en un área donde hay un brote de cólera. Si no se ha confirmado la presencia de cólera en un área determinada, se puede recurrir al diagnóstico microbiológico con un kit de diagnóstico rápido y un cultivo.

1. ¿Cuáles son las señales de deshidratación que se presentan, si hubiera alguna?

Letargo severo, estado cercano a la pérdida del conocimientoPulso radial débil (no obstante, tenga en cuenta que el enfermero toma el pulso braquial) Presión sanguínea bajaOjos muy hundidosLa piel vuelve lentamente a su lugar al plegarla (>3 segundos)Respiración acelerada (debido a acidosis)Manos resecas “de lavandera”

2. ¿Cuál es el grado de deshidratación?: ninguno, moderado o grave
GRAVE, debido al letargo severo, el pulso débil y la incapacidad de beber.

3. Describa su plan de tratamiento para las primeras cuatro horas.

Es necesario hidratar al paciente de inmediato por vía intravenosa (i.v.). Utilice lactato de Ringer, si está disponible. Utilice solución salina normal si no hay lactato de Ringer disponible (aunque esto no ayudará a tratar la acidosis) Si el paciente es capaz de beber, administre una solución de ORS por vía oral a la vez que realiza el goteo intravenoso Comience con 1800 ml (30 ml/kg) de líquido por vía intravenosa durante los primeros 30 minutos. Repita este paso si el pulso radial del paciente aún es débil Luego, administre 4200 ml (70 ml/kg) de líquido por vía intravenosa durante las siguientes dos horas y media Vuelva a evaluar al paciente cada 1 ó 2 horas como mínimo Es posible que el paciente necesite 12,000 ml (200 ml/kg) o más durante las primeras 24 horas de tratamiento También administre al paciente una solución de ORS (5 ml/kg por hora) ni bien pueda beber Vuelva a realizar una evaluación completa a las 3 horas. Comience a utilizar la solución de ORS solamente si la hidratación mejora y el paciente es capaz de beber

4. ¿Qué evidencia buscaría de que este hombre está bien hidratado?

Está más alerta Los ojos ya no están hundidos El pulso radial es marcado Bebe normalmenteLa piel vuelve lentamente a su lugar al plegarla Orina con normalidad

5. ¿Cuándo interrumpiría la terapia intravenosa?
Cuando el paciente esté bien hidratado y pueda beber la ORS.

6. ¿Qué antibiótico utilizaría?  ¿Cuándo lo administraría?
Debido a que sufre una deshidratación grave, el paciente debe recibir un antibiótico.
Consulte la tabla de antibióticos de CDC/PAHO. Para los adultos:

La primera opción es 300 mg de doxiciclina por vía oral en una sola dosis. Las opciones secundarias son azitromicina, tetraciclina, ciprofloxacina y erotromicina.

Administre el antibiótico después de comenzar la rehidratación, cuando el paciente pueda consumir líquidos por vía oral.

7. ¿Cuáles son las complicaciones a tener en cuenta en pacientes de este tipo?
Hipoglucemia: Puede ocurrir después de una diarrea grave. La mejor manera de evitarla es comenzar a alimentar al paciente tan pronto como sea posible.

Insuficiencia renal (anuria): Esta complicación poco frecuente ocurre cuando el shock no se soluciona rápidamente. Normalmente, la excreción de orina se reanuda dentro de 6 a 8 horas de comenzada la rehidratación. Todos los pacientes deben poder orinar antes de recibir el alta del Centro de Tratamiento de Cólera (Cholera Treatment Center, CTC).

Edema pulmonar: Líquido en los pulmones como consecuencia de una hidratación excesiva por vía intravenosa. Los niños pequeños, los ancianos y los pacientes con anemia grave tienen mayor riesgo de sufrir esta complicación. Las señales de edema pulmonar incluyen dificultad para respirar, tos seca y crepitaciones en la auscultación. Reduzca la frecuencia del goteo intravenoso y siente al paciente.

Hipopotasemia (nivel de potasio bajo): Considere la presencia de hipopotasemia si se producen varios episodios de calambres dolorosos. Esto puede ocurrir después de las primeras 24 horas de rehidratación intravenosa si los pacientes no comen ni beben las ORS (las ORS proporcionan suficiente potasio).

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NASA launches satellite to study how sun's atmosphere is energized

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Multiple tests needed to detect infection in low birth-weight newborns, study suggests

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Men with erection problems are three times more likely to have inflamed gums, study finds

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Human microbe study provides insight into health, disease

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Study promoting coffee drinking benefits needs more research, says dentist

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Study of recalled medical devices faults lax FDA testing methods

A new analysis is raising questions about how good a job the Food and Drug Administration is doing at protecting Americans from faulty medical devices.

Researchers examined the 113 devices that the FDA recalled between 2005 and 2009 for posing serious health risks, including endangering patients' lives. Most of the devices - 71 percent - had been approved without undergoing testing in people, the researchers reported Monday in the Archives of Internal Medicine.

That's because under a process designed to get products on the market as soon as possible, they were deemed to be similar to another product already being sold. Only 19 percent underwent more stringent review.

"Our findings reveal critical flaws in the current FDA device review system and its implementation that will require either congressional action or major changes in regulatory policy," wrote Diana M. Zuckerman of the National Research Center for Women & Families in Washington, D.C., and Steven E. Nissen of the Cleveland Clinic in Cleveland.

One-third of the recalled devices were for heart disease, including automatic external defibrillators, or AEDs. Those are the gadgets that have been increasingly showing up in airports, office buildings and other public places that shock the hearts of people who suffer sudden cardiac arrest. Defective AEDs reportedly have resulted in hundreds of patient deaths, the researchers said.

The findings indicate that the agency is allowing too many medical devices onto the market using the less stringent approval process, the researchers said.

"The FDA is now using the . . . process for 98 percent of the medical devices that they review, including heart valves, glucose meters and artificial hips and knees," Zuckerman said in a statement released with the report. "We think patients will be shocked to learn how often new medical products using different materials, made by a different manufacturers, are not scientifically tested in humans to see how well they work."

Nissen said the findings should be a "wake-up call" to the agency and doctors.

Officials at the FDA, however, dismissed the findings, saying that it was not surprising that most of the recalls involved devices approved through the accelerated process since most of the devices on the market were approved that way.

"Even one recall is too many," said FDA spokeswoman Karen Riley in an e-mail. "But, considering that more than 19,000 devices were cleared via the ... process between 2005 and 2009, it's important to keep the 80 recalls in perspective. They represent a small numbers of the devices cleared via this program and don't reflect the thousands of people who have benefited from these devices."

Riley noted that the agency had recently completed a review of the program and was making 25 changes designed to make the approval process even safer.

In an editorial accompanying the study, Rita Redberg, editor-in-chief of the journal, agreed the findings indicate the need to improve safeguards.

"Doing the right thing will require withstanding the pressure of industry lobbyists," she wrote. "Without any data to support their statements, the lobbyists suggest that the proposed FDA changes--which could improve public safety--will 'chill device development.'"

Officials representing the medical device industry also dismissed the findings. The big problem with the FDA's medical device review process is that it is too slow, a trade group officials said. Many products, including those made in the United States, routinely become available in Europe years before they are approved in this country, he said.

"The real problem at FDA is not that they are clearing unsafe devices. They are doing a very good job of making sure devices are safe and are taking steps to make the process even better," said David Nexon, senior vice president at AvaMed, the industry's trade group. "The bigger problem is the efficiency and consistency of the process deteriorated so dramatically in recent years."

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Solicitation for Concepts for Large Study Programs at KISS

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Study Finds Severe Climate Jeopardizing Amazon Forest

At left, the extent of the 2005 megadrought in the western Amazon rainforests during the summer months of June, July and August as measured by NASA satellites. The most impacted areas are shown in shades of red and yellow. The circled area in the right panel shows the extent of the forests that experienced slow recovery from the 2005 drought, with areas in red and yellow shades experiencing the slowest recovery. Image credit: NASA/JPL-Caltech/GSFC
› Larger image January 17, 2013

PASADENA, Calif. - An area of the Amazon rainforest twice the size of California continues to suffer from the effects of a megadrought that began in 2005, finds a new NASA-led study. These results, together with observed recurrences of droughts every few years and associated damage to the forests in southern and western Amazonia in the past decade, suggest these rainforests may be showing the first signs of potential large-scale degradation due to climate change.

An international research team led by Sassan Saatchi of NASA's Jet Propulsion Laboratory, Pasadena, Calif., analyzed more than a decade of satellite microwave radar data collected between 2000 and 2009 over Amazonia. The observations included measurements of rainfall from NASA's Tropical Rainfall Measuring Mission and measurements of the moisture content and structure of the forest canopy (top layer) from the Seawinds scatterometer on NASA's QuikScat spacecraft.

The scientists found that during the summer of 2005, more than 270,000 square miles (700,000 square kilometers, or 70 million hectares) of pristine, old-growth forest in southwestern Amazonia experienced an extensive, severe drought. This megadrought caused widespread changes to the forest canopy that were detectable by satellite. The changes suggest dieback of branches and tree falls, especially among the older, larger, more vulnerable canopy trees that blanket the forest.

While rainfall levels gradually recovered in subsequent years, the damage to the forest canopy persisted all the way to the next major drought, which began in 2010. About half the forest affected by the 2005 drought - an area the size of California - did not recover by the time QuikScat stopped gathering global data in November 2009 and before the start of a more extensive drought in 2010.

"The biggest surprise for us was that the effects appeared to persist for years after the 2005 drought," said study co-author Yadvinder Malhi of the University of Oxford, United Kingdom. "We had expected the forest canopy to bounce back after a year with a new flush of leaf growth, but the damage appeared to persist right up to the subsequent drought in 2010."

Recent Amazonian droughts have drawn attention to the vulnerability of tropical forests to climate change. Satellite and ground data have shown an increase in wildfires during drought years and tree die-offs following severe droughts. Until now, there had been no satellite-based assessment of the multi-year impacts of these droughts across all of Amazonia. Large-scale droughts can lead to sustained releases of carbon dioxide from decaying wood, affecting ecosystems and Earth's carbon cycle.

The researchers attribute the 2005 Amazonian drought to the long-term warming of tropical Atlantic sea surface temperatures. "In effect, the same climate phenomenon that helped form hurricanes Katrina and Rita along U.S. southern coasts in 2005 also likely caused the severe drought in southwest Amazonia," Saatchi said. "An extreme climate event caused the drought, which subsequently damaged the Amazonian trees."

Saatchi said such megadroughts can have long-lasting effects on rainforest ecosystems. "Our results suggest that if droughts continue at five- to 10-year intervals or increase in frequency due to climate change, large areas of the Amazon forest are likely to be exposed to persistent effects of droughts and corresponding slow forest recovery," he said. "This may alter the structure and function of Amazonian rainforest ecosystems."

The team found that the area affected by the 2005 drought was much larger than scientists had previously predicted. About 30 percent (656,370 square miles, or 1.7 million square kilometers) of the Amazon basin's total current forest area was affected, with more than five percent of the forest experiencing severe drought conditions. The 2010 drought affected nearly half of the entire Amazon forest, with nearly a fifth of it experiencing severe drought. More than 231,660 square miles (600,000 square kilometers) of the area affected by the 2005 drought were also affected by the 2010 drought. This "double whammy" by successive droughts suggests a potentially long-lasting and widespread effect on forests in southern and western Amazonia.

The drought rate in Amazonia during the past decade is unprecedented over the past century. In addition to the two major droughts in 2005 and 2010, the area has experienced several localized mini-droughts in recent years. Observations from ground stations show that rainfall over the southern Amazon rainforest declined by almost 3.2 percent per year in the period from 1970 to 1998. Climate analyses for the period from 1995 to 2005 show a steady decline in water availability for plants in the region. Together, these data suggest a decade of moderate water stress led up to the 2005 drought, helping trigger the large-scale forest damage seen following the 2005 drought.

Saatchi said the new study sheds new light on a major controversy that existed about how the Amazon forest responded following the 2005 megadrought. Previous studies using conventional optical satellite data produced contradictory results, likely due to the difficulty of correcting the optical data for interference by clouds and other atmospheric conditions.

In contrast, QuikScat's scatterometer radar was able to see through the clouds and penetrate into the top few meters of vegetation, providing daily measurements of the forest canopy structure and estimates of how much water the forest contains. Areas of drought-damaged forest produced a lower radar signal than the signals collected over healthy forest areas, indicating either that the forest canopy is drier or it is less "rough" due to damage to or the death of canopy trees.

Results of the study were published recently in the Proceedings of the National Academy of Sciences. Other participating institutions included UCLA; University of Oxford, United Kingdom; University of Exeter, Devon, United Kingdom; National Institute for Space Research, Sao Jose dos Campos, Sao Paulo, Brazil; Boston University, Mass.; and NASA's Ames Research Center, Moffett Field, Calif.

For more on NASA's scatterometry missions, visit: http://winds.jpl.nasa.gov/index.cfm . You can follow JPL News on Facebook at: http://www.facebook.com/nasajpl and on Twitter at: http://www.twitter.com/nasajpl . The California Institute of Technology in Pasadena manages JPL for NASA.

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

2013-025

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New Study Finds Ocean Warmed Significantly Since 1993

The international science team analyzed nine different estimates of heat content in the upper ocean, based on ocean temperature data from a global array of more than 3,200 Argo free-floating profiling floats and longer data records from expendable bathythermographs dropped from ships. Image credit: International Argo Project
› Larger view May 19, 2010

The upper layer of Earth's ocean has warmed since 1993, indicating a strong climate change signal, according to a new international study co-authored by oceanographer Josh Willis of NASA's Jet Propulsion Laboratory, Pasadena, Calif. The energy stored is enough to power nearly 500 100-watt light bulbs for each of the roughly 6.7 billion people on the planet continuously over the 16-year study period.

"We are seeing the global ocean store more heat than it gives off," said John Lyman, an oceanographer at the National Oceanic and Atmospheric Administration's Joint Institute for Marine and Atmospheric Research, who led the study that analyzed nine different estimates of heat content in the upper ocean from 1993 to 2008.

The team combined the estimates to assess the size and certainty of growing heat storage in the ocean. Their findings will be published in the May 20 edition of the journal Nature. The scientists are from NASA, NOAA, the Met Office Hadley Centre in the United Kingdom, the University of Hamburg in Germany and the Meteorological Research Institute in Japan.

"The ocean is the biggest reservoir for heat in the climate system," said Willis. "So as the planet warms, we're finding that 80 to 90 percent of the increased heat ends up in the ocean."

A warming ocean is a direct cause of global sea level rise, since seawater expands and takes up more space as it heats up. The scientists say that this expansion accounts for about one-third to one-half of global sea level rise.

Combining multiple estimates of heat in the upper ocean – from the surface to about 610 meters (2,000 feet) down – the team found a strong multi-year warming trend throughout the world's ocean. According to measurements by an array of autonomous free-floating ocean floats called Argo, as well as by earlier devices called expendable bathythermographs, or XBTs, that were dropped from ships to obtain temperature data, ocean heat content has increased over the last 16 years.

The team notes that there are still some uncertainties and some biases.

"The XBT data give us vital information about past changes in the ocean, but they are not as accurate as the more recent Argo data," said Gregory Johnson, an oceanographer at NOAA's Pacific Marine Environmental Laboratory. "However, our analysis of these data gives us confidence that on average, the ocean has warmed over the past decade and a half, signaling a climate imbalance."

Data from the array of Argo floats -- deployed by NOAA and other U.S. and international partners -- greatly reduce the uncertainties in estimates of ocean heat content over the past several years, the team said. There are now more than 3,200 Argo floats distributed throughout the world's ocean sending back information via satellite on temperature, salinity, currents and other ocean properties.

For more information, see http://www.noaanews.noaa.gov/stories2010/20100519_ocean.html

Alan Buis (818) 354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

2010-169

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New Study Shows Very First Stars Not Monstrous

Scientists are simulating how the very first stars in our universe were born. This diagram shows a still from one such simulation. The cube on the right is a blown up region at the center of the box on the left. Image credit: NASA/JPL-Caltech/Kyoto Univ.
› Full image and caption November 10, 2011

PASADENA, Calif. -- The very first stars in our universe were not the behemoths scientists had once thought, according to new simulations performed at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Astronomers "grew" stars in their computers, mimicking the conditions of our primordial universe. The simulations took weeks. When the scientists' concoctions were finally done, they were shocked by the results -- the full-grown stars were much smaller than expected.

Until now, it was widely believed that the first stars were the biggest of all, with masses hundreds of times that of our sun. The new research shows they are only tens of times the mass of sun; for example, the simulations produced one star that was as little as 43 solar masses.

"The first stars were definitely massive, but not to the extreme we thought before," said Takashi Hosokawa, an astronomer at JPL and lead author of the new study, appearing online Friday, Nov. 11 in the journal Science. "Our simulations reveal that the growth of these stars is stunted earlier than expected, resulting in smaller final sizes."

The early universe consisted of nothing more than thin clouds of hydrogen and helium atoms. A few hundred million years after its birth, the first stars began to ignite. How these first stars formed is still a mystery.

Astronomers know that all stars form out of collapsing clouds of gas. Gravity from a growing "seed" at the center of the cloud attracts more and more matter. For so-called normal stars like our sun, this process is aided by heavier elements such as carbon, which help to keep the gas falling onto the budding star cool enough to collapse. If the cloud gets too hot, the gas expands and escapes.

But, in the early universe, stars hadn't yet produced heavy elements. The very first stars had to form out of nothing but hydrogen and helium. Scientists had theorized that such stars would require even more mass to form, to compensate for the lack of heavy elements and their cooling power. At first, it was thought the stars might be as big as one thousand times the mass of our sun. Later, the models were refined and the first stars were estimated to be hundreds of solar masses.

"These stars keep getting smaller and smaller over time," said Takashi. "Now we think they are even less massive, only tens of solar masses."

The team's simulations reveal that matter in the vicinity of the forming stars heats up to higher temperatures than previously believed, as high as 50,000 Kelvin (90,000 degrees Fahrenheit), or 8.5 times the surface temperature of the sun. Gas this hot expands and escapes the gravity of the developing star, instead of falling back down onto it. This means the stars stop growing earlier than predicted, reaching smaller final sizes.

"This is definitely going to surprise some folks," said Harold Yorke, an astronomer at JPL and co-author of the study. "It was standard knowledge until now that the first stars had to be extremely massive."

The results also answer an enigma regarding the first stellar explosions, called supernovae. When massive stars blow up at the end of their lives, they spew ashes made of heavier elements into space. If the very first stars were the monsters once thought, they should have left a specific pattern of these elements imprinted on the material of the following generation of stars. But, as much as astronomers searched the oldest stars for this signature, they couldn't find it. The answer, it seems, is that it simply is not there. Because the first stars weren't as massive as previously thought, they would have blown up in a manner akin to the types of stellar explosions that we see today.

"I am sure there are more surprises in store for us regarding this exciting period of the universe," said Yorke. "NASA's upcoming James Webb Space Telescope will be a valuable tool to observe this epoch of early star and galaxy formation."

For technical details and videos visit http://www-tap.scphys.kyoto-u.ac.jp/~hosokawa/firststarstop_e.html .

The California Institute of Technology manages JPL for NASA.  More information about JPL is online at www.jpl.nasa.gov .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

2011-348

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Computational study of ionic liquids illuminates detailed CO2 interactions

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There is no single sexy chin, study shows

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Multiple genes robustly contribute to schizophrenia risk in replication study

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Oceans may explain slowdown in climate change: study

The tide comes in as the sun sets on the seafront in Scarborough, northern England February 26, 2013.

Credit: Reuters/Dylan Martinez

By Environment Correspondent Alister Doyle

OSLO | Sun Apr 7, 2013 1:04pm EDT

OSLO (Reuters) - Climate change could get worse quickly if huge amounts of extra heat absorbed by the oceans are released back into the air, scientists said after unveiling new research showing that oceans have helped mitigate the effects of warming since 2000.

Heat-trapping gases are being emitted into the atmosphere faster than ever, and the 10 hottest years since records began have all taken place since 1998. But the rate at which the earth's surface is heating up has slowed somewhat since 2000, causing scientists to search for an explanation for the pause.

Experts in France and Spain said on Sunday that the oceans took up more warmth from the air around 2000. That would help explain the slowdown in surface warming but would also suggest that the pause may be only temporary and brief.

"Most of this excess energy was absorbed in the top 700 meters (2,300 ft) of the ocean at the onset of the warming pause, 65 percent of it in the tropical Pacific and Atlantic oceans," they wrote in the journal Nature Climate Change.

Lead author Virginie Guemas of the Catalan Institute of Climate Sciences in Barcelona said the hidden heat may return to the atmosphere in the next decade, stoking warming again.

"If it is only related to natural variability then the rate of warming will increase soon," she told Reuters.

Caroline Katsman of the Royal Netherlands Meteorological Institute, an expert who was not involved in the latest study, said heat absorbed by the ocean will come back into the atmosphere if it is part of an ocean cycle such as the "El Nino" warming and "La Nina" cooling events in the Pacific.

She said the study broadly confirmed earlier research by her institute but that it was unlikely to be the full explanation of the warming pause at the surface, since it only applied to the onset of the slowdown around 2000.

THRESHOLD

The pace of climate change has big economic implications since almost 200 governments agreed in 2010 to limit surface warming to less than 2 degrees Celsius (3.6 F) above pre-industrial levels, mainly by shifting from fossil fuels.

Surface temperatures have already risen by 0.8 C. Two degrees is widely seen as a threshold for dangerous changes such as more droughts, mudslides, floods and rising sea levels.

Some governments, and skeptics that man-made climate change is a big problem, argue that the slowdown in the rising trend shows less urgency to act. Governments have agreed to work out, by the end of 2015, a global deal to combat climate change.

Last year was ninth warmest since records began in the 1850s, according to the U.N.'s World Meteorological Organization, and 2010 was the warmest, just ahead of 1998. Apart from 1998, the 10 hottest years have all been since 2000.

Guemas's study, twinning observations and computer models, showed that natural La Nina weather events in the Pacific around the year 2000 brought cool waters to the surface that absorbed more heat from the air. In another set of natural variations, the Atlantic also soaked up more heat.

"Global warming is continuing but it's being manifested in somewhat different ways," said Kevin Trenberth, of the U.S. National Center for Atmospheric Research. Warming can go, for instance, to the air, water, land or to melting ice and snow.

Warmth is spreading to ever deeper ocean levels, he said, adding that pauses in surface warming could last 15-20 years.

"Recent warming rates of the waters below 700 meters appear to be unprecedented," he and colleagues wrote in a study last month in the journal Geophysical Research Letters.

The U.N. panel of climate scientists says it is at least 90 percent certain that human activities - rather than natural variations in the climate - are the main cause of warming in recent decades.

(Reporting by Alister Doyle, Environment Correspondent; Editing by Peter Graff)

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