Dust Bowl Ballads

“It’s a twister! It’s a twister!”

Or at least it looked like one. In any event, the driving conditions during what was supposed to be our relatively short ride from Gunnison to La Junta, CO were certainly less than ideal. The wind slapped and banged at the truck in irregular bursts, and spooky tumbleweeds rolled across the road in the hundreds; the landscape churned with bits of grass and dead plants. Looking further up the highway, we saw a hazy, brown cloud that resembled a fire.

We soon realized that the “fire” was actually a rolling cloud of sand and dust formed by the fierce winds blowing out from the thunderstorm. Lucky for us, visibility was only slightly reduced. Here, take a look:

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The area surrounding our sample site at the Alamosa/San Luis Valley contains the highest agricultural land in the United States. Here, elevations average around 7500 feet, with surrounding peaks over 14,000 feet. Local farmers specialize in “cool season crops” like potatoes, head lettuce, and barley. In fact, Coors beer (love it or leave it) is made exclusively from barley grown here in the Intermontane Plateaus of the Colorado Plateau Province.

IMG_2815Regional soils broadly consist of two types—the soils of alluvial fans and floodplains located at the valley floor (which we sampled), and those found on the hills and mountains. Had the weather permitted, with a little more digging around we would have expected to come across Colorado’s state soil, “Seitz soil,” which consists of very deep, well-drained, slowly permeable soils formed from igneous, sedimentary and volcanic alluvium. Seitz soils are abundant near the valley edges and on mountains, mainly in southwestern and central Colorado.

IMG_3604This was definitely one of the dustiest places we encountered; the valley regularly experiences periods of drought, with most precipitation occurring either during the winter months as snow, or during the short, summer monsoon season. However, much of the moisture from these precipitation events is lost through evaporation due to the region’s characteristically clear skies and dry, thin, high-elevation air. Thus, it comes as no surprise that the dry, heavily cultivated soils of the Intermontane Plateaus are easily influenced by the summer storm systems and strong winds.

After we arrived in La Junta, we discovered that several tornadoes had indeed touched down in northeast Colorado—hundreds of miles from where we’d been driving. Oh, well—we’re geochemists, not meteorologists.

P. S. Dust isn’t the only thing the La Junta wind transports (my sleeping bag exploded). Hopefully local birds and other critters have since put the down feather to good use.

“When it’s dusty, it’s dusty”

We couldn’t have said it better than a local cowboy who stopped to give us his scientific opinion while we collected material from the cattle-spotted ranchland of northeastern Utah’s Green River Basin—“Well, I’ll tell ya, when it’s dusty, it’s dusty.” Way to hit the nail on the head, huh? Sure enough, we’ve spent the last three weeks shaking dust from our shoes, wiping it out of our eyes, blowing it from our noses. We’ve navigated many of the most arid places in the country, starting off just above sea level, eventually reaching elevations as great as 10,000 feet. Hard to believe we’re all done—for now, at least!

IMG_3526Along this dusty road, we’ve encountered a truly astonishing number of landscapes; each and every evening we pitched our tents, we did so in a totally different setting than the one in which we’d made breakfast. For instance, after we sampled the Green River Basin, we set up camp in Ashley National Forest near the Sheep Creek Geological Area, a place surrounded by enormous, rocky, red and yellow cliffs, thick with quaking aspen, ponderosa, juniper, and lodgepole pines. We watched pronghorns skip across distant ridges, and that night, made sure to watch out for bears, too.

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Bright and early the next morning, we set out towards Moab. The drive from northern to southern Utah was full of beautiful, winding roads and spectacular colors, although Sarah and I weren’t really keen on the heat! Still, we were excited about visiting Arches and Canyonlands, as well as the fact that despite the long drive, we were able to cover three sample sites, and manage to snag the last camping spot in the whole park. A successful day indeed!

The formations of Canyonlands and Arches speak to the powerful force of wind in the evolution of landscapes. The salmon-colored Entrada sandstone, where most of the arches occur, was deposited around 200 million years ago. Over time, water and ice infiltrated the surface cracks of  the sandstone layers, breaking off bits and pieces of rock. The holes formed from the cracking continued to be attacked by wind and water, forming arches. While many of these arches gave out long ago, the loose particles left behind carried away by the wind, the most resistant sandstone became the famous arches we see today.

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We drove through thunderstorms, sunshine, across deserts and mountains, past rivers, lakes, and hot springs. Colors, plants, animals and temperatures—they all varied. These are just two of the amazing places we saw during our collection campaign.

Although we have collected our final sample and the Unimog is headed back up to Alaska, there are still many observations, photos, and stories left to share. Plus, our great American dust quest will resume later on in July when we travel by horse to the Upper Fremont glacier in Wyoming’s Wind River Range. Until then, keep on our your toes for my next update, with photos from our drive across tornado territory and a crazy Colorado dust storm.

Getting the Dirt

Sarah, Charlie, and Molly here, reporting from Gunnison, CO. It’s our eighth day into GIGL’s dust collection quest in the great American West (add on six days on the road for S & C—they drove down to the Lower 48 from Anchorage to meet me in Spokane, WA), and already we’re gearing up to hit the tenth of our thirty proposed sample collection sites.

First thing’s first: you may be wondering why on earth a team of cold weather-loving folks like us has decided to devote an entire month to driving around the desert in the hot summer sun—and stranger yet, why we’ve got big, metal boxes packed with dirt and sand. Don’t worry, we’re already quite used to folks asking questions—just take a look at our ride:

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The goal of our trip is easy enough to explain: we’ve set out to identify the major dust source areas of the western United States. Oftentimes we think of dust as the stuff that collects on our bookshelves and countertops when we get behind in our household chores, but in more arid parts of the country, say Oklahoma or southern California, you can see tiny bits of dust and sand all over the place—sweeping through fields along the freeway, collecting in piles in grocery store parking lots, or even blowing across your own backyard.

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We all know that dust is small—sometimes so small you need a microscope to see it—so it may be hard at first to believe that dust plays such a big role in regional and global climate change. But just think: increased temperatures result in drier land conditions (think of how muddy your front yard can get in the rainy springtime, and how dry it becomes later on in the summer). With less moisture to hold soil particles together, the ground material becomes less consolidated and easier to blow away in the wind. The wind is a powerful mode of transport, and can carry tiny bits of sand and clay vast distances—even across continents—but no matter where the dust ends up, there remain a variety of important consequences. For starters, when windblown dust settles on land, it can supply nutrients to the local soil and plant life, and the same goes for dust settling in the ocean, or carried by rivers out to the ocean. Dust also darkens snow and ice surfaces, thereby decreasing Earth’s albedo, or it’s ability to reflect solar radiation.

IMG_2759Many studies have pointed towards increased dustiness on snow cover in the western US over the past two centuries, most likely due to land-use changes like agricultural practices and livestock grazing…but where exactly is all of that dust coming from? And why? Are the most prominent dust sources in areas where humans have made major changes to the landscape? At the end of the summer, we’ll haul our treasure chest full of dirt back to our lab at the University of Michigan and begin our geochemical analyses so that we may answer these important questions. In the meantime, we hope you’ll check back with us as we continue “getting the dirt” on arid regions throughout the American northwest, southwest, and Colorado Plateau. We’re excited to talk a bit more about what we’ve collected so far, and show you some of the incredible landscapes we’ve encountered. Until we next run into some WiFi, this is the GIGL dust team from our big, blue UNIMOG, going clear!

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Work hard, play hard

The last day of work for me in Tromso this time was to put all the shells back into their individual home, and did the final check of the pH levels.

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Here you can see the calcein were released from the shell after we put them back!

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As all the pH levels were stable, we were ready to go for the next half of experiment.

Aside from the work, I also experienced the beauty of the the northern Norway. In February, I was really lucky to see the northern light on one night before I left.

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Also, working on the coast means you might have some luck for fresh seafood! Thanks people there let me taste the “real halibut”! That’s yum!!!

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Of course, the most important event in May here is Norway’s national day on the 17th. I was pretty lucky to anticipate this big celebration in both last and this year, enjoying the crowds and atmosphere, especially seeing the parades downtown.

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Work hard, play hard. To have chances going different places when doing fieldwork is one of the most important reason why I like geology!

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Midpoint check in Tromsø

I am in Tromsø again!

The main tasks this time are measuring the dimensions of the shells, weighing them and staining the shells, so that we can have an idea how the shells grew in the past three months, and comparing the growth rates to the rest of the culturing season. Furthermore, by staining them again, we can got additional time control as well.  Also, I am still trying to find a way to extract the extrapallial fluid for boron and other isotopes or major ion concentration analysis.

The EPF extractions are more challenging than we expected. We prepared capillary tubings and syringe this time, however, as the shells were took out from the water, they would spill out the waters inside and made the extraction being more difficult due to the limited fluid left. To overcome the problem, we might try to seal the hole with wax and use hard tubing to penetrate the seal directly next time. Hope that could help to get more fluid from the inner shell environment.

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Here you can see the shells spilled the water out once we took the flower pot out from the tanks!

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All the shells in the experiment were carefully measured and weighed at this point.

As the growth season starts, we also discovered more and more fecal pellets accumulated in the flower pots and tanks. Mike collected some of them to figure out what are the possible food sources for our shells.

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After measuring all the shells, there were ready for being stained again!

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While they were left in calcein bath, we calibrate all the instruments and cleaned the tanks at the same time, preparing for the second half of the experiment.

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Hope the shells will be happy to come back to their cleaned home!

Happy shells in Norway

Woohoo! Our pH control measurement has been running for two months! According to our continuos monitoring, everything worked properly. Although there are a little bit fluctuations, basically we kept the designed pH levels with CO2 bubbling method successfully, and let the other environmental factors remain relatively constant.

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Also, the shells live happily so far here. Look at the fecal pellets that have been building up on the top of the flower pot, it shows that our Arctica were fed by nature seawater, and poop crazily!

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Next Month we are going to have our mid-point growth check, then we can know how much they have grown in turns of shell height, length, and width, as well as their total weight. At the moment we will have the second shell staining so that we can have an external time control inserted into the shell records.

I can’t wait to measure them again. So excited for their growth!

Fieldwork in Barrow!

Our site on the sea ice is first year, meaning that it is newly formed this year, and will likely melt in summer. It is usually 0.5-1.5 m thick. Multi year ice persists for years and is usually thicker (3-5 m). It is also a landfast site, meaning that the sea ice is still attached to the coast (as opposed to free floating ice).

DSC01547Here is David, one of the researchers from CRREL (Cold Regions Research Engineering Laboratory) walking on the sea ice. They are laying out transects of flags on the ice so that twin otter planes with remote sensing equipment such as LIDAR can fly over. 

DSC01535Here are the sleds full of our gear. The plan is to measure the thickness of sea ice on the ground, and then to mark the site so that the planes can fly over and use remote sensing to gauge the thickness of sea ice. Scientists use this kind of ground truthing to help correct the remote sensing data from flyovers often used to assess the thickness of sea ice in the Arctic.

DSC01545As you can see, sea ice can deform and make piles. This means that measuring the thickness remotely is not necessarily straightforward.

DSC01540 And here are the researchers drilling a core from the sea ice. Holes are drilled into the ice at intervals to measure temperature and salinity, to create a profile of the ice characteristics with depth.

DSC01557We have laid the core onto this measuring board. You can see the snow on top, transitioning into ice at about 20 cm, and then towards the bottom of the core the ice looks dirtier. This is perhaps due to the presence of ice algae that live in the bottom of sea ice. We will melt and filter the sea ice in Barrow, and then return to Ann Arbor to conduct a full geochemical analysis of the ice. We hope to learn about the concentration and provenance of dust in the sea ice here.

Arctic Sea Ice, Barrow

Meghan Taylor here! I am in Barrow, AK this week to obtain cores of sea ice on the Chukchi Sea, offshore from town. We start at the UMIAQ hangar to pick up our snow machines. UMIAQ is the native corporation that manages permitting and logistics for scientists working on the sea ice. They also provide us with an armed guard who stands watch for polar bears. His name is Mike and he likes to play reggae music from a radio in his coat while we work.DSC01528 There is thick ice fog on the shore to day and everything is hazy. The ice fog was dense and close to the ground so that you could still see that it was a bright, sunny morning 40ft above you. DSC01530   Here we are filling a couple of sleds with gear needed for today’s field work. DSC01534   This is me, geared up for a ride on the snow machines. Our site is about 7 miles away, which is a 30 minute ride on the skidoos. We cover up because we are riding in temps around 1˚F, and you don’t want any skin exposed! DSC01541   Here you can see the edge of the sea ice. This lead was solid sea ice just a few days before, and has just opened up. There are faded prints, barely visible, of polar bear tracks here. Our bear guard thinks that they are a day or two old, where a polar bear pulled itself out of the ocean and walked towards shore. Now that the ice is breaking up, bears will become more common near town, but Mike says that their presence is more noticeable after the whale season starts and the the first whale of the season is taken. DSC01567   DSC01569   Me again, and another researcher, Andre. He will not let me drive! It is nearly 8:30 pm here and still fairly bright and sunny. It does not become truly dark until after 9:30 pm in early spring. Long daylight hours are conducive to a long day on the ice: I had no idea of the time until someone starting passing out cookies and I realized it was well after dinner. Next time I’ll post some pictures of the really nice ice core we got, and some of the other field work going on out here.

pH Culture Experiment is running now!

More work has been done in the past week, the seawater was heated and acidified for our experiments

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We also staining our shells so that we can have a better time control for which part of the shell mass is growing under the assigned pH in this experiment. Those shells were separated into different flower pots.

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In order to evaluate how the animal adjust the pH inside the shell, we also aim to measure the pH from the extrapallial fluid (EPF), in which the chemical compositions were considered directly related to the formation of the carbonate shell. To measure the pH in the shell, we need to drill a small hole on some of the shell. A segment of pipet tip will be glue on it so that we can keep the entrance for future pH measuring.

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To ensure the EPF won’t exchange with the seawater outside the shell, we have to seal the opening. And then put them back to their home!

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When you see the shells open their valves like the pictures below or they dig into the sands, they are telling you, “We are happy living here!!!”

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After two weeks of efforts, our pH control flow through system is running, and we take the first measurement last Saturday.

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Wish us the best of luck for the next eight months. We feel excited to learn how the boron isotopic compositions in the shells relate to the ambient seawater pH, as well as the pH in the shells, do you?