What caves and underground lakes lack in sunlight and plants, they make up for with an astonishing diversity of fauna: intricately shaped arthropods and other invertebrates, many of which might be new to science. If you’re a subterranean biologist like me, you have to be a competent caver as well as a committed scientist.
In this photo, I am in Križna jama cave, in Lož Valley, Slovenia, in June 2021. The cave is dotted with numerous underground lakes. I’m holding my rope tightly and staring into a single spot, trying to catch with my tweezers one of the tiny, semi-aquatic animals that are swimming below me. After I capture one, I place it gently into the bottle beside me, and take it to a laboratory for DNA analysis as soon as possible. The photo was taken when I worked as a researcher at the Subterranean Biology Lab at the University of Ljubljana.
It took millions of years of evolution for the underground world to adapt to these dark and humid habitats. Niphargus, a genus of troglobitic crustacean whose evolutionary dynamics I studied in my PhD in Ljubljana, originated in the middle of the Eocene Epoch, meaning that some species might be 48 million years old.
Today, I work as the coordinator at a non-governmental Europe-wide initiative called Scientists for Balkan Rivers (SBR). We’re trying to protect the networks of rivers here in the Balkan region of Europe, a unique and largely untouched ecosystem with a high number of endemic fish species, such as the Prespa barbel (Barbus prespensis), which lives in Lake Prespa, Greece, and the Neretva brook trout (Salmo marmoratus), which is indigenous to the Neretva River in Bosnia and Herzegovina and Croatia.
Our rivers are threatened by as many as 3,500 hydropower projects. At the SBR, I work to assist communication between scientists, making sure that everything goes well in the field. It’s not cave-diving, but it’s nice to be above ground sometimes.