Friday, May 27, 2011

Wrapping Things Up

It's our last week in Barrow, at least until next year. We'll fly out on Monday evening, but there's still plenty to get done in the lab before then: processing the cores we collected this week, running a few more settling column experiments, and packing everything up.

Andy, in red cap, and Craig working during one of our final field days.
Yesterday was our last day out in the field. We had some very bad luck on Wednesday when our ice corer broke. Nonetheless, we're extremely grateful that we were able to recover it from the ice, and that this didn't happen early on in the month!

In addition to taking ice core sections, we've collected a number of other types of samples and data:

Craig (left) and Mark deploying the plankton net, which we hang horizontally in the current for about half an hour at a time to collect both plant and animal plankton just below the ice.

We've collected more sediment samples with our benthic grab. This amphipod was in one of those samples.
The benthic grab. We lower it down to the bottom, then send a "messenger" (a weight that travels along the rope) to activate the mechanism that closes the jaws at the base of the device.
This ctenophore, or comb jelly, floated up into one of our auger holes yesterday. It was about 7-8" long. We collected it for isotopic analysis (see the end of the previous blog post for more info about isotopes), though because jellies are comprised mainly of water, there might not be enough tissue to run such an analysis.
Also, we've shot some fantastic videos of algae under the ice and the macrofauna on the seabed (mainly isopods and jellies). We'll be able to upload some of those clips soon.

There's been evidence of even larger animals at one of our sampling sites: this auger hole wasn't frozen after several days, and the dark oval to the right indicates a seal was lounging there recently!

We also saw several polar bears in the distance on Monday, lurking in the fog, but thankfully they stayed away from our field station.

Though the weather's been steadily warming up, our field excursions have been a mix of cloudy, gray days, when seagulls and flocks of ducks disappear like ghosts into the mist, and brilliantly sunny days, when we get so warm we toss our heavy coats aside. The snow has melted so much that we've occasionally had problems navigating the snowmobiles over the slush.

The science team and our bear guards extricating a snowmobile and our equipment sled from a drift.

Ice blocks standing about 15-20' high.

Blue, salt-free ice in the foreground contrasts starkly with sediment-laden ice in the background.

Blue ice on a sunnier day.

Snow drifts around mounds of sea ice.

Friday, May 20, 2011

Barrow Macrofauna

Things have warmed up considerably here in Barrow. The roads were all coated in snow and ice when we arrived, but most are now muddy and ridden with potholes. Our snowmobile trails are also turning slushy and bare in spots; thankfully, though, we're still able to drive out to our field sites. The high tomorrow is projected to be 39˚F. Yes, 39˚! So warm! Earlier this week, when the weather was a bit cooler, we captured these beautiful frozen fog formations on our front railing.

We took time a few days ago to visit the Iñupiat Heritage Center, the local cultural museum. Bowhead whale hunting has been a central tradition of the Iñupiat for thousands of years and is the primary focus of the heritage center.

A bowhead whale skull outside the museum.

A hanging replica of a bowhead in the entrance of the heritage center, along with a painting of whale hunters in an umiaq, or seal skin boat, and a piece of baleen.

Thankfully, this is the closest encounter we've had with a polar bear!
The museum is full of displays demonstrating how people have survived in this frozen world for generations by making the most of natural resources, from waterproof parkas made of seal intestines to squirrel fur coats to this unique water bag.

The caption below reads, "Water Bag (Puukataq): Tundra swan feet, sinew. Iñupiaq, Barrow. This bag is one example of how we use all parts of an animal. it is made from the dried feet of many tundra swans sewn together with sinew into a single waterproof piece."
A display of artifacts and materials used for hunting and trapping in spring.

Snow goggles like these protected hunters' eyes from temporary snow blindness.

In the lab, we're continuing our work processing and analyzing algae from the ice core sections we collect in the field. We also sorted through benthic, or sediment, samples we collected earlier this week.

Team members rinsing a sample of muddy sediment through a sieve to collect macrofauna (animals visible to the naked eye). We use filtered sea water to rinse the organisms, since salt-free tap water would send them into osmotic shock!
Among the creatures we collected were two marine isopods. These are relatives of the pill bugs you've probably seen crawling around on land in temperate climates. While not as terrifying as the giant deep-sea isopods, the ones living under the ice here are still considerably bigger than your garden variety roly-poly bugs!

Rinsing one of the isopods with filtered sea water.

In the lab, the sea monster makes a desperate bid for freedom.

Let's take a look at this creature through a dissecting microscope (a scope that has a large distance between the lens and the sample, as opposed to a compound microscope used with glass slides):

One of the isopod's many legs.

Here's a video of the underside of the isopod:

Other critters in the benthic sample included an amphipod, a polychaete worm, and lots of copepods.

The amphipod. Unlike isopods, which are generally flattened top to bottom (dorso-ventrally), most amphipods are flattened left to right (laterally).

This polychaete worm is an annelid, or segmented worm. Earthworms and leeches are also annelids.

Appropriately enough, this specimen is in the family Aphroditidae. Invertebrate love! <3
Here's the polychaete viewed through the dissecting scope. In the first photo, you can see it extending the proboscis it uses to burrow through sediment.

After a minute, the polychaete starting lifting up its tail. Check out those spines!

Setae, or hair-like appendages, on the polychaete.

Calanus glacialus (the smaller guys) and Calanus hyperborea (the larger ones) copepods in a large drop of water.
Craig Aumack collected and froze the benthic macrofauna for later isotopic analysis. Isotopes are different forms of the same element, like hydrogen or carbon, with the same number of protons but a different number of neutrons. He'll determine the isotopic signature of their tissues (that is, the ratios of carbon isotopes (C13 and C12) and nitrogen isotopes (N15 and N14)) and compare that information to the isotopic signatures of other organisms in this environment.

Each type of organism has its own particular isotopic signature, like a barcode, depending on where it lives and how it gets carbon, nitrogen, and other elements. Based on the signatures that Craig determines for the polychaete worm, amphipod, or other critters, he'll be able to tell what those creatures fed on and how much of their diet ultimately originated in the sea ice above versus in the sediment down below.

Friday, May 13, 2011

Snippets of Life on the Ice

Susanne Neuer left earlier this week, but we were joined by ASU undergraduate Mark Wiener. Here are a few portraits of the current science team:

Mark Wiener digging out a spot for drilling an ice core.
Craig Aumack warming up with some tomato soup, our lunch of choice when we're out on the ice.
Amy Hansen taking a break to build a snowman. Arctic snow is far too dry and powdery to pack, but you can cut out styrofoam-like blocks!
Andy Juhl using the ice auger to drill a hole through the sea ice.

This ice auger is a different tool from the one we use to take ice core sections. Instead of collecting the ice, the auger lets us cut out holes through which we can lower various kinds of equipment. The tricky part is that we have to drill several holes side by side to achieve a hole wide enough to use anything larger than the underwater camera. This is much harder than it sounds.

See the ice bridge in the lower left? That's not conducive to lowering large equipment into the water.
The underwater video camera, which sends a video feed to a monitor we can watch from our dry perch above the water.
Once our specialized camcorder arrives, we'll be able to capture and upload videos of the creatures that live under the thick layer of sea ice, from carpets of algae to marine isopods to comb jellies!

Speaking of algae, here's a shot taken through the eyepiece of our lab microscope of a dense sample of ice algae. Most of the organisms you see are diatoms, single-celled photosynthetic organisms with cell walls made of silica.

 The algae carpet the bottom of our ice cores, as evidenced by this photo:

 In an earlier post, we mentioned the pure blue ice you find breaking the monotony of the largely barren, colorless Arctic landscape.

The exterior of this block is covered in snow, but you can see the blue interior through a crack in the ice.
The other thing that interrupts the pristine white fields of snow? Polar bears. We haven't seen any more since our distant sighting last week, but we did come across the tracks of two bears--likely an adult and a cub--that crossed our snowmobile trail sometime yesterday between when we drove out to the ice and when we came back.

Monday, May 9, 2011

Cold Inside and Out

The thing about researching life in the ice is that these creatures generally don't appreciate it when you take them out of their frigid environment. Some types of preserved samples are stable at room temperature, but when we're working with live samples, we have to keep them cold... which sometimes means we must brave chilly temperatures inside and out.

Of the three ice cores we take at each sampling station, we dilute two in filtered seawater and leave the remaining core sections undiluted. That means the first step when we get back to the lab from a field sampling session is to run the water we collected in a cubitainer (see the photo below) through 0.2 micron mesh to strain out the microorganisms living inside.

A 5 gallon (~19 liter) cubitainer
The cores sections chill out in ziplocs in the refrigerator, slowly thawing. We don't want to melt them too quickly, because the algae and other critters living inside are psychrophilic (cold-loving) and could die at warm temperatures.

In the lab, we measure a number of different parameters, from salinity (how salty the ice core is) and concentrations of nutrients to the density of different types of particles, like organic carbon, carbohydrates, and sticky substances called EPS. Some of these things we can measure or analyze here in Barrow, while others, like chlorophyll and DNA, will have to wait until we're back at our home labs in Columbia and Arizona State Universities.

To make microscope slides, we filter different amounts of melted, fixed (preserved)  ice core water onto special filters. Our filtration apparatus is somewhat temperamental, but we seem to be succeeding in sweet-talking it into leaking less often!

Researcher Amy Hansen filtering samples for slides
All of these tasks can be accomplished in the nice, warm lab as long as we keep the samples in the fridge until we need them. For some experiments, though, we must venture into walk-in cold rooms.

Because of their salinity, our ice cold samples stay liquid below freezing. The cold room above is set at -1˚C (30.2˚F).

Andy Juhl and Susanne Neuer in the cold room. "It's coooold!"
Indoor icicles
We use this room to store our melted samples until they can be processed, and for settling column experiments.

One of the main drivers of our research here is to gain some insight into particle flux and carbon export in sea ice ecosystems. In a nutshell, particle flux refers to how particles--including cells, cell aggregates, and the fecal pellets of tiny algal grazers--sink to the ocean floor. How fast and how much of this marine snow falls to the sediment impacts not only the chemistry and biology of the sea bed, but also has implications for climate: carbon is a major component of these sinking particles, and carbon that ends up at the bottom of the ocean won't be respired, or converted to carbon dioxide, and released back into the atmosphere for decades, even centuries.

To investigate the science of particle flux and sinking speeds at our study site, we pour well-mixed, thawed ice core sections into graduated cylinders.

Craig Aumack, left, and Andy staying warm while setting up new settling columns.

We take initial samples from the columns, then let them settle for several hours before sampling again, this time from the upper and bottom sections of the cylinder. Over that time, larger, heavier particles sink to the base of the column, while smaller, more buoyant particles stay near the surface.

Tomorrow we'll be heading out into the field again to collect more ice cores at our various sampling stations. The weather is slowly warming up here as the time between sunrise and sunset shrinks into nothing. We'll leave you with a parting shot of the ice-covered ocean near midnight: