Ecosystems

Rainforest greener during 'dry' season
July 26, 2016 04:28 PM - University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES) via ScienceDaily

Although the Amazon Jungle may appear to be perpetually green, a University of Illinois researcher believes there are actually seasonal differences of photosynthesis, with more occurring during the dry season and less during the wet season. Understanding how a rainforest that occupies 2.7 million square miles of South America functions is crucial to the future health of the entire planet.

"With the potential negative effects of climate change, one key question we are trying to answer in the study of tropical ecology is how a tropical forest responds during a long-term drought," says Kaiyu Guan, an environmental scientist at the University of Illinois. "If we don't know their daily performance or their seasonal performance, what confidence can we have to predict the forests' future 20 years, 30 years, or longer?"

Distant volcanic eruptions foster saguaro cacti baby booms
July 25, 2016 05:07 PM - Ecological Society of America via EurekAlert!

One hundred and thirty years ago, the volcano Krakatoa erupted in what is now Indonesia, unleashing a cataclysm locally and years of cool temperatures and rain globally. On the far side of the world, a bumper crop of saguaro cacti were getting their start in life in Arizona's Sonoran Desert. Many of the large exemplars of the famous cacti standing spiny and tall with arms akimbo in the Southwest today started their lives in the shadow of the 1883 eruption.

Biogeographer Taly Drezner believes that distant volcanic paroxysms and the emergence of bountiful saguaro age-mate cohorts are connected. Volcanic climate perturbations that delivered disastrously cold and stormy weather to much of the Northern Hemisphere generated a combination of conditions in the Sonoran Desert that were just right for the delicate young cacti. Drezner will present her research on the first known example of regional population effects on a species from volcanic eruptions in distant parts of the world on 9 August 2016 at the 101st Annual Meeting of the Ecological Society of America, gathering this year in Fort Lauderdale, Florida.

Marine carbon sinking rates confirm importance of polar oceans
July 25, 2016 03:52 PM - University of Washington via EurekAlert!

About the same amount of atmospheric carbon that goes into creating plants on land goes into the bodies of tiny marine plants known as plankton. When these plants die and sink, bacteria feed on their sinking corpses and return their carbon to the seawater. When plankton sink deep enough before being eaten, this carbon is taken out of circulation as a greenhouse gas to remain trapped in the deep ocean for centuries.

How much of this happens in different regions of the ocean would seem like an academic question, except during an era when humanity is spewing carbon dioxide into the air at record-high levels and wondering where all that carbon will go in the future.

A University of Washington study published this week (July 25) in the Proceedings of the National Academy of Sciences uses a new approach to get a global picture of the fate of marine carbon. It finds that the polar seas export organic carbon to the deep sea, where it can no longer trap heat from the sun, about five times as efficiently as in other parts of the ocean.

Spiders spin unique phononic material
July 25, 2016 01:50 PM - Rice University via EurekAlert!

New discoveries about spider silk could inspire novel materials to manipulate sound and heat in the same way semiconducting circuits manipulate electrons, according to scientists at Rice University, in Europe and in Singapore.

A paper in Nature Materials today looks at the microscopic structure of spider silk and reveals unique characteristics in the way it transmits phonons, quasiparticles of sound.

The research shows for the first time that spider silk has a phonon band gap. That means it can block phonon waves in certain frequencies in the same way an electronic band gap - the basic property of semiconducting materials - allows some electrons to pass and stops others.

The researchers wrote that their observation is the first discovery of a "hypersonic phononic band gap in a biological material."

Global Economy Has Reduced Its Energy Intensity by One-Third Since 1990
July 25, 2016 01:41 PM -

The global economy is becoming less energy intensive, using fewer fossil fuels to power productivity and economic growth, according to new data from the U.S. Department of Energy. Global energy intensity — a measure of energy consumption per unit of gross domestic product (GDP) — has decreased nearly one-third since 1990, the agency said. The U.S., for example, burned 5,900 British thermal units per dollar of GDP in 2015, compared to 6,600 BTUs in 2010.

Bird ranges vary more than thought
July 24, 2016 01:32 PM - University of Massachusetts at Amherst via Science Daily

A new study of population trends among 46 ecologically diverse bird species in North America overturns a long-held assumption that the climate conditions occupied by a species do not change over time. Instead, birds that have increased in abundance over the last 30 years now occupy a wider range of climate conditions than they did 30 years ago, and declining species occupying a smaller range.

A new study of population trends among 46 ecologically diverse bird species in North America conducted by avian ecologist Joel Ralston and colleagues at the University of Massachusetts Amherst overturns a long-held assumption that the climate conditions occupied by a species do not change over time.

Trees' surprising role in the boreal water cycle quantified
July 21, 2016 04:55 PM - University of Alaska Fairbanks via EurekAlert!

Approximately 25 to 50 percent of a living tree is made up of water, depending on the species and time of year. The water stored in trees has previously been considered just a minor part of the water cycle, but a new study by University of Alaska Fairbanks scientists shows otherwise.

Research published this week in Nature Scientific Reports is the first to show that the uptake of snowmelt water by deciduous trees represents a large and previously overlooked aspect of the water balance in boreal watersheds. The study was led by Jessica Young-Robertson, who worked with other scientists from the National Weather Service and UAF's International Arctic Research Center and Geophysical Institute.

Oceans may be large, overlooked source of hydrogen gas
July 21, 2016 11:33 AM - Duke University via ScienceDaily

Serpentinized rocks formed near fast-spreading tectonic plates under Earth's seafloor could be a large and previously overlooked source of free hydrogen gas, a new study finds. The finding could have far-ranging implications since scientists believe hydrogen might be the fuel source responsible for triggering life on Earth. And, if it were found in large enough quantities, hydrogen could be used as a clean-burning substitute for fossil fuels today.

The finding could have far-ranging implications since scientists believe H2 might be the fuel source responsible for triggering life on Earth. And, if it were found in large enough quantities, some experts speculate that it could be used as a clean-burning substitute for fossil fuels today because it gives off high amounts of energy when burned but emits only water, not carbon.

Recent discoveries of free hydrogen gas, which was once thought to be very rare, have been made near slow-spreading tectonic plates deep beneath Earth's continents and under the sea.

'Perfect storm' brought sea louse epidemic to BC salmon
July 20, 2016 04:52 PM - University of Toronto via ScienceDaily

High ocean temperatures and poor timing of parasite management likely led to an epidemic of sea lice in 2015 throughout salmon farms in British Columbia's Queen Charlotte Strait, a University of Toronto-led study has found.

The sea lice spread to migrating juvenile wild salmon, resulting in the highest numbers of sea lice observed on wild salmon in a decade.

In spring of 2015, a team of U of T ecologists led by postdoctoral researchers Andrew Bateman and Stephanie Peacock found that more than 70 per cent of fish the team sampled in the Strait's Broughton Archipelago had at least one sea louse: the highest prevalence of such parasites since 2005.

"It was sort of a perfect storm of environmental conditions and mismanagement of treatment," says Peacock, a postdoctoral fellow in the U of T's Department of Ecology & Evolutionary Biology when the research was conducted. "A lot of people talk about how sea lice are natural, but in farms, you have these parasites in larger numbers. Juvenile wild salmon are then exposed as they migrate past these areas."

Birds on top of the world, with nowhere to go
July 20, 2016 10:57 AM - University of Queensland via EurekAlert!

Climate change could make much of the Arctic unsuitable for millions of migratory birds that travel north to breed each year, according to a new international study published today inGlobal Change Biology.

The University of Queensland School of Biological Sciences' researcher Hannah Wauchope said that suitable breeding conditions for Arctic shorebirds could collapse by 2070.

"This means that countries throughout the world will have fewer migratory birds reaching their shores," Ms Wauchope said.

Arctic breeding shorebirds undertake some of the longest known migratory journeys in the animal kingdom, with many travelling more than 20,000 kilometres per year to escape the northern winter.

The bar-tailed godwit flies from Alaska to New Zealand in a single flight of 12,000 kilometres without landing.

The study predicts that, in a warming world, migratory birds will become increasingly restricted to small islands in the Arctic Ocean as they retreat north.

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