Spangly cupcakes

I have an ugly confession to make. Like Shane at Gallomanor‘s blog, I left last Thursday’s UK Science Blogging Talkfest slightly disappointed. I feel bad admitting to this because the people were lovely, I am grateful to the organisers and there were spangly cakes.

Having blogged for a week now, I rocked up at the Talkfest full of practical questions about blogging. How do I share interesting science with my readers more effectively? What’s a good WordPress theme for science blogging? How do I respond if climate skeptics converge en masse on my site?

Cake beforehand and the pub afterwards (sadly, I had to leave early) allowed some opportunity to chat. The business part of the event, however, was a Q&A session with six ‘celebrity’ bloggers. The questions focused on the wider social impact of blogging, something I couldn’t care less about in my role as a blogger.

I’m starting an OU part-time MSc in Science and Society in January and, from an academic science communication perspective, it was an interesting event. But, speaking as a science blogger, I felt getting some of the most widely-read science bloggers in the world to talk about social impacts wasted their talents. I wanted to hear about blogging.

Is this the secret of Not Exactly Rocket Science's success? Sadly, we didn't find out

Ed Yong from Not Exactly Rocket Science – for example – seems a lovely bloke with loads to say about how to build readership, how to entertain readers with science and keep them coming back. Duck penises help, but I’m definite he has much more to say. If I’d known the session was going to be so academic and theoretical, I would have dropped in a few questions. But hindsight ain’t worth a damn.

You can find more information about research into the dunes on this website run by Professor Melany Hunt from Caltech, one of the scientists on the video. You can also hear dunes that burp, croak and whistle.

Booming dunes are pretty rare, but there are squeaking or whistling dunes in the UK. The aptly-named Whistling Sands in Wales is one famous site. Another is on the Isle of Islay in the Hebrides.

My piece explaining booming dunes will appear in a future issue of How It Works magazine.

Guardian blogs: Love trumps loss when it comes to the conservation message.

The Washington Post: NASA eyeballs glacial melt in Greenland. More on the Jakobsahvn Isbrae glacier, which last week lost a chunk of ice an eighth the size of Manhattan.

The Guardian: Last six months second driest in the UK in 96 years, say scientists. ’nuff said.

EurekAlert: Footloose glaciers crack up. When glaciers that rest on the sea floor ‘lose their grip’ and begin to float in the ocean, they behave erratically, a recent study has found. The study was press released by the American Geophysical Union (AGU) and is on EurekAlert.

Sydney Morning Herald: Prince attacks climate change sceptics. Prince Charles has blasted climate sceptics, according to – funnily enough – an Australian newspaper.

University of Bristol: Honorary degrees awarded. Only included because Professor Paul Valdes is the orator for the ceremony and he’s really good looking.

Car 'eaten' by sinkhole. WTSP

Look at this image carefully and you can see a car about halfway down the hole. According to newspaper reports, it’s a Toyota Camry. Sadly, there isn’t a record of what the owner said when they returned to their Toyota. I assume it was something like “Oh, s**t!”

The hole is in Tampa, Florida near the University of South Florida. When it opened up on Sunday, it ‘ate’ this car in the process. The car has now disappeared from view and the growing hole is threatening a car park and a block of flats.

This isn’t the first time Tampa residents have unexpectedly stared into the abyss. In January, a whole rash of holes (or maybe a ‘hole rash of wholes’) suddenly appeared, including a 2.5 m wide pit in someone’s back garden. Another hole near the University of South Florida burst a water pipe.

The underlying reason for Tampa’s problem is rock type combined with water use. Perhaps 1000m thick limestone and dolomite rocks lie under most of Florida. These are covered by sands and clays of various thicknesses.

Florida aquifer system (from Tihansky, 1999) and http://water.usgs.gov/ogw/ karst/kigconference/abt_karstfeatures.htm

Limestone and dolomite are mainly made of carbonates – the alkali chemicals used in some indigestion tablets for neutralising stomach acid. As with indigestion tablets, carbonate rocks react with acid water. The products of the chemical reactions are washed away. The water seeps into and widens any rocks that are full of cracks and joints, water seeps into and widens them. Over time, this process forms cavities, underground tunnels and caves.

The carbonate rock under Tampa are riddled with tunnels and cavities. Water has had many opportunities to sculpt the rocks because the sea level around the Florida Peninsula has risen and fallen many times since they were laid down beneath the sea millions of years ago.

Water also gets trapped and stored in the carbonates because they’re holey like Swiss cheese and the surrounding rocks are less permeable. It’s a bit like sandwiching a wet sponge between two glass plates. In fact, the carbonate rocks form an aquifer (a group of rocks that store water) under Florida that holds one-fifth of the water in the US Great Lakes.

Cut forward to the present day and the people of Tampa get their water by drilling into the carbonate rock aquifer and pumping it out. In winter, farmers pump lots of water from the aquifer onto their strawberries to stop them freezing.

The water filling underwater cavities and caves in the carbonates helps support the weight of the cave roof and overlying soil. When the water is pumped out, soil from above moves through cracks in the cavity roof and plugs the gap left by the water.

Sinkholes open up overnight for two main reasons (see a) and d) on the diagram below). First, water flowing downwards to fill the drained cavities eventually washes away the soil plug, causing a sudden slump of soil into the cavity and a hole to open up at the surface (figure d). Alternatively, so much water is removed that it no longer supports the cavity roof and walls. They weaken catastrophically, the cavity roof collapses and a hole opens in the ground (figure a).

Types of sinkhole (after Jennings 1985): http://www3.uakron.edu/geology/ facpages/ids/mdinsmore/

One of these explanations is likely to explain the car-’eating’ sinkhole. As an aside, all this doesn’t explain another giant ‘sinkhole’ that consumed a Guatemala clothing factory and road intersection at the end of May. From what I can gather, Guatemala City is underlain by volcanic deposits that were washed away by rain from tropical storm Agatha.

Daily News, Los Angeles: The polluting of L.A.’s groundwater is a slow-motion disaster.

TreeHugger: Rising Greenhouse Gases Amplify Sea Level Rise in Indian Ocean. Sea levels in the Indian Ocean are rising faster than the world average no thanks to climate change, a study in Nature Geoscience has found.

Metro: Save Our Seas – Public urged to help conservationists target troubled spots. Natural England are asking ocean lovers to let them know what’s happening in their corner of the sea to help improve scientific knowledge.

NASA: Researchers Witness Overnight Breakup, Retreat of Greenland Glacier. A chunk of ice an eighth the size of Manhattan, New York, fell off Greenland’s Jakobshavn Isbrae glacier literally overnight.

EurekAlert: Staggering tree loss from 2005 Amazon storm. An enormous storm wiped out 500,000 trees in the Amazon, far more than scientists suspected, the American Geophysical Union (AGU) say in this press release. It’s the first time researchers have made a ‘body count’ of lost trees and they now think storms could be quite important to how these rainforests work.

ScienceNews: Africa’s bumper crop of dust. The dust thrown into the atmosphere from Africa has skyrocketed since commercial agriculture started in the 1800s, a study in Nature has found.

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For a dust storm to start, you need lots of sand or dust that’s dry enough to be picked up by the wind. But it’s expensive and difficult to keep track of dust wetness over large areas by sticking instruments into the soil or using rainfall gauges. This is especially the case in deserts, which are inhospitable places for scientists to work. So, instead, researchers use satellite instruments to take regular snapshots of the condition of dust and vegetation. But, traditionally, they’ve used instruments that produce quite low-resolution digital images. Each pixel on images produced by a satellite called the Advanced Microwave Scanning Radiometer (AMSR-E), for example, covers 25km of the Earth’s surface. Compare this to the iPhone 4, which has 326 pixels per inch!

These big pixels were the problem facing Dr Stephen Scheidt and colleagues, who were trying to predict dust storms coming off the White Sands Dune Field in southern New Mexico. White Sands is the world’s largest area of gypsum – the bright white mineral used in plasterboard – sand dunes. Gypsum doesn’t normally form sand because it’s soluble in water, but it gets trapped in White Sands area because of its unusual geology. The white sands cover the floor of an enormous bowl-shaped hollow – the Tularosa Basin, which is ringed by the San Andres and Sacramento mountains. Water dissolves gypsum out of the mountain rocks and runs into the basin, but the basin has no river running from it toward the sea. So the water gets stuck and eventually evaporates away, leaving the gypsum behind.

When the basin is very dry, it’s prone to dust storms that can travel for more than 200km and inundate the nearby city of Alamogordo. Unfortunately, the dry river basins and dunes are too small to be monitored by instruments like AMSR-E. So the University of Pittsburgh team used a different satellite instrument – the Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer, which has pixels between 30 and 90m across. They compared images collected by ASTER with those from an instrument with bigger pixels – the Moderate Resolution Imaging Spectroradiometer (MODIS), which collects data more frequently. ASTER sweeps over White Sands every 16 days, but MODIS passes over the area every 12 hours.

The team used the ASTER and MODIS data to calculate the wetness of the sand and the wind speed needed to carry the sand away. From this, they could predict when the gypsum was susceptible to a dust storm. However, ASTER and MODIS don’t actually measure soil moisture directly. They work a little like cameras but, instead of detecting light, they detect infrared radiation – the electromagnetic radiation given off by hot objects like people’s bodies. The infrared radiation given off by sand can used to work out if it’s wet or dry because wet sand is harder to heat than dry sand. Once the team knew if the sand was wet or not, they could calculate how high the wind speed would need to be to move the sand.

They tested whether this worked using images collected by ASTER and MODIS on seven different dates between 2000 and 2008. And, this is where it gets interesting, the driest image was from March 10th, 2008. Four days later – there was a big dust storm. The team have still got some issues to iron out, for example, testing their results against measurements made on the ground and refining their equations, but they think this approach might be useful for monitoring dust storms in deserts elsewhere. In fact, they hope it could be part of a global dust storm monitoring system.

The paper was published in Journal of Geophysical Research Earth Surface, and is available to download from EurekAlert. The story was also covered by PhysOrg.com.

TreeHugger (and others): Glaciers get a coat of paint and their own cool bag

In other news:

The Independent: Building craze threatens to end Lanzarote’s biosphere status

Smithsonian: How much plastic is there in the North Atlantic? Volunteers find out

LA Times: Indonesia’s mud volcano flows on “After two years, spewing about 100,000 tons a day, the Lusi mud volcano in East Java shows no signs of letting up. Initially laid to an earthquake, the spill is now being linked to drilling”

Circle of Blue: Ten countries – five in Africa – risk conflict because of water shortages

The Times: Ace Wimbledon weather is set to continue. We’ve already had a hot, dry Wimbledon and Glastonbury, thanks to the Azores High. Now UK wine growers are hoping for a bumper grape harvest too, thanks to the continuing influence of this atmospheric high pressure system. The Azores High sits over the Atlantic Ocean south of the Azores (guess what) in winter. When it moves northwards in summer, it can cause a ridge of high pressure to form over the southeast UK to cause  heat waves like the one we’re experiencing.

Physorg.com: Breath of the Earth: Cycling carbon through terrestrial ecosystems.

Science News: Methane releases in arctic seas could wreak devastation.