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Wed, 10 Feb 2016
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Science & Technology


Standard ship noise causes interference with orca communication

© beamreach.org
Sharing the sound.
Ship noise may be making it harder for endangered orcas (Orcinus orca) that live in the coastal waters off Seattle, Washington, to catch salmon.

Known to scientists as Southern Resident Killer Whales, this population comprises the only known resident orcas in the United States. In the late 1800s, they numbered about 200. But their numbers crashed in the 1960s, after some 47 were captured for display. Today, there are about 80, and they are protected by the Endangered Species Act.

The whales already suffer from depleted stocks of Chinook salmon. Now, scientists report online today in PeerJ that commercial ships entering Haro Strait where the orcas live (as shown in the photo above), are likely interfering with the calls the whales make to communicate and locate prey.

For 28 months, from March 2011 to October 2013, the researchers used a hydrophone placed 50 meters offshore in the center of the orcas' summertime habitat to measure the noise from 1582 individual ships, including ore carriers, tugs, oil tankers, cargo, military, yachts, and fishing vessels. They found that ships are radiating underwater noise at high frequencies, 10,000 to 40,000 hertz—the same range that orcas and other toothed whales use.

Although the scientists do not yet know specifically how the ships' sounds are affecting the orcas, they note that other researchers have shown that the whales increase the amplitude of their most common calls when loud boats pass nearby. The study adds to global concerns about commercial ships' noise and whales' (including baleen whales, like blue whales) hearing. For instance, scientists have found that North Atlantic right whales have lower stress levels in areas without the sound of ships.

Quieting technology to limit ships' noise already exists, and is used by the military vessels, which are surprisingly silent, the scientists say. And, they note, there's potentially an even easier fix: Slow down.

Comment: See also: Shhh ... Ocean Noises Stress Out Whales

Bizarro Earth

Research: Dehydration of mineral lawsonite could trigger intermediate depth earthquakes in some subduction zones

© Hirth Lab / Brown University
The mineral lawsonite undergoes brittle failure at high temperature and pressure, as evidenced by the cracks seen in the sample above. That brittleness could trigger earthquakes in subduction zones where lawsonite is present.
Geologists from Brown University may have finally explained what triggers certain earthquakes that occur deep beneath the Earth's surface in subduction zones, regions where one tectonic plate slides beneath another.

Subduction zones are some of the most seismically active areas on earth. Earthquakes in these spots that occur close to the surface can be devastating, like the one that struck Japan in 2011 triggering the Fukushima nuclear disaster. But quakes also occur commonly in the subducting crust as it pushes deep below the surface -- at depths between 70 and 300 kilometers. These quakes, known as intermediate depth earthquakes, tend to be less damaging, but can still rattle buildings.

Intermediate depth quakes have long been something of a mystery to geologists.

"They're enigmatic because the pressures are so high at that depth that the normal process of frictional sliding associated with earthquakes is inhibited," said Greg Hirth, professor of earth, environmental, and planetary sciences at Brown. "The forces required to get things to slip just aren't there."


Biological compass: Light receptor proteins are sensitive to the direction of geomagnetic fields

Many animals including birds and insects have been observed to perceive geomagnetic fields. Past studies have demonstrated that cryptochrome/photolyase family (CPF) light receptor proteins are involved in animal behavioral responses to the presence of geomagnetic fields, but so far, no studies have determined whether these proteins are linked with the direction of the magnetic field vector.

Recently, an international collaborative of researchers explored the possibility that CPF proteins provide directional magnetosensitivity in cockroaches. By combining behavioral and genetic approaches, they demonstrated the first evidence that animal-type cryptochrome (Cry2) proteins are sensitive to the direction of geomagnetic fields in two cockroach species. They've published their results in the Proceedings of the National Academy of Sciences.


Earth's magnetic field history

© Peter Driscoll and David Evans
This figure illustrates superchrons of both normal and reversed polarity over time as the Earth's molten core formed and solidified. It is provided courtesy of Peter Driscoll and David Evans.
Earth's magnetic field is generated by the motion of liquid iron in the planet's core. This "geodynamo" occasionally reverses its polarity—the magnetic north and south poles swap places. The switch occurs over a few thousand years, and the time between reversals can vary from some tens of thousands to tens of millions of years.

When magnetic polarity remains stable in one orientation for more than 10 million years the interval is dubbed a "superchron." Within the last 540 million years—the time when animals have roamed the Earth's land and seas—there are three known superchron periods, occurring about once every 200 million years.

The question of how frequently reversals and superchrons occurred over a longer segment of Earth's history is important for understanding the long-term evolution of the internal and surface conditions of our planet. But so far, such information has only been pieced together by fragmentary evidence. New work from Carnegie's Peter Driscoll and David Evans of Yale University now identifies as many as 10 additional superchrons over a 1.3 billion-year stretch of time during the Proterozoic Eon, or Earth's middle age, which occurred 2.5 to 0.54 billion years ago. Their work is published in the March 1st issue of Earth and Planetary Science Letters.

Records of magnetic field reversals can be found in rocks that maintain the magnetic polarity of the era in which they formed. In order to establish evidence of a polarity shift, this kind of ancient magnetic, or "paleomagnetic," data must be gathered from around the globe, ideally sampling every tectonic plate.


Pharmaceutical drug residues are devastating to aquatic life

Let's forget about the climate for a minute. Largely hidden from public view, another global change is causing increasing disruption. Residues of medicines in water can kill aquatic animals and play havoc with their food web and reproductive cycle. An international team of researchers led by the Netherlands Institute of Ecology (NIOO-KNAW) makes an urgent case for better wastewater treatment and biodegradable pharmaceuticals.

Algae that are becoming far less edible for water fleas and fish, leaving them to starve. Aquatic animals undergoing unwanted sex changes. And fish on their annual run struggling to locate their spawning ground. These are some of the disruptive effects of pharmaceutical residues on the aquatic environment.

"Chemical substances from pharmaceuticals wreak havoc on underwater chemical communication," says the head of the NIOO's department of Aquatic Ecology, Ellen van Donk. She's been heading a team of Dutch, German and US researchers, who take stock of the problem in the next issue of Reviews of Environmental Contamination and Toxicology. "The effects are becoming more and more visible in lakes and ponds worldwide, if you know what to look for."

Comment: An ideal solution, but one that is unlikely to gain traction would be to reconsider the wholesale drugging of the population and indiscriminate prescribing of 'medicines' that are often ineffective, if not outright dangerous.


Slow-motion Death Star: Super-massive black hole blast travels 300,000 light years (PHOTO)

© nasa.gov
Likened to a scene in the sci-fi epic Star Wars, a new image released by NASA shows what happens when a blast of energy beams across the galaxy from a super-massive black hole.

A composite photograph taken over the course of 15 years by the space agency's Chandra X-ray Observatory looks like the superlaser from the Death Star planet destroyer.

But fear not: the phenomenon is nearly 500 million light years from earth and is apparently part of the normal workings of the universe.

2 + 2 = 4

Ravens exhibit capacity for 'theory of mind'

Ravens are capable of imagining being spied on.
An experiment has proven that ravens can imagine being spied on and adapt their behaviour accordingly showing an ability to engage in abstract thinking, previously attributed exclusively to humans and apes.

Ravens have an understanding of what could be going on in another raven's mind, a study carried out by a group of Austrian and American scientists and published in the Nature Communication journal suggests. The birds are particularly capable of imagining being watched which comes in handy when hiding food.

It materialized that ravens, believed to be one of the most intelligent birds as it is, pay particular attention to the hiding process if there's any suspicion that another bird might be present.

The scientists watched over 10 ravens that had been raised in captivity over six months. The birds were kept in separate rooms and could monitor each other through windows that initially had not been covered. The next step was covering the windows with cloth and leaving a peephole that could be closed or opened.

Ravens demonstrated extra carefulness while finding a place to hide their treats only when a peephole was open and they knew that other birds may be watching them.

"Ravens.. take into account the visual access of others, even when they cannot see a conspecific," the study states.

Comment: Ravens and their relatives the crows have shown the capacity for a wide variety of human-like behaviors.


Study finds dog owners are happier and more conscientious than cat owners

© Rex Features
Dog owners are happier, more conscientious and less neurotic than cat owners, according to researchers at Mahattanville College, New York.

In a new study, Is Happiness a Warm Puppy? Examining the Relationship between Pets and Well-Being, academics surveyed 263 people in order to investigate the relationship between pet ownership and subjective well-being,

The results indicated that pet owners did not significantly differ from non-pet owners when it came to levels of happiness, positive emotions, negative emotions or major personality traits.

However, pet owners were found to be more satisfied with life than non-owners - and dog owners scored higher than cat owners on all measures of well-being.

Researchers said: "It's unclear whether the lack of differences between pet owners and non owners are due to adaptation to pet ownership or if pets do not have a strong effect on well-being.


Mussels and oysters consume microplastic particles similar in size to their phytoplankton prey

Tiny pieces of plastic may endanger Pacific oysters by adversely affecting their reproduction, according to a new study. They may have similar effects on other marine bivalves, raising questions about their impacts on marine ecosystems more broadly.

The plastic pieces are known as microplastics are, which are defined as being anywhere from 5 mm in size to just 1 nanometer (0.000001 mm). Scientists refer to primary microplastics and secondary microplastics: the former are intentionally manufactured super-small, primarily used in cosmetics and personal care products, industrial scrubbers used for abrasive blast cleaning, microfibers used in textiles, and pellets used in plastic manufacturing processes; the latter are the result of larger pieces of plastic disintegrating over time.

Imagery of plastic pollution in the ocean often focuses on more visible impacts, such as trash that has become entangled around the neck of a marine mammal, or the appalling sight of vast amounts of plastic in the stomachs of seabirds on Midway Atoll. It is of course far harder to demonstrate the impacts of pollution that can not be seen, but those impacts are very real.



Scientist in Britain given go-ahead to genetically modify human embryos

© Reuters/Michael Daider
A scientist works with human genetic material at a laboratory.
Scientists in Britain have been given the go-ahead to edit the genes of human embryos for research, using a technique that some say could eventually be used to create "designer babies".

Less than a year after Chinese scientists caused an international furore by saying they had genetically modified human embryos, Kathy Niakan, a stem cell scientist from London's Francis Crick Institute, was granted a licence to carry out similar experiments.

"The Human Fertilisation and Embryology Authority (HFEA) has approved a research application from the Francis Crick Institute to use new 'gene editing' techniques on human embryos," Ms Niakan's lab said on Monday.

It said the work carried out "will be for research purposes and will look at the first seven days of a fertilised egg's development, from a single cell to around 250 cells".

Ms Niakan plans to carry out her experiments using CRISPR-Cas9, a technology that is already the subject of fierce international debate because of fears that it could be used to create babies to order.

CRISPR can enable scientists to find and modify or replace genetic defects, and many of them have described it as "game-changing".