The path of totality

This summer, many North Americans will witness a celestial wonder—a total solar eclipse. The moon will completely cover the sun for two minutes and forty seconds. This rare sight has not been viewed from coast to coast in the United States since 1918. The relatively narrow path of totality (~120 km wide) will begin in Oregon and end in South Carolina. Because the path traverses many highly populated areas, it’s anticipated to be the most photographed and shared event in human history.

The eclipse will occur on Monday, August 21, and will first be seen on the west coast just after 10:00 am PST. It will speed across the continental United States at 2,700 km/hour and arrive on the east coast 90 minutes later. The solar eclipse will last the longest and result in the greatest duration of darkness in Kentucky and Illinois.

To understand how solar eclipses work, it’s best to put things in perspective. Although the sun and the moon appear to be the same size from Earth, the sun’s diameter is 400 times that of the moon. But it’s also approximately 400 times further away—from Earth, this makes the sun and the moon look nearly the same size and allows the moon to perfectly eclipse the sun, which happens every 12–18 months. This may seem like a common occurrence, but because the Earth’s surface is 70% water, it’s quite rare to glimpse a total eclipse over land.

A solar eclipse occurs when the moon passes between the sun and the earth and the path of the moon either completely or partially obstructs the sun. Image courtesy of NASA.

A solar eclipse occurs when the moon passes between the sun and the earth and the path of the moon either completely or partially obstructs the sun. Image courtesy of NASA.

If you’re in the narrow path of totality (locations where you can view the total solar eclipse), you’ll have a chance to see the sun’s atmosphere, called the corona, which will appear like a bright white orb against the darkness for a few minutes. If this is your first eclipse, there is one important thing you should adhere to—never stare directly at the sun. If you want to view the eclipse, you can buy solar eclipse glasses, which cost $5–30 and filter ultraviolet, visible and infrared light. For information on how to view the solar eclipse, including how to make your own sun funnel and solar viewing projector, check out these informational videos.

A total solar eclipse. Image courtesy of NASA.

A total solar eclipse. Image courtesy of NASA.

Don’t be disheartened if you don’t have a road trip planned to a location along the path of totality. The partial eclipse (when the moon covers a portion of the sun) can be viewed across North America and will last several hours depending on your location. NASA has an interactive website that can tell you exactly when to view the eclipse from any location in the world. And if it’s cloudy, don’t fret; you can connect to NASA’s live streaming event.

A partial solar eclipse. Image courtesy of NASA.

A partial solar eclipse. Image courtesy of NASA.

A multitude of airborne and ground observations will be made as the eclipse moves across the continental United States. One notable event is The Citizen Cate project, which will work with citizen scientists at 60 locations along the path of totality to document for the first time in high resolution how the sun’s corona changes over 90 minutes. This information will help scientists better understand the dynamics of the sun’s magnetic fields.

If you haven’t booked accommodation for the eclipse yet, you may want to start planning now. Many vacation rentals and campgrounds along the path of totality are already full, as people will flock from all over the world to see the event. If you want to avoid the crowds, consider hiking to a less visited National Park or wilderness area, where you’ll find less noise and light pollution during the eclipse.

If you want to join the crowds, events along the path include public astronomy sessions equipped with viewing stations, music festivals, cult gatherings and group weddings held in complete darkness. Whatever your interests, there’s probably an eclipse event for you. The website National Eclipse has a list of events in every state under the viewing path.

A Tale of Two Rivers

By Kira Hoffman, A Science Borealis post

In December 2014, residents of Jordan River received some unwelcome news. The 103-year-old Jordan River Dam, located 7 km upstream of this tiny seaside community on southwestern Vancouver Island, had been deemed unlikely to endure a major earthquake.

The Jordan River Dam (upper Jordan River) on Vancouver Island, British Columbia (BC Hydro photo).

The Jordan River Dam (upper Jordan River) on Vancouver Island, British Columbia (BC Hydro photo).

Six years earlier, BC Hydro had commissioned a peer-reviewed study on the seismic soundness of its 79 dams in British Columbia. The Jordan River Dam was found to be the most likely of these to fail. It was believed that if this happened, the sudden release of water stored in the reservoir behind the dam would produce catastrophic flooding and destroy the community.

As a result, residents were forced to sell their homes at market price to BC Hydro. The campground at the river mouth was closed, and residents received hand-delivered letters containing the promise that BC Hydro would provide compensation for their losses. With little notice and almost no public consultation, the decision had been made.

On the other side of the Strait of Juan de Fuca, less than 50 km as the crow flies south, the Elwha Dam in Washington has a similar story, but a very different ending. Like the Jordan River Dam, it was built over a hundred years ago in an era of mega hydroelectric construction projects, and was heralded as a progressive structural and economic feat.

Both the Jordan and Elwha rivers were blocked by two major dams, built to supply power for local communities (Victoria in B.C. and Port Angeles in WA) and support major industries such as logging and milling. The Jordan River Dam (upper Jordan River) and the Glines Canyon Dam (upper Elwha River) were once the tallest dams in their respective nations.

The locations of the two Jordan River and two Elwha River dams. Map adapted from the USGS.

The locations of the two Jordan River and two Elwha River dams. Map adapted from the USGS.

At the beginning of the 20th century, rivers were known to possess massive amounts of energy that could be harnessed for economic gain. Little consideration, however, was given to the 10 different runs of anadromous (ocean-going) fish that relied on the Jordan and Elwha rivers to spawn. The dams on the Jordan and Elwha rivers were constructed without fish ladders and completely obstructed salmon migration. Historically, the Elwha River had annual runs of some 300,000 salmon (ten salmon species). The Jordan River had runs of about 10,000 salmon (potentially six salmon species), but it is unclear whether these estimates were established prior to dam construction or before copper and gold mine tailings heavily contaminated the river beginning in 1919.

 

The Jordan River Dam under construction in 1910 (upper and lower left). The Glines Canyon Dam (upper Elwha) after its completion in 1927 (middle). The Elwha Dam construction camp in 1910 (upper right). The Elwha River prior to flooding the reservoir in 1913 (lower right). Images courtesy of Clallam County Historical Society and the Royal BC Museum.

The Jordan River Dam under construction in 1910 (upper and lower left). The Glines Canyon Dam (upper Elwha) after its completion in 1927 (middle). The Elwha Dam construction camp in 1910 (upper right). The Elwha River prior to flooding the reservoir in 1913 (lower right). Images courtesy of Clallam County Historical Society and the Royal BC Museum.

By the 1970s, the dams had outlived the industries they once supported, and required millions of dollars in upgrades to maintain safety. This is where the tale of the two rivers diverges.

The Jordan River dams were upgraded in the 1970s, and again in the early 1990s, at a cost of millions of dollars. Today, approximately 80% of Vancouver Island’s electricity is delivered through underwater cables from the B.C. mainland. Although the Jordan River dams are still operational, they only supply power to the city of Victoria during times of peak power usage (about 10% of the city’s needs)

In 2014, the Jordan River dams again required hundreds of millions of dollars in seismic upgrades, and BC Hydro evaluated three potential courses of action. The company decided that decommissioning and removing the dams would be too expensive, and that lowering the level of the reservoir would eliminate flood risk but entail the loss of a backup power source for the city of Victoria. To BC Hydro, the choice was clear: the solution was to keep the dams in place, maintain the level of the reservoir, and buy the nine waterfront homes and the $3 million campground to clear the danger zone. (As salmon had not been seen spawning in the river since the 1950s, fish were not considered in the assessment.)

On the American side of the Strait, the raison d’etre of the Elwha dams had been rethought. In the 1980s, perspectives on rivers and environmental policy were beginning to shift and governmental bodies, including the Lower Elwha Klallam Tribe, the Department of Fish and Wildlife, and the US Geological Survey, and several non-governmental organizations concluded that the Elwha dams, which had devastated the Elwha’s native fish populations, were obsolete and should be removed.

In 1994, the Elwha Act was passed by Congress, which required that both Elwha dams be decommissioned and removed to restore critical fish habitat. After 20 years of planning, dam removal began in 2011, an event documented in the film Damnation. Click here to watch a time lapse of the Elwha Dam removal.

The total cost of the Elwha River restoration, including the purchase of the two dams, construction of two water treatment plants, the construction of flood protection, and a fish hatchery, was US $327 million. The estimated cost of removing the Jordan River dams was CAN $100–200 million.

The Glines Canyon Dam (upper Elwha) pictured in 2014 after its removal. Photo by James Wengler.

The Glines Canyon Dam (upper Elwha) pictured in 2014 after its removal. Photo by James Wengler.

The planned demolition that breached the Elwha Dam in the summer of 2011 could be heard for miles. Three years later, the Glines Canyon dam on the upper Elwha was removed. Today, the Elwha River is still carving a new path to the Strait of Juan de Fuca. The removal of the dams has come with some hiccups—including widespread flooding in the fall and winter of 2015/16, which damaged several park facilities that had been built in the historic river channel.

River restoration efforts are ongoing, but early scientific studies are clear—almost overnight, access to critical salmon habitat was restored. One week after the blast, salmon were seen spawning above the Elwha Dam site for the first time in over a century.

Coho salmon are blocked from migrating past the lower Elwha dam. Image from the Seattle Times.

Coho salmon are blocked from migrating past the lower Elwha dam. Image from the Seattle Times.

Back on the Canadian side, as of October 2016, BC Hydro had successfully purchased the public campground and eight of the nine homes in the village of Jordan River; one resident was refusing to move.

Meanwhile, salmon are still unable to move into their historic spawning grounds and water levels in the river are often too low to maintain viable habitat. Although the Jordan River was not as famed as the Elwha for its salmon runs, it was a valued salmon river. Over the last decade, salmon stocks in many B.C. rivers have been considered below normal. The depletion of salmon has been attributed to several causes, including habitat loss, and removing deteriorating dams and renewing salmon habitat would assist long-term salmon recovery.

Although keeping the status quo on the Jordan River may be the simplest and cheapest short-term solution, it doesn’t answer one of the many difficult questions that B.C. and Canada are facing—how do we deal with derelict dams that restrict the free flow of rivers and cause significant ecological damage? It’s not just an economic question, it’s also an environmental one. In the longer term, who can put a price on wild salmon re-populating their ancestral homes and bringing a once-wild river back to life?

Conversations with Dolphins

Conversations with Dolphins: Film Review

October 18, 2016 Science Borealis

By Kira Hoffman and Josh Silberg

People love dolphins. Flipper and his brethren, with their permanent “smile” and happy-go-lucky reputation, are widely regarded as one of the most intelligent species on the planet. But what makes dolphins so intelligent? Are humans not so special after all?

In Conversations with Dolphins, which aired on CBC’s The Nature of Things on October 13th, filmmakers Jérôme Julienne and John Jackson dive into dolphin intelligence and how their smarts can lead to astonishingly resourceful behaviours.

Dramatic footage from New Zealand reveals wild orcas learning to eat stingrays while avoiding a nasty barb in the face. In Western Australia, bottlenose dolphins use a sea sponge, an animal, as a protective glove to scare up fish in coarse sand. Off the coast of South Africa, tens of thousands of dolphins cooperatively hunt massive bait balls of sardines.

Along with scientific research from the wild, the filmmakers show dolphins’ apparent affinity for humans using a story about a pod of dolphins that “saves” a long distance swimmer from a shark. If we see dolphins as intelligent, human-loving creatures then this narrative makes sense. But interpreting these actions as an altruistic, interspecies miracle is partly based on our preconceived feelings about dolphins.

Because an observation precedes a result does not mean that one caused the other. In statistics, a common idiom is “correlation doesn’t imply causation”. The website Spurious Correlations outlines some quirky correlated relationships to illustrate this point.

To further highlight dolphins’ intelligence, the film also delves into several studies that use captive dolphins as subjects. Researchers challenge them to the classic  animal self-awareness test—the mirror. An animal is presented with a mirror and tasked with showing that it can recognize the reflection as itself rather than another animal. The dolphins pass.

Few other animals pass the mirror test. Only one individual elephant has ever passed. Even the smartest dogs fail. However, the mirror test is purely visual. Dogs potentially fail because their primary senses are smell and hearing. Other animals get so caught up in aggressively posturing at the mirror that they never reach a mental state to evaluate the situation calmly. Unfortunately, that evenly matched opponent in the mirror never backs down. We are testing the animals’ intelligence based on human terms.

Comparing intelligence between animals is rife with bias. Studies on captive subjects differ from studies on wild subjects in important ways. A wild dolphin doesn’t have to count dots or recognize itself in the mirror. The film would have benefitted from a sceptical scientist who evaluated the studies on captive subjects. For instance, a recent Russian study, which was widely reported in the media, purported to show two dolphins having a “conversation” with each other. However, on closer review, the experimental design was flawed and the results appear less convincing.

The film succeeds in its goal of demonstrating that humans aren’t the only intelligent animals on the planet. It includes stunning footage of novel behaviours in the wild, and some intriguing experiments in captive arenas. Dolphins are undoubtedly clever creatures, but we cloud our perception of a complex species by judging them through a purely human lens.

Such simplistic comparisons diminish the subtleties and talents of other animals. A pigeon, not exactly the poster child for braininess, outperforms humans on certain spatial tests. So if we could have actual conversations with dolphins, we might discover that they’re smarter than we ever imagined.

Source: http://blog.scienceborealis.ca/conversatio...

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