Viviendo

A rainbow rising from the Beagle Channel

Apologies for the late post here, there hasn't been to much new information to report since the last time I updated. However, there is still plenty I can share with you!

Simple but dependable kitchen

Lately I've been living the CADIC life, which has a nice hotel like space for visitors like me and actually has shared apartments for students who study here. It's simple living, but definitely comfortable. The old gas stove heats up my food maybe a little too fast, but it works! Last weekend the power went out, but I managed well enough cooking in the dark. This time of year there aren't very many visitors so I've had the kitchen and dining room to myself. I end up spending most of my spare time in the office since the internet doesn't really make it to my room (short of holding my phone next to the window) and really only venture out into the world when I need to go shopping. I would go out more often, but by the time I'm finished working for the day the sun has long since set, and its too dark and cold to really enjoy sight seeing. At the very least the weekends give me an opportunity to explore the town a bit and to get to know people. This weekend I'm planning on taking a walk across town to check out the maritime museum, located in the old prison. I'll be sure to share more details about that later on. Today I discovered that the shower is actually capable of getting hot and not just lukewarm, it turns out that I wasn't waiting long enough for it to reach temperature. Knowing this will make my life much more comfortable!

The dining room, straight out of a 70s designer catalog

Over the time I've spent here, I've been learning a ton about the species of seals I'm studying. As it turns out, there's still quite a bit unknown about fur seals and their evolutionary relationships, which strikes me as somewhat odd given that they're common large mammals occurring in many different oceans (Pacific, Atlantic, Indian and Southern.) The majority of Fur seals live in the southern hemisphere, except for one species off of California, the Guadalupe Fur seal, very nearly driven to extinction in the 19th century. Pinnipeds (all seals and sea lions) are divided into two groups: Otariids and Phocids. Fur seals are joined by Sea Lions in Otariidae, while true seals are in Phocidae. My Californian friends are probably familiar with the Otariid California Sea lion, which tends to bark very loudly and keep people up at night. You'll notice that Otariids have ears that stick out and can pose upright, supporting themselves on their front flippers. True seals, Phocids, are unable to do this and are also missing those ear flaps, signalling potentially stronger adaptations to the marine environment.

A picture of A. australis I found on the internet

In South America, only Otariids exist today (except for lost or wandering Antarctic or sub-Antarctic Phocids, and a small colony of southern elephant seals hanging out at the very south-eastern edge of the continent).  Phocidae once had a significant presence in South America, however changing sea levels during past ice ages effectively removed the open beaches that they loved so much several million years ago, leaving behind only rocky shorelines. A-ok for Otariids, bad for Phocids. Some Otariids that took over during this time were the Fur seals, which proliferated throughout the whole southern hemisphere, diversifying into at least six different species in South America, Australia, New Zealand, South Africa, and the sub-Antarctic islands. In 2011, researchers proposed re-classification of most of the fur seal species into a new genus: Arctophoca, (formerly Arctocephalus, only Arctocephalus pusillus kept the genus name) based on a review of genetic data.

The taxonomic situation gets even more tricky for my primary target species, Arctophoca (née Arctocephalus) australis, the South American Fur seal. In the mid 20th century, Judith E. King proposed two subspecies based on comparison of two skulls from the Galapagos and the Falkland Islands. This classification never really stuck though since the skull from the Galapagos was deemed to be a separate species completely (the Galapagos Fur seal) and for many years no subspecies were considered, despite the huge geographic range of A. australis, stretching from northern Chile to Uruguay. In the same review of genetic data that reclassified the genus of most Fur seals, the authors found that the South American Fur seal could have as many a four different subspecies, though more data is needed to confirm these distinctions. At the very least there are three different evolutionarily significant units (ESUs) of A. australis, occurring in northern Chile, Tierra del Fuego, and Uruguay. Interestingly, most of our knowledge about the A. australus comes from the huge colony that lives by Uruguay. The seals from here have smaller body sizes than the seals to the south, potentially hinting at a phenotypic indicator of differences between ESUs (and possibly subspecies). 

The uncertainty about some of these evolutionary relationships has intrigued me to the point where I'm getting serious about another type of analysis that will be helpful: Ancient DNA extraction. I plan to bring back some samples to do a test run to extract ancient mitochondrial DNA. If successful, I can use ancient DNA not only to disentangle some of these complicated relationships between the ESUs, but also find out how the population of Fur seals in Tierra del Fuego has changed over time, from 6,000 years ago to present.

Weighing time

In more other science news, I'm starting to get really busy on the isotope side of things. While I'm demineralizing the last set of bones, I've begun weighing pieces of dried collagen to find out how much is actually left after all that chemical treatment. So far, it appears that I've recovered amounts consistent with previous extraction runs, which is excellent. The weighing step is easily the most time consuming and boring, but it does allow me to listen to a lot of music and podcasts. After measuring the collagen yield, I place a small amount of the collagen into very tiny tin boats, which will later be incinerated at around 900 degrees C to measure those carbon and nitrogen isotopes I'm after. I'll write more about what happens next when I'm back in Merced. 

A closer look at the tin capsules

In a future post I intend to talk a bit about the post-European contact history of A. australis and a bit about the Sea lions. which has important implications for my research! Also some Ushuaia (prison) history. Stay tuned!