Early American DNA in Rapa Nui islanders suggests Polynesians visited Americas

Evidence that Polynesians visited the Americas has been intriguing, if controversial, but new genetic studies of Rapa Nui (Easter Island) natives seem to confirm it.

Results of thorough genetic studies on 27 Rapa Nui natives reveal the presence of South American DNA that showed up 19 to 23 generations ago. That takes it back to 1280 to 1495, before Europeans were in the Pacific. 

There is European DNA there, too, but it showed up much later, in the 1800s. Rapa Nui wasn’t discovered by Europeans until the Dutch voyager Jacob Roggeveen visited on Easter of 1722. 

This new genetic work adds to other evidence: The presence of American sweet potatoes and possibly American bottle gourds throughout the Pacific, and the presence of Polynesian chicken DNA at El Arenal in Chile. RaisingIslands covered the Polynesian chicken research here. 

 The new genetic evidence, published in the 23 October issueof Current Biology, seems to lock up once and for all the mystery: Is it possible that Polynesians, having discovered every single habitable island in the tropical and subtropical Pacific, could have missed the American continent?

The authors of the paper, entitled Genome-wide Ancestry Patterns in Rapanui Suggest Pre-European Admixture with Native Americans, write:

“We generated genome-wide data for 27 Rapanui. We found a mostly Polynesian ancestry among Rapanui and detected genome-wide patterns consistent with Native American and European admixture. By considering the distribution of local ancestry tracts of eight unrelated Rapanui, we found statistical support for Native American admixture dating to AD 1280–1495 and European admixture dating to AD 1850–1895,” the authors wrote.

“These genetic results can be explained by one or more pre-European trans-Pacific contacts,” they said. 

The paper was written by a dozen scholars: J. Víctor Moreno-Mayar, Simon Rasmussen, Andaine Seguin-Orlando, Morten Rasmussen, Mason Liang, Siri Tennebø Flåm, Benedicte Alexandra Lie, Gregor Duncan Gilfillan, Rasmus Nielsen, Erik Thorsby, Eske Willerslev, and Anna-Sapfo Malaspinas.

It is theoretically possible that the American genes got there from South American sailors making the voyage to Rapa Nui, but since Polynesians have a famous voyaging and navigation culture and South Americans did not, it seems unlikely. 

This sets up interesting speculations. Polynesians are believed to have reached Rapa Nui about 1200 AD. Was it members of that same initial voyaging group that went on to visit the South American coast and then return? Or did Polynesian navigation continue between the Eastern Pacific islands and South America for generations after the initial Rapa Nui visit.

There’s a lot of stuff happening in the first few centuries of the millennium in Eastern Polynesia. Sweet potato showed up in the Pacific around 1000 AD. Rapa Nui folks arrived at an uninhabited Rapa Nui about 1200. South American genes got into the Rapa Nui gene pool between 1280 and 1495.  The El Arenal chicken bones were dated at 1321 to 1407.

It was all going on during the period when Polynesian cultures were known to be actively voyaging across the Pacific. It may be a stretch, but it seems that this new genetic data suggests not a single accidental voyage to the Americas, but a series of voyages, in which at a minimum:

            -- Sweet potatoes were collected in the Americas and delivered into the Pacific.

            -- Polynesian moa (chickens) were delivered from the Islands to the American Coast.

            -- And there was some genetic mixing. Did a Polynesian sailor bring home a mate, or did 

 Polynesians stay long enough to have children and bring them home, or did a couple of venturesome South American natives join the Polynesian canoe for the trip to Rapa Nui?

Here is Science Daily’s story on the paper. 

As a side note, the evidence is also another piece of evidence for the quality of Polynesian navigation. Unlike many of the islands in the Pacific, Rapa Nui is a loner. It is small, and not part of a chain of islands like Hawaii, Tahiti, the Marquesas, Samoa and so forth. Those would be easier to find since they’re a much bigger target--you just have to find the archipelago.

But Polynesian navigators appear to have found tiny Rapa Nui repeatedly, and from both the east and the west. That is a prodigious navigational feat.

© Jan TenBruggencate 2014

Citation: J. Víctor Moreno-Mayar, Simon Rasmussen, Andaine Seguin-Orlando, Morten Rasmussen, Mason Liang, Siri Tennebø Flåm, Benedicte Alexandra Lie, Gregor Duncan Gilfillan, Rasmus Nielsen, Erik Thorsby, Eske Willerslev, Anna-Sapfo Malaspinas. Genome-wide Ancestry Patterns in Rapanui Suggest Pre-European Admixture with Native Americans. Current Biology, 2014 DOI: 10.1016/j.cub.2014.09.057

Does efficiency make you use more? It's the rebound effect.

If you switch to new energy-efficient LED lights, are you less concerned about switching them off when you leave the room?

If you get a new-fuel-efficient car, do you drive more?

It’s called the Rebound Effect—the tendency to conserve less when you’ve become more efficient.

It’s real, according to a series of studies out in the past couple of years. Among those is The Rebound Effect and Energy Efficiency Policy, by Kenneth Gillingham of Yale University, David Rapson of the University of California, Davis, and Gernot Wagner of the Environmental Defense Fund.  

But the rebound effect is also complex. It can behave differently in different sectors.

The bottom line is that some folks argue that the rebound effect is a bad thing—promoting excessive use of resources.

The paper argues the opposite. To the degree that efficiency gains let you use lights, refrigeration, transportation or even air conditioning without additional costs, that rebound improves life—it’s a good thing.

“While the energy savings from energy efficiency policies will be reduced by the presence of a rebound effect, a (zero cost energy efficiency improvement)  is likely to both conserve energy and increase welfare,” the authors say.

The American Council for an Energy Efficient Economy yesterday published a paper, The ReboundEffect – Mountain or Molehill?

It estimates that the Rebound Effect can reach 20 percent, meaning that you only get 80 percent of the benefit from efficiency efforts. But AEEE argues that’s still a very good thing.

“The truth is that for 40 years energy efficiency has had a dramatic effect on worldwide energy consumption. In the United States, if we were to use energy today at the rate we were in 1974, we would be consuming more than twice the amount that we are actually using,” writes ACEEE Executive Director Steven Nadel.

© Jan TenBruggencate 2014

Want more fish? Throw back big females.

If we were talking about humans, the acronym, BOFFFF would be a horribly inappropriate term.

But we’re talking about fish, and the term represents the most valuable and important members of the school—animals that are big, old, fat, female, fecund (or fertile) fish.

(Image: Bluefin trevally in the Northwestern Hawaiian Islands. You want to save the big ones. Credit: Dwayne Meadows, NOAA/NMFS/OPR)

And what’s important about them is that they reproduce more, have healthier and bigger eggs, have young more likely to survive, they may spawn at different times than younger fish so they increase species’ chance of success, and they are more likely to survive hard times than smaller, skinnier fish.

And what does that mean for the fishing community? They’re the ones you ought to throw back.

“Increasingly, fisheries managers are realizing that saving some big old fish is essential to ensure that fished populations are stable and sustainable,” said Mark Hixon, the University of Hawai`i researchers who was the lead author in a new paper, BOFFFFs: on the importance of conserving old-growth age structure in fishery populations.

 

His co-authors are Darren W. Johnson of California State Long Beach and Susan M. Sogard of the National Marine Fisheries Service. Theypublished in the ICES Journal of Marine Science.

“The loss of big fish decreases the productivity and stability of fishery stocks,” Hixon said.

The big old fat females have been shown to be important in a broad range of fish, both in fresh and salt water. They have the resources to survive periods of low food. They produce enormously more eggs than smaller fish. Their eggs are bigger and more likely to produce successful young. 

And the difference in egg production is amazing. A 27-inch ‘ōmilu or bluefin trevally, as an example, produces 84 times more eggs than a 12-inch fish. The increase with age is not the case with every fish species, but it seems to be the case with most of them.

And yet, we are removing them from the fish population faster than others. 

“Fishing differentially removes BOFFFFs, typically resulting in severe truncation of the size and age structure of the population. In the worst cases, fishing mortality acts as a powerful selective agent that inhibits reversal of size and age truncation, even if fishing intensity is later reduced,” the authors write.

Another way of saying that: If you keep taking the big, fat, females out of the population, you’re likely to end up with few fish overall, and fewer big, fat fish.

One of the solutions to this issue is slot limits—you keep the fish in the middle size slot, while releasing keiki as well as the biggest fish. But there are other ideas for fishery enhancement, as well.

“A growing body of knowledge dictates that fisheries productivity and stability would be enhanced if management conserved old-growth age structure in fished stocks, be it by limiting exploitation rates, by implementing slot limits, or by establishing marine reserves, which are now known to seed surrounding fished areas via larval dispersal,” the authors wrote.

A University of Hawai`i press release on the paper is here. 

© Jan TenBruggencate 2014

Big tsunami: Just 500 years ago, a 9.25 magnitude Aleutian quake blasted Hawaiian shores

A stunningly large Aleutian-sourced tsunami hit the Hawaiian Islands 4-500 years ago, requiring a much more aggressive assessment of potential shoreline damage from future waves.

Much of the preliminary evidence for the big wave comes from the Makauwahi Sinkhole on south Kaua`i, but scientists expect to find more evidence once they start looking for it on other islands.

(Image: Researchers simulated earthquakes with magnitudes between 9.0 and 9, and found that the unique geometry of the eastern Aleutians would direct the largest post-earthquake tsunami energy directly toward the Hawaiian Islands. The red circles are centered on Kaua‘i and encircle the Big Island. Credit: Rhett Butler)

And what that means is that it could happen again.

A report on the wave was published this month in the journal Geophysical Research Letters. The article, “Paleotsunami evidence on Kaua‘i and numerical modeling of a great Aleutian tsunami,” was written by Rhett Butler of the Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, David Burney of the National Tropical Botanical Garden and David Walsh of the Pacific Tsunami Warning Center.

 Burney’s investigations of the sinkhole revealed a huge layered collection of marine debris that he determined could only have come from a tsunami, ripping up coral and rock from the ocean floor and depositing it over a limestone shelf into the sinkhole. 

The wave came 300 feet inland and rose more than 20 feet to dump debris into the sinkhole.

A news release summarizing the report is here. 

It was the massive 2011 Tohoku quake in Japan, with a magnitude of 9.0, that raised the awareness of researchers that such events were possible. They now assume at a quake that large may occur from the Aleutians every 1,000 years or so.

To account for the Makauwahi dune debris layer, they figure the quake would have needed to be even bigger than Tohoku.

“Using high-resolution bathymetry and topography we model tsunami inundation of the sinkhole caused by an earthquake with a moment magnitude of Mw ~9.25 located in the eastern Aleutians. 

“A preponderance of evidence indicates that a giant earthquake in the eastern Aleutian Islands circa 1425–1665 A.D… created the paleotsunami deposit in Kaua‘i. A tsunami deposit in the Aleutians dated circa 1530–1660 A.D. is consistent with this eastern Aleutian source region,” said the paper.

And why is this kind of study important? The authors write:

“The focus of tsunami energy from the Aleutians directed toward the State of Hawaii, and the short 4.5 (hour) tsunami propagation time, underscores the importance of tsunami readiness for Aleutian events. Hawaii State Civil Defense must make evacuation decisions 3 (hours) prior to tsunami arrival.”

© Jan TenBruggencate 2014