ريتشارد دوكنز's Blog, page 728

July 11, 2015

Shark Bites Are Up, But Attack Risk Is Down?

TV’s celebration this week of everything sharky came during a summer with a record-high number of shark bites to swimmers in North Carolina. But that doesn’t mean the risk of getting bitten by a shark is getting worse in North Carolina or anywhere else in the world. In fact, a new study suggests that the risk might be dropping globally, just as it is for white shark bites off the California coast.


California coast visitors are now 91 percent less likely to be bitten by a great white than they were in 1950, researchers report in a paper set to be published in Frontiers in Ecology and the Environment in the next few weeks. That’s despite the fact that actual shark bites have increased, from 0.9 per year in the 1950s to 1.5 per year in the decade from 2004 to 2013.


How does that work? A whole lot more people in the water. "Even if the number of attacks has increased since the 1950s, the number of people engaging in ocean activities has increased much faster over the same period of time, resulting in a reduction of the individual probability of suffering an attack," says Francesco Ferreti, a researcher at Stanford University Hopkins Marine Station in Pacific Grove, Calif., and the lead author of the study.


And that's the same pattern playing out in North Carolina. "The population has been going up and the number of people going in the water is always increasing," says Chuck Bangley, a shark researcher at East Carolina University. North Carolina is setting near-record numbers for people at the beach this year, in part due to a heat wave that coincided with schools letting out for summer. According to Visit North Carolina, the state tourism office, more than 6.5 million people visited the North Carolina coast in 2014, an 18 percent increase in visitation since 2010.


The risk of any shark bite is already incredibly low—far less likely than drowning or many other rare risks, he says. But, “the more people you have going into the water, the better the odds are that something bad is going to happen, whether it's a shark bite or getting pulled under on a riptide.”


While Ferreti's paper focuses on California, the basic conclusions almost certainly apply throughout the world, given the increase in world population and the even greater increase in commercial and recreational use of the ocean, he says. In their analysis, he and his coauthors focused on white sharks because the damage inflicted by their bites is nearly always significant enough to require medical attention, making it more likely that reporting of bites remained constant from 1950 to 2013.


Meanwhile, a study in 2013 found, based on global catches and shark mortality, that humans kill an average 100 million sharks annually across the world.


The researchers used data from the Global Shark Attack File (GSAF), a large, comprehensive active surveillance organization for shark bites across the world. The GSAF, dating back to the 1930s, relies on an interdisciplinary team of on-site researchers, including historians, shark researchers, archaeologists, ER doctors, plastic surgeons and other types of researchers, to gather information on local incidents, investigate them to be sure the incident involved a shark and analyze the factors and species involved.


The scientists also assumed that the likelihood a shark bit a person it encounters remained constant, so it was a matter of analyzing the abundance of humans, the estimated number of sharks and the spatial overlap of both. Ferreti’s team used annual California surfing events and other published data along with the number of annual diving days of certified scuba divers to estimate the changing numbers of surfers and divers over the years. Published data about beach tourism and population increases in California coastal communities were used to extrapolate an estimate of beach visitors and swimmers over the past six decades.


Much research has documented the decline of shark populations across the world, though it's unclear whether that's the case for white sharks in California. But the number of scuba divers, surfers and beachgoers has exploded in California over the past six decades.


For example, Ferreti and his team estimate surfers increased by a factor of nearly 125, from 7,000 in 1950 to 872,000 in 2013. Scuba divers increased more than 200-fold, and the number of overall beachgoers tripled, from 53 million in the 1950s to 165 million today, the researchers estimated. Given the more modest increase in shark bites over that time, the authors went on to calculate the actual risk of an attack. The rate dropped 2.4 percent per year, translating to a 91.2 percent drop over the full time period.


The risk varies by activities. For swimmers, the risk of a bite in 2013 was 1 per 738 million beach visits, a drop of 81.5 percent since 1950. . Although the risk for surfers didn’t drop, their likelihood of a shark bite has remained steady at 1 in 17 million. For scuba divers, the risk was 1 in 1.44 million in 2013, a drop of 99.7 percent since 1962.


The mechanism behind the reduction in shark attacks remains unclear. It’s likely relevant that many species have declined by 50 percent to more than 90 percent over the past several decades worldwide, primarily due to overfishing. In California, the recovery of elephant seal colonies that sharks feast on may play a role. (The seals are thought to draw predators away from humans.)


Any focus on shark bites that result in human injury or death should also be viewed in the context of humans’ massive impact on sharks worldwide, largely driven by consumer demand for shark fins. "If you put it in perspective, we're killing 10 million sharks for every 1 that kills us," says George Burgess, director of the Florida Program for Shark Research and curator of the International Shark Attack File.


Still, Burgess and Bangley both acknowledged that North Carolina's eight attacks in two months is exceptional given the previous record of five in 2001, the same year as the last fatal shark bite. The spike likely occurred because of a confluence of factors. The same heat wave that brought more humans into the water may also have condensed the normal seasonal migration of sea life that passes through North Carolina waters each summer, Bangley says. For example, he explains, the annual migration of menhaden fish, a favorite shark food, appears linked to water temperature, which jumped 10 degrees in a week during the heat wave.


Understanding the factors influencing shark behavior can help humans adjust our behavior to avoid bites, Burgess says. "We're the animals with the brains, they're the ones with the teeth, and we're in their house," he says. "So it's incumbent upon us to adjust our behavioral patterns and not to expect the animals, be they sharks, jellyfish or whatever, to adjust theirs."


A smart practice for humans in the sea includes keeping a wide berth from seal and sea lion colonies and from fishing piers, which tend to attract populations of sharks hanging around for scraps. Avoiding schools of fish can also reduce the risk of a shark bite, especially at times that fish dart quickly or sea birds dive at the surface.


"If you see predator-prey interactions in front of you, get out of the water," Bangley says. "When you're in the ocean, that's where the shark is supposed to be. It's a wilderness experience just like walking in the woods where you might encounter a bear."


An attitude of awareness is certainly ecologically wiser than shark culls—such as a $22 million elimination endeavor implemented in 2014 in Western Australia—which end up being more destructive for both sharks and humans, Ferreti says. For example, a century-old fishery for bay scallops in North Carolina collapsed when rapid declines in sharks no longer kept a local population of cownose rays in check, thereby leading to an increase in rays that fed on the scallops. No evidence exists to demonstrate that culls actually reduce attacks, Bangley says. But changing human behavior does: Ferreti’s paper found that surfing in Mendocino County in March instead of October and November reduces the risk of an attack 24-fold. And surfers’ risk of a shark bite drops more than 1,500 times if they surf between San Diego and Los Angeles instead along the coast of Mendocino County. In addition, most bites are cases of mistaken identity: surfers look similar to the pinnipeds that great whites primarily feed on. In North Carolina, bull sharks and blacktips are most likely mistaking an errant foot or hand for the foot-long bait fish they usually go after.



More studies like these conducted elsewhere in the world would help researchers identify more patterns of shark bites, learn the preference and behavior of local shark populations and use that knowledge to tweak human behavior. "Our results indicate that investing in increasing and communicating our understanding of the behavior, distribution and ecological role of sharks, as well as the factors influencing the risk of shark bites, may ultimately be the most effective way to increase safety of people," Ferreti says. One piece of advice already is clear: If people can learn ways to avoid being near shark food during feeding times, we become far less likely to end up an accidental appetizer.

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Published on July 11, 2015 04:30

How Do Bats Find The Right Carnivorous Plants For Safe Roosting?

Plants and Animals





Photo credit:

To maintain mutualism, Paleotropical carnivorous plants specifically appeal to their partners' perception. Their reflective structure is acoustically attractive for bats. Schöner et al., Current Biology 2015 with additional images courtesy of C.C. Lee



A few years ago, researchers discovered a delightful instance of mutualism in the dense greenery of Borneo. A little insect eater called Hardwicke's woolly bat (Kerivoula hardwickii) likes to rest in the carnivorous pitcher plant Nepenthes hemsleyana. Compared to its other carnivorous relatives, this plant is pretty bad at luring insects, and that’s because it gets a third of the nitrogen it needs from bat poo. The bats fertilize the plants with their guano in exchange for a temperature-controlled roosting spot that’s free of parasites and competitors.

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Published on July 11, 2015 03:15

Philae Wakes Up… Again!

Space





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Philae touching down on the comet. ESA/ATG medialab



After its hotly anticipated and dramatic landing on comet 67P/Churyumov-Gerasimenko, the Philae lander captured the world’s attention. Landing a robot the size of a washing machine on a lump of rock traveling 135,000 kilometers per hour (84,000 mph) more than 482 million kilometers (300 million miles) away is probably one of humankind’s greatest achievements so far.

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Published on July 11, 2015 03:14

Russia’s Largest Private Science Funder Shuts Down After Kremlin Labels It A “Foreign Agent”

Editor's Blog





Photo credit:

The Kremlin in Moscow, shown, has been blamed for the closure. Credit: Julmin/Surendil/Wikimedia Commons



Russia’s first and largest funder of private science has shut down after being labeled a “foreign agent” – meaning it was suspected of espionage – by the government.

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Published on July 11, 2015 03:13

Switzerland Could be Receiving Post by Drone

Technology





Photo credit:

Close-up of a drone in glorious flight. Swiss Post.



If you’re in Switzerland, your post could be winging its way to you by drone.


California-based drone delivery company Matternet has joined forces with the Swiss postal system Swiss Post to develop and test drones that can cross over the country's assorted landscapes – from its expansive lakes to its mountainous terrains.

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Published on July 11, 2015 03:12

Scientists Dissociate Benefits Of Medical Marijuana From Its Negative Side Effects

The Brain





Photo credit:

Brian Goodman/Shutterstock



Interest in the use of medical marijuana, or more specifically THC, has grown significantly in recent years, with research suggesting it could be used to relieve pain, treat muscle spasms in multiple sclerosis, stimulate appetite in cancer patients and even shrink some tumors, to name a few. But then there are the drawbacks: memory problems, anxiety and dependence, which all reduce its desirability as a therapeutic agent.

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Published on July 11, 2015 03:11

July 10, 2015

Why are GMOs Bad?

Why are GMOs bad? They aren’t. They just aren’t, not intrinsically, and certainly not for your health. We’ve been eating them for decades with no ill effects, which makes sense, because a genetically modified organism is simply an organism, like every other organism, produces hundreds of thousands of proteins, but one or two of them are proteins that were chosen specifically by humans.


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Sources:

GMO Salmon

http://www.independent.co.uk/news/science/a-giant-leap-into-the-unknown-gm-salmon-that-grows-and-grows-2085856.html

http://www.aquabounty.com/products/products-295.aspx


How are GMOs Made

http://cls.casa.colostate.edu/transgeniccrops/history.html

http://www.hudsonalpha.org/education/kits/gmod/gmos-made


Glycophosphate / Monsanto

http://npic.orst.edu/factsheets/glyphogen.pdf

http://www.scientificamerican.com/article.cfm?id=do-seed-companies-control-gm-crop-research

http://www.nature.com/scitable/topicpage/genetically-modified-organisms-gmos-transgenic-crops-and-732

http://blogs.scientificamerican.com/guest-blog/2011/08/11/genetically-engineered-crops/


http://californiaagriculture.ucanr.org/landingpage.cfm?articleid=ca.v054n04p6

http://www.scq.ubc.ca/transgenic-crops-how-genetics-is-providing-new-ways-to-envision-agriculture/

http://www.ca.uky.edu/entomology/entfacts/ef130.asp

http://agbiosafety.unl.edu/education/summary.htm

http://medicine.jrank.org/pages/2902/Transgenic-Plants.html

http://www.news.cornell.edu/stories/Aug11/BtLooper.html

http://www.ucsusa.org/assets/documents/food_and_agriculture/failure-to-yield-brochure.pdf

http://www.chiefscientist.gov.au/2011/11/genetically-modified-food-explained/

http://www.independent.co.uk/news/science/ready-to-eat-the-first-gm-fish-for-the-dinner-table-8430639.html

http://www.scientificamerican.com/article.cfm?id=genetically-modified-crop

http://www.independent.co.uk/news/science/ready-to-eat-the-first-gm-fish-for-the-dinner-table-8430639.html

http://www.popsci.com/science/article/2011-01/life-cycle-genetically-modified-seed

http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=958077244&topicorder=4&maxto=7&minto=1

http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=958077244&topicorder=3&maxto=7

http://www.nytimes.com/2009/02/20/business/20crop.html

http://benthamscience.com/open/tonutraj/articles/V004/3TONUTRAJ.pdf

http://www.gov.pe.ca/af/agweb/index.php3?number=72724

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Published on July 10, 2015 13:48

Fossil Friday!

Fossil Friday

We covered the Burgess Shale in my last Fossil Friday, and this week keeps up the theme of famous localities.




Anyone recognize the distinctive color of this rock? Where is it from? And what is the UFO-looking thing preserved in it? No hints this week—it’s too easy. After all, you can see something just like this at many beaches along the east coast. Shoot. Was that a hint?



Bragging rights on the line…who’s going to get them?



credit: Museum of Comparative Zoology, Harvard University

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Published on July 10, 2015 13:00

High Heat Measured under Antarctica Could Support Substantial Life

Temperatures on the West Antarctic Ice Sheet can plummet below –50 degrees Celsius in winter. But under the ice scientists have found intense geothermal heat seeping up from Earth’s interior. The heat production that they measured is nearly four times the global average—“higher than 99 percent of all the measurements made on continents around the world,” says Andrew Fisher, a hydrogeologist at the University of California, Santa Cruz, who worked on the project. This excessive heat could melt up to 35 cubic kilometers of water off the bottom of the West Antarctic Ice sheet each year, according to results reported July 10 in Science Advances.


This meltwater could help create a vast, hidden habitat for aquatic life under the ice—a region that some scientists call the largest swamp on Earth. It could also influence the mechanics of the ice sheet by creating lubricated areas, which guide the flow paths and speeds of major glaciers that carry ice to the ocean. “We think that water is the knob that controls whether ice moves fast or slow,” says Slawek Tulaczyk, a glaciologist at U.C. Santa Cruz. Scientists like him need to understand that process if they are to predict just how much ice Antarctica will spill into the ocean as temperatures rise.


Researchers had already measured geothermal heat production at more than 34,000 sites around the world. But for decades, they could only make educated guesses about how much heat was seeping up under Antarctica’s ice—an area almost twice the size of Australia that had never been directly explored. That changed in January 2013 when a team co-led by Tulaczyk ventured deep into Antarctica and bored a hole through 800 meters of ice.


Tulaczyk’s team was drilling into a body of water called Subglacial Lake Whillans, which is sealed under the ice in West Antarctica—the part of the continent that sits directly south of the Pacific Ocean, between the lowermost tips of New Zealand and South America. The team hoped to see what kind of life might inhabit the lake. Their experiment also created the perfect opportunity for jabbing a giant thermometer into its bed—a metal spear, three meters long, accurate to one one-thousandth of a degree C. Fisher had spent two years building and testing the device. The critical moment came on January 31, 2013. The entire endeavor hung from a thread—or rather, a hastily knotted rope.


Geothermal night-light

I accompanied Tulaczyk and a dozen other researchers to the remote drill site that year. It sat on a monotonous plain of snow and ice 600 kilometers from the South Pole. Tulaczyk blinked in the brilliant sunlight as he crawled out of his tent around 1:00 A.M. that morning. He quickly received bad news: The massive winch that he needed to lower the probe half a mile into the lake had broken down. The probe weighed 550 kilograms, more than a full-grown horse—a hefty mass that would help drive it into the subglacial mud. But now Tulaczyk and his PhD student, Kenneth Mankoff, spent eight frantic hours disassembling and redesigning it to cut its weight in half so that a smaller winch could handle it.


This slimmed-down version of the thermometer had one major drawback: It now had no ring of any sort that would allow them to clamp it onto the end of the winch’s cable. In fact, it consisted of nothing more than a slender metal pole. They improvised by simply knotting a rope around its smooth shaft—a workaround that seemed destined to fail. “It either works or it doesn’t—it’s a one-time thing,” Tulaczyk told me during a brief break that morning. He worried that the rope would pull off the metal probe when they tried to lift it back up—leaving it jammed for eternity in the viscous mud almost a kilometer below.


And so people were understandably relieved when it was hoisted from the borehole several hours later. The chocolatey mud coating its lower half revealed that it had stabbed more than a meter into the lake bed—just enough to measure the heat flow.


The results published on July 10 show that heat energy is seeping out of the planet at a rate of 285 milliwatts per square meter. That’s a tiny amount of energy—equal to the heat dissipated by a small LED night light. But it’s two or three times the amount of geothermal heat that scientists had previously estimated for West Antarctica. In fact, it’s similar to measurements taken in volcanically active areas, such as Yellowstone in Wyoming and Mount Lassen in California. This higher heat measurement, if multiplied across all of West Antarctica, could liberate an extra 10 to 20 cubic kilometers of meltwater under the ice sheet each year—effectively doubling the amount produced.


Slick and slide

“This is one measurement,” Fisher cautions—the heat flux probably varies from place to place. But that raises some fascinating possibilities: The area where they measured geothermal heat contains half a dozen subglacial lakes, with water flowing from one to another through shifting, braided subglacial rivers. Those lakes might owe their existence to a local geothermal hotspot, which supplies them with water, Fisher says. Hotspots might also account for many of the other 60-plus lakes thought to reside under the ice in West Antarctica.


Those lakes are of great interest due to the aquatic life that they might harbor. Water taken from Lake Whillans (where Tulaczyk, Mankoff and Fisher measured heat flow in 2013) was found to hold 130,000 living cells per milliliter (just over half a million per teaspoon)—a surprising amount, similar to some parts of the open ocean.


West Antarctica probably exudes more heat than the higher-elevation eastern part of the continent, Tulaczyk says. Unlike its eastern counterpart, West Antarctica forms a broad, low saddle; its subglacial bed slopes hundreds, even thousands of meters below sea level. This topography was formed by a broad tectonic rift, he adds, “similar in many ways to the Basin and Range [Province] in Nevada and eastern California.” Gradual stretching has thinned Earth’s crust in this region, allowing hot rocks and magma to bulge up from below.


Much of the ice in Antarctica’s interior creeps only a few meters per year—but a handful of major ice streams, up to 100 kilometers across, flow hundreds or even thousands of meters per year—massive conveyor belts that carry hundreds of cubic kilometers of ice out of the interior yearly and dump it into the ocean. Tulaczyk and others believe that local hotspots influence the flow paths and speeds of these ice streams.


In 2014 scientists reported that one major West Antarctic ice stream, called Thwaites Glacier, sits atop several local hotspots (inferred using ice-penetrating radar and computer modeling). These could melt water and lubricate the glacier, says Duncan Young, a glaciologist with the University of Texas at Austin who was part of that study. The hotspots sit beneath several critical spots in the glacier’s inland tributaries, potentially increasing the supply of ice that is poured into the main trunk of the glacier—and eventually, the ocean, where it contributes to sea level rise. Thwaites Glacier is of particular interest because it is already accelerating and thinning in response to rising temperatures.


Much remains to be learned about the vast landscape hidden beneath the West Antarctic Ice Sheet but one possibility is becoming increasingly clear. Aerial surveys using ice-penetrating radar show numerous isolated high spots in the subglacial topography. These often correspond with strong magnetic anomalies—a marker of iron-rich lava rocks. “There have been at least three subglacial volcanoes identified under the ice sheet now,” Young says—“and we have suspicions of a bunch more”—perhaps hundreds. Dozens of these suspected volcanoes possess unusually squat profiles, suggesting that they actually erupted and grew while buried under the crushing weight of the ice sheet. At least one subglacial volcano is thought to be active right now—a submerged peak named Mount Casertz.


The upper surface of the ice sheet dips 50 meters as it flows over the buried crest of this volcano. Maintaining that low spot year after year is no small thing, because the crushing mass of the surrounding ice sheet should ooze inward and fill even a shallow depression. Calculations suggest that Mount Casertz exudes 700 million watts of geothermal heat—roughly equal to the energy produced by a medium-size nuclear power plant. It maintains the topographic depression above it by melting 70 million tons of water off the bottom of the ice sheet each year.


It’s entirely possible that Casertz or another of these hidden volcanoes could erupt in the future. No one believes that even a catastrophic eruption would rip apart the ice sheet—it’s simply too massive. But the meltwater that it produces could still cause a large glacier like Thwaites to speed up in a way that’s never been seen before.


Young and his colleagues in Texas continue to analyze radar and magnetic data, hoping to assemble a clearer picture of volcanoes under the West Antarctic Ice Sheet. “We haven’t looked everywhere,” Young says. “Our resolution of the topography [under the ice] is basically early 20th century, maybe 19th century, of what we had of North America.”

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Published on July 10, 2015 11:01

Giant Wall of Christian Crosses in Texas County Clerk’s Office Comes Down

I posted yesterday about how, in Texas, Gregg County Clerk Connie Wade refused to issue marriage licenses to gay couples because she was waiting for direction from the Attorney General.

But I didn’t believe her because she didn’t hide her personal faith-based opposition to marriage and there was a giant wall of crosses in her office:

Two important updates to this story.

First, the Wall of Crosses has come down:

“The employee voluntarily took the crosses down,” [County Judge Bill] Stoudt said, noting that he did not order the crosses to be removed.

“If the crosses have been removed, we consider that a victory for state/church separation,” [Freedom From Religion Foundation attorney Rebecca] Markert said. “There’s nothing further to do.”

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Published on July 10, 2015 11:00

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