SNEAK PREVIEW: WHALE SHARKS GET NOSEY

A whale shark tilts upright and yanks on a net, trying to make off with a fisherman's catch. Credit: �Michael Aw/National Geographic.

  
An amazing National Geographic photo essay in the October issue�due on newsstands 27 September�tells of the novel relationship between whale sharks and fishermen off Papua, Indonesia.

Vying for position under a feeding platform, male whale sharks�two of about twenty that visit this spot�scramble for a snack. Credit: �Michael Aw/National Geographic.

  
Normally these 50,000-pound/22,680-kilogram behemoths are tough to find. They cross ocean basins and can dive more than a mile/1.6 kilometers deep. Some travel to Australia's Ningaloo Reef for the annual coral spawning�a feast for filter feeders. No one yet knows where they mate or give birth.

Sarmin Tangadji, the Papua police officer who escorted the photographic team to where the sharks congregate, was so excited to see them up close that he jumped in. Credit: �Michael Aw/National Geographic.

  
Whale sharks also gather off Papua, where artisanal fishermen�hoping to keep their nets and catches intact�offer the whale sharks food. 

From the National Geographic article Sharing With Sharks: 

Whale sharks are ordinarily loners. But not in one corner of Indonesia. The photographs on these pages, shot some eight miles off the province of Papua, reveal a group of sharks that call on fishermen each day, zipping by one another, looking for handouts near the surface, and nosing the nets�a rare instance when the generally docile fish act, well, like the rest of the sharks.

You can see all the images and read the photo essay here.

ILLUSTRATED: THE CRAB NEBULA THROUGH TIME

M1: The Crab Nebula, captured by the Hubble Space Telescope, 2009. Credit: NASA, ESA.

Towards the end of my book DEEP BLUE HOME I wrote about the cave paintings of Mexico's Baja Peninsula�truly a wonder of the world�including an image of the Crab Nebula supernova from the year 1054.

[O]ne of the most modest paintings on view anywhere in Baja California: a small depiction in ochre of a childlike sun, with lines radiating from a circle, nestled beside the outline of another circle more than half ?lled with ochre pigment.

North American rock art depicting the Crab Nebula supernova, circa 1054. Illustration: Harry W. Crosby, from The Cave Paintings of Baja California.

  
You can see the art I'm describing on the far left in the image above: 

The story of this image has a long lineage, and the starting place for its rediscovered meaning dates back to the year 1054, when Chinese astronomers noted a guest star in the constellation Taurus and recorded that its glow was visible in the daytime sky for twenty-three days and in the nighttime sky for six hundred ?fty-three days.

Little more thought was given to this celestial light for a long time. It was not noted in 1731 when the English doctor and astronomer John Bevis ?rst observed a nebulous cloud within our own Milky Way galaxy nor, more than a century later, when another English astronomer named it the Crab Nebula. The visit of the guest star was nearly forgotten until the early twentieth century, when�working backward in time to calculate the rate of expansion�astronomers surmised that the Crab Nebula was the remains of the 1054 supernova observed by ancient astronomers.

The crablike sketch made in 1844 by William Parsons, 3rd Earl of Rosse, for which the nebula was named. Image courtesy Wikimedia Commons.

And:

Later the American astronomer William Miller calculated that the 1054 supernova appeared in western North America in dazzling conjunction with a crescent moon. He correlated this sight to two pieces of prehistoric rock art in Arizona, each depicting a star beside a crescent moon. Later astronomers found strikingly similar rock art of conjunct stars and crescents at other sites in the American Southwest. In 1971 the explorer Harry Crosby, traveling by mule in the Sierra de San Francisco, came upon this image of a star and a moon�the only painting of its kind in the murals of Baja California, which he later surmised was also an image of the 1054 supernova.

Chaco Canyon, 1054 supernova rock art. Photo via.

Astronomy Picture of the Day (APOD) describes the Crab Nebula as "the mess left after a star explodes," filled with mysterious filaments:

The filaments are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second. 

Crab Pulsar Wind Nebula, 2008. Credit: NASA.

  
This deep x-ray image of the Crab Pulsar taken from the orbiting Chandra Observatory provided the first clear view of the ghostly edges of the pulsar's wind nebula. From APOD:

The pulsar's energy accelerates charged particles, producing eerie, glowing x-ray jets directed away from the poles and an intense wind in the equatorial direction. Intriguing edges are created as the charged particles stream away, eventually losing energy as they interact with the pulsar's strong magnetic field.

It's astonishing to think how much we've seen�and learned to see�in less than the blink of a universe. Of course the real timeline of events is even more profound. Back to my excerpt:

The 1054 supernova occurred 6,300 years before anyone on Earth witnessed it. The explosion dismantled a star more than 37,000 trillion miles away from us. The blast radiated as much energy as our sun will emit in the course of its life, and its light traveled at the fastest speed possible, the speed of light itself, yet it still took more than sixty centuries to get here.

Credit: Danny LaCrue & the ESA/ESO/NASA Photoshop FITS Liberator.

 

The beautiful mess of the Crab Nebula.

ILLUSTRATED: THE EKMAN SPIRAL

(The ocean off Tasmania, Australia. This is an unfiltered false-color MODIS {Moderate Resolution Imaging Spectroradiometer} satellite view designed to enhance the reflections from phytoplankton, dissolved organic matter, sediments, and bubbles in the sea�though it may have also picked up reflections from Earth's atmosphere and even from the spectroradiometer itself. Normally, the MODIS images we see have been filtered clean of most of these data. This unfiltered image gives a sense of the ocean's dynamic complexity. HT Discovery Earth. Credit: NASA/GeoEye.)

I've been getting feedback from readers of my book DEEP BLUE HOME wishing for photos or illustrations of some of the species and subjects I wrote about. So I thought I'd post some clarification here on the blog.

First up, the Ekman Spiral, from Chapter 7, "Whorls." Here's the excerpt from the book, now illustrated:

Upwellings are the most biologically productive of all currents: vertical conveyor belts rising from the abyss to the surface, bearing the sunken components of dead plants and animals in the form of dissolved organic matter. This rich broth is destined to fertilize the phytoplankton in the sunlit zone, whence much of the dissolved organic matter originally came. 

(Upwelling in the Northern Hemisphere. Image courtesy of Sanctuary Quest 2002, NOAA/OER.)

Upwellings occur anywhere, including in midocean, though the superproductive ones develop along coastlines, where prevailing winds blow parallel to the shore, pushing the surface waters ahead of them. But because the flow of wind-driven water is also influenced by the Coriolis effect (a spin-off of the Earth�s rotation), the wind-driven current is deflected to the right of the wind in the Northern Hemisphere and to the left in the South. 

(Credit: Office of Naval Research.)

In the image above you can see how the Coriolis effect causes ocean gyres in the Northern Hemisphere to spin in a clockwise direction and those in the Southern Hemisphere to spin in a counterclockwise direction as a result of Earth's spinning rotation.

(Credit: Eumetsat.)

The same process drives low pressure storm systems in the atmosphere. You can see a low sweeping across Ireland and Britain in the top of this image, and numerous southern hemispheres lows swirling around Antarctica at the bottom.

BTW, if you really want to trip out in this image, check out this super high-res close-up of it.

The Coriolis effect is a deceptively complex process, as you can see when BBC filmmakers spring the question on some unsuspecting experts in the video below.

Annoyingly, you may have to go here to be amused by this BBC clip.

Back to the excerpt:

And because the ocean is stratified into density layers, the Coriolis effect redirects these tiers too. The surface-driven current, spun by the Coriolis effect, tugs on the layer below it, which tugs on the layer below it, to successively lesser degrees. The end result is a downward whorl known as an Ekman spiral, which corkscrews miles below its originator, the wind. The net work of all the layers is known as the Ekman transport, with a theoretical power to deflect water ninety degrees off the wind. 

(This schematic shows how ocean currents change direction in relation to the wind direction as a result of the Coriolis effect: (1) wind (2) force of water from above (3) direction of current prior to the Coriolis effect (4) direction of water after the Coriolis effect. Each layer of ocean water exerts pressure on the layer below it and the process is repeated downward. Courtesy Wikimedia Commons.)

Consequently, breezes blowing parallel to a coastline actually result in water flowing offshore at a right angle. The offshore flow is then replaced by water rising from the deep, bearing its Miracle-Gro of nutrients destined to feed blooms of phytoplankton, which feed zooplankton, who feed the sardines, who feed the tuna, dolphins, whales, and seabirds. The plankters that escape being eaten sink to the seafloor upon death, their ghosts eventually resurrected back to the surface to fertilize their own kind, maybe their own kin, some generations hence. Thus the deep blue home recycles matter and energy with impeccable efficiency. 

(From Planet Philippines.)

RANDOM EXCERPT: FILMING FROM THE BLUFFS

(Colony of northern gannets at Cape Saint Mary's Ecological Reserve, Newfoundland. Photo by Bigg(g)er, courtesy Wikimedia Commons.)  

Cape Saint Mary's Ecological Reserve on the island of Newfoundland is one of my favorite places on Earth. 

Look at the monster continental shelf all around it. That's none other than the Grand Banks, the fishing grounds that fueled Europe for 500 years. 

Cape Saint Mary's lies on a point of land between fjords. In bird-world economics, that's like living between Costco and Home Depot.

(Photo by Johnath, courtesy Wikimedia Commons.) 

Only way bettah.

(Capelin spawned out on a beach in Newfoundland. Photo by Litehouseman, courtesy Flickr.) 

The birds are here for these waters' many piscivorous banquets, including the annual capelin feast: aka, the spawning run, known locally as the scull. This is the time each summer when capelin by the millions head up onto dry land to spawn.

More on that in a later post.

(Atlantic puffin with capelin off Newfoundland. Photo by Nilfanion, courtesy Wikimedia Commons.)

(A mated pair of northern gannets performing their courtship display, including fencing with their bills. Photo by naturepicsonline, courtesy Wikimedia Commons.)

Cape Saint Mary's is widely recognized as one of the most accessible seabird rookeries in the world, where you can see�from dry land and from as little as 30 feet away�spectacular aggregations of northern nesters:

• 24,000 northern gannets
• 20,000 black-legged kittiwakes
• 20,000 common murres
• 2,000 thick-billed murres
• 200 razorbills
• black guillemots
• double-crested cormorants 
• great cormorants
• northern fulmars

(Northern gannet with nesting material. Photo by Andreas Trepte, courtesy Wikimedia Commons.)

(Razorbill, in similar nesting conditions to Cape Saint Mary's, in Westfjords, Iceland. Photo courtesy Wikimedia Commons.)

(Black guillemot at Oban Harbour, Scotland. Photo by Kelson, courtesy Wikimedia Commons.)

Here's an excerpt about time I spent at Cape Saint Mary's. From DEEP BLUE HOME.

Filming from the bluffs, we are buffeted by the collective voice of the birds, as rough as the sea below and likewise rising, cresting, breaking into squawks, chuckles, squalls, trills, shouts. Dr. Charles W. Townsend, visiting the gannets in 1919, described their calls as "the sound of a thousand rattling looms in a great factory."

Thousands of long-winged, long-tailed birds are woven onto the wind, white crosses billowing on veils of fog. Heads down or cocked to the side, the gannets call to their mates below, sifting through the mayhem for familiar return calls, their personal homing beacons. When heard, the receiving bird retracts its wings, extends its legs, and drops�as light as a falling handkerchief that neatly folds itself upon landing.

The great looms of the gannets are joined by other calls: the breaking-glass kitt-ih-wake! of the kittiwakes; the purring and moaning of turrs�Newfoundland for murres; the grumpy growling of razorbills; the piping and hissing of guillemots; the strangled croaks of cormorants; the adenoidal cackling of fulmars. Add to these the high-pitched peeps of chicks, including those still in the egg, yet already talking to their parents (as with the murres), and you have a fully fledged United Nations of multispecies languages�as if all the tongues you heard on the New York City subway were not just of humans but also our relatives, gorillas, chimpanzees, bonobos, orangutans, gibbons, macaques, baboons, complete with their children in utero and ex utero... a loud, loquacious, repetitive, insistent, hurried, harried, and vital discourse.

We capture as many dramas as we can crowd onto our limited allotment of film, the courtships, the copulations, the pipping of eggs, the chicks diving into the gullets of their parents, the parents diving into the thrashing waters, the varieties of flight in all its aerodynamic design, stretched on the stop-motion of the wind. With long lenses we investigate the nests of diving birds on the cliffs below in search of interesting finds from the deep. To the north, off the coast of Labrador, fishermen report nests full of pocketknives, smoking pipes, hairpins, and ladies combs, salvaged by cormorants diving onto the wrecks of old trading vessels.

(Double-crested Cormorant in breeding plumage. Photo by Mike Baird, courtesy Wikimedia Commons.)

 

The video is of Cape gannets�close relatives of northern gannets�feeding on the sardine run off South Africa. I had the good fortune years ago to work with the first South African film crew to land this spectacle on celluloid.

 

Seeing that clip was so rudely edited in mid-action, here's another.

 

Older film footage, but really lovely. You can see the great buoyancy of these birds and the world of wind they inhabit.

HOW TO CATCH A MULLET

This short video is an excerpt from the BBC Life series showing the amazing cooperative hunting technique of bottlenose dolphins working Florida Bay in pursuit of mullet. This video was published on their new website, Life Is, which will release monthly embeddable videos from the entire BBC catalogue of nature programming. I'm glad to hear it.

The research behind this film was published in a 2005 paper: A division of labour with role specialization in group�hunting bottlenose dolphins (Tursiops truncatus) off Cedar Key, Florida. DOI: 10.1098/rspb.2004.2937 Proc. R. Soc. B 22 January 2005 vol. 272 no. 1559 135-140. 

From the abstract:

Individual role specialization during group hunting is extremely rare in mammals. Observations on two groups of bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida revealed distinctive behavioural roles during group feeding. In each group, one individual was consistently the �driver�, herding the fishes in a circle toward the remaining �barrier� dolphins. Aerial fish�capture rates differed between groups, as well as between the driver and barrier dolphins, in one group but not in the other. These differences between the two groups may reflect differences in group stability or in prey school size.

(Mullet from here.)

I wrote about mullet living in the waters around the atoll of Rangiroa�and a different way of catching them�in my book The Fragile Edge. Here's an excerpt:

The littlest ?sh are less than six inches long, and their schools are sleek and whippy as cat-o�-nine-tails. They are behaviorally circumspect, skittering only through the protected water around the dock�s pilings. In contrast, the schools of the larger mullets, with individuals reaching more than a foot in length, parade aggressively under the dock, around the pilings, and out into the open water, their pectoral ?ns ?ipping open and closed like golden fans
as they root out the diatomaceous and detrital scum of the sandy bottom. As one of the few species of ?sh that feed almost exclusively on single-celled plants�diatoms, dino?agellates, and phytoplankton�vegetarian mullet have a taste unlike any other ?sh, or so I�m told. 

Sucr� et huileux (sweet and oily), says the Tahitian woman who has joined me on the dock with her hand-?shing line. She has settled onto the pier not far from me, her bare legs and feet dangling over the edge, the sunset square in front of her, where all sunsets always seem to be in Rangiroa. Like many Tahitian women, her hair reaches past her waist, blue-black and shiny as the inside of a mussel shell, the long plait unfastened at the bottom, the hair holding the shape from habit alone. 

She cooks the mullet whole in a pan with just salt, no oil, she says, since the ?sh are oily enough. Sometimes she adds milk. I recognize her from the hotel, where she works as a maid, and this dock is apparently one of the perks of her job because I�ve seen her ?shing here most evenings. She seems relaxed and happy at the end of her workday, carrying nothing of the emotional and psychic exhaustion of a Western worker at shift�s end�and this is one of the many miracles not only of Polynesia but of French Polynesia, where the Gallic embrace of the sensual allows time for the enjoyment of life as it comes.

It's possible this video (the Oprah-Winfrey-narrated version) will stream only on computers based in the US. Sorry if that's true. Copyright Is, too.

(Photo by Endless Vacation on Flickr)  

RANDOM EXCERPT: BIOLUMINESCENCE

(UPDATE: Photo by Phil Hart. And, by the way, well worth a visit to his website for his explanation of the complex factors that led to this photograph. Plus more really beautiful images of bioluminescence.)

I wrote about bioluminescence, the brilliant aurora stirred by motion in the nighttime sea, in THE FRAGILE EDGE. Here's an excerpt:

The light show we observe near the surface, at least as we understand it, is produced largely by the dino?agellates�those unicellular plants possessing microscopic whiplike tails that enable them to move, however slightly, this way and that. Large creatures such as you or me or a spinner dolphin will activate billions of these bioluminescent plants as we move through the surface layer of the nighttime waters. Even small zooplankton, for instance, the predatory krill traveling on their swimmerets, will ?nd themselves spotlighted.

As to why plants in the sea produce bioluminescence, a hypothesis known as the burglar alarm theory postulates that the chemical production of light acts as a visual siren: the plants turn on their lights when their predators (for example, krill) are in motion, illuminating them so that their predators (for example, lantern?sh) can catch the krill and eat them ?rst.

Tricksy.

You can read a classic science paper on the phenomenon: 
Mark V. Abrahams and Linda D. Townsend. Bioluminescence in Dinoflagellates: A Test of the Burglar Alarm Hypothesis (pdf). Ecology, Vol. 74, No. 1 (Jan., 1993), pp. 258-260

(Photo from here.)

More about bioluminescence from THE FRAGILE EDGE, an excerpt about sailing the Pacific one stormy winter:

In the trough between the swells, an incandescent waterfall of radiance tumbled from the wave breaking directly ahead. Time and again, we sailed into this cascade, which outlined the bow of the sailboat in a vibrating aura of electric blue and electric green. Behind us, our wake writhed like an aquamarine serpent before fading from view over the precipice of the receding wave.

Most nights schools of dolphins�generally common dolphins (Delphinus delphis)�arrived seemingly out of nowhere to ride our bow-wave. Alone on watch in the open-air cockpit, I would glimpse a streak of blueish-green heading towards the bow, looking for all the world like a torpedo until it porpoised through the surface to breathe. The first streak was invariably followed by others, sometimes dozens, all racing across the beam, carving glowing turns before settling into bow-riding position: on their sides, tail flukes nearly touching the bow as it hobby-horsed through the swells. No matter how violent the action of the bow, the dolphins held fast in their position, their bodies outlined in the pulsing blue light of an underwater St. Elmo�s fire. 

Common dolphins were not the only cetaceans we encountered in the course of these bioluminescent nights. We also came upon migrating gray whales headed for their breeding lagoons on the western coast of the Baja Peninsula. Their bioluminescent wakes mimicked the wakes of boats. If conditions were right, when the whales blew, the plugs of water covering their blowholes flared into faint, blue-green mists of luminous organisms, as if the behemoths were exhaling pixie dust.

(Photo by Jed Sundwall, courtesy Wikimedia Commons)

RANDOM EXCERPT FROM "DEEP BLUE HOME:" THE TRUTH ABOUT BARNACLES

"Not only are barnacles hermaphrodites, with two sets of genitalia, they are also in possession of the longest penis in relation to body size of any animal on Earth, up to eight times their body length. When the mood is right and the waters begin to warm the tiny creatures snake their appendages out their doors to fertilize the eggs of their neighbors. The favor is reciprocated by the same neighbor, by a different one, or by many. Barnacles living alone fertilize themselves."

DEEP BLUE HOME

Chapter 8

The Unreefed World

Photo by Christopher Neufeld at LiveScience

RANDOM EXCERPT FROM "DEEP BLUE HOME:" SEA TURTLES IN THE ICE REALM

"It's not surprising to see a leatherback up here
on the edge of the ice, since this is one of the most traveled
of all vertebrate species, perpetually on the move along
jellyfish highways between the tropics and the high latitudes."

DEEP BLUE HOME
-Chapter 14
The Distant Geography of Water

Photo courtesy COML.org