Monday, October 5, 2015

Kapa plant Wauke confirms Polynesian migration theories

When Polynesians cane across the Pacific, a 5,000-year migration, they brought familiar products with them.

A new paper tracks genetically one of those products, paper mulberry, which is known in Hawai`i as wauke (Broussonetia papyrifera). 

(Image: An indication of the wide range of the wauke plant, this one was photographed within the volcanic crater of Rano Kau on Rapa Nui or Easter Island. Credit: Kuo-Fang Chung.)

And its genetic makeup in different locations across the ocean confirms modern theories of  migration from the island now known as Taiwan, through New Guinea, and eventualy into the Eastern Pacific and Hawai`i.

The paper, entitled “A holistic picture of Austronesian migrations revealed by phylogeography of Pacific paper mulberry,” was written by by Taiwan and Chile researchers Chi-Shan Chang, Hsiao-Lei Liu, Ximena Moncada, Andrea Seelenfreund, Daniela Seelenfreund and Kuo-Fang Chung.
The paper was printed in the Proceedings of the National Academy of Sciences

Various theories start the migration of the people who would be the Polynesians in South China, Taiwan, Vietnam or elsewhere in southeast Asia. 

“We test these propositions by studying phylogeography of paper mulberry, a common East Asian tree species introduced and clonally propagated since prehistoric times across the Pacific for making barkcloth, a practical and symbolic component of Austronesian cultures,” the authors write.

Wauke, whose inner bark was converted into bark cloth for clothing, ornament and other uses, may be the most widely distributed fiber product of early prehistory, the authors write.

“We demonstrate a tight genealogical link between its populations in South China and North Taiwan, and South Taiwan and Remote Oceania by way of Sulawesi and New Guinea, presenting the first study, to our knowledge, of a commensal plant species transported to Polynesia whose phylogeographic structure concurs with expectations of the “out of Taiwan” hypothesis of Austronesian expansion,” they write.

A commensal relationship is one in which two different things—in this case humans and wauke—work together to the benefit of both. Humans got clothing, and the paper mulberry got to dramatically expand its range.

The authors studied 600 or so samples of wauke tissue collected from across the Pacific, and looked at genetic variation in them. They were able to track the migration of the wauke, and thus the Polynesians, across the ocean. 

Separately, they were able to show that the earliest Taiwan residents may have brought a predecessor plant from southeast China.

© Jan TenBruggencate 2015

Monday, September 28, 2015

Ancient insects, lost in time, in Kaua`i's amazing Makauahi Cave

Deep in the sediments of Kaua`i’s Makauahi sinkhole is evidence of an entire collection of insects, lost in time and now extinct.

They represent some of the diverse life forms of the Hawaiian lowland forest that once spilled from the foothills of Ha`upu mountain. 

The beetles are in the genus Blackburnia, and help fill in missing pieces in the evolution of the Islands, according to anarticle in the journal Invertebrate Systematics, by James K. Liebherr and Nick Porch, of Cornell University and Australia’s Deakin University, respectively.   

 “The addition of extinct Kauai species to clades previously known only from extant species on Maui Nui and Hawaii Island reinforces the biogeographic pattern of progressive colonization by Blackburnia beetles from older Hawaiian islands to younger,” they write.

The paper is entitled “Reassembling a lost lowland carabid beetle assemblage (Coleoptera) from Kauai, Hawaiian Islands.”

The new findings link known species of beetles from ancient Laysan Island to young Hawai`i Island.

Scientists had some fun with naming the new species. They are Blackburnia burneyi, B. cryptipes, B. godzilla, B. menehune, B. mothra, B. ovata and B. rugosa

Several of the newly named species are significantly larger than any of the living relatives on Kauai, which explains their names. B. godzilla is the biggest of all, and mothra is another big one. 

The first, B. burneyi, is named for David A. Burney, who led the excavation of the famous south Kaua`i limestone feature known as Makauahi. His wife and partner, Lida Pigott Burney helps manage the cave reserve. 

For more information on the amazing sinkhole and associated caves, and the program to re-establish many of the native plant species that once existed on this landscape, see (If you like what they'd doing, please consider sending a donation.)

The beetles are believed to have gone extinct largely because of human-caused destruction of their habitat. The beetle parts were found in sediments dated to before the arrival of Polynesians in the Islands, and they disappear from sediments soon after.

“Seven of the species discovered in these deposits are not known  from  any  historically  collected  specimens,  supporting the conclusion that these species suffered extinction through the agencies of Polynesian agricultural land conversion and introduction of invasive predators such as the Pacific rat,” the paper says.

The authors of the paper don’t believe they have yet collected enough material to be able to describe all of the insects of this prehistoric South Kaua`i habitat, but there’s a suggestion more may be learned.

“We do not claim to have an accurate representation of the lowland carabid fauna of Kauai that was destroyed through the agencies of man. But now that there are fossils, there are some interesting tales to tell,” they write. Carabids are part of a global family of fast-moving ground beetles.

© Jan TenBruggencate 2015

Sunday, September 27, 2015

Battery technology exploding, in a good way

If the future of energy is the ability to cheaply and safely store intermittent renewables, then there’s lots of good news on the battery front.

Renewable plus storage means decarbonizing the grid. Public policy argues that’s something we should do effectively and as quickly as possible.

One of the problems is that batteries haven’t been up to the task. Some are too expensive, some are too toxic, some are too fragile, some lose too much energy charging and discharging, some die too soon and need to be replaced. 

The list goes on.

But there’s amazing work being done globally on battery technology. We have reviewed some of that in an earlier series that starts here.  

But since that 2013 series, there’s lots of new stuff. We’ll review a couple of innovations here, starting with flow batteries. .

Researchers at Harvard have been looking for non-toxic alternatives to flow batteries using bromide electrolytes. Flow batteries have energy-rich electrolytes in external tanks, and the electrolytes are pumped through the battery, meaning battery capacity can be increased simply by increasing electrolyte storage.

“Harvard chemistry professor Roy Gordon said they found a formulation using cheap, common materials that “deliver the first high-performance, non-flammable, non-toxic, non-corrosive and low-cost chemicals for flow batteries.  They reported their research in the Sept. 25 issue of Science.

Project chief investigator Michael Aziz said it would be a great way to store solar power: “"This is chemistry I'd be happy to put in my basement. The non-toxicity and cheap, abundant materials placed in water solution mean that it's safe -- it can't catch on fire -- and that's huge when you're storing large amounts of electrical energy anywhere near people." 

Scientists at Ohio State have combined a solar cell and a battery in what they’re calling an aqueous solar flow battery. It’s still a ways from commercial production, but its inventors believe it has a lot of potential.

"This solar flow battery design can potentially be applied for grid-scale solar energy conversion and storage, as well as producing 'electrolyte fuels' that might be used to power future electric vehicles," said lead author Mingzhe Yu. They reported their findings in the Journal of the American Chemical Society. 

Stanford researchers have written about their new aluminum battery, which they say is fast-charging, inexpensive and lasts a long time. They believe it can replace alkaline and lithium-ion batteries. How fast a charge? Think about charging a cell phone in a minute, and a battery that can handle daily charging for decades.

The battery has an aluminum anode and graphite cathode in a liquid salt electrolyte. It still needs some work, but shows great potential, its inventors say.

And it’s not just for small electronics. “The grid needs a battery with a long cycle life that can rapidly store and release energy. Our latest unpublished data suggest that an aluminum battery can be recharged tens of thousands of times,” said Stanford chemistry professor Hongjie Dai. 

But this isn’t to say that all the research is on new battery technologies. There’s also still a lot of work underway on improving existing batteries. As an example, South Korean researchers are reporting on a new lithium-ion design that improves its performance while reducing the problem of overheating. 

And MIT researchers say they’ve developed a way to cut in half the cost of building lithium-ion batteries. That, and they work better, too.

Furthermore, there’s research underway in figuring out how to improve the amount of energy lost in charging and discharging a battery. Generally, you can lose 20 percent or more of the energy it takes to charge a battery when to draw that energy back out.

Researchers at Case Western Reserve University say they’ve adapted solar cells to dramatically increase that efficiency. They wired four perovskite solar cells in series and were able to charge a lithium-ion battery with 7.8 percent loss—the best performance seen to date, they say.
Here is the paper, but it’s a little technical. The Science Daily report on the work is here. 

Perovskite solar cells are comparatively new on the solar scene. They can be manufactured inexpensively, and reportedly can convert into electricity a larger proportion of the sun’s light than other solar panels.

A lot of folks have wondered whether supercapacitors can be adapted to provide long-term energy storage. Supercapacitors are units that can store a lot of power, but they discharge almost instantaneously. Great for a sudden need for power—like when a motor starts up—but less useful as a continuing source of energy.

But there are a lot of applications for bursts of energy that are inefficiently met with standard batteries. Researchers at Department of Energy's Oak Ridge National Laboratory and Drexel University looked at new ways to use water materials—specifically old tires—in the manufacture of supercapacitors. 

The point here has not been to cover the universe of battery innovation, but to show that there’s a lot going on. Some of this stuff may not pan out, but a lot of it will, and it will change the energy landscape. 

Some of these technologies may end up in our phones, in our cars, in our houses, out on our utility grids--and maybe even in places where we've never imagined a role for energy storage.

© Jan TenBruggencate 2015

Monday, September 21, 2015

Butterflies, wasps and interspecies gene transfer

The more we look, the more we find that transgenic behavior—moving genetic material between unrelated life forms, is common in nature.

One of the hallmarks of the anti-GMO movement seems to be the argument that it’s unnatural to move, for example, bacterial DNA into plants to make them resistant to certain bug predators.

It not only isn’t unnatural, but it happens all the time in nature.

“Breaching the species barrier,” it’s called. It turns out this barrier is pretty porous.

We’ve reported earlier about naturally transgenic sweet potatoes. 

And we’ve reported on virus DNA movement into human DNA and bacteria DNA into animals. 

New evidence released just last week shows that parasitic wasps have inserted viral DNA into butterfly genomes. The viral DNA turns off portions of the butterfly immune system. 

All of this interspecies trade allows the wasps to insert their eggs into the butterfly caterpillar phase without their being attacked by the butterfly immune systems. Creepy, but that's nature.

Here is the Sept. 17, 2015,paper reporting on that finding. It's in the latest PLOS Genetics and is problematically entitled "Recurrent Domestication by Lepidoptera of Genes from Their Parasites Mediated by Bracoviruses."

The process of moving genetic material between species is called horizontal gene transfer. 

The new paper concludes that while science has assumed that species have needed to reshuffle their own genes to fight off  new threats, in fact,  horizontal gene transfer is “recognized as an important factor in…evolution.”

“We show here that in several lineages, lepidopteran genomes have acquired genes from a bracovirus that is symbiotically used by parasitic wasps to inhibit caterpillar host immune defences,” the paper says.

The research suggests that the wasps initially collected the viral DNA, carried it within their bodies, and then transferred it to the butterflies. They used the viral DNA as a kind of tool kit to allow them to carry out their own life cycles.

And there’s more. It appears that the butterflies have then been able to use the borrowed genes to fight off a virus that can attack them.

“Additionally, we present functional analyses suggesting that some of the acquired genes confer to caterpillars a protection toward baculovirus, a very common pathogen in the field. This phenomenon may have implications for understanding how caterpillars acquire resistance against baculoviruses used in biological control,” the paper says.
Evolutionary biologist Louise Johnson, at the British University of Reading, said it’s a fine example of just how adaptive evolution can be.

"This three-way gene shuffle is a particularly clear and clever example: wasps use viruses to attack butterflies, but those viruses have also allowed the butterflies to steal genes from the wasps. 

“It’s clear that the stolen genes are useful to the butterflies, so naturally occurring genetic engineering helps them to survive. 

“From my perspective as an evolutionary biologist, it’s also a perfect illustration of how evolution uses every trick in the book, and the book is bigger than we think,” Johnson said.

© Jan TenBruggencate 2015

Wednesday, September 2, 2015

Sea level rise has been artificially low in Hawai`i—but it’s going to catch up

Sea levels are rising globally at an increasing rate—three inches in the last 25 years or so--but we’re not seeing that much in Hawai`i.

So what’s up?

One answer to this mystery is that our islands are in a kind of temporary sweet spot. Satellite imagery shows that while most of the globe has seen dramatic rises in sea levels—as much as 3 inches in the past 25 years—Hawai`i has been flat to actually lower.

(Image: The red shows areas of dramatic sea level rise. Blue shows areas where it’s flat or down. Hawai`i appears in the blue zone. But how long will that last? Credit: NASA.)

At a human scale, this makes no sense. If you fill a bathtub, clearly it fills all around the tub.

But global scales are different. There are humps and valleys in the oceans across the scale of thousands of miles. Winds can push water up against a coast, creating a hump. Eddies can change sea levels regionally. Currents and storms and tides and even temperatures can all impact the height of the ocean.

“In a nutshell it's due to changes in winds and ocean circulation that counteract the global sea level signal regionally. That should shift as part of a long-term fluctuation but no projections on when that is likely to occur. This big El Nino may herald the start of a shift, but we have to see how that plays out,” said University of Hawai`i oceanographer Mark Merrifield.

Here is NASA’s recent report on accelerating sea levels and related issues. 

“Sea levels are rising rapidly—much more rapidly than they have any time in the last several thousand years,” said NASA’s Joshua Willis, at the Jet Propulsion Laboratory. 

And the rate of increase has been increasing as well, he said. It was about 1 millimeter annually in 1900, rose to 2 millimeters annually in the mid 1900s, and is now at 3 millimeters annually. That works out to more than an inch a decade.

I wrote to Willis to ask whether our islands can continue to dodge this bullet.

“In the long run sea level rise will affect Hawaii as well. Because it is in the central Pacific, the impacts of the long-term natural cycles may not be quite as large. Eventually, however, the global rates of rise will be felt in Hawaii also,” he said.

University of Hawai`i coastal geologist Charles “Chip” Fletcher agreed.

“The global oceans cannot keep rising without us experiencing the rise as well - we just may be able to avoid the worst aspects of the variability. On the other hand, models show that the tropics as a region will experience the upper end of global sea level change, so that makes us part of a more dangerous region.

“I have held for several years that Hawaii should plan for one meter of sea level rise by end of century and as far as I can see that is still a valid number,” he said.

© Jan TenBruggencate 2015