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FOR THE AGES Single-celled foraminifera helped to create the materials used in some of the world's great monuments, and are also very valuable in telling Earth's history because they produce shells that make good fossils.
‘Nature’s Masons’ Do Double Duty as Storytellers
By SEAN B. CARROLL, The New York Times, June 25, 2012
GUBBIO, Italy — North of Rome, in Umbria, a series of picturesque, ancient towns perch on the tops or sides of the foothills of the Apennine Mountains. Their placement here was a defensive imperative for successive Umbrian, Etruscan, Roman and Christian occupants over the millenniums. But these hillside locations were also of great advantage for constructing massive buildings, fortified walls and aqueducts, because of to unlimited local supplies of limestone.
Tourists flock to places like Gubbio, on the slope of Mount Ingino, to admire its impressive medieval churches and palazzos. But no one gives any thought to the tiny creatures that helped to create the materials necessary for making such spectacular, long-lived monuments.
Limestone is composed largely of crystallized calcium carbonate. Some of it comes from the skeletal remains of well-known creatures like corals, but much of the rest comes from less appreciated but truly remarkable organisms called foraminifera, or forams for short.
Forams have been called “nature’s masons,” and deservedly so. Most of the 6,000 species of these single-celled protists construct surprisingly complex, ornate and beautiful shells to protect their bodies.
After forams die, their shells settle in ocean sediments — and may eventually become rocks that can be used to shelter our bodies.
While tiny relative to ourselves and most familiar marine creatures, forams are extremely large for single-celled organisms, often reaching a third of a millimeter in size. That is one hundred times larger than most bacteria and three times as large as a human egg cell, one of the largest cells in our bodies.
The largest forams can reach a few centimeters. The most impressive of all, now extinct, were flat, disk-shaped species called nummulites (from the Latin meaning “small coins”) that were abundant in the limestone used to build the great pyramids of Egypt.
In more recent times, forams have served an altogether different service — to science.
Because they produce shells that make good fossils, and have long been abundant and widespread in the oceans, forams are particularly valuable to geologists and paleontologists in telling us about Earth’s history.
The forams in the limestone just outside Gubbio provided the first clues to one of the most exciting scientific discoveries in the past century.
In the 1970s, the geologist Walter Alvarez (now at the University of California, Berkeley) was studying the exquisite limestone formations around this town. Because different species with different shell shapes evolved at different times, foram fossils have been widely used to date rocks.
Dr. Alvarez was trying to figure out the ages of the rocks around Gubbio. He learned that the topmost layer of the rocks from the Cretaceous period always contained a diverse array of large fossil forams.
But the layer of rock just above it, which signaled the beginning of the later Tertiary period, lacked most of those Cretaceous species and contained only a few, much smaller species of forams. Separating the two rock layers was a thin layer of clay that appeared to lack fossils altogether.
The geologist Jan Smit, now at the VU University in Amsterdam, discovered a similar pattern in rocks in southern Spain.
The abrupt disappearance of forams in these layers of rock indicated that something had happened at the boundary between the Cretaceous and Tertiary periods. The end of the Cretaceous period also coincided with the extinction of the dinosaurs, as well as once-abundant marine animals such as ammonites.
Dr. Alvarez, Dr. Smit and their colleagues wondered: What on earth could have caused the disappearance of widespread, tiny organisms like forams, as well as much larger creatures?
As it turned out, it wasn’t something on earth but something from space. Chemical analyses of the clay marking the boundary of the two periods, carried out by these geologists and their collaborators, revealed that it contained extraordinary levels of the element iridium, a material rare on earth but more abundant in certain kinds of asteroids. The scientists proposed that the iridium was fallout from an asteroid that struck earth at the end of the Cretaceous period, 65 million years ago.
It took a while to locate where that happened, but the impact crater was ultimately identified underneath the Mexican village of Chicxulub on the Yucatán Peninsula.
The asteroid was about the size of Mount Everest and traveling at about 50,000 miles an hour when it hit the earth, drilling a 120-mile-wide crater and ejecting so much material into (and even out of) the atmosphere that food chains on land and in the oceans were disrupted for thousands of years. The impact caused one of the greatest mass extinctions in history, from the largest animals to tiny forams.
Eventually, forams and the oceans rebounded, and new species evolved. But today, forams are warning us of a new threat, for they are not merely witnesses to earth’s history, but critical participants in it.
Forams are a vital part of a “biological pump” that removes carbon dioxide from the atmosphere. When carbon dioxide dissolves in seawater, one reaction product is carbonate. In making their calcium carbonate shells, the large mass of so-called planktonic forams floating in the upper levels of the oceans sequester about one quarter of all carbonate produced in the oceans each year.
The increasing levels of carbon dioxide in our planet’s atmosphere, now at a greater level than at any time in the past 400,000 years, threaten to overwhelm this biological pump by inhibiting the formation of calcium carbonate shells. As more carbon dioxide dissolves in the ocean, the waters acidify, decreasing the concentration of carbonate and making it more difficult for these organisms to form calcium carbonate shells.
The ocean surface is now about one-tenth of a pH unit more acidic than in preindustrial times. And indeed, a recent study of forams in the Southern Ocean found that their shells are now 30 percent to 35 percent thinner than in the preindustrial era.
As terrestrial animals, we are most focused on how climate change affects our immediate habitat. But ocean acidification may be a sort of stealth asteroid of environmental change.
At current rates of carbon dioxide production, ocean acidity is projected to increase by another three- to four-tenths of a pH unit by the end of the century, with potentially catastrophic effects on shell-forming creatures and food chains.
And in the present geologic period, guess who is at the top of those chains?
Immigrants Are Crucial to Innovation, Study Says
By ANDREW MARTIN, The New York Times, June 25, 2012
Arguing against immigration policies that force foreign-born innovators to leave the United States, a new study to be released on Tuesday shows that immigrants played a role in more than three out of four patents at the nation’s top research universities.
Conducted by the Partnership for a New American Economy, a nonprofit group co-founded by Mayor Michael Bloomberg of New York, the study notes that nearly all the patents were in science, technology, engineering and math, the so-called STEM fields that are a crucial driver of job growth.
The report points out that while many of the world’s top foreign-born innovators are trained at United States universities, after graduation they face “daunting or insurmountable immigration hurdles that force them to leave and bring their talents elsewhere.”
The Partnership for a New American Economy released a paper in May saying that other nations were aggressively courting highly skilled citizens who had settled in the United States, urging them to return to their home countries. The partnership supports legislation that would make it easier for foreign-born STEM graduates and entrepreneurs to stay in the United States.
“Now that we know immigrants are behind more than three of every four patents from leading universities, the federal laws that send so many of them back to their home countries look even more patently wrong,” Mayor Bloomberg said in a statement.
But some worry that the partnership’s ideas for immigration reform would undermine similarly skilled American workers while failing to address broader problems with immigration policy.
“No one is asking what is in their best interest, the American worker,” said Eric Ruark, director of research for the Federal for American Immigration Reform, an advocacy group that is pushing for reduced immigration. “It’s what is best for the employers. What is best for the foreign workers. It’s not as if the foreign workers aren’t skilled. What’s being ignored is we already have a domestic work force that has the same skills.”
The most recent study seeks to quantify the potential costs of immigration policies by reviewing 1,469 patents from the 10 universities and university systems that had obtained the most in 2011. The schools include the University of California system, Stanford and the Massachusetts Institute of Technology.
Patents, the study maintains, are a gauge for a nation’s level of innovation and an important way for the United States to maintain an edge in STEM fields.
In one illustration of the issue, the study notes that nine out of 10 patents at the University of Illinois system in 2011 had at least one foreign-born inventor. Of those, 64 percent had a foreign inventor who was not yet a professor but rather a student, researcher or postdoctoral fellow, a group more likely to face immigration problems.
Some of the patents that were reviewed for the report have become business ventures. Wenyuan Shi, a professor at the University of California, Los Angeles, earned a patent for an ingredient in a lollipop he developed that works as a dental treatment for children. A native of China, Mr. Shi has created a company to commercialize his inventions.
But current immigration laws can make it difficult for foreign-born students to remain in the United States after graduation. And employers may be wary of hiring them because green cards, allowing for permanent residency status, are limited and the process of obtaining one is cumbersome and expensive.
Under the current system, foreign-born students are allowed to stay in the United States for 12 to 29 months after graduation, provided they find a job or internship in their field.
After that, more permanent visas are difficult to obtain, restricted by factors like country quotas. The study notes that China is entitled to the same number of visas as Iceland.
Dr. Ashlesh Murthy came to the United States from India in 2001 to pursue a master’s degree in molecular biology at the University of Texas at San Antonio. Working with his professors there, he developed a vaccine for the sexually transmitted disease chlamydia, which obtained patents in 2011 and 2012.
Nonetheless, Dr. Murthy had to negotiate a bureaucratic maze to remain in the United States, and at one point was stuck in India for an extra month because American officials in India doubted a previously approved visa.
Noting that university officials petitioned a congressman to intervene on his behalf, Dr. Murthy, said, “If I was not in a position where they really wanted me, I seriously doubt I would have gotten back.”
Really? Eating Soy Increases the Risk of Breast Cancer
By ANAHAD O'CONNOR, The New York Times, JUNE 25, 2012
THE FACTS
Soy milk, tofu and other soy products contain phytoestrogens, chemicals that can mimic the behavior of the hormone estrogen. Because estrogen fuels many breast cancers, soy has long been a source of concern: Can it heighten the risk of breast cancer or raise the odds of recurrence?
In the lab, phytoestrogens can stimulate the growth of breast cancer cells. But in human studies, scientists have not found that diets high in soy increase breast cancer risk. In fact, most have found the reverse.
In a report in The Journal of the American Medical Association in 2009, scientists who looked at 5,042 people in the Shanghai Breast Cancer Survival Study found that soy was linked to a significantly lower risk of breast cancer recurrence and mortality. But the study, while encouraging, was carried out in China, so questions lingered about the extent to which the findings applied to women elsewhere.
In a more recent multiyear study, published in May in The American Journal of Clinical Nutrition, scientists followed nearly 10,000 breast cancer survivors, many of them in the United States. They found that women who ate the most soy had lower rates of cancer recurrence and mortality.
Though the findings reflect only a correlation, they suggest that the concerns about soy and breast cancer may be unfounded.
THE BOTTOM LINE
Despite concerns about its phytoestrogen content, eating soy has not been shown to promote breast cancer.
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Date: 2012-06-28 05:38 am (UTC)Yes, if we seriously mess up the oceans, we will have effed up big time. And we be doing our best- ah, worst. Kee-kee-kee-CHRist!
What was the 80's joke, "what is 800 lawyers at the bottom of the ocean?" Ans: "It's a start!"
Well, these days we'd better substitute "self-serving politicians". What am I going to tell my daughters?
[pardon the irreverent sense of humah-] I always wondered, if something similar happened today, ignoring l-t effects, would we all get broken legs if standing on the ground? "Everybody drag your mattress out to the biggest clear space nearby!"
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Date: 2012-06-28 05:40 am (UTC)