Ecosystems

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.

Which island holds the greatest concentration of mammals?
July 20, 2016 07:22 AM - Jessica Ramos, Care2

In this scary time of global species extinctions and loss of biodiversity below “safe” levels, The Field Museum recently announced some good news: Luzon Island, an island the size of the Indiana in the Philippines, holds the greatest concentration of mammals. The pressing question now is will we be able to protect this rich biodiversity in time?

NASA science flights target melting Arctic Sea ice
July 19, 2016 05:22 PM - NASA/Goddard Space Flight Center via ScienceDaily

This summer, with sea ice across the Arctic Ocean shrinking to below-average levels, a NASA airborne survey of polar ice just completed its first flights. Its target: aquamarine pools of melt water on the ice surface that may be accelerating the overall sea ice retreat.

NASA's Operation IceBridge completed the first research flight of its new 2016 Arctic summer campaign on July 13. The science flights, which continue through July 25, are collecting data on sea ice in a year following a record-warm winter in the Arctic.

The summer flights will map the extent, frequency and depth of melt ponds, the pools of melt water that form on sea ice during spring and summer. Recent studies have found that the formation of melt ponds early in the summer is a good predictor of the sea ice yearly minimum extent in September: if there are more ponds on the ice earlier in the melt season, they reduce the ability of sea ice to reflect solar radiation, which leads to more melt.

Using urban pigeons to monitor lead pollution
July 19, 2016 02:02 PM - University of California – Davis via EurekAlert!

Tom Lehrer sang about poisoning them, but those pigeons in the park might be a good way to detect lead and other toxic compounds in cities. A new study of pigeons in New York City shows that levels of lead in the birds track with neighborhoods where children show high levels of lead exposure.

"Pigeons breathe the same air, walk the same sidewalks, and often eat the same food as we do. What if we could use them to monitor possible dangers to our health in the environment, like lead pollution?" said Rebecca Calisi, now an assistant professor in the Department of Neurobiology, Physiology and Behavior at the University of California, Davis, who conducted the study with undergraduate student Fayme Cai while at Barnard College, Columbia University. The work is published July 18 in the journal Chemosphere.

Decades after it was banned from paint and gasoline, lead pollution remains a significant concern. The New York City Department of Health and Mental Hygiene carries out routine screening of children in areas of the city identified as hot spots for lead contamination.

Ship engine emissions adversely affect macrophages
July 19, 2016 11:00 AM - Helmholtz Zentrum München - German Research Center for Environmental Health via EurekAlert!

In cooperation with colleagues of the University of Rostock, the University of Luxembourg, the Max Delbrueck Center for Molecular Medicine, the Karlsruhe Institute of Technology and the University of Eastern Finland, the Munich Scientists have now published the results in the journal PLOS ONE. In 2015 they already showed that exposure to particle emissions from heavy fuel oil (HFO) and diesel fuel (DF) adversely affects human lung cells and is responsible for strong biological responses of the cells ("How Ship Emissions Adversely Affect Lung Cells"). For example, inflammatory processes are triggered that may influence the development of interstitial lung diseases. Now the team led by Professor Ralf Zimmermann has found in further studies that macrophages are also influenced by the exhaust gases. These are much more sensitive than lung epithelial cells and therefore react more strongly to exposure. Zimmermann is speaker of the international consortium Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health (HICE), head of the cooperation group Comprehensive Molecular Analytics (CMA) at Helmholtz Zentrum Muenchen and head of the Department of Analytical Chemistry at the University of Rostock.

Hummingbird vision wired to avoid high-speed collisions
July 18, 2016 04:10 PM - University of British Columbia via EurekAlert!

Hummingbirds are among nature's most agile fliers. They can travel faster than 50 kilometres per hour and stop on a dime to navigate through dense vegetation.

Now researchers have discovered that the tiny birds process visual information differently from other animals, perhaps to handle the demands of their extreme aerial acrobatics.

"Birds fly faster than insects and it's more dangerous if they collide with things," said Roslyn Dakin, a postdoctoral fellow in the UBC's department of zoology who led the study. "We wanted to know how they avoid collisions and we found that hummingbirds use their environment differently than insects to steer a precise course."

Note: Watch a video of the experiments here: https://youtu.be/6Z45BaswaOs

Scientists at UBC placed hummingbirds in a specially-designed tunnel and projected patterns on the walls to figure out how the birds steer a course to avoid collisions when they are in flight. They set up eight cameras to track the movement of hummingbirds as they flew through a 5.5-metre long tunnel.

Trees rely on a range of strategies to hunt for nutrient hot spots
July 18, 2016 03:59 PM - Penn State via EurekAlert!

On the surface, trees may look stationary, but underground their roots -- aided by their fungal allies -- are constantly on the hunt and using a surprising number of strategies to find food, according to an international team of researchers.

The precision of the nutrient-seeking strategies that help trees grow in temperate forests may be related to the thickness of the trees' roots and the type of fungi they use, according to David Eissenstat, professor of woody plant physiology, Penn State. The tree must use a variety of strategies because nutrients often collect in pockets -- or hot spots -- in the soil, he added.

"What we found is that different species get nutrients in different ways and that depends both on that species' type of root -- whether it's thin or thick -- and that species' type of mycorrhizal fungi, which is a symbiotic fungus," said Eissenstat. "What we show is that you really can't understand this process without thinking about the roots and the mycorrhizal fungi together."

Tree species with thicker roots -- for example, the tulip poplar and pine - avoid actively seeking nutrient hot spots and instead send out more permanent, longer-lasting roots. On the other hand, some trees with thinner roots search for nutrients by selectively growing roots that are more temporary, or by using their fungal allies to find hot spots.

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