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| Digging for answers |
I have something to confess. In spite of myself, I have been buried under the efforts of my thesis and have emerged as something of a soil geek. Here I was, 7 years along my career path as an entomologist when of all places, it is at the top of a tree that I find myself falling head over heels down a rabbit hole into the wonderland of underground ecosystems. For it is in beginning to study the interactions amongst insects and their environment that I have become titillated by discussions of tillage and leaching, moved by talk of porosity and mycorrhiza.
These were words which previously meant little to me. But like the first glimpse of a coral reef underwater, or turning over a rock to reveal the inner working of an ant’s nest, studying the soil beneath our feet is like entering a new world. Heading underground, the rules learned to understand our ecosystems can be left at the door. Like an Escher drawing, a hall of mirrors or an image within an image within an image, the closer that you look, the more that detail is revealed and the more lost you can become. For the microbial world is surreal and intimidating for the uninitiated, where a single gram of soil can contain millions of individuals and several thousand species of bacteria, where a drop of water can spark a rush of activity to such an extent that a soil of today is unrecognisable tomorrow.
The complexity of these ecosystems means that in spite of the complete dependence of the human race on soils for our survival, we still know frighteningly little about their functioning. Soils have been treated as something of a black box, or a magician’s hat, where certain things enter and others emerge, with little understanding as to what occurs within. With 2015 declared the UN’s International Year of Soil, and with global efforts to consolidate scientific knowledge such as the Global Soil Biodiversity Atlas (free copy here), it is becoming increasingly feasible to navigate what previously felt like an underground labyrinth. But even with tentative advances in our understanding of soil processes, agricultural industries, wholly dependent on the quality of their soil, can appear woefully uninformed when enacting management decisions.
And so it rests with the scientific community to make headway in their research on the subterranean world, but also to share their findings and instigate change in land management policy. What we put into the soil can impact what comes out, as shown by this research, which demonstrated that cattle manure from cows given antibiotics resulted in a soil which emitted 80% more methane (an important greenhouse gas) than from non- antibiotic treated cows, and also influenced the survival and reproduction of dung beetles. Invertebrates such as these which live within the soil are an important component for the decomposition of organic matter, with this study highlighting the importance of a high number of species and individuals for effective organic matter breakdown. Another study showed how ants in particular (those guys!) determine how much decomposition the whole soil community can provide in certain habitats. But whilst invertebrates could be seen as undertakers in a funerary processing chain, for the release of dead material and its return to the living, it is the microbial community who act as necromancers. Below the surface, the fungi and bacteria envelope and entwine rotting matter so that it dissolves down into a nutritious soup of future plant feed.
It is in this underworld domain of the microbes which I currently find myself, attempting to understand the complex processes which affect the soil community, and allow it to function the way it does. In the sciences, a burst of new perspectives and ideas can be incredibly stimulating and liberating. I had gone from studying ants, to their place within their larger ecosystem, to trying to understand the way these invertebrates influence the processes which help to maintain natural ecosystems. By figuratively burying my head in the soil, I have emerged enlightened as to how vital soils are for our planet, how complicated yet fascinating a topsy-turvy world it is, and how it is the unseen elements of this ecosystem which hold sway over our planet's resurrection.
