Scientist (Paleontology, Geochemistry, Geology); Writer (Speculative and Science Fiction, plus technical and non-technical Science); Mom to great boy on the Autism spectrum; possessor of too many hobbies.
There are a lot of adjectives I could end that sentence with. Most of them would not be good. Many are definitely not G-rated.
The past two days have been spent in a not-to-warm-and-snuggly place called Proposal Hell. Some of you have probably been there before. It’s close to finished; the deadline is Friday. But in the meantime, there has been a certain amount of banging the head on the desk.
What’s most frightening is that my contribution to this proposal has been fairly minimal. It’s a collaborative proposal. All I had to come up with is a budget. Well, ok, I admit it. Preparing budgets is really un-fun. There’s overhead rates and fringe benefits rates and equipment costs and the list goes on and on. And you have to write a separate budget for each year of the grant. And don’t forget cost of living increases!
</headdesk>
I’m up for air here for a moment to say hi to everyone. Then it’s back to the grindstone.
National Blog Posting Month – February 2013 – Love
Prompt – What is the most romantic book you’ve ever read?
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I’ve read a few books in my day. I can’t say I’ve ever gone for romance as a genre. Most of the stories I really like have action and adventure, and the occasional love interest. But ‘romantic’? Yeah, I don’t know.
Then again, if I’m allowed to do this, I must admit that the book that I’m writing, Prince of Herongarde, is action and adventure, with a love story built in. So maybe, the romantic story I want to read is the one I’m writing?
There are lots of names for it, some good, some bad: Climate Change, Global Warming, Climate-gate, The Climate Hoax. Unless you’ve had your head in the sand, you’ve heard at least one of these things. You know that there is a lot of talk about how every year seems to be warmer than the last – “the warmest on record” – and that there have been a lot of wacky weather phenomena of late, including Hurricane Sandy, heat waves in Australia and Europe, massive wildfires in the western United States. Some reports are pretty alarmist, while others claim that these are merely coincident anomalies that we only know of due to more complete modern measuring techniques and records. Some say that the Earth is warming at an alarming rate and we need to prepare for a “The Day After Tomorrow” type scenario, while others say that we have no need to worry and that it’s all hype. And really, how bad can one or two degrees of temperature increase be?
If you’ve read other posts of mine, you probably know where I stand on this. For this post, my views on the legitimacy of modern global warming are irrelevant. What I want to address here is not whether warming is occurring, but what would happen if those noisy scientists are right and we are heading toward a warmer Earth? What could the possible outcomes of a few degrees of warming be? There are models, of course, all mathematical and computerized, that show where things will get wetter or drier and such, but let’s think about something more real.
What if the hype is correct and we are warming? What will happen if we do nothing to mitigate it?
The fossil record provides an opportunity to look at past climate changes and see what effects these changes had on the animals that were alive during that time. The fossil record shows that there have been multiple episodes of global warmth in Earth’s history, much warmer than is projected as a possible outcome of today’s warming. But being warm and warming rapidly are two different things. Gradual warming occurs slowly enough that organisms can adapt. But modern warming is occurring within a single to just a few generations of animals, much too quickly for adaptation to occur. What happens then?
Does the fossil record capture any past episodes of rapid global warming? If so, what happened?
The short answer is ‘yes,’ and it was bad news for many animal groups.
The specific example I will use is the Paleocene-Eocene Thermal Maximum (PETM). This is an episode of global warming that occurred about 55 million years ago (about 10 million years after the dinosaurs went extinct). The entire PETM lasted 150,000 to 200,000 years, with the warming occurring over the span of about 10,000 years. Depending on what you read, the warming was between 5-9° Celsius (9-16° F). Compare that with modern projections of warming of 4° Celsius (or more) in a few hundred years. Warming rates are much faster today than they were at the PETM, and rates at the PETM were much, much faster than most other rates of climate change recorded in the rock record.
The warming associated with the PETM is particularly interesting for two reasons. 1) It’s thought that the warming was due to an increase in carbon dioxide in the Earth’s atmosphere, much like today’s warming. 2) Mammals were around then, and the dominant large-bodied animals living on land. We can look at the record of change in mammals at the PETM as an analogue for what might happen if modern global warming is ‘true.’
The chart above shows a lot of things. It was published in 2003 in Geological Society of America Special Paper 369. It is available here, from Philip Gingerich’s personal web page focusing on his research on the PETM. I suggest reading the entire paper to get the full context, but for the sake of this post focus only on the columns on the right hand side. There are two columns labeled ‘stable isotopes,’ and a series columns (some highlighted in green and others in red) that represent the stratigraphic ranges of specific vertebrate groups. The heavy red line marks the Paleocene-Eocene boundary, and the box in the stable isotope column encloses the isotopic evidence of the PETM – a negative spike in carbon isotopes and a positive spike in oxygen isotopes. It is the positive spike in oxygen that provides the evidence of warming. The negative spike in carbon provides information about the source of the warming (carbon dioxide in the atmosphere). The details of how the isotopes provide such information is a topic for a different blog post.
Focus now on the highlighted vertebrate groups. In green are the Plesiadapidae. Plesaidapids are a group of mammals thought be closely related to modern primates. They go extinct at the Paleocene-Eocene boundary. Modern primates, highlighted in red, appear after the Paleocene-Eocene boundary. It’s possible, then, the the PETM, was responsible for the extinction of the the plesiadapids and appearance of modern primates. Perhaps one evolved into the other, we are not sure at this point, but the loss of one and appearance of the other coincides with the PETM.
You also see, highlighted in red, the first appearance of the groups Perissodactyla and Artiodactyla. These are all the modern hoofed mammals. (Perissodactyla includes horses, rhinos, and tapirs. Everything else is in the Artiodactyla.) It is the appearance of the first perissodactyl, Sifrippus (also called Hyracotherium or Eohippus) that defines the beginning of the Wasatchian North American Land Mammal “age” which is thought to be coincident with the Paleocene-Eocene boundary. Prior to the PETM, there were no true hoofed mammals, though it’s though that the ancestors to perissodactyls and artiodactyls could be found in a group of mammals loosely called the condylarths. Condylarths dwindled after the PETM, to be replaced by the recognizable, modern groups of mammals.
Thus it’s possible that rapid global warming at the Paleocene-Eocene boundary resulted in the rapid evolution of mammalian species, resulting in the loss of many groups that had previously been dominant, and their replacement with new groups. This is a big change. This is not an example of just a few species going extinct. We’re talking about entire orders of mammals here, including the Order Primates, of which we are a member.
Now consider again that warming at the PETM took place over several thousands of years. Modern global warming is occurring over several hundreds of years. If warming at the PETM forever altered mammalian history, what would modern global warming do? Perhaps we should think about this before we say that there’s no need to be concerned.
***UPDATE***
This post has been translated into Spanish by Jorge Moreno-Bernal, a student at the University of Nebraska-Lincoln. See the translation here. How cool is that?
I was recently interviewed by Gary Vecchiarelli for a lovely website called Jersey Boys Hunt Dinosaurs. He was particularly interested in my take on the science of paleontology from the perspective of a geoscientist.
It was a fun little interview, and might be of interest to any budding paleontologists or folks just interested in what my scientific world is like. Read the interview here.
You should visit the Jersey Boys Hunt Dinosaurs website and/or follow them on Twitter.
Below are the answers to a series of questions asked of me by a friend from way back in high school. His questions were interesting enough, that I thought I’d post the answers here. Other folks might be interested, too.
These answers come off the top of my head. I did not research them, so I might have a few details wrong. But the overall story should be about right.
A meteor hit in Russia’s Ural mountains at about 9:30 in the morning, local time. The following shock wave (whether from a sonic boom, or the impact itself) caused the shattering of windows and resulted in nearly 1000 injuries, mostly from broken glass. As yet, no fatalities have been reported. The videos and photographs of the event are astounding!
Meteor streaking across the Russian skies…
Update:
From NBS’s TODAY. Neil deGrasse Tyson: Radar could not detect meteorite.
A paper in the journal Science published last Friday provided more support that the asteroid impact that happened about ~65 million years ago near Chicxulub (along the Yucatan peninsula of Mexico) probably dealt the deathblow to the dinosaurs.
The new study shows that, within the measurement precision of age, the impact event occurred at the same time as the extinction of dinosaurs. The impact and the extinction occurred no more than 33,000 years apart. Previous studies have argued that there was a substantial time gap between the impact and the extinction.
Arrow points to a coal layer just above the K-T boundary in Montana
This does not preclude the possibility that dinosaurs were already on their way out prior to the impact, but it gives more confidence that the impact itself marked the total demise of dinosaurs.
A fascinating topic in biology is how, exactly, to migrating organisms know where their going. How do birds know in what direction and how far to fly each winter? How do Monarch butterflies find their roosting sites in Mexico after being born in the United States? How do salmon find their way back to the streams where they hatched? New research had provided an answer to at least the last of these questions.
Salmon swimming upstream to spawn.
Many organisms have tiny bits of magnetite in their brains. Even the most primitive of organisms, bacteria, are known to possess magnetite, which they use to orient themselves to the Earth’s magnetic field, much like how a compass needle points North. Organisms can then orient themselves North to South.
The Earth’s magnetic field, simplified.
At a first pass, it is easiest to think of the Earth’s magnetic field as a simple bar magnet inserted along the Earth’s axis of rotation. But the Earth’s magnetic field is much more complex than that, resulting in it actually being quite different and unique at every point on the Earth’s surface. These differences make every place magnetically unique, and with a sensitive enough magnetometer, one can tell where they are based only on the Earth’s magnetic field.
The Earth’s magnetic field, showing its real complexity.
So a salmon, when it decides to spawn, uses the magnetic field to identify the place where it first swam from river to ocean. Once it’s there, the salmon just starts swimming upstream.
National Blog Posting Month – February 2013 – Love
Prompt – How did this Valentine’s Day compare with Valentine’s days of years past?
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Yesterday was Valentine’s Day. I may have griped in earlier posts about how uninspiring past Valentine’s Days have been. So how did this one compare?
My husband gave me roses yesterday morning. That’s how I got out of bed. That’s never happened before. It was a nice way to wake up. We had a typical work day, going our separate ways as always, but met up again for dinner. I was worried that dinner was going to be the usual frantic meal that one so often gets at a restaurant, especially when one has their child along, but it wound up being a pleasant meal. The boy was calm and quiet and my husband and I enjoyed an unrushed steak dinner. And there was wine. I’m sure that helped. And then I ate dessert. It was delicious.
We got home just in time for the boy’s bed-time. My husband and I were both exhausted, so we quickly followed suit. The day was mostly filled with work, but the few conscious moments my husband and I shared were enjoyable.
When all was said and done, and I look back on yesterday, I think this was one of the best Valentine’s Days on record, at least for my adult life. Thank you, husband, for making that possible!
National Blog Posting Month – February 2013 – Love
Prompt – How do you feel about Valentine’s Day?
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When I was a kid, Valentine’s Day was totally my favorite holiday. I loved all the hearts and the expressing of love. I had my crushes (remember Indiana Jones?), and could spend all day thinking about them.
As I got older, I got a little jaded about Valentine’s Day. I never had a boyfriend. Or if I did, they wouldn’t do anything special for the holiday. Usually they’d forget. I got through high school, college, and graduate school feeling more and more removed from Valentine’s Day and the entire concept of love. Sure, I’d had a few boyfriends over the years, but I still hadn’t met ‘the one.’
In 2000 as I prepared to defend my Ph.D. dissertation, I realized that it was a possibility for me to do the defense on Valentine’s Day. I jumped on the chance. This, I thought, would finally give me something to celebrate on the 14th of February. That’s exactly what I did.
That day, I dyed my hair bright red. I donned all black clothes. I went into the gauntlet. Somehow, I emerged victorious, despite the fact that I couldn’t actually answer any of the questions asked of me by my committee. But I won! They signed off! I had my Ph.D.! (OK, really, I had a bunch of revisions to do, but still, I was basically finished.)
In November of 2000 I did finally meet the guy I ultimately married. You might think, then, that my opinion of Valentine’s Day has changed. Well it hasn’t. He forgets. Or does the usual guy thing of buying the card on the way home from work. That’s OK. I’m over it. To me, February 14th is Doctoral Day. And I still have cause to celebrate.
A while ago, I proposed an experiment in which I collected snow at regular intervals during a Lake Effect Snow event. I made some predictions and collected the snow, and have now finally succeeded in analyzing the waters. The results weren’t quite what I expected.
I had predicted that isotopic values in the snow would not change over the course of the event. This was because all the snow would be forming directly off the lake, which is only a few miles away from the collection point. (This is in contrast to other synoptic storms, where we have precipitation coming from a single vapor mass, which will evolve isotopically over time. Read more about that here.) The temperature of the lake water, and its isotopic value would not change consequentially over the course of such a short event.
What I saw instead was an increase isotopic values overnight, and then a decrease the next day.
Results from January 22-23 Lake Effect Snow Event. Click to enlarge.
I compared the isotopic values with measures of air temperature during that period of time. I selected first the air temperature measured at the Rochester International Airport (ROC). Isotopic values do track temperature changes, thus I realized that what is most likely happening is the fractionation of isotopes (the selective evaporation of the heavier versus the lighter water) in both the formation of the water vapor off the lake and more importantly the freezing of that vapor into snow which is changing over time due to temperature.
I realized that ROC is actually sufficiently removed from the lake, that its measured temperatures are likely to be different than those directly adjacent to the lake. Shoreline temperatures are moderated by the warmth of the lake water itself. Temperatures between ROC and the lake shore are known to differ by as much at 20 or 30 degrees. I retrieved data from a WeatherBug weather station right on the lake shore (Forest Lawn Beach, FLB on the plot. Thanks to Parker Zack and Kevin Williams for helping me find this.) as it happens, for this snow event, temperatures at ROC and at FLB track each other quite closely for much of the event, until the event peters out. In either case, isotopic values track air temperatures.
The snow gets isotopically ‘heavier’ during the colder overnight hours. Does this make sense?
Under warmer conditions, more of the heavier isotope will be incorporated into water vapor. In isotopic terms, this means that δ18O and δ2H of the vapor will be more positive when air temperatures are warmer. For freezing (or crystallizing snow), one might expect that more of the heavy isotope would remain in the vapor when the air temperatures are warmer. Or, since we’re measuring snow, warmer air temperatures means isotopically ‘lighter’ snow. If it’s colder, more of the heavy isotopes go into the snow, causing the δ18O and δ2H values of the snow to become more positive.
Oh thank goodness! It does make sense! That is if the changes in isotopic value of the snow is directed by air temperatures during the crystallization of the snow and we assume that air temperatures have minimal effect on the fractionation during evaporation.
Can we make the latter assumption?
I think we can. The temperature of the water is close to freezing (approximately 4 degrees C, data found here). Evaporation stops if the water freezes. The difference in fractionation of evaporating water at 4° C and 0° C is negligible (see article here). We can assume it is essentially the same. Thus any isotopic change we see must be due to changing air temperatures during the freezing of snow.
Other observations
Snow was collected at two sites in Wayne County affected by this Lake Effect event. One site in the Town of Williamson, and one about seven miles further west in the Town of Ontario. Isotopic values of snow from these two sites are essentially the same and follow the same pattern. Thus we can say there is likely to be little lateral isotopic variation in snow isotopic values. That makes sense given that the snow is all coming from evaporation off the same lake.
Further work
If the isotopic value of the original lake water is known, along with air and water temperatures, it is possible to look at the extent of fractionation both during evaporation of the lake water and crystallization of the snow. We were unable to collect a lake water sample at the onset of this event, but we do have one collected from November of 2011, as well as snow measurements also from 2011. Alas, for the November 2011 event, we lack temperature data. But we can make some assumptions and try to look at fractionation. I’m working on those calculations now. And they make my head hurt.
For the next lake effect event, I’m hopeful we can get a sample of Lake Ontario water for a starting point. We will also collect snow from the weather station at FLB to see if there is a gradient in the snow isotopes from nearer the source to farther outboard (like Williamson). Sublimation may be occurring in the clouds, which might cause the snow to be isotopically heavier than ordinary fractionation would predict, in which case we would predict that shoreline snow would have more positive δ18O and δ2H values than snow collected further inland.
National Blog Posting Month – February 2013 – Love
Prompt – If you could send out valentines this year as you did back in grade school, what type of valentine would you send out to your blogosphere class?
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The horrifying thing about this prompt today is the realization that my grade school son must bring valentines to class tomorrow. And I totally forgot. It’ll be a quick stop at Wally-World tonight, I’m sure.
What will I hand out to my blog-buddies tomorrow? Probably something silly with a bad pun in it. Perhaps something about swordplay and armor? “Brevor I knew you, I didn’t know what love was.” (I admit, I lifted that from the Higgins Armory MuseumFacebook page.) Something paleontological? “I always Smilodon when I see you.” Isotopes perhaps? “Let’s fractionate together and call ourselves clumped!”
I’ll come up with some ‘bad’ valentines and will probably post them to Twitter. Maybe you should watch…
Penny Higgins - Storyteller • Artist • Scientist 