A new leaf

So, as the title of this post implies, I am in the process of turning over a new leaf. I know, I know, the plant biologist makes a lame plant pun... bear with me.

At the end of the week, I will start my new job at Harvard Forest, where I'll be studying the effects of climate change on plant populations- particularly ragweed, which causes allergies in humans. I'm excited to start a new project, and I was fortunate enough to meet my new P.I., Kristina Stinson, at the Ecological Society of America's annual meetings last week, which were conveniently held in Portland. She's awesome! I think she's going to be a great mentor, and it will be exciting to get involved with a project that has a lot of momentum going already. Apparently, I will be the 27th person to contribute to this project... how crazy is that? I also met a few of my soon-to-be fellow researchers at the conference, and they seem like great people to be working alongside of for the next few months. The whole job-finding process was  challenging (as other recent grads likely know well) and filled with lots of courteous rejection letters and, even in seemingly promising options, lots of bureaucracy and delays. In the end, I got extremely lucky to be able to find a spot on Kristina's research team, since the status of her projects, her current funding availability, and my plans to return to Costa Rica in January left her seeking assistance for almost exactly the amount of time I am available in between my current job ending and heading back to the tropics to work on my own research next year.

As exciting as this is, my new job also marks the official end of my time at Reed. While for many college students graduation is "the end," I've spent my summer working on an additional experiment related to the research I did for my thesis; save for the dramatically decreased stress levels, conspicuously absent student body on campus, and regular doses of sunshine in Portland, my daily life has really not been terribly different than it was during my senior year at Reed. Now, when I leave work tomorrow, I am leaving the Reed biology department for good! It's pretty weird to acknowledge how final this is: I will no longer be contributing to my adviser's research, and, essentially, whatever I have for him by the end of the week is all I will ever be able to say about my current project. Since I got involved in the project that became my thesis so early on in my time at Reed, this will be a huge change for me. Granted, I haven't been working on it constantly for the past 2.5 years, but every time I left in the past I've had the promise of continuing to work whenever I returned. Leaving the lab for good will be weird. Also, obviously, starting to work at Harvard Forest will mean moving to Massachusetts, i.e., leaving Portland indefinitely. I have loved living here so much that I am slightly apprehensive about moving back to the East Coast, and while many of my friends have already left Portland for the summer and/or beyond, leaving this time feels like saying goodbye for real.

So, understandably, I am feeling kind of down about leaving. However, the past week of packing, finishing up lab work, cleaning out my office and house, and saying goodbyes has given me a lot of time to think about how lucky I was during my time at Reed. After all, the only reason it's hard to go is because I have had some amazing experiences here! Sure, I've had my stressful moments (read: years), but I feel like I've grown a lot from being pushed to my personal academic limits. And, despite demanding classes, jam-packed scheduling of school and several jobs, and seemingly impossible-to-please professors, one of the greatest privileges that I've gotten as a Reedie is freedom. Underneath all of the structure, at the end of the day, the faculty here give us so much freedom to pursue our  interests, work independently, and learn from our own mistakes. Having worked elsewhere, too, I can say that this flexibility is not something that every undergraduate student is privy to... nor is the trust and respect that are necessary in order for professors to feel comfortable giving us such freedom. Reedies routinely accomplish amazing things both in the classroom and beyond, and I truly believe that a big part of that starts here, either during thesis or prior independent projects where we are given the incredible license to do something important, something that we care about. And, because we are told that we can, we do. I am so grateful to have been able to spend four years with a faculty and staff that both encourages us to develop our passions and gives us the guidance, resources, and freedom necessary to pursue them... not to mention a student body of amazing people who rise to and exceed the expectations that come with these privileges. 

OK, so I guess that will suffice as my final love letter to Reed.  I'll be honest and say that there were days when I hated it and days when I wished I went to another school, but in the end I truly feel that Reed is an amazing school in an amazing city filled with amazing people. I am also practical enough to realize that the confidence and joy that I feel while here is a good sign that it's time to try something new and push myself outside of my comfort zone. But now, as I leave, I just feel the need to acknowledge how much the past four years have meant to me. I will carry so much of what I've learned here with me for the rest of my life... to Harvard Forest, to Costa Rica, and beyond!

Palo Verde, pt. 4: Independent projects

At the beginning of FLP week, I still had no solid idea to work with for the upcoming independent project. I knew that I was vaguely curious about trade-offs in anti-herbivore defenses in acacia trees, wondering if species with obligate ant interactions produced lower concentrations of secondary compounds than species with facultative ant interactions. However, I had talked to my professor Erika about this idea and she told me that because there are only about 4 species of acacia at Palo Verde, I wouldn't be able to gather enough data to make generalized conclusions about the potential trade-offs between biotic and chemical defenses in plants. I was also interested in the agroecosystem in and surrounding the rice fields that we had visited earlier for class, but didn't at first see any connection between these two ideas. However, at some point during the week it clicked for me, and I decided that I wanted to study anti-herbivore defenses in non-agricultural plants near the rice fields, predicting that they would have decreased defenses because of agrochemical use lowering the herbivore pressure in the region. Once I had my idea formulated, I talked to my professors about it and they gave it the OK. Rukhshana and Owen also decided to work with me, so by Thursday we had a team, a question, and a plan of attack.

Rice fields near Palo Verde where we did our IP

Wastewater flowing out from the flooded fields

The wastewater, contaminated with pesticides, flows out from the fields in exit canals like this one. The big trees on either side of the canal are guazumas.

 After our FLP presentations on Thursday morning, a bunch of students including me, Rukhshana, and Owen took a ride back out to the rice fields to make preliminary observations for the IPs. Most people were still looking for a question to work with, but we were out scouting for plants with quantifiable anti-herbivore defenses that grow abundently near the rice fields. We took about 20 samples and brought them back to Palo Verde, where the three of us met with our professor Susan. Our original plan was to compare plants near the rice fields to plants at Palo Verde, so Susan helped us sort through and identify our samples, pointing out the plants that plants that we might also find in the park. Unfortunately most of the abundant non-agricultural plants in the rice fields are weeds that don't  grow much in Palo Verde, so we had limited options to work with. However, we did notice some familiar faces growing along the edges of the irrigation canals in the fields: Guazuma ulmifolia, a large tree with trichomes on its leaves, and Vachellia collinsii, an acacia species that depends on agressive ants to protect itself against herbivores. Trichomes are like little tufts of hair on leaves that help prevent dessication and also discourage insect herbivory by making the leaf fuzzy and difficult to bite. Because they are discrete, they can easily be quantified just by counting their density using a dissecting microscope with a grid. The acacia trees use extrafloral nectaries (EFNs) to encourage ant inhabitation, so counting EFNs and measuring their size is a way to quantify the trees' defenses.

Guazuma trichomes, as seen through a dissecting microscope.

Vachellia extrafloral nectaries (EFNs)

To make our experimental design more robust, we wanted to find a third plant species to examine, and do some sort of additional analysis of chemical defenses on all three species. Unfortunately, one thing that OTS sorely lacks (in my opinion) is good lab space and equipment at the field sites, so most of the chemistry protocols we encountered for quantifying anti-herbivory chemicals in leaf tissue were way too advanced for our situation... The most serious equipment we had were mortars and pestles, and the most heavy-duty chemicals we could get our hands on were acetone, ethanol, vinegar, and  water (tap or bottled, but neither deionized or sterile). Needless to say, we were feeling pretty limited. When it came time to present our proposal on Friday morning, we still had not worked out the details of the third plant species or the second test we'd be using.

Regardless, we started to work. Data collection officially started on Saturday, but we spent the afternoon walking around Palo Verde and looking for forest edges facing the same direction as the irrigation canals in the rice fields. Because trichomes on leaves also help prevent water loss, it was important that our control site plants be getting approximately the same exposure as our plants at the fields. While we were flagging usable trees with fluorescent tape, something amazing happened: it rained! In the dry season! And when I say rained, I mean it POURED. After having been at Palo Verde for over a week already and sweating almost constantly, everyone was ecstatic. We all ran back to the building, dropped what we were doing, and sat in the rain, ecstatic. It felt amazing, and was a welcome last bit of freedom before the true work of IPs began the next morning.

Enjoying the rain on a hot and muggy day

Like I said, it was pouring!!! Miguel said that this is what the rainy season is like every day. I can't even imagine!

At dinner, we talked again with Susan, who told us that we should find a new control site closer to the rice fields to use in our experiment. Because Palo Verde is about 30 minutes away by car and is also partially wetlands, the soil types between the rice fields and the park are very different, and our professors thought it would be better to try to eliminate that as a potential confounding factor. So, the next morning when we began collecting samples, we went to a new site northeast (upstream of wastewater exit canals) of the rice fields and got 21 samples of vachellia. We needed 30 samples at each site with three individual leaves per sample, and getting just 21 took all morning because of the ants. As it turns out, vachellia's biotic defenses are pretty effective against herbivory, and all other sorts of threats. As soon as you touch a leaf to snip it off and take a sample, the ants come running down the stem and attack, biting all over your hands (or wherever else they land). We had to be really careful, and even so we still got eaten alive, literally. We came back for lunch and went back into the fields at 1:30, getting our 30 samples from the rice fields and our 9 remaining control samples. After dinner Rukhshana, Owen and I spent lots of hours up in the lab building counting and measuring the extrafloral nectaries on all 180 vachellia leaves, and then enetering our data into a spreadsheet. We also had decided on an herbivore preference test for chemical defenses, which our professors recommended because of the relative ease of the protocol. The general idea is to make a crude leaf extract and present it to ants, and see how much the ants eat compared to a sugar-water control. So, on night 1, we also made an ethanol-based extract from vachellia leaves from both sites. By the end of the first day, we were already exhausted!

The next morning, Owen and I went back out into the field to collect our guazuma samples. Rukhshana stayed behind to do our ant bioassays for the vachellia leaf extracts, which we had to repeat on 20 different ant colonies of the same species. Because another student needed to be driven to a different off-campus site to gather data, the driver couldn't stay with us all morning like he had the day before, and dropped us off at the control site. We collected 30 samples from our control site, and then started to walk to the rice fields since we weren't getting picked up until later that afternoon.

Owen climbing a tree to get a guazuma leaf sample

Unfortunately there are a LOT of rice fields near Palo Verde, and they all look really similar, so we got lost and were wandering around the roads for THREE HOURS, all while carrying around a garbage bag full of leaf samples and an 8-foot long pole pruner for clipping high-up branches. We realized in retrospect that we had walked all the way around the entire region because we missed a turn down the road that took us to the fields we were working at, and by the time we found our way back to the right place by walking back to Palo Verde and going back out from there, the driver was already waiting to bring us back. He doesn't speak any English and we were too hot and exhausted to explain what had happened in Spanish, so since we weren't sure whether or not someone else needed to be driven somewhere in the afternoon, we went back to Palo Verde with zero of the 30 samples we needed from the fields. After a bit of rest and SHADE (which does not exist in rice fields), we went back out for two more hours and collected all 30 of the samples we needed. I took the most glorious shower of my life when we had finished our hot and exhausting field work for the day, and ate a very satisfying dinner. Then I spent several hours counting the trichome density on some of the guazuma leaves, since lack of microscopes and issues of inter-observer reliabilty prevented us from sharing the work among all three of us. While I was counting, Rukhshana and Owen made the leaf extracts for the guazuma samples. Because I was so exhausted from our crazy day, I only got through about 1/4 of the leaves that I needed to look at, but I decided to just go to bed and finish it the next morning.

After getting some rest, I spent the entire next day counting trichomes at the microscope. Rukhshana completed all of the ant bioassays that we needed for the leaf extracts, and Owen went back out into the field with Susan to try to find a third species that we could use. Miraculously they were able to find one that grew at both sites, a shrub with trichomes called Malvaviscus arboreus, and collect the 30 samples from each one all in one day. I finished counting trichomes around 8:30 pm (seriously!), and handed off the trichome-counting responsibility to Owen for our malvaviscus samples. While he was working, Rukhshana made leaf extracts and I assembled a datasheet for our grazuma trichome information. We were all tired again, and Owen and I had gotten sunburn while lost the day before, so we went to bed at 9 pm, which felt wonderful.

Rukhshana observing ant responses to extracts made from leaves near the rice fields, far from the rice fields, and a sugar control.

By counting the number of ants present on each petri dish after a certain amount of time and dividing by the number at the sugar control, we could determine the relative palatability of the leaf extracts. A leaf extract that is less palatable to herbivores presumably contains more chemical defenses against herbivory.

Tuesday was our last day of data collection for the IP! Owen counted trichomes all day, literally from about 8 in the morning until about 1 am the next morning. Rukhshana and I did the remaining ant assays, and I started analyzing whatever datasets were complete. We met with Susan, and realized that we had significant results! She was very excited for us (as were we!), and it was amazing to comprehend that we had actually accomplished something both interesting and kind of important in just four days. The next day was dedicated to finishing our analyses and putting together our results, whichw e had to present on Thursday. We met with Susan several times to create our Powerpoint and interpret our results. The next morning was spent rehearsing our presetation, which we gave that afternoon. As soon as the presentations were done (which were really neat to listen to, since everyone had done completely different projects), we had a little bit of time to break down everything from our experiments, i.e. washing some glassware and un-flagging the 20 ant colonies we had used for bioassays. After dinner, I started writing my lab report rough draft, which was due the next day! I stayed up all night and it took me until 6:15 the next morning, but I finally finished, just in time for the first break we had had in a long time.

Palo Verde, pt. 3: Faculty-led projects

Tuesday 2/22 through Thursday 2/24, we worked on faculty-led projects with Jordan, a professor from Tulane, and Ignacio, a graduate student at the University of Costa Rica. On Tuesday and Wednesday we did data collection, splitting up into two groups and working on one of the two projects each day. I worked on Ignacio's project first, and collected data on Green Lynx Spiders all day. We were testing to see whether spiders gain experience with age by looking for relationships between spider age (juvenile/adult) and responses when encountered with a predator.

A green lynx spider (Peucetia viridans)

Ruellia inundata, the plant where green lynx spiders live. Rather than building webs, they perch on the plants, wait for pollinators to pass by, and then pounce on them.

We did this by simulating predation with a false bird beak (aka a stick sharpened to a point and wrapped in black electrical tape) and measuring how close we could get to the spider before eliciting a response, the response distance, response type (run, jump, shift, etc.), and response location (leaf, stem, flower, or ground). 

A "simulated predation event." Chelsea is moving the stick, or model bird beak, towards the spider, and Carolyn is waiting to measure and record its response distance and type.Photo by my professor, Mau.

While 14 of us were gathering data all day, a smaller group of six was responsible for compiling all the data, writing it up, and presenting it to the class. I was in the small group for Ignacio's project, so after a long morning of finding, poking, and observing 50 or so spiders, I spent the afternoon making a giant dataset of all of our observations from day one.

On Wednesday, the other group was collecting spider data with Ignacio, and my half of the class went with Jordan to work on his project. He was observing bird behavior based on population density to see if behaviors that decrease vigilance toward predators (e.g. foraging) is more prevalent in areas of higher bird density, overall looking at the osts and benefits of social behavior in birds. We spent the day observing Northern Jacanas at three different sites in Palo Verde, focusing on one individual at a time for five minutes of observation. We worked in pairs so that one person could record the behaviors that the person with binoculars observed; however, I was working with Rukhshana, and she got sick that morning, so I ended up working in a group of three with Ashur and Inca.

A really terrible picture of Jacana spinosa, the Northern Jacana. If you look closely you can see one on the right hand side about half way down. Everything else in the picture is water hyacinth in the marsh. Northern Jacanas are actually really cool looking, and Google images can probably show you much better stuff than this!

Birdwatching in the marsh at one of our lookout points

Justin simulating the Jacana's aggressive wing-display behavior on Matt.

The big croc!

Because both small groups had to present on the research the next day, we only gathered data in the morning so we could work on analyzing the data later in the day. Although we were only out for about five hours, it was an exciting morning. First, Inca got chased by a herd of cattle that live out in the marsh to keep the invasive grasses under control, which was scary! Then, at our last observation site, we saw some crocodiles out in the marsh from the bird observation tower, which was really cool. We found a small one at first but then went back down onto the ground to tell other people, and Ashley came over and spotted one that was at least 6-8 feet long off in the distance. We watched it for a while as it swam around in the marsh and over to a flock of whistling ducks, which we thought it might try to attack. Unfortunately we didn't get to see the crocodile eat anything, but it was awesome to watch nonetheless.

After lunch,  I spent the afternoon compiling the second day's spider data and running statistical tests on the complete dataset. I gained a lot of respect for professors like Bob Kaplan at Reed, who have to piece together huge datasets for class-wide ecology experiments... it's hard work! You have to be very careful to try to notice errors in data input by all of the contributors, figure out what they did wrong, and fix it, as well as making sure everyone's data is consistent in units and format. It took me a few hours just to get everyone's data into a usable form to run statistical tests, since for some of the observational components (e.g. response type) people had recorded a lot of things that were not in our list of options or were entered differently. When the dataset was complete, I spent the rest of the afternoon analyzing it with eight different tests. Then after dinner my group of six met to discuss and interpret our results, exchange notes on some literature we had read, and put together our presentation to give the next day. It took a long time to get everything together, but we finished up our presentation by midnight (which is very late for us!). In the end we found that adult spiders had significantly lower predator distances at the time of response than juvenile spiders, and that while some adult spiders had no response whatsoever (they stayed still even when the "predator" was at a distance of 0), juvenile spiders always responded in some way. These suggest that the adult spiders may be better able to identify our "predators" as a non-threat, since they were not entirely realistic replicas of bird beaks and since they were approaching the spider very slowly. This would support the experience hypothesis, that older, more experienced spiders can more accurately evaluate the costs and benefits of fleeing from a predator and losing their perch on the plant, which they require to catch their food (pollinators like honey bees). Our presentation the next morning went relatlively smoothly, and I was impressed that we could actually gather enough data in a day and a half to get interesting results. Prior to the FLPs I had been pretty skeptical of the OTS independent projects, in which we only have four days to gather data; the shortest IP I've ever done at Reed has been about six weeks, and all of them have felt like I could have used more time if it were available. However, after seeing how much we could pull together in just two days, I was feeling more optimistic about our IPs, which were our next big task at Palo Verde. 

An unrelated picture of Palo Verde as seen from the dining hall, just because I want to post it. Haha.