September 17, 2013
“Call me Migaloo,” would start the memoir of the most famous white humpback whale out there. He’s not quite from the pages of Moby Dick—Herman Melville’s white whale was a sperm whale and not entirely white—but Migaloo still makes quite a splash when he lifts his head or tail above the waves.
First spotted in 1991, he’s been seen more than 50 times since, including a few times around the Great Barrier Reef this summer. But the probable-but-unconfirmed spotting by Jenny Dean, a Queensland, Australia native, takes the cake. A few weeks ago, she captured Migaloo breaching in a spectacular photo, showcasing the whale’s bright whiteness that nearly looks photoshopped.
But what’s the deal with Migaloo and white whales? Let us ocean enthusiasts from the Smithsonian Ocean Portal answer your questions.
What do we know about Migaloo?
In the past 22 years since whale watchers first spotted the exceedingly social Migaloo—so-called after the Aboriginal word for “white fella”—scientists have been able to learn a bit about him. They think he was around 3-5 years old when first spotted, which makes him 25-27 now. Barring an unfortunate accident, he may have another 50 years ahead of him, although scientists don’t know for sure how long humpback whales live because they don’t have teeth—like tree rings, analyzing concentric layers in teeth is a common way to measure age in mammals.
They know he’s a male from his song. While both male and female humpback whales produce sound, only males sing the melodic humpback songs that long ago captured our imaginations. In 1998, researchers first recorded Migaloo singing—and his knack for melody gave it away.
His maleness was further confirmed by DNA after researchers from Lismore, Australia’s Southern Cross University, collected skin samples from Migaloo in 2004.
Are white humpbacks rare?
As far as we know, exceedingly so. Besides Migaloo, there are three other known white humpbacks. Willow lives up in the Arctic and was spotted along the coast of Norway in 2012. Meanwhile, Bahloo lurks in Migaloo’s territory in the Great Barrier reef, first seen in 2008. But these two are not as gregarious as Migaloo, rarely showing their faces.
The other known white humpback is a calf first seen swimming around the Great Barrier Reef in 2011. Unofficially named “Migaloo, Jr.,” the calf is not known to be the child of Migaloo—in fact, the two whales may not even be related. If a DNA sample from the calf is obtained someday, they could compare it with Migaloo’s genetic profile to find out.
There probably are more white whales out there, however. These are just the ones that have surfaced near people with cameras. Two years ago, an unknown white whale washed up on a beach, and if you dig around on the web, you can find even more.
How do we know these aren’t the same white whale?
In the case of Migaloo, Jr., it’s pretty obvious: he’s much smaller than the Migaloo Australians are so familiar with.
Bahloo and Migaloo hang out in the same area and, because Bahloo rarely shows its face, you could argue that the two are actually the same whale. But photos taken in 2010 showed a few black spots on Bahloo’s head and tail, differentiating it from Migaloo. Willow also has black patterns on the underside of its tail, making Migaloo the only documented all-white whale. These patterns and markings are distinct for each whale, white or otherwise, allowing researchers to track the creatures through detailed observations.
Why is he white anyway?
Many articles describe Migaloo and the other white whales as albino. But making that diagnosis is easier said than done.
Albinism is a genetic disorder in which the protein tyrosinase, which helps to produce the pigment melanin, is completely absent or damaged by a variety of possible mutations. Fully albino animals and people have no melanin whatsoever; they are white or pink from head to toe, including their eyes.
Willow and Bahloo are not albino: they have black spots or patches on their bodies. It’s more likely that they have leucism, a condition where all pigment types are lost in patches of cells.
Even though Migaloo is all white, scientists are skeptical that he is albino because he doesn’t have red or pink eyes—like other humpbacks, he has brown eyes. Instead, he’s considered the more conservative “hypo-pigmented,” describing a generic loss of skin color. It’s also possible that Migaloo is leucistic.
The Southern Cross University researchers could analyze his DNA for different genetic variants associated with pigment disorders to pinpoint the exact form. But there are many variants and, as Megan Anderson, who originally tested Migaloo’s DNA, said in a press release, “It’s going to be a long and complex process to test for albinism in this humpback whale as it has not ever been done before.”
And what about the calf? There isn’t enough known about it to be sure.
Are there other white whales that aren’t humpbacks?
Yes! These skin disorders are not exclusive to humpbacks. There have been several other wild spottings of white whales recently.
A white right whale calf (incorrectly described as albino) was filmed last year off the coast of Chile by a group of surfers. Last April, researchers spotted a white killer whale off the coast of Alaska, and they named it “Iceberg.” And a truly albino pink dolphin has been seen around Florida and the Gulf of Mexico repeatedly over the years.
In fact, whales aren’t the only creatures that can lack pigment. A plethora of other all-white examples—such as koalas, penguins, and gorillas—can be found throughout the animal kingdom.
September 16, 2013
If you think extracting globs of earwax from your own ear is gross, imagine handling a nearly foot-long, inch-thick tube of whale earwax.
To protect delicate eardrums, around 8 to 10 baleen whale species have ear canals that are naturally sealed off from the external environment. Over the years, earwax begins to build in the narrow tubes. Whales don’t hear like humans–fat deposits in their jaw funnel low-frequency sound vibrations toward their eardrum, so the wax does not get in the way of their hearing.
By the end of a blue whale’s life, the wax forms a solid, permanent tube of what researchers refer to as an earplug in the animal’s ear canal. While most people would likely consider the prospect of handling this stuff rather off-putting, for scientists the earwax provides “unprecedented lifetime profile” of the animal, according to a new paper published in Proceedings of the National Academy of Sciences.
Like tree rings, layers found within whale earplugs are already used to help researchers estimate an animal’s age. In this new study, scientists guessed that the wax may have more secrets to tell.
Traces of events recorded from birth to death may leave their mark in the whale’s ear wax, they figured. Chemical pollutants, for example, are a problem for ocean creatures, included endangered blue whales. Many of these contaminants build up in whales’ fatty tissues, but fat offers no clues as to when a whale might have been exposed to those chemicals. Perhaps the earplug would.
However, testing this hypothesis requires invasively getting at that golden substance–a difficult task while the whale is alive. But in 2007, a 12-year-old, 70-foot long blue whale washed ashore near Santa Barbara, dead from a ship strike. The recovered 10-inch long earplug sat in a freezer for a couple years, until the team sampled it. They also took samples of its blubber to compare it with the wax and get chemical profiles of these two lipid-rich materials’.
Earwax is continuously deposited throughout the whale’s lifetime, but forms alternating light and dark layers on approximately 6 month intervals. The light corresponds to periods in the whale’s lifecycle when it’s feeding, while the dark represents times of fasting and migration. The team performed numerous chemical analyses to produce a profile of the whale’s life, told at a 6-month resolution.
Within the wax, they found markers of the stress hormone cortisol, growth-inducing testosterone, contaminants such as pesticides and flame retardants, and mercury. Much like humans, this particular whale’s stress levels increased as it got older, effectively doubling over its lifetime. Testosterone peaked when the whale was about 10 years old–the height of puberty for male blue whales.
The contaminants tell an interesting story. From the whale’s birth until about 12 months old, anthropogenic chemicals such as dichlorodiphenyltrichloroethanes (better known as DDT), chlordanes, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers appeared in his earwax. About 20 percent of the the whale’s total organic contaminants turned up during this first year, indicating that although the whale’s mom likely did a good job nursing her son, she also inadvertently transferred toxins to her baby during gestation and through her milk.
After the whale was weaned, the bulk of pollutants that built up in the whale’s body likely came from krill, it’s main food source. Blue whales can consume up to one ton of the little shrimp-like crustaceans each day, so small contaminants present in the tiny creatures can accumulate over time in the whale’s body. The contaminants also work their way into bodily secretions such as earwax.
Mercury, which gets into earwax the same way as the other pollutants, peaked in two separate events much later in life, first when the whale was about five years old and then again at about ten years old.
Both the organic pollutants and the mercury continued to accumulate throughout the whale’s lifetime, meaning that the older the whale became, the more pollutants built up in its ears. About 90 percent of these contaminants also turned up in the blubber, confirming that both blubber and earwax can be used as markers of exposure, but that earwax provides a method of tracking when exposure occurred.
“DDT was banned 30 years before this animal was born, but it was still exposed to DDT over its entire lifetime,” study author Sascha Usenko of Baylor University pointed out in an interview. “It was exposed to both historical and current chemicals, like brominated flame retardants.”
Pollutants like DDT and mercury are known to cause a host of problems for animals, including developmental disorders and thyroid issues. While these findings don’t bode well for the health of the ocean’s creatures–especially endangered ones like the blue whale–the researchers are excited about using the chronically archived wad of wax to better understand the extent to which humans are tampering with marine fauna’s health. It also provides marine biologists with a new tool for studying of whale life events. “For a majority of the species on the planet, lifetime profiles such as these are simply unattainable,” the researchers write.
The team hints at the wax’s research possibilities. For example, they noticed that stress hormones began to rage after the whale went through testosterone-triggered puberty, indicating the big guy may have been flustered over competition and pressure to win a lady friend. On the other hand, some of the whale’s ever-growing stress may be due to accumulating pollutants, though this study only scratches the surface of that question. Large pulses of pollutants, like the mercury seen in this whale, may indicate that the animal came near a polluted shore (the coast of California in this case, perhaps) or was exposed to a major contamination event.
“To be able to scientifically measure chemicals that are not as persistent, such as hormones that degrade in the body, is outstanding,” Usenko said. “We can ask questions like ‘Do contaminants have impacts on changes in stress?’ and maybe do a better job at addressing those questions.”
Examining old museum specimens’ ear wax from the 1950s and onwards, the team thinks, may reveal significant changes to the ocean and its creatures’ health over the years. Additionally, the researchers have confirmed the method works on grey whales, and they suspect it should also apply to other species of baleen whales. “This innovative tool increases the feasibility of accurately assessing anthropogenic impact on everything from an individual organism to marine ecosystems,” they write.
The earplug is no doubt only beginning to reveal its secrets. In the meantime, whale researchers may celebrate over less of a need to handle whale blubber, poop and blood–up until now the conventional means of studying whale health, and probably even more unpleasant than handling a giant tube of years-old wax, even though the earplug does reportedly have a pungent fishy smell. “It’s not something you want to get on your clothes, it sticks around with you for a while,” Usenko said.
August 30, 2013
You’re at the beach for a weekend with family or friends. Splashing and jumping, dunking your head beneath the waves, you start to cool off. Then you feel something soft brush against your leg—and suddenly, the coolness is replaced by a hot, shooting pain. You’ve been stung by a jellyfish. But what do you do now?
First let’s take a look at exactly what’s happening to your leg. Jellyfish have special cells along their tentacles called cnidocytes. Within these cells are harpoon-like structures full of venom, called nematocysts. The nematocysts shoot out when triggered by touch and can penetrate human skin in less time than it takes you to blink.
Once the venom is injected into your skin, the pain, redness and blistering begin. One of the main causes of this discomfort is a type of protein called a porin found in the venom of all jellyfish—and in all their relatives, including corals and anemones, which together form a group of creatures collectively known as cnidarians. Angel Yanagihara, a research professor studying box jellyfish venom at the Pacific Biosciences Research Center at the University of Hawaii, explains that the porins in box jellyfish are fast-acting and “promiscuous:” they are indiscriminate and “will punch holes in all types of cells” including blood, skin and nerve cells. The complex concoction of these proteins varies (along with the stinging cell mechanism) from species to species, which is why we might only feel a small sticky sensation when we come in contact with some anemones, while a box jelly sting may cause a trip to the emergency room or even kill you.
So after you’re stung, you should pee on it, right? Or get someone else to? That’s what you’ve seen on TV—maybe you’re thinking of a certain incident from Friends. But don’t pull those board shorts off too quickly—urine can do a lot of things, but it doesn’t help the sting. It may actually make it worse.
That’s because pouring freshwater—or urine—on the area will change the composition of the solution surrounding the remaining cells and may actually trigger the release of more nematocysts and venom. Instead, experts suggest rinsing the area with saltwater to help reduce discomfort. Before you do any rinsing, however, remove any jellyfish tentacles that remain on the skin, as nematocysts on loose tentacles can continue to sting even after they are detached from the jelly. Making sure that sand stays clear of the wound is also an important task, but likely a difficult one while on the beach. In the case of a box jelly sting, it would be helpful to have Yanagihara nearby with the two treatments she has developed—or even better would be to make use of her preventive ointment before going in the water. Because these aren’t yet available to the public, putting vinegar on the affected area and seeking medical attention are the suggested treatments.
It’s good to have this information in-hand when you go to the beach just in case—though it’s unlikely that you’ll be stung. But that possibility could be on the rise if, as has been suggested, jellyfish numbers are increasing. A study from April 2012 in Hydrobiologia found increasing jellyfish populations in 62 percent of the regions analyzed, including coastal areas of Asia, the Black Sea and the Mediterranean Sea. “Our study confirms these observations scientifically after analysis of available information from 1950 to the present for more than 138 different jellyfish populations around the world,” said Lucas
Brotze Brotz, the lead author of the study in a press release.
However, jellyfish are a difficult species to study: their life cycles aren’t well understood, and catching them by net is not a good option due to their fragile, gelatinous bodies. Because of this, sweeping claims about global changes in jellyfish populations are up for debate. Their historical numbers are largely unknown, making it hard to be sure whether jellyfish populations are increasing over the long term, or whether the increases we see are a part of natural population fluctuations or an artifact of more people reporting sightings. And there is evidence for these caveats: a different 2012 study found that the perceived rise in the number of jellyfish is actually the peak of a normal 20-year boom and bust cycle.
But if jellyfish are increasing globally, it is likely that human influences are the cause. Overfishing has reduced some jellies’ competition for food; increased nutrients running into the ocean create oxygen-depleted environments that jellies can tolerate better than other animals; and warmer water can help some species of jellyfish larvae to grow more quickly. Even jellies without a nasty sting can cause problems, clogging up pipes in nuclear power plants that use seawater to cool their reactors and pushing fish out of the ecosystem.
There still is much to learn about the fascinating and pulsing lives of jellyfish that can help to determine if their populations are increasing long-term. Scientists are making use of observant beachgoers, with websites where you can input your jelly sightings onto a map to generate global data on jelly populations. So if you do have the bad luck to get stung by a jellyfish, remember: wash it with salt water, not pee, and maybe pop your location into the map to help us all learn something from the experience.
Learn more about the ocean from the Smithsonian’s Ocean Portal.
August 28, 2013
Over the past 15 years, a strange thing has happened. On one hand, carbon dioxide concentrations have kept on shooting up thanks to humans burning fossil fuels—in May, we passed 400 parts per million for the first time in human history.
On the other hand, despite certain regions experiencing drastically warmer weather, global average temperatures have stopped increasing. Climate change deniers have seized upon this fact to argue that, contrary to the conclusions reached by major science academies (PDF) around the world, greenhouse gas emissions do not cause global warming.
As it turns out, the truth is much grimmer. A pair of scientists from Scripps Institution of Oceanography have determined that the underlying process of global warming has merely been masked by natural decade-scale variations in the temperature of Pacific Ocean surface waters, related to the El Niño/La Niña cycle. Once that’s finished, our planet’s warming will march onward as usual.
Climate scientists have speculated about the possibility that ENSO (the El Niño-Southern Oscillation, the proper term for the cycle) was behind the apparent hiatus in warming for some time, but the scientists behind the new study—Yu Kosaka and Shang-Ping Xie—are the first to take a quantitative look at the role of Pacific surface temperatures in pausing global warming as a whole. Their paper, published today in Nature, uses climate models to show that the abnormally cool surface waters observed over the Pacific since 1998 can account for the lack of recent warming entirely.
Why has the Pacific been abnormally cool for the past 15 years? Naturally, as part of ENSO, a large swath of the ocean off the western coast of South America becomes notably warmer some years (called El Niño events) and cooler in others (La Niña events). Scientists still don’t fully understand why this occurs, but they do know that the warmer years are related to the formation of high air pressures over the Indian Ocean and Australia, and lower pressures over the eastern part of the Pacific.
Because winds move from areas of high pressure to low pressure, this causes the region’s normal trade winds to reverse in direction and move from west to east. As they move, they bring warm water with them, causing the El Niño events; roughly the reverse of this process happens in other years, bringing about La Niña. As it happens, colder surface temperatures in the Pacific—either official La Niña events or abnormally cool years that don’t quite qualify for that designation—have outweighed warm years since 1998.
That, say Kosaka and Xie, is the reason for the surprising lack of increase in global average temperatures. To come to this conclusion, they developed a climate model that, along with factors like the concentration of greenhouse gases over time and natural variations in the solar cycle, specifically takes the ENSO-related cycle of Pacific surface temperatures into account.
Typically, climate models mainly use radiative forcing—the difference between the amount of energy absorbed by the planet and the amount sent back out to space, which is affected by greenhouse gas emissions—as a data input, but they found that when their model did so, it predicted that global average temperatures would increase much more over the past 15 years than they actually have. However, when the abnormally-cool waters present in the eastern Pacific were taken into account, the temperatures predicted by the model matched up with observed temperatures nicely.
In models, the presence of these cooler waters over a huge area (a region within the Pacific that makes up about 8.2% of the Earth’s surface) serves to absorb heat from the atmosphere and thus slow down the underlying warming process. If the phenomenon is representative of reality, the team’s calculations show that it has caused the planet’s overall average temperature to dip by about 0.27°F over the past decade, combating the effects of rising carbon dioxide emissions and causing the apparent pause in warming.
This isn’t the first localized climate-related event to have effects on the progression of climate change as a whole. Last week, other researchers determined that in 2010 and 2011, massive floods in Australia slowed down the global rise in sea level that would have been been expected from observed rates of glacier melting and the thermal expansion of sea water. In many cases, it seems, the subtle and complex dynamics of the planet’s climate systems can camouflage the background trend of warming, caused by human activity.
But that trend is continuing regardless, and so the most obvious impact of this new finding is a disconcerting one: the Pacific will eventually return to normal temperatures, and as a result, global warming will continue. The scientists don’t know exactly when this will happen, but records indicate that the Pacific goes through this longer-term cycle every decade or so, meaning that the era of an abnormally-cool Pacific will probably soon be over.
Perhaps most distressing, the study implies that the extreme warming experienced in recent years in some areas—including much of the U.S.—is actually less warming than would be expected given the amount of carbon dioxide we’ve released. Other regions that haven’t seen much warming yet, meanwhile, are likely in line for some higher temperatures soon.
August 20, 2013
The menu says red snapper, but it’s actually tilapia. The white tuna, meanwhile, is really escolar, while the seabass is Antarctic toothfish.
Welcome to the wild world of modern seafood, where not everything is as it seems. New research is revealing that merchants and fish dealers often mislabel their product as an entirely different species to fetch a better price at market. A study realeased last week by UK researchers found that a number of species in the skate family are sold as “sting ray wings,” while a separate study produced in February by the group Oceana found that, of 1215 seafood samples from 674 restaurants and grocery stores in 21 U.S. states, a full third were mislabeled. In Chicago, New York, and Washington, DC, every single sushi bar that was tested was found to sell at least one mislabeled fish species.
How did the researchers figure all this out? Through the innovative use of DNA barcoding, in which a specific segment of genetic material (analogous to a product’s barcode) in a piece of fish is used to determine exactly which species it truly belongs to. For years, we had no real way of determining the true species of a piece of seafood—a filet of fish, after all, often looks like any other filet—but this new application of an existing scientific technique is rapidly becoming a crucial tool in combating seafood fraud.
Testing a piece of fish to determine its species is fairly straightforward—scientists perfected DNA barcoding years ago, albeit typically as part of other sorts of projects, like cataloging the complete assortment of species in a given ecosystem. Analyzing the DNA in a piece of fish is a relatively similar process.
To start, researchers acquire a piece of fish and freeze it, as fresher and better-preserved tissue samples generally yield more accurate results. Then, in the lab, they slice off a tiny piece of the sample for testing.
To extract and isolate the DNA from the tissue, scientists break open the cells—either physically, by grinding them or shaking them in a test tube filled with tiny beads, or chemically, by exposing them to enzymes that chew through the cell membrane. Next, they remove other components of the cell with various chemicals: proteases digest proteins, while RNAase digests RNA, an alternate form of genetic material that could cause errors in DNA testing if left in place.
Once these and other substances are removed, the remaining sample is put in a centrifuge, which spins it at high speed so that the densest component—in this case, DNA—is isolated at the bottom of the tube in a pellet. A variety of different approaches are currently used to sequence the DNA, but all of them achieve the same end—determining the sequence of base pairs (the building blocks of DNA that are unique to each organism), at one specific location in the fish’s genome. All fish of the same species share the same sequence at that location.
As part of broader DNA barcoding projects, other scientists have analyzed the sequence of base pairs at that same genetic location in thousands of pieces of fish tissue that can definitively linked to species. Thus, by comparing the genetic sequence in the mystery fish tissue to databases of other species’ known genetic sequences, such as FISH-BOL (which stands for Fish-Barcode Of Life and contains the barcodes of 9769 fish species so far), scientists can tell you if, say, the grouper you thought you were buying was actually Asian catfish.
Figuring out which species a piece of fish truly belongs to has significance that goes far beyond gastronomy. For one, cheaper fish species are most often substituted for more expensive ones: tilapia, which goes for around $2.09 per pound, is billed as red snapper, which can commonly fetch $4.49 per pound. (The fact that inexpensive fish is so commonly passed off as a pricier variety, while the reverse occurs much more rarely, indicates that intentional mislabeling by sellers is at play, rather than innocent misidentification.)
Additionally, species that are dangerously overfished and are on the verge of ecological collapse—such as orange roughy—are sometimes substituted for more environmentally-benign varieties. Customers that make the effort to choose sustainable types of seafood, in these cases, are thwarted by mislabeling.
Eating different species can also have vastly different effects on your own health. For one, different fish species can have different fat and calorie contents, so mislabeling can lead the nutrition-conscious astray. Moreover, certain species, like tilefish, are on the FDA’s “do not eat” list for sensitive groups of people (such as pregnant women) because of their high mercury content. The Oceana study, though, found several instances of tilefish being sold as red snapper. Perhaps even worse, 94 percent of the white tuna tested in the study was actually a fish called escolar, which has been found to contain a toxin that when ingested, even in small quantities, can cause severe diarrhea.
So, what to do? Testing the fish’s DNA at home is probably beyond most people’s capabilities. So to avoid being duped, Oceana recommends asking sellers lots of questions about a fish’s origin, scrutinizing the price—if a fish is being sold far below market value, it’s probably mislabeled as a different species—and buying whole fish at markets when possible.