How One Scientist Is Helping Plants Survive California’s Worst Drought

Every living thing has its own natural responses to stress.

When critical nutrients are in short supply, our bodies, for example, find ways to maintain normal function until those nutrients are replenished. Plants do the same. In drought conditions, natural processes kick in to keep them alive until they can be watered again.

When faced with a water shortage, plants produce a stress hormone known as abscisic acid (ABA), which signals the plant to consume less water. ABA binds to a specific protein receptor in the plant, signaling stomata—or unique guard cells—to close and reduce the amount of water lost. This receptor is so important that its discovery by UC Riverside’s Sean Cutler, his team and others was listed as one of 2009′s breakthroughs of the year by Science magazine.

To help plants survive extreme drought conditions, some have tried spraying ABA directly on crops during water shortages. The move can improve crop yields, but ABA is expensive to produce and breaks down easily, even before a plant can absorb and use it.

Read more about how Sean Cutler is helping plants survive California’s worst drought

Image credit: Adam Shomsky

How Do Our Bodies Fight Off Dangerous Chemicals?

We’re all subjects in a massive experiment. Humans have created about 80,000 synthetic industrial compounds — including plastics, the flame retardants that cover our sofas, and pesticides. These compounds have structures that are not commonly seen in nature and present a risk to our health. Everybody on the planet is exposed.

It’s important to understand what these substances are doing to our bodies so that scientists can create a rule book for making these chemicals safer.

The challenge to understanding how dangerous compounds get into our body is complex. The way we have been doing this in the past is to test if a synthetic compound dissolves in fat. If it does then theres a high likelihood that it can easily enter our body’s cells where it can cause harm.

The problem with this method is that it doesn’t always accurately predict how much a compound accumulates in organisms. A historic example of this is DDT which was used on crops to get rid of pests, but ultimately found its way through the food chain. It’s now considered a risk factor for breast cancer in humans.

At UC San Diego’s Scripps Institute of Oceanography, Amro Hamdoun is looking at the biological properties of how these compounds interact with cells. The focus is on how the cell decides which compounds to let in and which ones to eliminate.

 

A New Species of Hummingbird?

UC Riverside researchers have discovered what could be a new species of hummingbird in the Bahamas.

The Bahama Woodstar comprises of two subspecies: Calliphlox evelynae evelynae, found throughout the islands of the Bahamas and Calliphlox evelynae lyrura (“lyrura” for lyre-tailed, refers to the forked tail of males that resembles a classical lyre harp). This lovely creature is only found among the southern Inaguan islands of the Bahama Archipelago.

Based on data from morphology, behavior, genetics and geology, UCR biologist Christopher J. Clark says the two subspecies should be recognized as two distinct species.

“The two subspecies were originally described as separate species, partly on the basis of small differences in the tail feathers between them, but were then classified in 1945 as subspecies of the Bahama Woodstar. It’s time now to call these two distinct species of hummingbirds.”

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Small volcanic eruptions explain warming hiatus

Scientists have long known that volcanoes cool the atmosphere because of the sulfur dioxide that is expelled during eruptions. Droplets of sulfuric acid that form when the gas combines with oxygen in the upper atmosphere can persist for many months, reflecting sunlight away from Earth and lowering temperatures at the surface and in the lower atmosphere.

Previous research suggested that early 21st-century eruptions might explain up to a third of the recent warming hiatus.

New research available online in the journal Geophysical Research Letters (GRL) further identifies observational climate signals caused by recent volcanic activity. This new research complements an earlier GRL paper published in November, which relied on a combination of ground, air and satellite measurements, indicating that a series of small 21st-century volcanic eruptions deflected substantially more solar radiation than previously estimated.

“This new work shows that the climate signals of late 20th- and early 21st-century volcanic activity can be detected in a variety of different observational data sets,” said Benjamin Santer, a Lawrence Livermore National Laboratory scientist and lead author of the study.

The warmest year on record is 1998. After that, the steep climb in global surface temperatures observed over the 20th century appeared to level off. This “hiatus” received considerable attention, despite the fact that the full observational surface temperature record shows many instances of slowing and acceleration in warming rates. Scientists had previously suggested that factors such as weak solar activity and increased heat uptake by the oceans could be responsible for the recent lull in temperature increases. After publication of a 2011 paper in the journal Science by Susan Solomon of the Massachusetts Institute of Technology, it was recognized that an uptick in volcanic activity might also be implicated in the warming hiatus.

Prior to the 2011 Science paper, the prevailing scientific thinking was that only very large eruptions — on the scale of the cataclysmic 1991 Mount Pinatubo eruption in the Philippines, which ejected an estimated 20 million metric tons (44 billion pounds) of sulfur — were capable of impacting global climate. This conventional wisdom was largely based on climate model simulations. But according to David Ridley, an atmospheric scientist at MIT and lead author of the November GRL paper, these simulations were missing an important component of volcanic activity.

Ridley and colleagues found the missing piece of the puzzle at the intersection of two atmospheric layers, the stratosphere and the troposphere — the lowest layer of the atmosphere, where all weather takes place. Those layers meet between 10 and 15 kilometers (6 to 9 miles) above the Earth.

Satellite measurements of the sulfuric acid droplets and aerosols produced by erupting volcanoes are generally restricted to above 15 km. Below 15 km, cirrus clouds can interfere with satellite aerosol measurements. This means that toward the poles, where the lower stratosphere can reach down to 10 km, the satellite measurements miss a significant chunk of the total volcanic aerosol loading.

To get around this problem, the study by Ridley and colleagues combined observations from ground-, air- and space-based instruments to better observe aerosols in the lower portion of the stratosphere. They used these improved estimates of total volcanic aerosols in a simple climate model, and estimated that volcanoes may have caused cooling of 0.05 degrees to 0.12 degrees Celsius since 2000.

The second Livermore-led study shows that the signals of these late 20th and early 21st eruptions can be positively identified in atmospheric temperature, moisture and the reflected solar radiation at the top of the atmosphere. A vital step in detecting these volcanic signals is the removal of the “climate noise” caused by El Niños and La Niñas.

“The fact that these volcanic signatures are apparent in multiple independently measured climate variables really supports the idea that they are influencing climate in spite of their moderate size,” said Mark Zelinka, another Livermore author. “If we wish to accurately simulate recent climate change in models, we cannot neglect the ability of these smaller eruptions to reflect sunlight away from Earth.”

To see the full research, go to Geophysical Research Letters and the Wiley Online Library.

The Livermore-led research involved a large interdisciplinary team of researchers with expertise in climate modeling, satellite data, stratospheric dynamics, volcanic effects on climate, model evaluation, statistics and computer science. Other Livermore contributors include Céline Bonfils, Jeff Painter, Francisco Beltran and Gardar Johannesson. Other collaborators include Solomon and Ridley of MIT, John Fyfe at the Canadian Centre for Climate Modeling and Analysis, Carl Mears and Frank Wentz at Remote Sensing Systems and Jean-Paul Vernier at the NASA/Goddard Space Flight Center.

Is The Secret To A Happy Marriage In Your DNA?

Are some people genetically predisposed to stay happily married? Researchers at UC Berkeley have found a major clue in our DNA.

Robert Levenson and his team have found a link between relationship fulfillment and a gene variant — known as the “short allele” — of the serotonin transporter gene. The gene is involved in the regulation of serotonin in the brain and can predict whether a person is attuned or oblivious to the emotional climate of their marriage.

In the study, Levenson found that participants with the short alleles were most unhappy in their marriages when there was a lot of negative emotion —like contempt— but were also happiest when positive emotions like humor were present. (About 30% of the population has this gene variation.)

On the other end of the spectrum, participants with long alleles were satisfied with their marriages regardless of the emotional atmosphere.

Why carrots taste sweeter in winter

UCLA’s Liz Roth-Johnson explains why carrots have more sugar when it’s cold outside.

Because plants are immobile, they must develop defense techniques against predators and the severe cold in winter. For example, carrots have developed the physiological response of increasing their sugar content when it’s cold outside. This helps stop ice crystal formations and prevents damage to the carrot’s cells.

Frost can do a lot of damage to a plant cell. It can squeeze and rupture the cells until they are completely demolished. But in some cases, the plant’s defense mechanism means a tastier vegetable for us to eat. When a carrot defends itself from frost, we get the benefit of enjoying sweeter carrots all winter long.

FEATURING: Liz Roth-Johnson, Ph.D. in Molecular Biology, UCLA

For more information: https://scienceandfooducla.wordpress.com/