Thursday, November 21, 2019

Everybody knows to avoid tuna when pregnant, right? Not so fast. Eating tuna might actually yield better results, says a large new study.

Eating ocean fish is good for you, but some fish have significant levels of methylmercury which is bad for you, so you should avoid those fish, right? Wrong, says a new study.

Mothers who ate seafood, even when it contained high levels of methyl mercury, had smarter kids than those who didnʻt eat seafood, says the comprehensive, peer-reviewed study.  

"Moderate and consistent evidence indicates that consumption of a wide range of amounts and types of commercially available seafood during pregnancy is associated with improved neurocognitive development of offspring as compared to eating no seafood," it said.

This flies in the face of conventional wisdom, and some medical wisdom. Both the U.S. Environmental Protection Agency and the U.S. Food and Drug Administration recommend against pregnant women eating ahi, over concerns about methyl mercury exposure.

There is no question that thereʻs methylmercury in yellowfin, bigeye and bluefin tuna, and that the amount has been increasing in recent years. There are also significant amounts of mercury in blue marlin and other species. 

The Hawai`i Department of Health warns against pregnant women eating any blue marlin, swordfish and shark and recommends severe limits on consumption of tunas. 

Yet the new study suggests women who eat some ocean fish, even when mercury levels are high, actually have kids who have better mental outcomes. The authors wrote: " No net adverse neurocognitive outcomes were reported among offspring at the highest ranges of seafood intakes despite associated increases in mercury exposures."

The paper is entitled, "Relationships between seafood consumption during pregnancy and childhood and neurocognitive development: Two systematic reviews." It is published in the journal, Prostaglandins, Leukotrienes and Essential Fatty Acids. Its authors come from some of the most prestigious medical and scholarly institutions in three countries, including the Center for Food Safety and Applied Nutrition, American Society for Nutrition, National Institutes of Health and others.

So whatʻs going on? The authors say thereʻs something in seafood that counteracts the impacts of mercury, and makes it even healthier for kids to eat seafood than not to eat it.

Here is the technical way they say that: "This evaluation of seafood consumption inherently integrates any adverse effects from neurotoxicants, and benefits to neurocognition from omega-3 fats, as well as other nutrients critical to optimal neurological development."

Even small amounts of seafood have a beneficial effect, and the study found no downside to large amounts: 

"Benefits to neurocognitive development began at the lowest amounts of seafood consumed in pregnancy (4 oz/wk) and up to >100 oz/wk, with benefits to age appropriate measures of neurocognitive development including an average increase of 7.7 IQ points, in evaluating 44 publications reporting on 102, 944 mother-offspring pairs, no adverse effects on neurocognitive development were found."

It is not that the mothers and children arenʻt exposed to methyl mercury. They are, but there appear to be no negative impacts from that exposure from seafood, the paper says: "No net adverse neurocognitive outcomes were reported in offspring at the highest ranges of seafood intakes despite associated increases in mercury exposures."

The authors are aware that this is controversial stuff, and they urge the scientific community to do more research. There needs to be work, they say, that follows the children into older age, research into whether fatty or oily fish like tuna are healthier than white-fleshed fish, on making sure the IQ tests in studies are comparable, and research on differences based on species of fish and of how it is prepared.

But how is it possible that mercury exposure in kids is dangerous, except when it comes from fish? 

The authors of this paper donʻt say in the publication, but others have suggested that seafood contains something else that protects against mercury- namely, selenium.

This study from 2010 argues that selenium protects against mercury poisoning, and it cites studies indicating selenium can actually reverse some of the effects of methylmercury toxicity. 

"Studies of populations exposed to MeHg (methyl mercury) by eating Se-(selenium) rich ocean fish observe improved child IQs instead of harm."

Tuna and most billfish tend to have high levels of selenium, which may help explain things. Hereʻs a useful report from NOAA and other agencies.

© Jan TenBruggencate 2019

Monday, November 18, 2019

Kauai koloa: the native ducks on the Garden Island are still pure

The native Hawaiian duck, koloa, still rules on Kaua`i—retaining nearly all its native genetic heritage.

You can see pairs and even families of ducks lift off the newly cleared sections of Niumaluʻs Alakoko Fishpond on Kaua`i, and from the ancient taro lo`i in Hanalei. You can see them swim in streams around the island of Kaua`i, and waddle along the banks of the ponds at Kaua`i Lagoons at Nawiliwili.

A new genetic study, published today in the journal Molecular Ecology, says most ducks on Kaua`i are pure koloa, although many on other islands have interbred with mallards.
Kaua`i koloa. Credit: FWS image.

The paper is entitled "Persistence of an endangered native duck, feral mallards, and multiple hybrid swarms across the main Hawaiian Islands." The lead author is Caitlin P. Wells, of the University of California at Davis. 

Co-authors are Philip Lavretsky, Michael D. Sorenson, Jeffrey L. Peters, Jeffrey M. DaCosta, Stephen Turnbull, Kimberly J. Uyehara, Christopher P. Malachowski, Bruce D. Dugger, John M. Eadie and Andrew Engilis Jr.

Koloa were once present on all the islands, but due to predation, hunting and other causes, they were gone by the 1960s from all islands except Kaua`i and Ni`ihau. Captive breeding and release have returned some koloa to other islands since, but the populations remain low.

The researchers, in attempting to get a sense of how significant was the hydbridization with non-Hawaiian birds, collected blood samples from 425 ducks across the Hawaiian Islands.

Their finding was that Kaua`i birds are still close to pure koloa, while those on the other islands are blends—hybrids between koloa and mallards.

"We found that despite a population decline in the last century, koloa genetic diversity is high. There were few hybrids on the island of Kauaʻi, home to the largest population of koloa.

"By contrast, we report that sampled populations outside of Kauaʻi can now be characterized as hybrid swarms, in that all individuals sampled were of mixed koloa × mallard ancestry," the paper reported.
Many species that have dropped to really low numbers suffer from a decline in genetic diversity, meaning they have a reduced capacity to evolve in response to changing conditions. 

In a press release about the study, lead author Wells said that the genetic diversity in the Kaua`i birds suggests they can respond well to changes in the environment. 

"Should the environment change, due to things like climate change, there's a lot of potential for the koloa to evolve on its own, given the genetic diversity we've seen," she said.

"The fact that the koloa on Kauai are pure and have a lot of genetic variation are two really positive things that came out of this study," Wells said.

The two-decade study involved researchers from the University of California at Davis, Fish and Wildlife Service, University of Texas at El Paso, Wright State University, Oregon State University and the Hawai`i state Division of Forestry and Wildlife. 

 © Jan TenBruggencate 2019

Sunday, November 10, 2019

Fiddling as the planet burns. Climate change is upon us.

We saw it coming, but we did not know it would come so fast.

Climate change, long a threat for future decades, for the grandchildren, is here now.

In part, after a century of comparatively stable climate, the very concept of sudden dramatic change seemed so bizarre that many scientists have underplayed the possibilities.

The International Panel on Climate Change (IPCC) in early years issued conservative predictions. Some say the authors felt nobody would pay attention to the more alarmist predictions. Bizarrely, when scientists couldnʻt agree on how much Antarctic and Greenland ice melting would add to sea level, they just left those contributions out of their calculations entirely, vastly understating possible sea level rise.

In the Hawaiian Islands, king tides now regularly flood low coastal areas that 50 years ago and 25 years ago were always dry. Thatʻs going to keep getting worse.

The IPCC is getting up to speed and has been more realistic in its 2018 report. It has had to: "One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1 degree of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes," said Panmao Zhai, co-chair of IPPCʻs Working Group 1.

In Hawai`i, as temperatures rise, mosquitoes are able to survive at higher and higher elevations—where they carry fatal diseases to Hawaiian forest birds. I attended a meeting last week at which a bird researcher, when asked what was happening right now with Kaua`i forest birds, he said "theyʻre quietly dying of malaria."

Recently 11,000 scientists, exhausted with inaccurately conservative predictions, raised the alarm in a paper in Bioscience Magazine. There is an "urgent need for action," they said. 

Our planet has a fever, itʻs just starting on a long uphill trajectory, and so far, weʻre doing virtually nothing about it.

In our Hawaiian Islands, reduced rainfall associated with climate change has parched forests, and exacerbated wildfires that have burned thousands of acres on all the major islands. 

So, if we continue doing too little, itʻll get a little hotter and weʻll just to adapt, right? Wrong. All the evidence suggests it will keep getting worse, keep getting hotter, keep getting less tolerable.

The central Pacific—our part of the ocean—is seeing corals bleaching and dying. They are impacted by changes in water temperature, changes in ocean acidity, changes in current patterns, all related to climate change.

Here is the summary for policymakers issued by the IPCC in October 2018.

Little blogs like this one have been raising the alarm for years, with little apparent impact on policymakers. Examples? Here from January this year, here from 2016,  here from 2015, here from 2012, here from 2010, here from 2009. And those are just a few of the articles. 

But itʻs hard to feel isolated, because mainstream science has been suggesting ever more alarming scenarios. And while smaller responses to climate change might have worked in the past, what is now required is perhaps more alarming than the threat.

"Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values."

That is from a paper, "Trajectories of the Earth System in the Anthropocene," published last year in the Proceedings of the National Academy of Sciences. 

It suggests that if we donʻt act fast and now, the warming instead of stabilizing, will run out of control. That we are on a path to a tipping point, a threshhold, that will keep driving despite our intervention: "If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies."

In the Hawaiian Islands, on several islands, coastal roads are already being eroded away, forcing highway engineers to consider alternative routes, or extraordinary coastal armoring scenarios.

Here is the list of the more than 10,000 scientists who signed the extraordinary paper in Bioscience. They represent 153 countries, including the U.S., China, Russia, Canada, India, France, most of the nations on the planet, and all the major nations.

Their message is stark: "Greenhouse gas (GHG) emissions are still rapidly rising, with increasingly damaging effects on the Earth's climate. An immense increase of scale in endeavors to conserve our biosphere is needed to avoid untold suffering due to the climate crisis."

It is not a long paper. Please consider reading it. Hereʻs the link again.

And yet globally, human populations continue to rise. Our energy use continues to rise. Weʻre raising more ruminant animals. Our forest cover is dropping.  In Hawai`i, we celebrate increased air travel as a good thing, we keep buying gas guzzler vehicles, we buy our air conditioners as we complain about the heat.

The first rule about holes is that if youʻre in one, stop digging.

Our Legislature this year started the session with a laudable array of bills to address climate change, and then killed almost all of them. Nathan Eagle at Honolulu Civil Beat reviewed the distressing result

© Jan TenBruggencate 2019

Thursday, November 7, 2019

Blazing sunsets, redux

Raikoke Volcano in the Kuril Islands
in the northwest Pacific, taken June 22, 2019.
Credit: NASA.

Those spectacular Hawaiian sunset photos that have been showing up recently on Facebook, Twitter and Instagram are likely the result of volcanic emissions being dumped into the upper atmosphere during the summer.

But volcanic activity hasnʻt stopped. Just in the past week, in addition to ongoing volcanic eruptions, there have been four new ones. The volcanic haze that gets ejected into the atmosphere can color sunrises and sunsets in blazing oranges and purples.

The recent eruptions include these:

Kikai at Japanʻs Satsuma Iwo-jima, which is a small eruption probably not contributing a lot to sunsets. The dust plume was estimated at a kilometer high.

Klyuchevskoy in Russiaʻs Central Kamchatka, which has a dust and steam plume blowing 130 kilometers downwind.

The volcano at Metis Shoal, Tonga, erupted Nov. 1 and created a new island, but it appears to have stopped.

And Shishaldin in the Fox Islands of Alaska is reported still an active eruption, but without reports of a lot of dust and steam.

So those volcanoes that erupted most recently are comparatively small have not created a lot of the color weʻre seeing in the early evening. Most of the impact of recent sunsets comes from Ulawun volcano in Papua New Guinea, which erupted June 26, 2019, and Raikoke in the Kuril Islands, which erupted June 22, 2019.

Ulawun sent up a plume 20 kilometers or more high. Raikoke went 13 to 17 or more kilometers high. At those elevations, the dust and gas got into upper level winds and were transported around the globe.

"The dominant aerosol layer is actually formed by sulfur dioxide gas which is converted to droplets of sulfuric acid in the stratosphere over the course of a week to several months after the eruption. 
Winds in the stratosphere spread the aerosols until they practically cover the globe. Once formed, these aerosols stay in the stratosphere for about two years," said a NASA article.  

If you want to keep track for yourself, hereʻs a website that monitors recent eruptions. It is produced jointly by the Smithsonian Institution Global Volcanism Program and the U.S. Geological Survey.  

For some reason, there has been an upsurge in sunset picture taking. Perhaps itʻs associated with clearer weather. But the underlying causes havenʻt changed much since RaisingIslandsʻ last report on the 2019 sunsets here. 

© Jan TenBruggencate 2019