I wasn’t expecting my first day in Ethiopia to be a long day in a lab but the team was given access to a lab at the University of Bahir Dar and we had to get it set up for the chemical analysis of the huge quantities of the soil samples we would soon have. I’ve been in lots of makeshift labs all over the world - labs with dirt floors, or set up in a hotel room or in the middle of a rainforest, another with a resident iguana and a family of bats in the ceiling - and one of my favourite parts of every science adventure is sorting out how to do solid lab work in a space that isn’t pristine and full of equipment. This didn’t disappoint.
We opened the door to the rank smell of warm standing water as condensation dripped from the windows in the overheated space. The room was packed with six rows of lab benches, at least 20 sinks, and multiple fume hoods (air ventilation systems that allow you to safely work with toxic chemicals). But nothing actually worked. There was no electricity, none of the sinks had water, none of the fume hoods ventilated. A large puddle had formed at one end of the lab and elsewhere the tiles were caked in layers of mud and filth from the nearby toilet that continuously overflowed. Dozens of dirty, unlabelled bottles filled with unknown chemicals were crammed onto shelves, some with crystals forming around the cap and others that had clearly spilled at some point. This lab was the reason why university safety committees exist.
With the help of every cleaning agent available, an assortment of brooms (some actual brooms, others makeshift), and the campus maintenance crew (which may have consisted of only one person), over the next few days we eventually got electricity, a couple of functional sinks (though one leaked and occasionally flooded the lab), one working fume hood, a cleaner floor and countertops, and all the bottles of mystery chemicals removed.
We brought back dozens of soil and leaf samples from every forest we visited so we quickly had hundreds of samples that needed processing. Just keeping up with washing glassware with limited water access was almost a full time job and days in the lab often exceeded ten hours. But the team found their stride and the lab benches were soon covered in carefully arranged sample containers and in the end, the lab work seemed to flow (mostly) seamlessly.
So what were they measuring in the lab?
Dr. Carrie Woods explained to me that they were trying to gauge the health of the sacred forests and one way of understanding how healthy an ecosystem is is to look at how nutrients like nitrogen are cycled.
“Ecosystem ecologists are interested in energy flow and how things move from abiotic to biotic and then back again,” she told me. When trees photosynthesize, they take in abiotic nutrients from the atmosphere or the soil and use them to produce biotic material. When they die and decompose, they release the nutrients and become a source of abiotic material.
“So the entire system is focused between photosynthesis and decomposition,” she explained, “and we get at that by looking at leaf nitrogen levels, measuring the trees each year to look at the rate they put on biomass, and collect decomposing leaf litter every two months to get at decomposition rates.”
In the lab therefore, they use the soil samples to measure nitrate, ammonium, nitrogen content in the microbial biomass, and the mineralization rate to determine how fast organic material is being converted into abiotic material - essentially, how quickly the system is producing nutrients to return back into the biotic cycle.
“All these things will tell us whether a forest is functioning properly.”