Team Larvae: Livin’ the dream

As I alluded to in my previous post, the members of the lab got to go on a very sweet “field trip” last week. Firstly we flew out to Granite Harbor. We have gone out there several times before and it’s always fun. We go there to collect the animals we use for our research. Graduate student Dave Ginsburg and DSO Rob Robbins do the diving and the rest of us do the dive tending. We help them get their gear on and get in and out of the water. Antarctic diving requires a hell of a lot of equipment and it’s a much easier time if you’ve got some people helping you out, especially putting on the water-tight “lobster gloves” and hauling your butt out of the dive hole. Granite Harbor is about 100 miles north of McMurdo Station on the continental side of McMurdo Sound. It’s a fun helo trip by itself, flying over icebergs and seals and the Coast Guard icebreaker (which is here breaking ice as we speak). We like to dive at Granite Harbor because there is a very active crack system in the sea ice. This allows us access to the water without the trouble of having to drill a hole through the ice.

On this particular trip we brought along the NSF Science Rep who is from the Geology program at NSF. He was interested in showing us the freshwater inputs from the continent into Granite Harbor specifically and McMurdo Sound in general. During the summer when it warms up, Granite Harbor comes alive with the sound of little streams of water (from the thawing glaciers) falling down the granite cliffs (hence, Granite Harbor) and into the harbor. The freshwater input is so much that it creates a freshwater lens that’s 10 to 15 feet thick and floats above the heavier seawater under the ice. Freshwater lenses like this can create very interesting distributions of marine animals that would not normally be seen (e.g. deep water species tend to come up to much shallower depths and thereby can be observed and collected by scuba diving).

After diving at Granite Harbor we flew back in a more long-winded fashion that allowed us to explore a bunch of the nearby glaciers. One of the glaciers (the Miller Glacier) had a cool structure on it called a ‘ring moraine’. A smaller glacier was feeding into the Miller from a cliff and all of the debris picked up by the glacier had been deposited in an arc forming a ring (bad description, but see picture) Best of all, we then got an incredible helicopter tour of the McMurdo Dry Valleys! The dry valleys are an amazing landscape which at times defy the imagination. It’s basically a valley system that receives no precipitation. This creates a stark landscape that appears completely devoid of life. Of course it only appears that way because life does exist there, albeit in a much less ambitious form than we are used to. To put the biology of the dry valleys in perspective, the apex predator of the dry valleys is a tiny nematode worm!

Although very little precipitation falls in the valleys, they are not completely dry. There are numerous glacier systems that come into the valleys from the polar plateau. These glaciers will melt during the warmer summer months and create streams. Over the course of centuries (if not longer) lakes have also formed in the lowest portions of the dry valleys. These lakes are frozen on the surface year-round. But under the ice life abounds! In fact in one of the lakes, Lake Vanda, the temperature of the bottom of the lake is quite warm, something around 25C! This is due to the ice trapping entering heat just like a green house. At the bottom of the lake are huge microbial mats. In the soils of the valleys life is a lot tougher, but still hanging on (as life is known to do). There are nematodes (called the Lions of the Dry Valleys), rotifers, tardigrades and the omnipresent bacteria. The ‘simple’ ecology of the dry valleys has made it an important model for understanding how environmental changes can influence ecosystems. The dry valleys have also been used as an analog for life on the early Earth as well as an analog to Mars and Europa (moon of Jupiter that has an ice surface, it is thought that under this ice there may be an ocean, where just maybe there could be life). The other thing about the dry valleys is that it’s a geologist’s heaven. Because life has so little influence on the area, the geological history of the valleys is laid bare for all to see. There are no plants to cover it, no animals to manipulate it and almost no water erosion to alter it. So written all over the vast openness of the dry valleys is its own geological history. I’m no geologist, but from what I hear it tells quite a story.

As a biologist, it has always been a dream of mine to get to see the dry valleys. Since we are typically only flying helicopters so we can go to our dive locations we usually aren’t in need of going through the valleys. But with this tour of the freshwater inputs it became entirely reasonable to get a tour and stop and look around, which is what we did. It really was an amazing, dream-come-true trip. We flew through the major valleys (Victoria, through Bull Pass and into Wright Valley and then into Taylor Valley). We stopped at Lake Hoare camp (in Taylor Valley) to check out the science facilities (I need to find a way to do science in the dry valleys). Then we stopped at the foot of the Taylor Glacier at a place called….Blood Falls! Damn that sounds like something out of a horror movie, Blood Falls, oh yeah. (Blood Falls is a rust colored part of the glacier where there is an inexplicably high concentration of iron seeping out due to some kind of subglacial artesian well). Then we flew over the Kukri Hills (much bigger than hills if you ask me) and onto the Farrar Glacier. Then it was back to McMurdo, which after spending so much of the day at Granite Harbor and the valleys really felt like the big city.

All in all, an amazing day. So here are a few pictures of the big day and a link to many more pictures of the big day. The weather wasn’t great (in fact it was pretty bad, we almost didn’t go at all due to clouds, snow, and lots of ground fog), so the pictures aren’t great, but they’ll hopefully get the idea across that the dry valleys are one of the strangest and most beautiful places on earth, to me at least. It represents the gray area between the abiotic, physically driven world of geology (where things are there because they’re there) and the intricate and adaptive realm of biology (where things are there because they’ve figured out how to survive). A world of vast scale, time, and process. To me, a religious experience.

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