But what about the microbes?

Hello! My name is Nikita Kowal and as Dr. Becky stated in her last blog post, I will be sharing my research experience on here throughout this summer. I am part of the Ecological Society of America SEEDS Fellowship, and am conducting an REU through the Central Arizona Project Long-Term Ecological Research (CAP LTER for short). This summer I am working for Dr. Becky Ball and Dr. Pam Marshall. Under Dr. Ball, we will be doing the chemistry behind the soil composition and Dr. Marshall is the expert in microbial communities. But enough about myself; let's get to the real fun - science! 

Usery Mountain Preserve

This project aims to find patterns in the different kinds of microbial communities who live in various levels of nitrogen-enriched environments. Nitrogen deposition is most common in inner-city ecosystems due to the nitrogen emissions in cars. Nitrogen deposition is when nitrogen from the atmosphere falls (or deposits) into the biosphere. Because there is more in the atmosphere in the middle of a huge metropolitan area, such as Phoenix, previous studies from CAP LTER have proven that preserves inside the city will have more nitrogen in the soil than farther out of the city. We will/have been sampling from different sites in the city as well as the outer edges of the city. Our inner-city sites include Piestewa Peak area and South Mountain and our outer-city sites include the White Tanks, Lost Dutchman Trail (in the Superstition Mountains), Salt River Reserve, the Usery Mountain region and the Estrella Mountains. So far, we have hit Piestewa Peak, Salt River Reserve, Usery Mountain, White Tanks, and one of the South Mountain sites. At each site, there is a control plot and there is a nitrogen plot, where nitrogen has been added to the soil. 

Carbon Utilization Plate

The field work is an enjoyment, because we get to enjoy nature while collecting our samples. The way samples are collected is by taking a soil core, which is shaped as a cylinder, and pound it into the dense desert soil, then scoop it up into a whirlpool bag. The cylindrical shape helps to ensure multiple layers of the soil is collected, and not just the surface. The samples are then taken back to the lab and prepared for the next steps. To test what kind of microbes are in the soil, we use carbon utilization plates, which have different types of carbon in each well. By putting our soil samples into these, the various microbes in the samples eat the different kinds of carbon and respire chemicals that turn the wells purple over time. The intensity of purple is tested every 24 hours for the next 4 days.

Additionally, the chemical composition of the soil will also be tested, including the phosphorus and nitrogen levels in the soil, the water content, and the texture of the soil. 

Lab member, Paul, and I collecting samples

A busy summer of Sonoran Desert research

We have begun what will be a very busy summer! There are several students and researchers working in the lab this summer on several different projects. Here is a brief overview:

Soil restoration project at the McDowell Sonoran Preserve

We are processing soil samples from an experiment testing methods to restore old mountain bike trails. Mountain biking might be fun, but it can have a hard impact on the soil. The soil along mountain bike trails becomes very compacted, making it difficult for plants to establish, and the constant action of the tires causes erosion. The McDowell Sonoran Field Institute is testing the best way to help restore old trails to be native desert. Coby is assisting with the soil sampling and analyses.

Elena and Matt are studying how different decomposer organisms influence plant leaf decomposition during composting. We made litterbags full of sycamore leaves, and each of the bags holding the leaves have different hole sizes. Some of the bags only let in microbial decomposers (like bacteria and fungi). Some of the bags let in very small invertebrates, like mites and nematodes. And some of the bags let in bigger invertebrates, like worms, beetle larvae, and termites. In this picture, Nikita and Paul are helping Matt bury the litterbags in the compost pile at Phoenix College's garden in downtown Phoenix. It's pretty rare for composters to think about invertebrates, but boy there's a lot of interesting critters living in that compost pile! At the end of the project, we will be able to show how important they are in the breakdown of the leaves as they turn into compost.

Sampling soil at the Salt River Rec Area in Tonto National Forest

We are also continuing our work to investigate the impacts of nitrogen deposition from air pollution on soil ecosystems here in Phoenix. Our main project this summer is to see how that extra nitrogen influences soil microbial communities. We are sampling soil from parks inside and outside of Phoenix, and we will profile the microbial community living in the soil, as well as characterize the chemical and physical properties of the soil that provides the habitat for these microbes. In this photo, three students are helping with the soil sampling: Nikita and Miranda in front and Paul behind. Nikita is the student responsible for the work. (Paul and Miranda are helping out, but they actually have their own, separate project to work on!) Nikita will be posting to the blog throughout the summer about what she's doing and learning:

Meet Nikita! Here she's collecting a soil sample.