Satellite views of Cape Royds on 9/21, 9/22, and 9/23 showing the rapid freeze up of the lead that opened on 9/20. Cape Royds is the southern (bottom) projection of land. The small islands south of Royds are the Dellbridge Islands. The odd white feature south of the islands is the Erebus Glacier tongue. This is an unusual instance of a glacier intruding far into marine waters, usually they break up into ice bergs relatively quick. The tongue does calve icebergs but not enough to prevent the extension.
It’s been good frost flower growing weather in McMurdo Sound over the last few days and we benefitted with an excellent collection on Friday. Heading out with Dan and Jen we got as close to our old sampling site at Cape Royds as we could, which it turns out wasn’t very close. The ice had sheared off further from the old edge than we had thought; you could see our old tracks go right off the ice edge! In this case the edge didn’t mean open water though, temperatures have been hovering between -30 and -40 C (approximately -20 to -40 F) driving a lot of new ice formation. The photo above shows the whole evolution of new ice edge, starting with the first satellite image of the area for the season on September 21. The middle image is from the 22nd, and the right image is from the 23rd. On the 21st the thick black line is the new lead between the land fast ice to the south (bottom in the image) and the drifting pack ice to the north. Only 24 hours later in the middle image the lead has frozen so solidly that it is indistinguishable in the satellite image from the older young ice present elsewhere on the 21st. That sudden growth of young ice seems have held everything in place between the 22nd and 23rd. Despite a persistent breeze from the south there is almost no change to the location of individual ice floes. Yesterday the wind really ripped through McMurdo Station and we don’t have the next satellite image yet. It’s entirely possible that an even newer lead has opened between the land fast ice and the pack ice!
Flat Stanley's excited to start collecting frost flowers.
Virtually every surface of the young ice that we visited or could see from standing on top of the Pisten Bully on the 23rd was completely covered in frost flowers. Out in the pack ice, where young is continually forming throughout the winter, the frost flower environment is impressively vast. Spatially it’s much like looking out over a vast grassland. It’s partially their extent that makes frost flowers interesting. Because the ice surface temperatures are so low any microbial metabolism within frost flowers must be low, but the cumulative effect within all the frost flowers present at any one time could have interesting consequences.
Going big with sample collection. In this haul we pulled in 300 kg of frost flowers and equal quantities of young sea ice and seawater. The seawater we have to keep in the vehicle so it doesn't freeze on the ride back.
On this sampling effort we needed to go really big. Our final analysis requires a lot of DNA, so we need a lot of bacteria! Taking advantage of the fact that we could drive nearly to the frost flowers we almost doubled our haul from September 19th, pulling in 300 kg of frost flowers (661 lbs) and equal amounts of young sea ice and seawater. Now comes the really hard part, getting all that material melted down and filtered! It will take us more than a week to get caught up on that part of the process, and in the meantime we still have to collect an equally large quantity of mature first year ice to round out our sample set. We might have to divide-and-conquer tomorrow to avoid falling behind schedule, with Shelly filtering and me getting more ice cores. Whether we can do that depends on whether we can get Dan or Jen to spend a whole day helping me in the field…
I haven’t yet spend a lot of time on this blog talking about working or living conditions here at McMurdo (both are pretty good). To give a little introduction to Crary Lab, the excellent new science building where we’ve been spending much of our time, I’ve prepared a short video tour of the -1 C cold room where we do most of our sample processing. To go along with it there’s a 360 degree photosynth of the room, and as a bonus a similar photosynth of the station from the Crary rooftop (I needed an excuse to play around with photosynth some more).
