Spectrogram animation

February 22, 2014 — Leave a comment

As some of you may know, I’ve been learning about video editing lately. For the most part, it revolves around the online introductory oceanography class I’m helping develop, but there are a couple of other things I’m playing around with too.

My family is visiting from Canada, and my brother-in-law, Christian, has been showing me some cool tricks in Adobe After Effects. I often use a spectrogram to help describe how we “look at” sounds. It is pretty straightforward if you’ve seen them before but can be a bit strange the first time you see one.

In the past, I’ve showed a spectrogram and then included a separate sound file to show how they work, describing how they fit together in words. But I’ve finally figured out how to pull it all together in After Effects, and it’s surprisingly easy.

This video is pretty simple and is not much more than a couple of masks and a glow effect, with (of course) strategically placed keyframes. Here it is – enjoy!

Argo Floats!!

January 26, 2014 — 2 Comments

If you have ever sat there and wondered to yourself, “What are Argo Floats? And why are they the coolest things ever?” – Look no further, my friend. I have just the (science-comics) video for you.  It’s based on an interview I did a while back with Rick Rupan, who runs the Argo Floats program at the University of Washington.

This format is a bit experimental for me, but I LOVE this style, and wanted to give it a whirl. I sort of just jumped in, and because I was (am!) so very clueless, I asked basically everyone I know (and some people who I don’t know) to give me feedback. The suggestions started rolling in, and I tried to incorporate as many as I could.

I really hope you enjoy this, and if I’m lucky, you’ll even learn something along the way :-) I do plan to make more of these, so if you have any feedback for me after watching this, it would be a great help.

Okay, enough babbling. Go ahead and watch the video already!

 

 

 

Doodle videos, heck yeah!

January 23, 2014 — 3 Comments

My latest project is figuring out how to make a doodle video. Or a speed drawing animation. I don’t actually know what they’re called, but you’ll get the idea if you check out the videos below. I started off attempting to use my iphone. Setting the iphone up to record was… awkward:

completely professional.

I did my video this way, posted it to youtube, and got a bunch of feedback from my awesome Facebook and Twitter friends. I tried to take that feedback into account as best I could and eventually moved on to my Nikon D5100 (dSLR).  I even set it up on an actual tripod (Thanks, Andrew Shao!).

slrvideo

Recording on my SLR was pretty easy too, once I got it adjusted. I did have some issues with focusing – not that it was hard, I just kept forgetting to check. oops. Editing for the SLR video was done in iMovie, and the audio was recorded in Hindenburg Journalist. Here’s a 30-second sample from this experiment. I hope that you agree that it has improved, at least marginally, from my first attempt!

Next, I decided to try doing the video using Camtasia. Luckily they have a free trial, so I gave that a whirl. Camtasia is for screen recording and video editing, and was really easy to jump into and start using right away. I did the drawings in Adobe Photoshop using my Wacom Intuos4 tablet/stylus. Here’s the 30-second sample using the “all-digital” method:

Dear reader, if you have been patient and kind enough to actually read all this, and more importantly, watch the two videos, please feel free to give me feedback in the comments (below) or in email or on Twitter or Facebook!

According to John, the best thing about Sharknado is that they drive around in a Landcruiser, quite a lot like this one:

LandcruiserMtBakerCloseup-1

John’s 1987 Toyota Landcruiser

If you know John at all, you know that he LOVES that truck, and spends large chunks of his free time fixing it, taking it apart, restoring it, replacing parts, etc.

Here’s a sample of his Sharknado commentary:

sharknado_landcruiser

The commentary continued even after the Landcruiser was obliterated, even if only to berate all other vehicles that turned up in the movie. Especially Hummers.

sharknado_comic2

All in all, despite the filmmaker’s poor decision to destroy the world’s best truck, Sharknado was as epic as we ever could have hoped for in our wildest dreams. We encourage you all to enjoy it this holiday season.

sharknado_poster

It started with “drunk” pelicans. While studying aquatic sciences at the University of Santa Barbara, Liz Tobin noticed that there was something wrong with the fish-gulping birds.  They exhibited unusual behavior, getting hit by cars, and sometimes simply falling out of the sky. The pelicans suffered from seizures induced by domoic acid poisoning, a particularly dangerous affliction when it hit mid-flight.  Biologists traced the source of the poisoning to rapid springtime growth (bloom) of Pseudo-nitzschia, a tiny, single-celled organism, distantly related to the giant kelps thriving in nearby coastal waters.  Small fish and shellfish consume these algae, and although they are not harmed, they store the toxins produced by algal cells and pass them on to their predators, including seabirds and marine mammals.

Scientists refer to these incidents as harmful algal blooms, or HABs.  They are not restricted to the waters of southern California, though.  And Pseudo-nitzschia cells are not the only culprits.  There are a number of other algal species that can cause trouble for local marine ecosystems. HABs occur in coastal waters around the globe, with larger and more frequent blooms being linked to a warming sea surface [1] and also to increased nutrient runoff from land [2], which is a common by-product of animal or plant agriculture.  Local economies suffer due to tourism losses and local residents can’t harvest shellfish from their beaches.

After wrapping up a bachelor’s degree at UCSB, Liz moved on to graduate school at the University of Washington so that she could study harmful algal species in Puget Sound.  One of the species she’s interested in is Alexandrium catanella, another single-celled marine alga that produces a suite of deadly neurotoxins causing paralytic shellfish poisoning, or PSP.  Alexandrium blooms can become so intense that they give the water a reddish-brown tinge, often called a “red tide” (although they don’t always cause water discoloration).

Oysters

If you eat a shellfish that has accumulated Alexandrium toxins, a series of unpleasant events unfolds. First, your fingers and toes will tingle and your lips will feel numb.  Next, you may become nauseous and unsteady on your feet.  If the toxins hit you at full force, your diaphragm will become paralyzed, which means that you are unable to pull oxygen into your lungs.  Without prolonged artificial respiration, a severe case of PSP can lead to death in a matter of hours.

In recent years, poisoning cases in Washington State have been rare, but they do happen. Washington Department of Health aims to prevent outbreaks by regularly testing shellfish along Puget Sound beaches.  Commercially harvested shellfish are tested exhaustively before hitting the markets. Unfortunately, it’s tough to predict the severity, location, and timing of an Alexandrium bloom ahead of time. That’s where Liz’s work fits in: she’d like to improve our ability to forecast where those blooms will happen ahead of time so that public health officials, fisheries managers, and the shellfish industry have more time to react.

LifeCycle

Alexandrium cells have a comfort zone, she explains.  They grow and divide furiously when the days are long and the surface waters are warm.  Once the spring bloom ramps up, zooplankton, fish, and shellfish feed on the algae, eventually decimating Alexandrium populations by early to mid summer.  Less Alexandrium cells means less food for their predators, and their predators begin to die off or find food elsewhere.  By late August, with newly lowered predation pressures and plenty of sunlight, a second bloom typically occurs.  As the season draws to a close, Alexandrium  algal cells feel the effects of shorter days and less sunlight.  They struggle to grow and divide and at some point cut their losses and transit down to the sediment to wait out winter.  -Settled into the muddy seafloor, they shift to survival mode, also known as the “cyst” stage.  The exact conditions that send them into their cyst stage are poorly understood, as are  the details of how they wake up and make their way to the surface come springtime.

Liz is particularly interested in how the Alexandrium cells swim, even though they are mostly at the whim of the currents.  Tides rush in and out twice each day, racing through narrows and washing languidly over mud flats.  Rivers pour into Puget Sound with irregular pulses of freshwater from rain and springtime snow melt. Alexandrium algal cells propel themselves through the water using a small whip-like appendage called a flagellum, but because of their tiny size – only about a third of the width of a single human hair – they can’t overcome even the weakest currents. However, if Liz knows their vertical swimming capabilities, she can better understand how quickly Alexandrium cells migrate from the seafloor to the surface (where blooms occur) and back again.

A lot of researchers, Liz included, study Alexandrium in the lab.  They blend solutions of water and various chemicals to imitate seawater, and observe how the cells behave and react to a variety of environmental triggers.  One of the labs she works in is a tiny bunker-like space on the second floor of the Ocean Teaching Building.  Two long black tables running along either side of the room are covered by a hodge-podge of beakers, elaborate video recording setups, and circuit boards sprouting nests of red and white wires.  At the back of the room, a giant insulated door opens to a fully programmable walk-in refrigerator, where algal cells can be subjected to controlled shifts in temperature and light.

Even at their best, however, lab experiments can’t possibly recreate the many complexities that exist in the natural world.  Liz knew that if she could monitor the emergence of the Alexandrium cells from the sediments she could combine those observations with detailed fluid flow models to better predict where the cells would eventually concentrate.  The only problem was that there were no “off-the-shelf” instruments that were capable of doing what she wanted.  So she set out to build her own.

soldering

When she starts describing the instrument she’s working on, I interrupt.  Pushing my notebook and pen across the table, I ask her to sketch her design for me.  She draws a tube a few inches in diameter, sitting upright on the seabed.  On one side of the tube a camera in waterproof housing points into a tiny window to capture any Alexandrium cells swimming past.  The end of a plankton trap sits on top, ready to catch any upward-swimming cells so they can be later compared with the video. She pauses her drawing to look up at me.  “It’s just like what we would do in the lab,” she says, “but instead of a camera looking at a tank, I have a camera looking into a chamber on the seafloor”.

As of mid-July 2013, Liz’s prototype of her seafloor camera was nearly ready to be deployed for testing.  If it works, she’ll try to capture Alexandrium cells emerging from the seafloor just prior to the late-summer bloom.  Her vision for the future, she tells me, is a network of these instruments deployed across Puget Sound, monitoring cyst emergence in real time.  Instead of only knowing about blooms once they are in full swing, they could be predicted days or weeks in advance, avoiding unnecessary closures and potentially saving lives.

[1] Climate change and harmful algal blooms, NCCOS http://www.cop.noaa.gov/stressors/extremeevents/hab/current/CC_habs.aspx

[2] Anderson, Donald M., Patricia M. Glibert, and Joann M. Burkholder. “Harmful algal blooms and eutrophication: nutrient sources, composition, and consequences.” Estuaries 25, no. 4 (2002): 704-726.
http://www.whoi.edu/fileserver.do?id=47044&pt=2&p=28251

 

Teaching and tweeting

September 26, 2013 — Leave a comment

MOR tweet

It’s been a while since I’ve been a TA in the traditional sense – you know, sitting in class, running and grading labs, answering questions from inquisitive minds (or at least referring them to smarter people than myself)… So I’m pretty excited to be back at it this quarter. Yesterday was our very first class and today is our first lab – huzzah!

I decided yesterday, somewhat on a whim, to take the class to Twitter – I’ll be tweeting class-related goodies using the hashtag #Ocean410TA, in case you want to follow along – whether you’re in the class or not. I’d be stoked to hear from people who are just curious about what we’re doing. The class is a senior level (4th year for you Canadian friends) marine geology and geophysics class – we basically learn about how the ocean basins form, and why the look like they do. Underwater earthquakes and volcanoes! The coolest.

Has anyone out there tweeted a class before? Any advice or thoughts?

And in case you’re wondering why scientists should tweet, check out this blog post on the AGU website and another one on the Deep Sea News site.

Learning to write

July 29, 2013 — 5 Comments

PickAPen

I took a writing class!  Yes I did.  I probably shouldn’t admit it, really, because now you’ll all expect me to have improved immensely, and that makes me nervous.

The class was with Stacey Solie (@StaceySolie), and it was fantastic. I learned a lot and here are a few of my favorite tips:

Freewriting: Every day, set aside a dedicated chunk of time to just write.  Don’t worry about punctuation, spelling, grammar, or anything.  It’s great for writer’s block: you don’t even need to start at the beginning or anything.  It just helps get the ball rolling and get you out of whatever funk you’re in.  I’m trying to do at least 15 minutes per day (minimum).

Read your work out loud:  Admittedly, this is one that I knew about before, but it bears repeating.  I don’t do it nearly enough and I really should because when I do, I always catch mistakes.

Stop apologizing for your work: It’s a terrible habit of mine and doesn’t really accomplish anything.  For example, when giving an essay to someone to proof-read, it’s pointless to say things like, “Oh, here you go. It’s really bad, sorry.”  It’s probably got some bad parts, and some good parts, and whoever is reading it will figure it out without you telling them.

So I’m working on building confidence in my writing…

Confidence

 

Know when to stop:  Try to recognize when you reach the point when your ongoing efforts cease to result in significant improvements. The “sweet spot”.  Stacey talked about this, and so did one of our guest speakers, Katie Arkema.  Here’s my own interpretation, in graphical form:

ListenToYourBladder2

Bonus materials!

Thanks to the terrific @realscientists followers, who pointed out a couple of important points that I missed before!

READ! Yup, to become a better writer, you have to read. A lot. I mean, you should read every day, and be critical about it, too.  Ask yourself, what is it that makes a certain piece of writing excellent or terrible? What techniques does the author use? Is there anything about their writing that could be improved upon? These observations will all eventually sink into your brain and make their way into your own writing. Hopefully not word for word though, because that’s not cool.

Practice. This sort of goes with the “free-writing” point above, but let’s give it a whole section unto itself. Because that’s how important it is. Like many skills, it’s more about hard work than innate genius. Have you read that book, Outliers, by Malcolm Gladwell? In it, he talks about what all of these wildly successful people have in common. Sure, there are loads of factors that lead to success, but the one in common between them all was that they’d put a metric butt-load of hours into their craft. Ten thousand hours, minimum, to be exact. So put in your time!

Well there you go.  You know I’m not a writing expert, I’ve just listed/regurgitated things that I thought were useful or inspiring. Hope it helped! Feel free to add to the list in the comments. :-)

 

 

Noisy-Neighbors_600px

In the ocean, sound rules.  Unlike on land, where animals (just like us humans!) get a lot of information from light, animals in the ocean have evolved to take advantage of sound, which is much more effective than light under water.  Light gets absorbed quickly, but some sounds, like the low-frequency calls of blue whales, can travel hundreds of kilometers under water, under the right conditions.

Whales have developed really fascinating ways of using moans and clicks and songs to help them get the things they need in life – friends, mates, food… what more could a whale want?  Some whales find food by making sounds and then listening for echoes that bounce off of their prey.  Using those echoes, they can figure out where their food is (mmm, delicious fish!).  Whales can also use sound to communicate with each other.  A mother and calf might need to keep track of each other as they swim.  Or a male might show off his sweet singing voice to attract a female.

comms3panel

Unfortunately, noise in the ocean is on the rise, and it’s making life tougher for whales. Some of the sources of human-caused noise include ship traffic, seismic exploration for oil & gas and sonar testing. It’s worth noting, though, that there is noise in the ocean that is not caused by humans. Earthquakes, volcanoes, breaking waves, rain and even lightning are some of the things that add to the background noise. The thing is, whales have spent thousands of years evolving to deal with these natural noise sources – but in the last few decades they have suddenly had to get used to the growing din caused by human activities. And, as Chris Clark from the Bioacoustics Research Program at Cornell University explains, “it’s not just one ship. It’s ten thousand ships”. It’s the same as if only one person litters on the side of the road, it might not be such a big deal. The problem arises when everyone does it, all at the same time.

Noisesources

Scientists are still not sure exactly how noise affects whales – different whales might be more or less sensitive to particular sounds, and might respond in different ways. For example, right whales in the Bay of Fundy showed lower levels of stress hormones when ship traffic stopped briefly following the 9-11 terrorist attacks [1]. Killer whales off the coast of Washington state and British Columbia have increased the volume of their calls so that they can be heard above vessel traffic [2]. And in the most severe cases, some beaked whale strandings have been linked to mid-frequency naval sonar operations [3].

Excessive noise in the ocean causes a sort of masking effect – meaning that the noise is loud enough that the whales can’t hear what they normally would need to hear in their environment, whether it’s echoes from fish, or a signal from another whale. Not being able to find a mate or find food or find each other is a serious problem, especially for species that are already endangered.

But there is still hope. Now that we’re starting to realize how harmful noise can be, we’re finally in a position to actually do something about it. Small steps can make a big difference. Even slowing ships down can substantially reduce the overall noise. In recent years, the US Navy has funded a lot of basic research that has taught us a huge amount about how marine mammals hear and use and produce sounds. We’ve still got a long way to go, but now that we’re aware that there is a problem, we can work on ways to fix it.

This post was done with help from Chris Clark and Kevin White from the Bioacoustics Research Program at Cornell University.  The PDF version can be downloaded here.

References

[1] http://news.sciencemag.org/sciencenow/2012/02/shhh-ocean-noises-stress-out-wha.html
[2] Holt, Marla M., et al. “Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise.” The Journal of the Acoustical Society of America 125.1 (2008): EL27-EL32.
[3] D’Amico, Angela, et al. Beaked whale strandings and naval exercises. Space and Naval Warfare Systems Center, San Diego CA, 2009.

If you play back this audio file, you’ll be listening to a couple of fin whales and an earthquake, and according to my dog, that’s some exciting stuff. No, seriously, I played it on my laptop the other day, and Trooper got all agitated, and started growling and barking in what I can only assume was confusion. (“where’s the fin whale?? it’s got to be around here somewhere!”)

The colorful figure at the top of the post is called a spectrogram.  Time marches across to the right.  Frequency increases upward.  And the colors basically indicate loudness – brighter colors are louder.  This particular chunk of data was recorded in the dead of winter just off the coast of British Columbia, Canada, under more than a kilometer of water. Even though the instrument is designed to measure earthquakes, it also picks up the very low, booming calls of fin and blue whales.  The spectrogram shows two slightly different calls alternating – one slightly higher pitched and one slightly lower.  We believe this is probably two fin whales passing near the seismometer.

You might notice that the audio clip is about 30 seconds long, but the spectrogram shows five minutes of data – that’s because the calls are down around 20 Hz, which is at the very lower end of the human hearing range.  (If you have tip top hearing, you are probably sensitive to sounds between 20 Hz and 20 kHz.)  I sped up the audio by a factor of 10, so that we can actually hear it – bloop… bloop… bloop…

At about 10:03am in the spectrogram, and 20 seconds into the audio recording, you can see/hear an earthquake in the background.  My seismologist colleagues tell me that this isn’t the distinctive crack of a primary or secondary phase arrival from an earthquake, but possibly the rumbling caused by a tertiary, or “T phase”, arrival.

So why did Trooper have a meltdown?  I guess you would too, if you thought you were suddenly surrounded by a couple of super high-pitched fin whales and an earthquake.

from nsf.gov (credit: Pacific Worlds)

From nsf.gov

This week’s science+comics interview is brought to you by Yen-Ting Hwang, a UW Atmospheric Sciences student in the final year of her PhD. Ting’s work is focused on large-scale climate dynamics.

The Sahel region in Africa is a semi-arid boundary along the southern edge of the Sahara desert. The people living in this region are balanced on the very edge of habitable terrain, and rely on a short annual rainy season for their crops to grow. The slightest shift in annual climate can result in devastating crop failures and ultimately widespread famine. During the second half of the twentieth century, the region was hit by year after year of drought.

For her final thesis chapter, Ting has tried to understand why that drought might have happened when it did. The life-sustaining annual rainfall in the region occurs as part of a seasonally migrating tropical rainfall pattern. Scientists call this the ITCZ, or the inter-tropical convergence zone, and it’s a rain band that circles the globe like a belt. Solar radiation near the equator is far stronger than at the poles, and when the moist air near the equator is heated, it rises. The rising air eventually reaches an altitude where it’s cooled, and the moisture that was carried aloft condenses to form clouds and rain.

This air is transported poleward at high altitude until it reaches about 30 degrees latitude either north or south, at which point it sinks down toward the earth’s surface. The air then moves back toward the equator, picking up moisture along the way. This cycle is called Hadley Cell circulation.

Hadley-Cells_600px

By piecing together climate observations, scientists know that the drought in the Sahel region between about 1950-1990 was related to a very slight southward shift of the tropical rain belt. This type of shift happens when the temperature difference between the northern and southern hemispheres changes. If the northern hemisphere is cooler, the northern Hadley cell will strengthen as it tries to pull warm air up from the south, and the tropical rainfall band will shift southward.

To answer this question, Ting compared results from twenty different IPCC models (IPCC = Intergovernmental Panel on Climate Change). She looked at a variety of different possible factors that could result in an uneven heating or cooling of the planet between the northern and southern hemispheres – things like clouds and ocean circulation. The factor that showed the strongest correlation was surprising: it was the aerosols!

Aerosols are basically tiny particles that are suspended in the air. Naturally occurring aerosols are always floating around our atmosphere – dust from deserts, smoke from forest fires, and even sea salt. But there are also anthropogenic aerosols – the ones that occur as a result of pollution. There are different types, but Ting found that the strong correlation was with sulfate aerosols, which are white in color. These aerosols have two main effects:

a) They reflect sunlight, which means less sunlight reaches the earth’s surface.
b) Aerosols in the air tend to cause clouds to persist for longer than they would other wise – you might imagine droplets of water staying aloft when they have a handy bit of sulfate to stick to.

Overall, both of these lead to a cooling effect.

Aerosols don’t stick around in the air for long though, and they don’t travel far from their source. It’s a bit counterintuitive to imagine that the smog from an American or European factory could be affecting tropical precipitation. But the slightest shift in the temperature balance between the northern and southern hemispheres is all it takes. Here’s a cartoon showing the basics of how this works:

Aerosols_600px

While the Sahel region was being decimated by drought in the twentieth century, industrialization in developed countries was on the rise.   Since most of the industrialization happening at the time was in the northern hemisphere, that hemisphere was cooler than it otherwise would have been.  And model results indicate that this change was enough to shift the tropical rain band southward.  By the 1980s and 1990s, air pollution was widely recognized as being harmful, and various environmental regulations were put into place.  And, lo and behold: that’s about the same time that the ITCZ shifted back to its previous position.

More recently, Ting has been looking at how we can use climate models to predict how the tropical rainfall band might shift or change given different climate scenarios that are tested by IPCC models.  Of course, the effect of aerosols is only one piece of the puzzle.  The northern hemisphere cooling that Ting was investigating was overlaid on an overall warming trend.  The northern hemisphere was actually warming between 1950-1990, just not as quickly as the southern hemisphere.  In fact, recent studies indicate that the northern hemisphere appears to be warming more quickly, which may have significant consequences for tropical precipitation patterns.

To learn more about Ting and her lab group, check out these links:

http://www.atmos.washington.edu/~yting/

http://www.atmos.washington.edu/~dargan/

Press releases about some of their other work:

http://www.washington.edu/news/2013/03/11/remote-clouds-responsible-for-climate-models-glitch-in-tropical-rainfall/

http://www.theverge.com/2013/3/25/4129026/clouds-are-hiding-the-the-truth-of-how-much-earths-climate-will-change

http://newscenter.berkeley.edu/2013/04/02/shifting-rainfall-patterns-in-tropics/

Also, this paper is in press, so you can read all the details soon!

Hwang, Y.-T., Frierson, D. M. W., and S. M. Kang. Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century. in press, Geophysical Research Letters