5 June, 1998

TEA Journal

Day 6

FRIDAY

6/5/98

Another busy day on Polar Star as the arctic journey continues. The box cores were not able to be collected until early this afternoon due to some problems with the winch. The MST's (Marine Science Technicians) and the mud people were up all night working on the problem but it was mid-morning before things were ready to go. Anyhow, three successful drops were accomplished and now we are moving on to the next station.

The ice is fairly dense out here even though it is all pretty much 1st year ice. It is quite jumbled and contorted and extends as far as the eye can see in all directions. The amount of dirt and sediment incorporated into the ice structure is amazing. As the ice is churned up and tossed aside by the ship, thick dark bands are visible. Some of the color is caused by ice algae which is also found in bands similar to the strata seen in metamorphic rocks. The role this incorporated algae and sediment has in the formation and break up of ice is of interest to many of the people working to better understand the arctic regions.

The dry lab was a hustle and bustle place today. Terry and Bill were working in the cold room cutting thin and thick sections from some of the ice cores that will be used to study structural properties. When viewed with polarizing filters the crystal structure of the ice is able to be observed and information about the formation temperature and age can be obtained. The Polar Sea is equipped with a refrigerated van about the size of an over the road trailer, that is used exclusively for the study of ice cores. It contains a band saw for cutting the cores, a microtome for making thin sections, and a light box for viewing crystal structure. It is lashed down to the deck with chains and binders and travels with the ship to both the Arctic and Antarctic. Aaron and I were busy for a good part of the day working with the samples we collected yesterday. The 10 cm sections were melted overnight and today we analyzed the meltwater for salinity, chlorophyll, and poured off samples to be worked on by the CRREL labs when we return. Aaron is also maintaining a science station log which will let anyone know at a glance exactly which sampling activities took place and which science party members were involved. It will also provide ships position, station number, and date so others will know what was found and where.

I am continuing to work with the computer interfaces that I brought along to try and simulate as many shipboard water and ice analysis activities as possible. Even though some of the analysis equipment we use aboard the ship is much more precise (and expensive) than that in the classroom I think the ideas of sampling and analysis can be cultivated using water and ice as our mediums. A winter long profile of sea ice from formation to break up could be quite do-able by students and very applicable to our location.