Here we are once again. Monday arrived on schedule. The time has come to gather around and take a well deserved hiatus from the politics of the day. Science talk is here. New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today's information world. Over the fold are selections from the past week from a few of the many excellent science news sites around the world. Today's tidbits include fossil teeth show what African animals ate, declining rainfall is a major influence for migrating birds, coastal mangrove forests may be key to lowering greenhouse gases, frozen comet had a watery past, drought-exposed leaves adversely affect soil nutrients, the mystery of naked penguins, west Antarctic warming triggered by warmer Pacific sea surface, and we waste more than half our energy. Gather yourselves around. Pull up that comfy chair and sit by the fire. There is plenty of room for everyone. Get ready for one more session of Dr. Possum's science education and entertainment.
Featured Stories
Fossils may offer different sorts of information with the proper study. Fossil teeth show the change in diet of African animals.
The diet record of East African herbivores from 10 million to 3 million years ago shows dramatic change occurred at different rates and times. The change was a shift from eating C3 plants - trees, shrubs and cool-season grasses - to eating warm-season, tropical C4 grasses, which first appeared in East Africa 10 million to 15 million years ago.
The animals' switch to grasses began after warm-season grasses first appeared in East Africa, but long before grasslands began to spread rapidly in the region. Previous evidence indicates East Africa was dominated by C3 ecosystems (trees, shrubs and cool-season grasses) during the Middle and Late Miocene Epoch about 16 million to 5 million years ago, but that mosaic landscapes with C4 grasslands were present.
Declining rainfall may be as disruptive to migrating birds' breeding areas as is rising temperature.
Precipitation in Jamaica is highly seasonal, with consistent rainfall from September to November and a pronounced dry season from January to March. The scientists observed the redstarts in their non-breeding territories for five years during the dry season. They paid special attention to the annual variation in dry season rainfall. The correlation between the amount of insects in a bird’s territory and the timing of its departure suggested to the team that annual variation in food availability was an important determining factor in the timing of spring migration. Had the redstarts relied on internal cues alone to schedule their spring departure, they would have all left their winter territories at the same time each year.
“Our results support the idea that environmental conditions on tropical non-breeding areas can influence the departure time for spring migration,” said Colin Studds, a postdoctoral fellow at the Smithsonian Conservation Biology Institute's Migratory Bird Center and lead author of the study. “We found that the same birds changed their spring departure from one year to the next in relation to the amount of rainfall and food in March.”
Coastal mangrove forests store more carbon than almost any other forest on Earth.
The mangrove forest's ability to store such large amounts of carbon can be attributed, in part, to the deep organic-rich soils in which it thrives. Mangrove-sediment carbon stores were on average five times larger than those typically observed in temperate, boreal and tropical terrestrial forests, on a per-unit-area basis. The mangrove forest's complex root systems, which anchor the plants into underwater sediment, slow down incoming tidal waters allowing organic and inorganic material to settle into the sediment surface. Low oxygen conditions slow decay rates, resulting in much of the carbon accumulating in the soil. In fact, mangroves have more carbon in their soil alone than most tropical forests have in all their biomass and soil combined.
This high-carbon storage suggests mangroves may play an important role in climate change management. Aside from the main greenhouse gas contributor of fossil-fuel burning, the forestry sector can play a part—especially carbon-rich forests that are being cleared rapidly on a global scale, such as mangroves.
According to conventional thinking comets are frozen by nature of their existence in space. New evidence suggests there may be other states in their past.
Comets are frequently called dirty snowballs because they consist of mostly water ice, peppered with rocky debris and frozen gases. Unlike asteroids, extraterrestrial chunks made up of rock and minerals, comets sport a tail – jets of gas and vapor that the high-energy particle stream coming from the sun flushes out of their frozen bodies.
"When the ice melted on Wild-2, the resulting warm water dissolved minerals that were present at the time and precipitated the iron and copper sulfide minerals we observed in our study," (researcher) Lauretta said. "The sulfide minerals formed between 50 and 200 degrees Celsius (122 and 392 degrees Fahrenheit), much warmer than the sub-zero temperatures predicted for the interior of a comet."
As bad news about climate change and its effects continue to pour in now comes a study telling the sad tale of drought-affected leaves and an adverse effect on soil nutrients.
red maple leaves accumulate about twice as much tannin when exposed to hot, droughtlike conditions. Those tannins, which defend leaves from herbivores and pathogens, were shown to interfere with the function of common enzymes in soil.
"When the leaves are particularly water-stressed by drought or drought with higher temperatures, we see more protective compounds, more tannins and a change in the chemistry of the tannins," said (researcher) Dukes.
(snip)
The increase in leaf tannins observed in this experiment could cause leaves to decompose more slowly and also interfere with critical soil enzymes, leaving fewer nutrients for plants. The tannins in the red maple leaves also were chemically different, making them interact more strongly with the soil enzymes.
Penguin chicks on both sides of the ocean are losing their feathers before they grow their adult pattern.
Since 2006, conservationists have been finding young penguins without a feather to their name. The disorder first emerged at a wildlife rehabilitation center in Cape Town, South Africa. Among the African penguin chicks (also called black-footed penguins) at the facility, 59 percent lost their feathers. The following year, 97 percent of chicks had the disorder, and in 2008, the numbers dropped to 20 percent.
Meanwhile in South America, WCS researchers found featherless Magellanic penguin chicks at four different areas along the Argentine coast in 2007. The scientists observed how the disorder affected the birds’ behavior and their growth. They saw that while healthy, feathered chicks sought shady refuge from the hot midday sun, featherless chicks remained in the sun’s warm but harmful glare.
Unfortunately, several chicks stricken with the disorder died during the course of the study.
Several causes are postulated while the quest for information continues.
The Antarctic peninsula has warmed over the past half century but until recently scientists were unsure of the cause.
New University of Washington research shows that rising sea surface temperatures in the area of the Pacific Ocean along the equator and near the International Date Line drive atmospheric circulation that has caused some of the largest shifts in Antarctic climate in recent decades.
The warmer water generates rising air that creates a large wave structure in the atmosphere called a Rossby wave train, which brings warmer temperatures to West Antarctica during winter and spring.
In these days of concern over energy and its conservation comes news that we in the US waste more than half our supply.
(A) flow chart of the estimated US energy use in 2009, assembled by the Lawrence Livermore National Laboratory (LLNL), paints a pretty sobering picture of our energy situation. To begin with, it shows that more than half (58%) of the total energy produced in the US is wasted due to inefficiencies, such as waste heat from power plants, vehicles, and light bulbs. In other words, the US has an energy efficiency of 42%. And, despite the numerous reports of progress in solar, wind, and geothermal energy, those three energy sources combined provide just 1.2% of our total energy production. The vast majority of our energy still comes from petroleum (37%), natural gas (25%), and coal (21%).
That percentage of oil illustrates that by far our biggest problem - or area of improvement - is transportation. As the chart shows, the transportation sector is the single biggest consumer of energy, accounting for nearly 40% of the energy consumed by the four sectors (along with residential, commercial, and industrial). In comparison, just 16% is used for residential use. And while the residential, commercial, and industrial sectors waste about 20% of their energy, the transportation sector wastes a full 75%, making it just 25% energy-efficient. Part of this waste is due to the fact that cars are an inherently inefficient way to move people around, since much of the energy must go into moving the massive car and not simply the person.
Other Worthy Stories of the Week
Poison could have set the stage for life
Record loss of ozone over the Arctic
Spitzer discovers time delayed jets around young star
Climate change effects on forests
Lions differ genetically across Africa
Leatherback sea turtle nests increasing in Florida
Caterpillar behavior helps them to avoid predators
Adult brains capable of rapid new growth
Genetically modified cows producing human breast milk
Gallery: Microscopic art hides inside computer chips
World's reef fishes tussling with human overpopulation
The meltwater stonefly, a rare alpine insect, may disappear with the glaciers
The shape shifting vortex of southern Venus
Shark teeth found in ancient ammonite shell
Underwater sculptures give sea creatures a haunting habitat Picture gallery.
Beetle foot-pads may inspire new artificial adhesives
Political views are reflected in brain structure
Nanoparticles increase biofuel performance, decrease emissions
Instant evolution in whiteflies: Just add bacteria
Antibiotic-resistant bacteria in Indian public water supply
Thermophiles lurking in your basement
Blueberries may inhibit the development of fat cells
For even more science news:
General Science Collectors:
Alpha-Galileo
BBC News Science and Environment
Eureka Science News
LiveScience
New Scientist
PhysOrg.com
SciDev.net
Science/AAAS
Science Alert
Science Centric
Science Daily
Scientific American
Space Daily
Blogs:
A Few Things Ill Considered Techie and Science News
Cantauri Dreams space exploration
Coctail Party Physics Physics with a twist.
Deep Sea News marine biology
Laelaps more vertebrate paleontology
List of Geoscience Blogs
ScienceBlogs
Space Review
Techonology Review
Tetrapod Zoologyvertebrate paleontology
Science Insider
Scientific Blogging.
Space.com
Wired News
Science RSS Feed: Medworm
The Skeptics Guide to the Universe--a combination of hard science and debunking crap
At Daily Kos:
This Week in Science by DarkSyde
Overnight News Digest:Science Saturday by Neon Vincent. OND tech Thursday by rfall.
Pique the Geek by Translator Sunday evenings about 9 Eastern time
All diaries with the DK GreenRoots Tag.
All diaries with the eKos Tag
A More Ancient World by matching mole
Astro Kos
SciTech at Dkos.
NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive.
Tien Shan mountain range, NASA, Public Domain