A team of scientists, led by Stanford’s Kevin Arrigo, broke through some of the Arctic ice last July as part of the NASA ICESCAPE mission and found the complete opposite—abundant life!

“If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible,” says Arrigo. “This discovery was a complete surprise.”

The researchers discovered an abundance of phytoplankton—microscopic life that forms the base of the marine food chain. Phytoplankton require sunlight for photosynthesis, just like plants. And sunlight has a tough time penetrating thick sea ice.

But that thick sea ice is changing. Not only are warmer temperatures thinning the ice, but as the ice melts in summer, it forms pools of water that act like transient skylights and magnifying lenses. These pools focus sunlight through the ice and into the ocean, where currents steer nutrient-rich deep waters up toward the surface. Phytoplankton under the ice evolved to take advantage of this narrow window of light and nutrients.

The phytoplankton displayed extreme activity, doubling in number more than once a day. Blooms in open waters grow at a much slower rate, doubling in two to three days. These growth rates are among the highest ever measured for polar waters. Researchers estimate that phytoplankton production under the ice in parts of the Arctic could be up to 10 times higher than in the nearby open ocean.

The phytoplankton bloom discovered by Arrigo and his colleagues in the Chukchi Sea (just north of Alaska) extends tens of meters deep in spots and about 100 kilometers (62 miles) across.

“At this point we don’t know whether these rich phytoplankton blooms have been happening in the Arctic for a long time and we just haven’t observed them before,” Arrigo says. “These blooms could become more widespread in the future, however, if the Arctic sea ice cover continues to thin.”

The discovery of these previously unknown under-ice blooms could have serious implications for the broader Arctic ecosystem, including migratory species such as whales and birds. Phytoplankton are eaten by small ocean animals, which are eaten by larger fish and ocean animals.

“It could make it harder and harder for migratory species to time their life cycles to be in the Arctic when the bloom is at its peak,” Arrigo says. “If their food supply is coming earlier, they might be missing the boat.”

The research is published this week in Science.

Image: NASA

The origin of our species was once firmly rooted in eastern Africa, but a new discovery may have shifted those roots much further to the south.

Exactly when and from where our species, Homo sapiens, first evolved and left Africa has been the subject of fierce debate. Most fossil and genetic evidence placed these origins in eastern Africa between 150,000 and 200,000 years ago. But a new study published earlier this month online in the Proceedings of the National Academy of Sciences reveals that our species may have evolved in southern, not eastern Africa.

Most Africans south of the Sahara are descended from early farmers spreading from western Africa about 8,000 years ago. But nestled within this vast dispersal of farmers are pockets of hunter-gatherers: The Khomani Bushmen of the Namibian Desert, the Pygmies of the central African rainforests, and the click-speaking Hadza and Sandawe of Tanzania. These peoples’ anatomy, culture, and language are distinct from their neighbors, and many believe that they offer a window into our species’ earliest days. But genetic data of these groups has been limited, and many questions on their origins remain.

The study’s authors, led by Brenna Henn of Stanford University, sought to fill in the gaps. “We started [this] project because southern Africa has been poorly sampled. Very few other studies have ever published on them in the last decade, certainly never with more than a dozen individuals,” says Henn.

Henn and colleagues analyzed over 55,000 individual points on the genomes of people from six hunter-gatherer populations, comparing them alongside other African populations. The team used this data to construct a genetic map of prehistoric Africa.

Not only had the hunter-gatherers been genetically isolated from the farming groups for thousands of years, they were also genetically distinct from each other.

In addition, long before the farmers swept across the continent, these hunter-gatherer groups were already well-established in their respective locales.

How does this relate to modern human origins? By using genomic data and a computer model, the team found the most likely starting point to be closest to the most ancient populations: southern Africa. Other experts have hypothesized this to be the case, and recent archaeological discoveries and climatic evidence have lent additional support to the fact that this region of Africa hosted our most ancient ancestors.

But the team has many questions left to answer. Henn and her colleagues also detected rapid evolutionary change among the groups, which may trace back thousands of years. They found that the Hadza of Tanzania have been going through a rapid decline, called a bottleneck, but have yet to understand why. “We would like to know when this bottleneck started – did it happen when the agriculturalists moved in?  Why don’t all hunter-gatherer populations show this signature?” says Henn.

Anne Holden, a docent at the California Academy of Sciences, is a PhD trained genetic anthropologist and science writer living in San Francisco.

Image of the Khomani courtesy of Brenna Henn

The evolution of our species’ most famous traits – big brains, walking on two legs, language – took hundreds of thousands of years. But in some cases, evolution doesn’t always take its sweet time.

In a new study published in BMC Evolutionary Biology, an international team of scientists believe they’ve found an example of evolution only a few thousand years in the making.

The research team, led by Andres Moreno of Stanford University, studied FOXI1, a gene involved in water retention in the kidneys. Moreno and his colleagues collected DNA samples from Europeans, East Asians, and the Yoruba, an African tribe living on the southern edge of the Sahara Desert. An analysis of the FOXI1 gene in each group found a considerably different genetic change in the Yoruba, compared to the other groups. This mutation in the Yoruba’s FOXI1 gene may improve tribe members’ ability to retain water, a big advantage if you live near a desert.

The team calculated that the FOXI1 gene mutation evolved between 10,000 and 20,000 years ago, just as the Sahara Desert was drying out from a brief wet spell. As a consequence of an increasingly harsh climate, the ancestors of the modern Yoruba evolved a way to retain water more efficiently than humans in other parts of the world.

This is not the first time scientists have demonstrated unique adaptations in our species’ more recent history. The July 2 issue of the journal Science reported the discovery of a 3,000-year-old genetic mutation that has allowed native Tibetans living at high altitudes to breathe easier than their low-altitude neighbors.

But this FOXI1 gene mutation has wider implications, especially in the light of our changing planet. The last several decades have seen temperatures rise, forests dwindle, and deserts expand, so mutations like the Yoruba’s may eventually help us adapt to the harsh effects of global warming.

As anthropological geneticist Anne Stone of Arizona State University told New Scientist, “Over the long term, if the Earth keeps warming, I would not be surprised to see genetic shifts.” Whether those will take the shape of improved water retention, resistance to disease or changes in body shape, however, remains to be seen.

How do you think humans will evolve over the next 10,000 years? Let us know!

Anne Holden, a docent here at the California Academy of Sciences, is a PhD trained genetic anthropologist and science writer living in San Francisco.

Image by Melvin “Buddy” Baker

Biologists at UC Berkeley initially broke down gecko movement up walls to figure out how they travel up walls. You can watch our Science in Action piece called “Bio-Inspiraton: Gecko Adhesive” about that research.

Since then, scientists’ imaginations have taken over. What can we accomplish using the same properties geckoes use to climb vertically? Last winter, the New York Times reported on a new tape based on gecko’s feet from biologist Kellar Autumn of Lewis & Clark College.

The tape, which is reusable, was so strong, Mr. Autumn said, that when they tested it, he was able to stick his 50-pound, 8-year-old daughter to a window with it.

That was a little more than two years ago; there are now at least 50 patent applications pending in gecko-adhesion technology, Mr. Autumn said, and he holds several patents himself.

The latest entry in gecko-adhesion technology is Stickybot, a robot developed at Stanford that can climb walls. The newest versions of the adhesive that holds Stickybot to the walls was published earlier this month in the journal Applied Physics Letters.

The molecules of gecko toe hair interact with the wall through a molecular attraction called the van der Waals force. A gecko can hang and support its whole weight on one toe by placing it on the glass and then pulling it back.

That’s because the toe of a gecko’s foot contains hundreds of flap-like ridges called lamellae. On each ridge are millions of hairs called setae, each one 10 times thinner than a human’s. Under a microscope, you can see that each hair divides into smaller strands called spatulae, making it look like a bad case of split ends. These split ends are so tiny (a few hundred nanometers) that they interact with the molecules of the climbing surface.

The new and improved versions support higher loads and also allow Stickybot to climb surfaces such as wood paneling, painted metal and glass. The material is strong and reusable, and leaves behind no residue or damage.  Robots that scale vertical walls could be useful for accessing dangerous or hard to reach places.

Next up for Stickybot, the technology of turning around, also gecko-inspired. According to Stanford’s Mark Cutkosky, “The new Stickybot that we’re working on right now has rotating ankles, which is also what geckos have.”

But wait there’s more… The Stanford team has started developing Z-Man—a gecko adhesive for human climbing.  Watch out, Peter Parker!  Spiders have nothing on geckos…

Awesome, right?

Creative Commons image by Bjørn Christian Tørrissen

In case you were wondering what an atoll is, according to the Encyclopedia of Earth:

Atolls are circular, oval, or horseshoe-shaped arrays of coral reef islands that are perched around an oceanic volcanic seamount and encircle a shallow central lagoon…. Because atoll formation requires coral reef building, atolls are limited to tropical waters.

(View this great animation here of an atoll forming over 30 million years.)

Healthy Fishing

To gain new insights on the ecology of reef fishing, Stanford researchers are comparing and contrasting the reefs of two atolls—Palmyra and Tabuaeran.

Palmyra is a protected U.S. wildlife refuge and prohibits fishing along its shores. Tabuaeran is part of the Republic of Kiribati and is home to about 2,500 people who depend on the reef for food and income.

Signs of a healthy marine ecosystem usually include the presence of large fish and sharks. “Palmyra has some of the highest densities of sharks and other large fish of any coral reef in the world,” said Douglas McCauley, a graduate student at Stanford. “That’s clear within seconds of jumping in the water there.”

But in Tabuaeran, where fishing is a way of life, sharks and other large species are in short supply, McCauley said. “That was surprising, because Tabuaeran is a somewhat lightly populated island. Most people arrived only a few decades ago, and fishing there is still very artisanal in nature.”

Big fish grow and reproduce slowly, so their populations take longer to recover, he added. “It appears that it takes very little harvesting to reduce populations of these sensitive, large reef fish.”

The Stanford researchers are hoping to pass this information along to the people of Tabuaeran so they can fish more sustainably. Over the past three years, the team taught science classes at local schools on topics such as reef ecology and genetics and conducted town hall meetings at every village on the atoll.

Because the livelihoods of so many Tabuaerans depend on healthy fisheries, locals are eager to preserve fish numbers, McCauley said. “Those who depend most on the environment can and should be its best stewards,” he added.

Millennium Atoll: A Pristine Ecosystem

Millennium Atoll, also part of the Republic of Kiribati, is one of the most remote, pristine atolls in the world. Its lagoon is highly enclosed, sealing it away from the outside world. Californian and Hawaiian scientists studied its life and published their findings last week in PLoS One:

This is the first comprehensive survey of the lagoon at Millennium Atoll, which contains some of the few remaining coral reefs that are relatively unaltered by human activity. The lagoon of the atoll is home to a variety of unique organisms that are threatened in many areas of the world.

Valuable resource species such as clams, sharks, Napoleon wrasse, sea turtles, and lobster are fairly abundant at Millennium but have been seriously overexploited elsewhere around the world.

Protection of Millennium’s coral reefs should be a priority for the Republic of Kiritbati as these habitats are not only unique but are some of the world’s least impacted reef systems.

Atolls Growing, Not Shrinking

Finally, last month Australian researchers published the incredible finding that despite warnings of small atolls and islands disappearing with sea level rise, they have found that in the Pacific, some have actually grown in the last 60 years.

Despite evidence of the sea level rising as high as five inches in the region, of the 27 islands they studied, four decreased in size, but the rest remained the same or grew.

It may simply be due to the nature of atoll formation itself. From New Scientist:

Because the corals are alive, they provide a continuous supply of material. “Atolls are composed of once-living material,” says Arthur Webb, “so you have a continual growth.”

The researchers stress these results reflect a small portion of atolls in one area in the Pacific and that “warnings about rising sea levels must still be taken seriously.”

With so much research emerging about atolls, it’s obvious we still have a lot to learn. These little islands are making big waves in the scientific community.

This is the first oceanographic research voyage sponsored by NASA.  The ICESCAPE (Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment) mission plans to take an up-close look at how changing conditions in the Arctic are affecting the ocean’s chemistry and ecosystems that play a critical role in global climate change.

NASA is hoping that this mission enhances the satellite data that already is collected of the area. More than 40 scientists, including six from Stanford University, will spend five weeks at sea sampling the physical, chemical, and biological characteristics of the ocean and sea ice.

According to today’s Stanford Report:

They will gather data on the state of the ice, the ocean and the microscopic plants and animals that dwell therein. The tiny organisms regulate the flow of carbon into and out of the sea, and the scientists are seeking to assess how the melting ice is affecting the organisms and ecosystem.

“The ocean ecosystem in the Arctic has changed dramatically in recent years, and it’s changing much faster and much more than any other ocean in the world,” said ICESCAPE chief scientist Kevin Arrigo, PhD, of Stanford. “Declining sea ice in the Arctic is certainly one reason for the change, but that’s not the whole story. We need to find out, for example, where the nutrients are coming from that feed this growth if we are going to be able to predict what the future holds for this region.”

(The Stanford team will be blogging about their adventures and research. You can follow them here.)

Often we try and gather clues from extinction events to get hints about our future, but perhaps we’ve been missing the forest for the trees. Now, a team of researchers from Stanford and UC Berkeley are looking at past biodiversity loss for clues.

“If we only focus on extinction, we are not getting the whole story,” said Jessica Blois, PhD, lead author of a study published online in Nature yesterday.

Focusing on the last major warming event about 12,000 years ago, Blois and her Stanford colleague Elizabeth Hadly searched the Samwell Cave near Mt. Shasta for small mammal fossils. They also sampled the modern small mammal community by doing some live trapping in the area of the cave. (Jenny McGuire, a graduate student at the UC Berkeley, did the radiocarbon dating of the samples.)

They found big changes in the small mammal population. “In the Pleistocene, there were about as many gophers as there were voles as there were deer mice,” Hadly said. “But as you move into the warming event, there is a really rapid reduction in how evenly these animals are distributed.” As some species such as deer mice flourished, many other species declined.

Deer mice are considered a “weedy” species and, like the plants, don’t have a strong habitat preference—they are generalists that will move in wherever there is an opening. When they replace other small-mammal species, the effects ripple through the ecosystem.

“Small mammals are so common, we often take them for granted,” Blois said. “But they play important roles within ecosystems, in soil aeration and seed dispersal, for example, and as prey for larger animals.” And different small mammals play those roles differently. What’s more, “Even though all of the species survived, small mammal communities as a whole lost a substantial amount of diversity, which may make them less resilient to future change,” Blois said.

And according to Hadly, an extraordinarily rapid change is looming.

“The temperature change over the next hundred years is expected to be greater than the temperature that most of the mammals that are on the landscape have yet witnessed as a species,” she said.

Creative Commons image by r.i.c.h.