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.

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