There are lots of weird signs and vehicles around McMurdo... here are some...
Monday, February 1, 2010
weird things around McMurdo
There are lots of weird signs and vehicles around McMurdo... here are some...
more pictures
We've been exchanging pictures... here's the biomechanics group picture that Jim took when we went to Cape Evans. From left to right, Jim, Dennis, Idan, Warren, Mark, Annaliese, and me.
This is at Cape Evans at the bottom of the hill we were sliding down. From left to right, Mark, Annaliese, me, and Warren. I think this picture was taken right after Mark got to the bottom.
Here's me looking windblown. Have I mentioned that it's very windy here?
Here's a picture I took around midnight the other night of the fata morgana. It's a mirage caused by abrupt changes in temperature. Here the maximum sunlight occurs around 4pm, so midnight is I guess sort of like sunset in that there's often really nice light in the sky even though the sun doesn't actually go down. We have noticed that the sun is much lower in the sky now than it was when we arrived but I think it'll be up for a couple more months still.
course blog
I wrote the entry for the course blog for yesterday...
http://summerinantarctica.usc.edu/2010/01/burrowing_worms.html
Connor asked me to write a blog entry reflecting on the course and I sat down to write and ended up writing much more than I had planned. I sent her a draft and had her cut it down to what she wanted, but here's the full version in case anyone is interested:
Looking back over the past month, and I guess since I first started thinking about applying for this course, I’m struck by how my perspective on my research has expanded on both spatial and biological scales. My interest in polar research was pretty much instigated by the opportunity to come to Antarctica. Perhaps you could say I had a destination-based research interest more than a question-based research interest. Being a determined young scientist, I delved into the literature on polar biology, trying to figure out if I could possibly convince myself that there was some justifiable reason for me to participate in the course and more importantly write a convincing application.
Let me back up. I’m an oceanographer/ecologist and I’m interested in how animals like worms and clams that live in muddy and sandy sediments interact with their environment and how physical processes affect individual organisms as well as community structure (who can live in different environments?) and ecological processes (what are they doing there?). To put it simply, I study how worms burrow in mud. Marine worms have similar functions to the earthworms in your garden: they mix the sediment, making it less compact and bringing oxygen down, which is important for the bacteria and smaller organisms in the community. There are also a lot of them – 70% of the earth’s surface is covered by marine sediments, and there are tens of thousands of worms in a square meter of sediment. Most worms eat mud and their activities affect nutrient cycling, the fate of pollutants, and burial of organic carbon (removal from the global carbon cycle). I know there are worms in Antarctica, but are the worms in Antarctica different than the worms I can collect on the coast of California, and are these differences important enough for me to fly around the world to study them?
So everyone knows that the water in Antarctica is cold, but what you may not know is that there are a lot of other properties of water that depend on temperature that are also important to organisms living here. Oxygen saturation depends on temperature, and cold water holds much more oxygen than warm water. Viscosity of cold water is higher too. (Viscosity is the resistance of a fluid to being sheared, which happens anytime part of a fluid is moved more than another part, like if you mix or pour something or if a worm pumps water through its burrow. Honey has high viscosity so is hard to pour.) The combination of high oxygen and high viscosity has some interesting implications for fish physiology. One problem with high viscosity is that it’s hard to pump blood through the circulatory system. Some fish reduce the viscosity of their blood by reducing the hemoglobin concentration (think of this as fewer big chunks that need to be carried along by the fluid, which makes it easier to flow) or even completely eliminating hemoglobin, which works for them because there’s so much oxygen in the cold water and their metabolism is pretty slow so they need less oxygen. Oxygen is a pretty big concern for anything that lives in the mud because there’s only oxygen in the top few mm of mud. This is because the oxygen comes from the overlying water and is rapidly consumed by bacteria and animals living in the mud. Lots of animals deal with this problem by pumping water down into tubes and burrows. Down here, where the water is -1.86C, there’s more oxygen in the water, but because the water is more viscous, it’s harder for worms to irrigate their burrows to get to the oxygen. On top of that, diffusion (which is important in transporting oxygen over small distances) is much slower in cold water. Based on what I know about the environment, I would hypothesize that worms that have external gills that they can stick up into the water would do better than those that pump water down into the mud, although maybe there’s enough extra oxygen that it doesn’t matter. For worms that do irrigate burrows, pumping water through a tube with a large diameter is much easier than through a narrow tube, so one solution to the viscosity problem might be to just build bigger tubes or stay closer to the surface so you don’t have to pump water as far. And of course, as we’ve learned over the past month, temperature affects metabolism pretty dramatically. I’m really interested in how much worms are moving and feeding and how these processes affect the sediment around them. How much thermal compensation do they exhibit and how does that affect their activity levels?
These are all big questions that I didn’t expect to answer on this trip, but I have definitely learned a lot about the challenges of conducting research in Antarctica, have gotten some new ideas, and met a lot of outstanding scientists with whom I hope to collaborate in the future. I was pretty excited to see some really big parchment tube worms – the worms are highly adapted to pump water through their tubes with modified flap-like segments. These worms are much bigger (and have bigger tubes!) than the parchment tube worms I’ve seen at home and their tubes are on top of the sediment. I also saw a big (about 4 inches long) worm crawling on the surface that’s closely related to a burrowing worm I’ve seen in Maine, but is much bigger (lots of invertebrates in Antarctica exhibit gigantism) and has these weird modified spines. It’s fun to see animals that are closely related but look really different because those differences indicate adaptations to different environments.
One of the groups studied phytoplankton communities and did some physical oceanographic measurements and their data showed that the area around McMurdo is really productive and has high nutrients, and while we have been here, there has been a huge bloom of one species of phytoplankton. Worms mostly eat detritus that comes from sinking phytoplankton and they regenerate nutrients that fuel more phytoplankton growth. Antarctica’s worm community has lots of food, lots of oxygen (if they can get it), but really cold temperatures so (theoretically) low metabolic rates. So how do carbon and nutrient turnover rates compare to those in temperate areas? Does it matter that most of the food comes from one species of phytoplankton? Dennis pointed out that some mud we had in the lab had a faint ammonia smell – what does that mean in terms of nitrogen cycling in mud?
I haven’t thought very much about processes occurring at smaller scales than whole animals, but most of the biologists in the course study small things like unicellular bacteria and phytoplankton, as well as enzymes, proteins, and DNA. Johanne and Wes did research on how thermal stress causes oxidative damage in fish and clams. The worms I study in California live in the intertidal and experience huge temperature fluctuations - compare a low tide in the middle of a hot summer day to normal water temperatures in the low 50’s (about 11-12C) – and experience huge fluctuations in oxygen in their tissues. I hadn’t even thought about how the combination of these stresses might affect their DNA and protein structure.
In addition to generating future research questions, I’ve really enjoyed learning about the history of Antarctic exploration and the important role of science in driving exploration. We’ve also learned a lot about the effects of climate change in Antarctica, which is both interesting and scary. And, of course, I’ve definitely had the fun and adventure I had hoped to experience – I rode helicopters and snowmobiles, skied 13 miles across the Ross Ice Shelf, saw glaciers and giant pycnogonids and isopods (oh yeah, and some penguins and seals), and made some great new friends.
http://summerinantarctica.usc.edu/2010/01/burrowing_worms.html
Connor asked me to write a blog entry reflecting on the course and I sat down to write and ended up writing much more than I had planned. I sent her a draft and had her cut it down to what she wanted, but here's the full version in case anyone is interested:
Looking back over the past month, and I guess since I first started thinking about applying for this course, I’m struck by how my perspective on my research has expanded on both spatial and biological scales. My interest in polar research was pretty much instigated by the opportunity to come to Antarctica. Perhaps you could say I had a destination-based research interest more than a question-based research interest. Being a determined young scientist, I delved into the literature on polar biology, trying to figure out if I could possibly convince myself that there was some justifiable reason for me to participate in the course and more importantly write a convincing application.
Let me back up. I’m an oceanographer/ecologist and I’m interested in how animals like worms and clams that live in muddy and sandy sediments interact with their environment and how physical processes affect individual organisms as well as community structure (who can live in different environments?) and ecological processes (what are they doing there?). To put it simply, I study how worms burrow in mud. Marine worms have similar functions to the earthworms in your garden: they mix the sediment, making it less compact and bringing oxygen down, which is important for the bacteria and smaller organisms in the community. There are also a lot of them – 70% of the earth’s surface is covered by marine sediments, and there are tens of thousands of worms in a square meter of sediment. Most worms eat mud and their activities affect nutrient cycling, the fate of pollutants, and burial of organic carbon (removal from the global carbon cycle). I know there are worms in Antarctica, but are the worms in Antarctica different than the worms I can collect on the coast of California, and are these differences important enough for me to fly around the world to study them?
So everyone knows that the water in Antarctica is cold, but what you may not know is that there are a lot of other properties of water that depend on temperature that are also important to organisms living here. Oxygen saturation depends on temperature, and cold water holds much more oxygen than warm water. Viscosity of cold water is higher too. (Viscosity is the resistance of a fluid to being sheared, which happens anytime part of a fluid is moved more than another part, like if you mix or pour something or if a worm pumps water through its burrow. Honey has high viscosity so is hard to pour.) The combination of high oxygen and high viscosity has some interesting implications for fish physiology. One problem with high viscosity is that it’s hard to pump blood through the circulatory system. Some fish reduce the viscosity of their blood by reducing the hemoglobin concentration (think of this as fewer big chunks that need to be carried along by the fluid, which makes it easier to flow) or even completely eliminating hemoglobin, which works for them because there’s so much oxygen in the cold water and their metabolism is pretty slow so they need less oxygen. Oxygen is a pretty big concern for anything that lives in the mud because there’s only oxygen in the top few mm of mud. This is because the oxygen comes from the overlying water and is rapidly consumed by bacteria and animals living in the mud. Lots of animals deal with this problem by pumping water down into tubes and burrows. Down here, where the water is -1.86C, there’s more oxygen in the water, but because the water is more viscous, it’s harder for worms to irrigate their burrows to get to the oxygen. On top of that, diffusion (which is important in transporting oxygen over small distances) is much slower in cold water. Based on what I know about the environment, I would hypothesize that worms that have external gills that they can stick up into the water would do better than those that pump water down into the mud, although maybe there’s enough extra oxygen that it doesn’t matter. For worms that do irrigate burrows, pumping water through a tube with a large diameter is much easier than through a narrow tube, so one solution to the viscosity problem might be to just build bigger tubes or stay closer to the surface so you don’t have to pump water as far. And of course, as we’ve learned over the past month, temperature affects metabolism pretty dramatically. I’m really interested in how much worms are moving and feeding and how these processes affect the sediment around them. How much thermal compensation do they exhibit and how does that affect their activity levels?
These are all big questions that I didn’t expect to answer on this trip, but I have definitely learned a lot about the challenges of conducting research in Antarctica, have gotten some new ideas, and met a lot of outstanding scientists with whom I hope to collaborate in the future. I was pretty excited to see some really big parchment tube worms – the worms are highly adapted to pump water through their tubes with modified flap-like segments. These worms are much bigger (and have bigger tubes!) than the parchment tube worms I’ve seen at home and their tubes are on top of the sediment. I also saw a big (about 4 inches long) worm crawling on the surface that’s closely related to a burrowing worm I’ve seen in Maine, but is much bigger (lots of invertebrates in Antarctica exhibit gigantism) and has these weird modified spines. It’s fun to see animals that are closely related but look really different because those differences indicate adaptations to different environments.
One of the groups studied phytoplankton communities and did some physical oceanographic measurements and their data showed that the area around McMurdo is really productive and has high nutrients, and while we have been here, there has been a huge bloom of one species of phytoplankton. Worms mostly eat detritus that comes from sinking phytoplankton and they regenerate nutrients that fuel more phytoplankton growth. Antarctica’s worm community has lots of food, lots of oxygen (if they can get it), but really cold temperatures so (theoretically) low metabolic rates. So how do carbon and nutrient turnover rates compare to those in temperate areas? Does it matter that most of the food comes from one species of phytoplankton? Dennis pointed out that some mud we had in the lab had a faint ammonia smell – what does that mean in terms of nitrogen cycling in mud?
I haven’t thought very much about processes occurring at smaller scales than whole animals, but most of the biologists in the course study small things like unicellular bacteria and phytoplankton, as well as enzymes, proteins, and DNA. Johanne and Wes did research on how thermal stress causes oxidative damage in fish and clams. The worms I study in California live in the intertidal and experience huge temperature fluctuations - compare a low tide in the middle of a hot summer day to normal water temperatures in the low 50’s (about 11-12C) – and experience huge fluctuations in oxygen in their tissues. I hadn’t even thought about how the combination of these stresses might affect their DNA and protein structure.
In addition to generating future research questions, I’ve really enjoyed learning about the history of Antarctic exploration and the important role of science in driving exploration. We’ve also learned a lot about the effects of climate change in Antarctica, which is both interesting and scary. And, of course, I’ve definitely had the fun and adventure I had hoped to experience – I rode helicopters and snowmobiles, skied 13 miles across the Ross Ice Shelf, saw glaciers and giant pycnogonids and isopods (oh yeah, and some penguins and seals), and made some great new friends.
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