Fourth time’s the charm

Made it! We had great weather Friday and no trouble reaching Taylor Glacier. The whole Taylor Valley is a remarkable place, but it was really something to stand on top of the glacier itself and take it all in. The scenery in the valley on the approach to Taylor is remarkable. The McMurdo Dry Valleys are often described as “Martian”, though I’m not sure how well the description fits. The soil’s the right color but everything else is wrong. The valley is narrow with jugged alpine peaks on both sides (some of the mountains and glaciers have famous namesakes in the Alps, and they really do look the part). Despite the lack of precipitation and the valley’s name it seems that every gully or saddle screams “water!”. It’s just that the water happens to be locked in glacial ice. The Dry Valley’s look Earth-like, just not from this era. Primordial is a word that fits well.

At the foot of Taylor Glacier is Lake Bonney; a bizarre perennially ice covered lake. Seasonal streams feed the lake and others further down the valley (ironically the Dry Valleys contain the continent’s largest river, the Onyx, in nearby Wright Valley). Like everywhere else in Antarctica the biology is hidden away below the ice of Lake Bonney, out of view of the casual observer in a helicopter. Glaciers and ice covered lakes hide rich ecosystems in their depths. Here temperatures are more moderate and bacteria can exploit geologic sources of energy. Life makes a showing at the surface only during the warmest weeks of the summer when parts of the glacial surface began to melt, forming cryoconite holes. These holes form where sand, rock, or other dark material collects at the surface. This material efficiently absorbs energy from the sun, warming a small area on the surface and causing local melting even when the air temperatures are well below freezing. This forms a small pocket which collects more sand causing it to melt a little further. By late summer these cryoconite holes host rich communities of cyanobacteria and other organisms.

We could see evidence for these holes everywhere on the glacier’s surface as puddles of solid, crystal clear ice. There won’t be any melting going on here for some time! Unlike many glaciers in wetter climates, the surface of Taylor is not composed of densely packed snow. The whole glacier is solid, blue tinted ice. Standing on Taylor Glacier is like standing on one giant blue ice cube. This very cold, very solid ice is also proved rather difficult to cut into with our coring equipment. In the same amount of time at Wilson-Piedemont Glacier two weeks ago we collected twice as much ice as we did at Taylor.

With the sampling going slower than expected we had little time to savor our surroundings. Only a few minutes past between filling our last sample container and hearing the thud of the helicopter working its way back up the valley. It was unsatisfying to leave such a beautiful place without a little more time to explore, but it was late in the day and we were exhausted.

Back at McMurdo there was little time to rest. Samples from Tent Island and Taylor Glacier needed to be processed quickly so that we could start packing up the lab. If the weather allows we fly back to Christchurch on Wednesday, which is rapidly approaching! The last ice from Taylor Glacier is still filtering in the lab, but almost everything else has been cleaned, broken down, packed up or returned! A few hours of work tomorrow to wrap up loose ends should be all that we need to conclude a remarkable nine week effort…