Ecosystems

'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.

New discoveries about photosynthesis may lead to solar cells of the future
July 18, 2016 11:01 AM - Lund University via EurekAlert!

For the first time, researchers have successfully measured in detail the flow of solar energy, in and between different parts of a photosynthetic organism. The result is a first step in research that could ultimately contribute to the development of technologies that use solar energy far more efficiently than what is currently possible.

For about 80 years, researchers have known that photochemical reactions inside an organism do not occur in the same place as where it absorbs sunlight. What has not been known, however, is how and along what routes the solar energy is transported into the photosynthetic organism -- until now.

"Not even the best solar cells that we as humans are capable of producing can be compared to what nature performs in the first stages of energy conversion. That is why new knowledge about photosynthesis will become useful for the development of future solar technologies", says Donatas Zigmantas, Faculty of Science at Lund University, Sweden.

Calcification: Does it pay off in the future ocean?
July 15, 2016 03:13 PM - University of Southampton via ScienceDaily

An international research team has calculated the costs and benefits of calcification for phytoplankton and the impact of climate change on their important role in the world's oceans.

Single-celled phytoplankton play an important role in marine biogeochemical cycling, in marine food webs and in the global climate system. Coccolithophores are a particular group that cover themselves with calcium carbonate shields, known as coccoliths. Some wrap themselves in an impenetrable coat of coccoliths, some make coccoliths in the form of sharp spikes, some use them as parasols against the sun and some form funnel-shaped light collectors.

But this requires a lot of energy -- and the price for the artful armour could rise further due to global change. With the help of a new model, the researchers analysed the energetic costs and benefits of calcification. The results, published in the current issue of the journal Science Advances, suggest that the ecological niche for calcifying algae will become narrower in the future.

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