Kristine’s Research in Panama

May 3, 2017

It is officially the end of my second week here in Panama. The plants for my experiment are finally starting to germinate, ending many panic attacks that I might have watered them too much or too little, or that maybe all the birds are eating the seeds while I wasn’t looking.

I myself have just begun to feel settled in. I know that Super 99 and El Rey are basically Kroger’s and that Novey and Do It Center are the Panamian Target and Home Depot equivalents. Most importantly, I know where and when to take the bus. I am a little ashamed to admit how much of my first week was spent either running after the bus or waiting for a bus that never came. In my defense, I didn’t know then that the website with the schedule is not to be trusted.

There are four places in Panama that, from my understanding, are hubs for the Smithsonian Tropical Research Institute (STRI): Tupper Center, Naos Laboratories, Barro Colorado Island (BCI) and finally Gamboa where I live. The Tupper Center (named after the maker of Tupperware, true story) houses the Visitor’s Office and many of the main offices for STRI researchers and their laboratories. It’s the place where we go for weekly seminars (my first one: “Canalization, Cryptic Genetic Behavior, and the Evolution of Complex Traits), to access the STRI library and, for me, to get amazing carrot cake bread at the cafe. Naos Laboratories on Naos Island is located just beyond Panama City and is connected to the city via the Amador Causeway (beautiful views of the city skyline). All molecular work for this project will be done in Naos, because to my knowledge, it is the base of molecular biology at STRI.

BCI is an island research site that can be reached by boat and features weekly seminars. The last one was about the importance of androgen receptors in controlling male mating behavior in these yellow birds (Golden Collared Manakins). Much like Gamboa, it is also a forest research area. Gamboa is the site of the newest lab facility as well as the location of the solar domes and greenhouse chambers where my plants will be exposed to elevated CO₂. Except for BCI, I’ll need to travel among these locations to process my samples. I figured it was good to learn the route before needing to haul coolers around too.

Gamboa is about an hour away from Panama City by bus, a little bit less by car. Either way, there is only one way in or out so the trip is sometimes much longer because of traffic. There is also no food in Gamboa, except for mangoes, but I try not to take too many because I feel like I’m stealing from the agouti and the monkeys who were here first. Technically, there is El Tiendo Viejo, a small shop behind someone’s house, but its more for snacks than anything else. All that aside, I can’t imagine wanting to live anywhere else in Panama.

Gamboa is the kind of place where you can sit on the road and watch leaf cutter ants and it’s perfectly acceptable behavior, as is setting up a light trap to catch insects at a party. It’s the kind of place where it’s never quiet, but most of what you hear isn’t cars or planes, it’s thunder or frogs or birds. What I love the most about being here is being so close to the forest, feeling enveloped in it, and STILL having Wi-Fi that is faster than in my apartment back in Knoxville (Comcast why?!). Mostly because of the forest though, definitely. Gamboa has decent roads and many nice houses, but it still feels like it hasn’t quite successfully kept the forest out and I like that this isn’t a goal. 

For example, there’s a family of geckos living in my apartment and we just accept that they’re probably watching us sleep. There are bats in our basement and iguanas that sit on the road and orchids that germinate on rooftops. Birds wake us up at 5:30 AM in the morning and we wage war on ants that want to invade our laptops. The forest is a constant, equal presence, and I love being part of a community that loves being here despite the inconveniences that this sometimes brings.

 

Feb. 15, 2017

The Tropics are typically considered the areas of land within the Tropics of Cancer (23° 28’N) and the Tropics of Capricorn (23° 28’S); basically places where is no winter.  This region encompasses a range of different types of tropical ecosystems: deserts, grasslands, savannas, and perhaps most iconic, rainforests (Osborne, 2000).

“Tropical rain forests: ‘the greatest celebration of life on Earth’ – Norman Myers

Tropical forests contain about two-thirds of all terrestrial biomass (Pan et al., 2013), meaning that they store a lot of carbon and act as like a sponge for CO₂. However, in climate models they are among the most poorly represented. The mission of the Next Generation Ecosystem Experiment – Tropics project (NGEE-Tropics) and also the Amazon Free Air CO₂ Enrichment project (Amazon FACE) is to understand what factors influence the exchange of CO₂ between tropical rainforests and the atmosphere. Essentially, we cannot and should not model everything so what are the physiological, biological, and geochemical factors that are most important to determining how much CO₂ goes into tropical forests and how much goes out?

Free Air CO₂ Enrichment (FACE) experiments involve infusing parts of the forest encircled by gigantic towers with CO₂. This figure is showing that wood increment is increasing with CO₂, up to a certain point. Then we see that plots that wee fertilized with nitrogen continued growing but plots without declined in growth.

The Smithsonian Tropical Research Institute (STRI) in Panama exists to understand biological diversity in all tropical ecosystems in many different parts of the world.  In tropical rainforests there can be an average of 20-86 tree species per acre versus about four tree species in a temperate forest (Smithsonian Tropical Research Institute). The evidence that nutrients can limit growth means that we need to be better understand what controls how trees get nutrients if we are going to accurately predict how much CO₂ tropical forests take in.

At the heart of my research at STRI is the idea that tree species and their associated microbial communities acquire nutrients (N and P) using different strategies. These strategies can be understood in terms of characteristics (aka traits) that we can measure such as the diameter of a root or the activity of an enzyme (phosphatase). What we will be doing is growing different tree species in native Panamanian soil in greenhouses with 800 ppm CO₂ and another at 400 ppm CO₂ (the control). By measuring these traits in roots and corresponding microbial activity, I hope to understand how nutrient acquisition affects the way tropical trees grow in elevated CO₂.

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References:

1. Mommer, L., & Hinsinger, P. (2016). Advances in the rhizosphere : stretching the interface of life. Plant and Soil. http://doi.org/10.1007/s11104-016-3040-9
2. Norby, R. J., Warren, J. M., Iversen, C. M., Medlyn, B. E., & McMurtrie, R. E. (2010). CO2 enhancement of forest productivity constrained by limited nitrogen availability. Proceedings of the National Academy of Sciences of the United States of America, 107(45), 19368–73. http://doi.org/10.1073/pnas.1006463107
3. Osborne, P. L. (2000). Tropical Ecosystems and Ecological Concepts. Tropical Ecology. http://doi.org/10.1017/CBO9781139057868
4. Pan, Y., Birdsey, R. a., Phillips, O. L., & Jackson, R. B. (2013). The Structure, Distribution, and Biomass of the World’s Forests. Annual Review of Ecology, Evolution, and Systematics, 44(1), 593–622. http://doi.org/10.1146/annurev-ecolsys-110512-135914
5. Smithsonian Tropical Research Institute. Rainforests – Diversity and Survival. February 2017 <http://www.stri.si.edu/sites/rainforest/diversity_and_survival.html>.