There are about 20,000 gray whales living in the eastern Pacific Ocean today, plus another 200 in a small group in the western Pacific. And, in the Mediterranean Sea, scientists have found one.

Over the weekend, oceanographers saw a solitary gray whale cruising the Mediterranean off the coast of Israel. To say they were surprised would be a vast understatement: gray whales haven’t lived in the Atlantic Ocean or the Mediterranean since their population crashed in the 1700s, possibly because of whaling operations. Yet today a solitary gray whale swims by the shores near Tel Aviv, halfway across the world from where the rest of its species resides (the researchers say they photographed the animal to be sure it wasn’t a different species, like sperm whale).

So what happened to get this whale to the far side of the world? Says Phillip Clapham of the US government’s National Marine Mammal Laboratory in Seattle:

“The most plausible explanation is that it came across an ice-free North-West Passage from the Pacific Ocean, and is now wondering where the hell it is” [New Scientist].

Suppose the whale belongs with that largest group of gray whales that lives in the eastern Pacific. They migrate from their calving waters off Baja California up the coast to the Arctic. But with the decreasing ice cover meaning that the the Northwest Passage is opening up, this lonesome traveler could’ve made it far enough east in those chilly Canadian waters that when it headed back south, it accidentally swam into the Atlantic Ocean. Then, seeking warm waters, it found them in the Mediterranean.

While that seems like an incredible journey, whale expert Nicola Hodgins says that gray whales are well known for making some of the longest migrations in the world each year:

“Over a lifetime, a gray whale migrates the equivalent distance of a return trip to the moon. However, these new images show that this particular whale would have had to beat all previous distance records to end up where it has” [BBC News].

Still, Clapham says, the Northwest Passage journey is far more likely than the alternative explanation: That a relic population of Atlantic gray whales has escaped attention for centuries. The scientists don’t have funding to tag and track the whale to be sure, but Clapham argues that this won’t be the last whale to find its way across the Arctic to points unknown.

Related Content:
DISCOVER: Arctic Thaw, on the opening Northwest Passage
80beats: Will Commercial Whale Hunts Soon Be Authorized?
80beats: Is the Whaling Ban Really the Best Way to Save the Whales?
Not Exactly Rocket Science: Scientists, Film-makers Team Up To Expose Illegal International Trade in Whale Meat

Image: Israel Marine Mammal Research and Assistance Center

I've talked in the last two posts about some of Elaine Ecklund's surprising findings about atheist scientists, as discussed on Point of Inquiry (show website here; listen here; download/subscribe here). In this blog post, then, I want to move on to discussing another group that she finds in her survey: spiritual scientists, some of whom are also atheists. This is a topic we discuss beginning around minute 25:20.
The first point about these "spiritual" scientists is that they aren't like spiritual Americans in general. They don't believe in angels and demons. They don't put together an eclectic blend of, say, Christianity, Buddhism, and New Age beliefs.
Rather, as Ecklund observes, they want their spirituality to be of a sort that is entirely consistent with science. And a considerable percentage of them actually overlap with the group of atheist scientists in Ecklund's sample.
For these spiritual but essentially atheistic scientists, "spirituality" involves a sense of awe and wonder at the complexity and beauty of nature. But this raises a pretty big question. Why call it "spirituality" at all? Why use the "S" word, if it does not mean what everyone thinks it means?
Scientific spirituality appears to be an important trend and one we need ...

The world’s coral reefs are disappearing. At least a third of the world’s reef-building species face extinction and in the Caribbean, the average cover of hard corals has fallen by around 80% in the last thirty years. The rich habitats they create are giving way to simpler, less vibrant communities, dominated by seaweeds. But seaweeds aren’t just opportunistic colonisers of waters abandoned by corals – they are coral-killers themselves.

Douglas Rasher and Mark Hay from the Georgia Institute of Technology have found that grazing fish typically keep seaweeds in check. If those fish start disappearing, as they often do because of human hooks, the seaweeds run rampant and corals suffer. Anywhere between 40-70% of the most common seaweed species release compounds that drive away the algae that allow corals to derive energy from the sun. Bereft of energy, the corals ‘bleach’ and die. The message is clear – through overfishing, we are accomplices in seaweed-mediated coralcide.

“Seaweed” is a loose colloquial term for a wide variety of algae, which hail from a few different kingdoms of life. For a while, it’s been clear that they can compete with corals for the same patches of ocean, but the exact nature of that competition has been controversial. To settle the debate, Rasher and Hay set up field experiments in two different reefs, one in Fiji and one in Panama. In both cases, they pit the common coral Porites porites against seven common species of local seaweed. The competitors were lashed against one another using a grid and some rope and left in place for 20 days.

At such prolonged close quarters, the corals became heavily bleached compared to others that were seaweed-free. Their ability to photosynthesise was shot by anywhere from 52 to 90%. Only the parts that actually touched the seaweeds were harmed; the areas on the sides stayed healthy.

It’s possible that the seaweeds damage the corals by shading them from precious energy-giving sunlight, or by cutting into them with sharp edges. But when Rasher and Hay exposed the corals to man-made substances that mimicked the same effects, nothing happened.

Instead, the real reason for the corals’ malaise was a chemical attack by the seaweeds. Rasher and Hay liquidised some of the seaweed species and applied the fat-soluble parts of these extracts to the corals. The result was the same levels of bleaching and disabled photosynthesis as before. This clearly suggests that seaweeds secrete a number of chemicals that damage corals whenever the two competitors touch. Some of the most chemically active species started hurting the corals after just two days of contact.

Rasher and Hay also showed that fish are extremely important for keeping seaweed at bay. In Fiji, they did their field experiments in cages designed to keep hungry fish away. After it was over, they transplanted the seaweeds to two sites. The first was a marine protected area where fishing is banned, coral cover is high and seaweed is rare; there, fishy gardeners cleared away 40 to 100% of the seaweeds, depending on the species. The second site was a heavily fished reef just 300 metres away where seaweed is king and coral is rare. At this location, the surviving fish removed just 0 to 40% of the seaweeds.

So as humans remove fish from a reef, we remove the gardeners that would normally keep seaweeds in check. That gives them an advantage in their chemical competition against corals, damaging the reefs. As the seaweeds become more abundant, the coral density falls, the fish they can support start to dwindle and the seaweeds gain an even greater edge. Rasher and Hay think that even a modest level of fishing can set off this vicious cycle.

And as gardeners, some fish are more valuable than others. The same chemicals that harm corals also deter many grazers from feasting on seaweeds, which makes those that can stomach these morsels that much more vital for the health of a reef. For example, a single species of fish – the streamlined spinefoot – is responsible for eating almost all of the seaweed Chlorodesmis fastigiata. If this one species were to be overfished, the risks to corals could be substantial. It’s yet more evidence to support increasing the proportion of coral reefs that are protected by complete fishing bans.

Reference: PNAS http://dx.doi.org/10.1073/pnas.0912095107

More on corals:

• Clock gene and moonlight help corals to co-ordinate a mass annual orgy
• Bleached corals recover in the wake of hurricanes
• Worrying slowdown of coral growth in the Great Barrier Reef
• Corals survive acid oceans by switching to soft-bodied mode
• Fishing bans protect coral reefs from devastating predatory starfish
• One in three species of reef-building corals face extinction

One of the most successful achievements of the “post-genomic era” has been the elucidation of the genetic architecture which undergird the variation in human pigmentation. I like to point out that in 2005 the geneticist Armand Leroi observed in his book Mutants that we didn’t know the genetics of normal variation in relation to the trait of skin color. In 2010 one couldn’t plausibly write that. We know the genes which control the vast majority of the interpopulational variation in human complexion. This is not due to human ingenuity, but the fortuitous hand that nature dealt us. Pigmentation is a very salient phenotype, evident by the classification of genetically very distinct populations in Africa, India and Oceania as “black.” But in terms of a genetic research project it has long been one of the ways to explore patterns of inheritance in model organisms such as mice, in particular in relation to coat patterns and pigment. And luckily for us, many of the genes which are implicated in pigment variation produce similar changes across diverse taxa. Additionally, the genetic architecture of human pigmentation variation is such that most of the variance is concentrated among a few loci of large effect. Concretely, it seems that well over 50% of the African-European difference in skin color as measured by reflectance of visible light is attributable to two genes, SLC24A5 and KITLG. In Europeans around 75% of the dichotomous variation between those with blue and non-blue eyes may be due to changes in the genomic region across HERC2 and OCA2 (these two genes are very near each other). These are the veritable low hanging fruit, amenable to studies with even small sample sizes and modest statistical power, so strong are the effects of the genetic variables.

And why is pigment important? Obviously there are social ramifications. But pigmentation is likely a major target of natural selection as well, as I suggested in relation to Neandertals. The results are sometimes confusing, but it does seem that pigmentation related loci are enriched in relation to those genomic regions which turn up as positive in tests of natural selection. Additionally, looking at variation around those genes which are correlated with lighter skin across Eurasia it also seems that it may be that our own lineage has become somewhat paler within the last 20,000 years, perhaps even more recently. And the same may have been true for our possible Neander-kin.

At the current rate in regards to pigmentation the age of revolutionary science may soon be over. Extraction of ancient DNA will probably resolve the rate and nature of evolutionary change, while further typing of current populations will flesh out our understanding of the variants responsible for normal human variation. To do that requires more than simply larger sample sizes or improved genomic techniques, it also requires better measurement. The utilization of reflectance indices in studies of study skin color are a step in the right direction, but a new paper in PLoS Genetics points the way toward the same in the study of eye color, Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci:

We measured human eye color to hue and saturation values from high-resolution, digital, full-eye photographs of several thousand Dutch Europeans. This quantitative approach, which is extremely cost-effective, portable, and time efficient, revealed that human eye color varies along more dimensions than the one represented by the blue-green-brown categories studied previously. Our work represents the first genome-wide study of quantitative human eye color. We clearly identified 3 new loci, LYST, 17q25.3, TTC3/DSCR9, in contributing to the natural and subtle eye color variation along multiple dimensions, providing new leads towards a more detailed understanding of the genetic basis of human eye color. Our quantitative prediction model explained over 50% of eye color variance, representing the highest accuracy achieved so far in genomic prediction of human complex and quantitative traits, with relevance for future forensic applications.

The main improvement was decomposing the elements of pigment variation which contribute to the phenotypes which we observe and recognize in a gestalt manner through inspection. In particular, they focused on two parameters, hue (H) and saturation (S). It seems to me that H correspondences to the quality of color, and S to the quantity of color. Figure 1C shows how the eye color categories map onto the quantitative metrics (it is somewhat confusing that red = brown, but I assume brown is less useful for display purposes as a contrast with blue or green).

The r-squared here is such that ~60% of the variation of H can be explained by variation of S. In other words, the two are correlated. This is clear in the plot above, as you see a distribution which moves from brown to green to blue. In fact the researchers could take the variation in H and S, yank out the independent dimensions of variance, and find that one dimension accounted for 90% of the variation.

What they found by treating eye color as a quantitative phenotype, instead of a categorical one, is that though the primary loci already known to affect variation still showed up in their associations, there were secondary loci which now emerged. This makes sense, as the original procedure whereby what is really a continuous trait was transformed into several distinct categories removes information. Smaller effect loci which impact the change in trait value only on the margins would naturally not show up when you removed variation on the margins so as to collapse the trait into a few broad classes. In other words, if loci X had an effect large enough to shift eye color from blue to brown (as HERC2-OCA2 does) then it would show up. But if loci Y only affects trait value slightly it will be unlikely to shift the trait across categories, and so it would not be discovered.

Table 3 shows the effect of different variables, primarily SNPs on the different loci of interest. Beta simply is a measure of the effect of a variable within a linear model. The bigger the beta, the larger the effect on the variable you wish to predict (here, eye color).

SNPs within HERC2 and OCA2 are still the primary variates, as we’d expect. But other loci also affect the trait on the margins, effects only discernible with a better measurement of the trait. Additionally, there is some evidence that they have independent effects on the two dimensions of the trait in question. With more modest effects and less clear phenotypic measures (at least to human intuition) I would be cautious about overemphasizing these results, but clearly they’re in the right direction when it comes to filling in the smaller pieces to the puzzle of eye color.

And these aren’t simply academic questions. They’re of strong forensic interest. Many of the pigment related markers are very good at distinguishing populations, and, they allow us to accurately reconstruct the appearance of perpetrators for crimes where we only have genetic material. With the model they have here they can explain more than 50% of the variation in the two dimensions that they define of H and S. The effect sizes of the marginal loci are modest already, so one might be running into diminishing returns, but from what I gather this is already a significant improvement over eyewitness recollection in relation to eye color. Pigment is hopefully just the tip of the iceberg, perhaps at some point in the future we could predict the rough outlines of someone’s whole physiognomy so that computer reconstructions of appearance could rely primarily are retrieved genetic data.

Citation: Liu F, Wollstein A, Hysi PG, Ankra-Badu GA, & Spector TD (2010). Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loc PLoS Genetics : 10.1371/journal.pgen.1000934