Visitors from Florida!

Pretty much everyone in our group.

 In an effort to show the field trip group as much as possible and to make their Spring Break worthwhile, every day this week has been spent at a different locality looking for different kinds of fossils. It's been a nice change of pace and has helped the time to go by substantially quicker than usual. We'll be returning to these sites many more times in the coming months, so it was also helpful to be able to see them all in such rapid succession and to piece together the time and space relationships between them.

All the work sites have been right along the canal, near
the Centenario Bridge.

On Monday we drove down into the canal zone to a site called Las Cascadas, which is part of (oddly enough) the Cascadas Formation (~21 million years old) and contains terrestrial fossils. No collecting had been done there since early December, so we spent the first half of the day just surface prospecting, meaning that we looked for any signs of fossil material in the loose debris within stream channels, at the bottoms of slopes, and on the eroding surfaces of the exposed rocks. The hope was that some of the rain showers in the past few months might have washed out material and left it ripe for the picking. For the most part, there was little to be found, mostly just unidentifiable fragments of bone, but Nicole (fellow intern) manged to spot a nearly complete, though fractured, tooth that turned out to be from a taxa never before seen in this area. The tooth was a molar to some kind of horse-like animal with European affinities, and Aaron was entirely blown away when he saw it. It was pretty cool to be right there when a big discovery like that was made - I just wish I had been the one to spot it! That great find turned out to be the last, so in the early afternoon we turned to quarrying in some of the more fossiliferous beds, picking out palm-sized bits of rock with screwdrivers and busting them open to see if there was anything inside (fossil material causes weakness within the rock matrix and fractures will tend to open up along that weakness). Between the ten or so of us there, we found a few rodent teeth, some turtle carapace fragments, and an ankle bone of a small artiodactyl, a pretty good haul, I'm told, for that locality.

Teeth and a vertebra, all found by me!

On Tuesday we had the biggest group of the week: all six students from Florida, all five of my group, Bruce, and a researcher from CTPA (the geology/paleontology department of STRI) and her student. The researcher took us out to her main site of interest, called San Judas, which is part of the Gatun Formation (~10 million years) and is quite literally overflowing with marine fossils, mostly invertebrates. Our goal for the day was to collect a large quantity of well-preserved shells for an educational project Bruce is working on with some California school district. Any vertebrate remains were to be kept in a separate bag for use by the CTPA researcher. Like I said, this site had exposed invertebrate fossils as far as the eye could see, so within half an hour I had a quart sized bag full of bivalves, gastropods, worm burrows, barnacles, etc., all of which were basically perfectly preserved. Then I was free to focus on the fun stuff: shark teeth. And I was seriously on my game! Within an hour or less I had found five of those little suckers, more than anyone else in our enormous group. I think it must have been a fluke or something, since every other trip to the field has resulted in very poor finds for me. For whatever reason, though, the stars aligned at San Judas that day and I was able to bask in the glory of being a master fossil finder, at least for a while.

And after returning from the field we all went to the weekly seminar at Tupper, which was about the relationship between bats and plants. Much of the data was collected through high-quality video monitoring set up in Panama's own Bocas del Torro region, so we got to watch a whole bunch of really cool clips. The talk covered a lot of different aspects of how bats interact with plants, but two parts in particular stood out as really impressive and interesting. First, I learned that certain varieties of nectar-eating bats will turn to eating fruits during low-nectar or non-flowering periods, but they do not effectively distribute the seeds as would a true fruit bat. The speaker showed some footage of both types of bats eating the same varieties of fruits, and the nectar-eater would at first glance appear to eat in more or less the same way as the fruit-eater, just slightly less efficient. But when you zoomed in on the bats' mouths, you could see that the nectar eater was really only going after the juice; every few bites they would spit out a wad of pulp. In examining the discarded cores or certain fruit varieties, you could also see that the nectar eaters left much more behind to rot (and therefore not to grow) than the true fruit-eaters. Thus when these types of bats go to eat fruit as a necessity, they are essentially "cheating" the plant out of the arrangement it has with its more regular visitors. The other neat bit was that the quality of the footage allowed the researcher to see that in some cases bats served as transporters of other, smaller pollinators. In particular, there was a great video of a bat landing an a plant to drink from a flower and while it was busy you could see dozens of little white specks (flower mites) crawling from the plant onto its body and wings. When the bat went to roost in a nearby tree(they do this to rest and digest between feedings) you could still see the specks, but they were perfectly still. Then, when the bat moved on to another plant, you could see them all scurrying off. It was really incredible stuff!

Wednesday and Thursday were fairly low-key field days. We spent each at Hodges Microsite and Las Cascadas, respectively. Hodges is a part of the Cucaracha Formation (~20 million years) and is our most productive microfossil site, containing tons and tons of fish teeth, turtle fragments, croc teeth, rodents, bats, and much more. We pull these things out from a series of small quarries that have been found to be plentiful in the past, so each of us more or less just chose a hole to work in and started poking around. If I remember correctly, we didn't exactly walk away with a great haul, just a few scattered teeth and lots of broken bits. The quarries were all surrounded by eight feet tall elephant grass, however, so at the very least we had some comfortable shade to work in! Our return to Cascadas was similarly anticlimactic, with only a few ankle bones from artiodactyls (see above) to show for hours of digging.

The real highlight of Thursday, at least for me, was going once again to Barro Colorado Island for the dinner and seminar. Basically everyone mentioned above came along, so our group constituted a fair share of the attendees  The boat ride to the island was done on the small taxi this time, and it was pretty overcast and even a little rainy, so there weren't as many good opportunities for sight seeing as on my previous trip. That little boat got us to the STRI station a hell of a lot quicker than the cargo boat, though, which ended up paying off for us - we were the first ones to get to the kitchen area for the pre-dinner beer social, and so we were able to claim the balcony seats overlooking the shoreline. The sun even came out for us as we sat there! It was great. Dinner was pretty standard cafeteria fare, except they really went all out on the fruit, including some phenomenal papaya, pineapple, and watermelon  Plus there was a juice dispenser filled with Arnold Palmer to wash it all down. I was feeling exceptionally content by the time we had to head over to the conference room for the talk. The guest speaker was from Scripps and was all about coral reef systems. He laied out for us a bunch of his past experimental apparati for simulating a natural reef (tanks of ever-increasing complexity) then went on to show us what he is currently working on: a system for altering the local environment of an in-place reef in the actual ocean. This new in-situ system really blew my mind with how precise and responsive it could be, using computer-monitored pumps and injection tanks of super-saturated seawater to tune in to exactly the desired parameters (with emphasis on the effects of CO2 loading). Using his apparatus he was able to run some pretty convincing simulations of what the future might look like for coral reefs. For the most part, prospects are terrible, but there is hope in certain red branching corals that were able to alter their carbonate chemistry in order to deal with the simulated decreasing pH. It really was a thought-provoking presentation and I've been caught up in it ever since.

I made a friend back at the apartment :)