Thursday, May 31, 2012

The 2012 Transit of Venus

Please install latest Flash Player to run SunAeon Venus Transit 2012

Mark your calendars. On June 5-6, 2012, Venus will pass across the face of the Sun. This is likely the last time you will see Venus transit in your lifetime. Transits of the planet are very rare, coming in pairs separated by more than 100 years. The first of this pair came in 2004, and after this year's transit there will not be another one until 2117. I've listed below some information you should know about where, when, and how to view the transit.

I'll admit that I went a little crazy with the links, there are a lot of them. The idea was to make a sort of one-stop-shop where you could find all of the transit information you could want or links to where you can find it. Because I've included so many links, I tried to break them up by topic, and hopefully that will help you navigate. First, let's start with some general information type links about the up-coming transit of Venus:

Location, Location, Location

People from all over the world will be looking up on June 5th and 6th, but where you live determines what time you should be looking for the transit. If you are in Europe, the Middle East, eastern Africa, western Australia, India, and western Asia you should be looking for Venus at sunrise on June 6th. If you are in North America, Central America, and the northwestern parts of South America you should look for Venus around sunset on June 5th.  If you live in central and eastern Australia then lucky you! You will be able to see the entire transit. For specific times of the transit at your location, see the Local Transit Times website.

Links about the where's and the whens:

How to Observe

First, and most importantly, NEVER look directly at the Sun without proper safety devices unless you prefer permanent blindness. Regular sunglasses do NOT qualify as a proper safety device. Venus covers too little of the solar disk to block the blinding glare of the Sun. Solar filters are widely available for safe solar viewing.
Here are some options for safe solar viewing:

Protective Eyewear: If you have access to a welding hood that houses a #14 or darker filter then you can use that. Or you purchase inexpensive Eclipse Shades.

Telescopes with Solar Filters: Not only do telescopes magnify Venus, but if they are properly filtered they can also give you a better view then you will have with most other viewing options. If you own an inexpensive, small, and/or older model telescope be careful to make sure you are using the correct type of solar filter. If you don't have these then look below in the links for Projection Methods to find out how to turn your telescope into a projector. Don't own a telescope? No problem, me neither. You can do what I'm doing and find your local astronomy club. They will have telescopes set up (probably nice, big ones) and amateur and expert astronomers on hand to answer questions.

Pinhole Projectors/Camera: These devices are a safe, indirect way to view the Sun. They are popular devices, especially with kids, because they are easy to make and use yourself. Unfortunately they suffer from the problems associated with indirect viewing, namely unmagnified images and lack of detail.

Projection Methods: There are a few types of projection methods, besides pinhole projectors, that you can use to indirectly view the transit. You can project the image of the Sun onto a white surface with a projecting telescope or binoculars (do NOT use the binoculars or telescope to directly look at the Sun!). Another option, especially for children, is to use a Sunspotter telescope viewer.

Use the Internet: You don't have to go outside to see the transit of Venus. You can go online and look for webcasts from around the world.

Experiments, Experiments, Experiments

Space agencies and astronomers around the world will be taking this time to study Venus and test some planetary hypotheses. Planetary transits are powerful methods for discovering exoplanets. It is not only one of the ways that astronomers find exoplanets, but it is also a way to learn more about the characteristics of those far away bodies. By measuring the refraction and scattering of light, lots of information can be gathered about the atmospheres of planets. To refine these techniques and to learn more about our own solar system, astronomers can observe planets close to home. Venus is not only one of the most intriguing bodies in our solar system, it also has a thick atmosphere and passes between Earth and the Sun. This combination of factors allows for the observation and measurement of its atmosphere. Techniques that are directly applicable to exoplanet study.

You can even contribute through citizen science. There is an IOS version and an Android version phone apps that will allow you to send your observations to a global experiment to measure the size of the solar system. Prior to the transit, you can use the app to practice your timing and see predicted times for your location. During the transit, you can use the app to assist you in measuring the time of the interior contacts. After the transit, you can use the app to access your data on a map. I recommend thouroughly reading the instructions so that you both recieve and send good information.

Links to some big experiments during the transit of Venus:

And finally, just a few fun links:

Friday, May 25, 2012

I'm Older and I Have More Insurance

If you've seen the 1991 movie Fried Green Tomatoes then you will remember this wonderful scene:

Believe it or not, this scene actually relates to today's post about territorial behavior in parking lots.

You are probably familiar with the concept of territorial behavior. In animals, it typically involves occupying a defined territory and marking and defending it against interlopers. This territory is desirable because it contains resources (food, mates, etc.). However, there can be risk involved in defending this territory, risk that must be weighed in a sort of cost-benefit analysis. If the risk is low you defend the territory and if it is too high you flee it. Now what about public territories? Those places that do not belong to any one individual but, instead, an individual occupies a portion of it for a short period of time. In this case, the territory is less important to the individual, and they only have minimal rights to occupy it. However, individuals occupying space in a public territory can show some territoriality. If you get a little more psychological with this train of thought then you start using terms such as "symbolic value," "identity," "control," and "competence." Basically, this is a way of explaining why an individual may defend a territory even if there is nothing to be protected or gained. And that is where we pick up the parking lot study.

An older paper published in the Journal of Applied Social Psychology tested these territorial behaviors in people leaving parking lots. The video example is of Evelyn Couch entering a parking lot and looking for territory. Here, the researchers are interested in whether the occupants of parking spaces defended those spaces even though their task at the location was complete and the space/territory no longer served any purpose for them. As with many psychological papers, this was broken down into three studies.

Study 1: Do departing drivers take longer to leave their parking spaces when someone is waiting for the space?
Here, the researchers observed 200 drivers in a mall parking lot and timed how long it took them to leave their parking spaces. The spaces were of prime real estate, in terms of mall parking, being the closest 52 spaces (excluding handicapped spaces) to the mall entrance. They started timing from when the departing shopper opened their car door until they had completely left the parking space, also noting if another driver was waiting for the departing driver's space. They also noted if the departing driver turned their head toward the waiting driver. They found that departing drivers took longer to leave their parking spaces if someone else was waiting for it. From this study it is unclear as to why they took longer. Sure, it could have been territoriality, but it also could have been caution to prevent collisions, distraction, or all sorts of other reasons.

Study 2: Do departing drivers take longer to leave their spaces because they are territorial or because of some other reason?
To test this they looked at four intrusion conditions (intrusion being the waiting car) in comparison to a no-intrusion condition. They also tested the distraction hypothesis by having someone drive by the subjects, independent of whether there was a car waiting for the space or not. They also tested the level of intrusion by having someone honk or not honk their horns. This study also found that drivers took longer to leave their parking spaces when another driver was waiting, regardless of the added distraction of a another car passing by. These departing drivers also took longer when the waiting driver was honking at them versus when they were not honking. Additionally, they found that male drivers took longer to leave than female drivers if the waiting car was of lower status or value than theirs. All findings that suggest territorial behavior.

Study 3: Are people aware of how a waiting driver affects how much time they take leaving a parking space?
In this study, the researchers gave questionnaires to 100 people who had parked at a shopping mall. This questionnaire contained scales that allowed the drivers to rate how they would feel while leaving a parking lot under three conditions: with  no one waiting, with one driver waiting, and with a driver waiting who honks their horn. They also rated their beliefs about how a driver waiting for their space and and honking driver waiting for their space would affect how long it would take them and others to leave. The survey results showed that people recognized their territorial behaviors but would leave faster if a car were waiting for them but not if that car honked at them.

I gotta say that if someone was sitting behind my car honking their horn at me to move faster that I would take my sweet time too. I don't even like that slow, creepy-, stalker-follow people do when they see you walking to your car. I'm tempted to weave through the aisles just to get them to stop.

Next I'd like to find a study that looks at how well people park between the lines in a parking space and how much space they leave on either side. If I have to crawl in through the passenger side of my car one more time I might start handing out tickets for parking like a jackass.

ResearchBlogging.orgRuback, R., & Juieng, D. (1997). Territorial Defense in Parking Lots: Retaliation Against Waiting Drivers Journal of Applied Social Psychology, 27 (9), 821-834 DOI: 10.1111/j.1559-1816.1997.tb00661.x

Wednesday, May 23, 2012

Seth Saves Science?

Seth MacFarlane is using his clout to bring back Cosmos. Here's an interview with Seth about science and his new show. I, for one, think it is a great idea (but I'm a little biased).

Sunday, May 13, 2012

Ants as Art

Andrey Pavlov is a photographer from Moscow, Russia and he takes wonderful pictures of ants. He spends hours setting up props and sets for the ants to explore, taking their pictures in wonderful detail. He doesn't use any digital effects on his photos, he simply uses his macro lens to capture their curiosity. Here are a few of his wonderful pictures:

View 80 more of Mr. Pavlov's ant photos here: Artist's Gallery

Story Links:
NY Daily News "Ants as art: Check out this f-ant-asy world"
Mirror "Weird ant-ics: Bugs pictured weightlifting and sewing a button"
The Telegraph "The fantasy world of ants: photographs by Andrey Pavlov"
Daily Mail "Antsy fantasy: Russian photographer creates a fairytale world with obliging insects"
Huffington Post "Andrey Pavlov, Russian Photographer, Takes Fairytale-Like Pictures of Ants"
Incrediblethings "Amazing Ant Photography"

Friday, May 11, 2012

Coprolite Happens

(image credit: Ron Morris, 1993; currently available as a t-shirt design, in print, and as a sticker)

Thursday, May 10, 2012

Dinosaur Farts: Climate Driver or Just Gas?

Hmmm, how do you begin a serious discussion about dinosaur farts? Maybe I should call it flatulence? How about methane emissions from sauropod posteriors? To be honest, it hasn't ever been something I've thought about before. A correspondence paper, published this month in Current Biology,on this topic caught my attention, and it caught the attention of several news outlets. Makes sense, I suppose. As one article put it, "It sounds like perfect journalist bait." Obviously perfect blogger bait as well. So I wanted to take a closer look at this paper and see what it's really talking about.

The paper, by researchers David Wilkinson, Euan Nisbet and Graeme Ruxton, concerns the methane produced by sauropod dinosaurs and if it helped to drive Mesozoic climate warmth. You'll remember our talk about sauropods from the Antarctic Sauraopod: No Longer a Cold Case post from January. These were often really really big creatures with a high level of diversity and large geographic range. It has even been suggested that they may have been a keystone species in many Jurassic and Cretaceous ecosystems.

But let's first start of with a modern comparison, probably one with which you are familiar: Livestock. Ruminant animals (cows, sheep, buffalo, and goats) have a unique digestive system that can convert otherwise unusable plant material into food. This digestive system, produces methane, a potent greenhouse gas that can affect climate directly through its interaction with long-wave infrared energy and indirectly through atmospheric oxidation reactions that produce carbon dioxide. A paper published in the Journal of Animal Science in 1995 estimates that ruminant livestock can produce 250-500 L (66-132 gallons [US, liquid]) of methane per day. The U.S. EPA estimates this to contribute about 80 million metric tons of methane annually. Ruminant livestock are one of the largest methane sources in the world. If you look specifically at cattle (as the J. Anim. Sci article does), they typically emit six percent of their ingested energy as methane. In the U.S. (which as about 100 million cattle) this accounts for about 5.5 million metric tons of methane per year. That's 20 percent of the country's methane emissions! I bring up this comparison because it is directly compared to sauropod emissions in this paper.

Now, dinosaurs, particularly sauropods, are a lot bigger than cows. But in terms of abundance, they were probably less numerous, with only a few tens of individuals per square kilometer. The digestive biology of these animals has, for a long time, stumped paleontologists. Sauropods have small teeth that are shaped for gripping and clipping plants, but not really for chewing or mashing those plants. How these plants were broken down is a bit of a mystery. There have been several hypotheses from small, swallowed stones called gastroliths to microorganism-assisted fermentation. The latter, as Wilkinson, Nisbet and Ruxton point out, could be the methane producing mechanism in these animals. However, it is unlikely that these dinosaurs had an endothermic, mammalian-style metabolism. And very unlikely that they were ruminant herbivores. So the authors did some calculations for these dinosaurs based on modern non-ruminant herbivores where methane (litres per day) = 0.18 (body mass in kg)0.97. This means that for a 20,000 kg sauropod (about a medium sized Apatosaurus louise or "Brontosaurus"), the methane emission would be 2,675 liters per day from one animal. This scales up to 6.9 tonnes/km2 of methane per year and a global methane production of 520 Tg (520 million tonnes) annually. Their estimation is similar to the amount of methane humans are currently pumping into the atmosphere each year rather than cows specifically.

OK. So what do we take away from this? Many news outlets have seized onto this and made pretty outrageous claims ("Dinosaurs may have farted themselves to extinction"....uhh, wow). The fact is that we don't know for sure.We don't know what the digestive systems of these animals was like. We don't even know if they produced methane at all. These estimates were derived from a modern animal model based on the methane output of rabbits and guinea pigs fed a hay-only diet. They might make me hand back my degrees if I called that a really great animal corollary. But, as one article put it, "If you know about croc fart research, please chime in." Then there is the issue of sauropod abundance. The estimations of population size were derived from the fossil record of the Morrison Formation, a 150 million year old sedimentary rock sequence in the western U.S. and Canada. Is this Formation an accurate slice of a prehistoric ecosystem? While we are on the topic of ecosystem, you should also consider the Mesozoic era which had slightly shorter days, more land area, and a warm, moist climate that supported greater primary productivity. How does this factor in?

Ultimately, the paper doesn't say that dinosaurs farted themselves to extinction. It doesn't mention dinosaur extinction at all. What it actually says is that "methane was probably important in Mesozoic greenhouse warming" and that their "calculations suggest that sauropod dinosaurs could potentially have played a significant role in influencing climate through their methane emissions." That's it. Dinosaurs may have farted. And big dinosaurs may have farted bigger.

Read the correspondence paper for yourself here:

ResearchBlogging.orgWilkinson, D., Nisbet, E., & Ruxton, G. (2012). Could methane produced by sauropod dinosaurs have helped drive Mesozoic climate warmth? Current Biology, 22 (9) DOI: 10.1016/j.cub.2012.03.042

More information about modern ruminant livestock emissions can be found at:
U.S. EPA site on ruminant livestock
Johnson, K.A. and D.E. Johnson (1995) Methane emissions from cattle. Journal of Animal Science: 73(8), 2483-2492.

And a couple of good articles about this paper:
Smithsonian's Dinosaur Tracking blog's post "Media Blows Hot Air About Dinosaur Flatulence"
Pharyngula's post "The reports of dinosaurs dying of farts are greatly exaggerated"

(image from the American Museum of Natural History)

Wednesday, May 9, 2012

Saturday, May 5, 2012

The Transparency of Nature

Here is some of the beautiful work from Japanese artist Iori Tomita and his series "New World Transparent Specimens". He uses a scientific techniques originally established to study the skeletal system, refining it for his art. For each specimen, Tomita first removes the scales or skin of specimen that has been preserved in formaldehyde. Then he leaves the specimen in a mixture of blue stain, ethyl alcohol, and glacial acetic acid. Next he enzymatically breaks down the proteins and muscles using the trypsin, stopping the reaction as soon as the specimen is transparent but before it loses it's form. Finally, he stains the bones magenta by soaking the specimen in a solution of potassium hydroxide and red dye, and he stains the the cartilages blue similarly before preserving the specimen in glycerin.
Here are just a few of his amazing images. Visit his website for more: New World Transparent Specimens

(via designboom)

Friday, May 4, 2012

Biodiversity Good, Extinction Bad, Climate Change Worse

This phylogenetic tree of life was created by David Hillis, Derreck Zwickil and Robin Gutell. It depicts the evolutionary relationships of about 3,000 species throughout the Tree of Life. Less than 1 percent of all the known species. Download the pdf from the Hillis Lab.
I hope we can all agree that: biodiversity = good, extinction = bad. This incredibly simplistic statement could be taken a number of ways, but, as we are doing with so many things lately, let's look at it through the lens of global climate change. How important is maintaining biodiversity? How bad is extinction? And how do these factors affect the function of ecosystems?

It has been established that the current rate of species extinction has far outpaced those rates we see in the fossil record. By "far outpaced," we're talking about a sixth mass extinction within 240 years (that's the projection as of now at least). There have been hundreds of experiments that have tackled this question of biodiversity and ecosystem processes, particularly in plant systems. Take a big statistical spoon and mix all the experiments together and you find that the loss of plant biodiversity affects biomass production and decomposition. Experiments to manipulate biodiversity in controlled environments have actually found that biodiversity can act as an independent variable that directly controls such ecosystem functions as nutrient cycling and biomass production. Studies have shown that greater biodiversity also increases these effects over time, likely by either a saturating response curve (large increases in ecosystem functioning as species are added to communities, leveling off after a while, with any additional species only increasing ecosystem functioning by small amounts) or a linear response curve (think: straight[er] line). These temporal aspects of diversity-productivity relationships are still somewhat obscure, particularly the mechanisms of these changes over time. Now add global climate change. It is uncertain the sizes these effects will be and how the direct effects of other types of environmental change (like atmospheric composition, nutrient pollution, etc.) will affect ecosystem functioning.

So far the month of May has yielded some big, interesting papers on the impacts of biodiversity loss. A paper by Peter Reich et al. in Science takes a look at the time component of biodiversity loss and how it affects the growth curves I mentioned above. In this paper, the authors present data from two long-running (≥13 years) grassland biodiversity experiments at the National Science Foundation's (NSF) Cedar Creek Long-Term Ecological Research (LTER) site in Minnesota, USA: the “Cedar Creek Biodiversity Experiment” (BioDIV), planted in 1994–1995, and the “Biodiversity, CO2, and N Experiment” (BioCON), planted in 1997. At these sites a number of plots are planted with different numbers of species of plants including various C3 and C4 plants and nitrogen (N)-fixing and non-fixing dicotyledonous herbs. The authors looked at the effects of diversity on biomass productivity and found that productivity (aboveground and belowground) increased and became less saturating over time; the diversity-productivity relationship became more linear and less strongly decelerating over time. Their evidence suggests that this may be due to the accumulating effects of complementary resource acquisitions and use and such ecosystem feedback effects as soil N cycling. Basically, the plants are complementing each other, increasing the functional diversity of the system. The greater the diversity of plants the more natural components (carbon, water, etc.) of the system can be capitalized on over time, a result that short-term experiments may underestimate.

The Cedar Creek LTER  site (Credit: David Tilman, UMN)
These ideas were discussed in a perspective paper by Bradley Cardinale, published in the same issue of Science. Here he points out that if Reich et al.'s conclusions prove to be general then they will have quantified how ecological impacts of extinction scale through time. Certainly not an insignificant conclusion. The Reich et al. paper doesn't spend a whole lot of time delving into niche theory (relational position of a species or population in an ecosystem, the where and how an organism makes its living), to the point that the word "niche" isn't even in their paper. But it is essentially what they are talking about, or at least hinting at.When species are accessing different resources then they are filling different niches, and the more diverse the species the more niches they can exploit. Cardinale knows quite a bit on this topic as he himself published a very nice study last year where he used a model system of stream biofilms, experimentally adding extra niche opportunities, to test the effects of algal biodiversity on water quality, showing that the more species in a stream the more ecosystem functions increased. Cardinale's examination of the Reich et al. paper points out some interesting points about the consequences these curves may have for conservation, specifically making the point that if the conclusions of the study hold true then biodiversity loss has probably already begun to degrade essential ecosystem processes.

Figure from Cardinale (2012)
Another paper published this month in Nature also takes a look at biodiversity loss as a driver of ecosystem change. In their study, David Hooper et al. use a series of meta-analyses of published data to look at the magnitude of the effects of species loss on productivity and decomposition. They focused on these two processes because they are major biological processes influencing carbon storage and other ecosystem services. Their analysis statistically summarized existing data, compared the environmental effect sizes to the estimated effects of species loss derived from a database of 192 peer-reviewed publications, summarized the results of 16 experiments that simultaneously manipulated plant species richness and some other environmental change variables (elevated CO2, nutrient pollution, etc.), and assessed a large range of projections of species loss. This analysis showed that the biodiversity loss in the 21st century could rank as one of the major drivers of ecosystem change. In areas where local species loss is low (1-20%) there will be negligible effects. In areas of intermediate loss (21-40%), species loss is expected to decrease biomass production by 5-10 percent. In areas of high species loss (41-60%), the effects would rank alongside other major drivers such as warming, ozone, and acidification. They estimate that a 50% species loss will reduce biomass production by 13%. These reductions in biomass and decomposition don't sound like a lot, but, at least for decomposition, they are equal or greater than the effects of CO2 or nitrogen. Hooper et al. also found that species loss would need to exceed that of prior mass extinctions (≥75% loss) to rival those environmental changes that have the greatest effect on primary production. Not a senerio that we will probably see globally, but locally or within certain taxa it could be realized if current extinction rates continue. Additionally, the types of species that are lost also have a huge effect. A good example of this was shown nicely in the Reich et al. paper above. When you add in other environmental changes to the meta-analysis it reinforces these conclusions.

I hope I've made my point that biodiversity = good, extinction = bad, and climate change = worse. I also hope I (and these authors) made the case that the loss of biodiversity isn't just a consequence but rather a major driver in key processes that affect our planet. Think about it.

You can read more in the articles:

ResearchBlogging.orgReich, P., Tilman, D., Isbell, F., Mueller, K., Hobbie, S., Flynn, D., & Eisenhauer, N. (2012). Impacts of Biodiversity Loss Escalate Through Time as Redundancy Fades Science, 336 (6081), 589-592 DOI: 10.1126/science.1217909

ResearchBlogging.orgCardinale, B. (2012). Impacts of Biodiversity Loss Science, 336 (6081), 552-553 DOI: 10.1126/science.1222102

ResearchBlogging.orgHooper, D., Adair, E., Cardinale, B., Byrnes, J., Hungate, B., Matulich, K., Gonzalez, A., Duffy, J., Gamfeldt, L., & O’Connor, M. (2012). A global synthesis reveals biodiversity loss as a major driver of ecosystem change Nature DOI: 10.1038/nature11118

ResearchBlogging.orgCardinale, B. (2011). Biodiversity improves water quality through niche partitioning Nature, 472 (7341), 86-89 DOI: 10.1038/nature09904

And here are some additional write-ups:
NSF story "Ecosystem Effects of Biodiversity Loss Rival Climate Change and Pollution"
NSF story "Plant Diversity Is Key to Maintaining Productive Vegetation" also at Science Daily

And some related websites you may want to visit:
Cedar Creak LTER site
LTER Network
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