Winner: "The Joy of Soil" by Joanna Brown
By Joanna Brown
Blankets of gaseous shields swaddle our planet and protect it from a harsh universe. Reckless emission of carbon transforms that protective mechanism into a specter of our own making. The carbon we have woken from its slumbering sub-soil state now haunts us. With an atmospheric lifespan of up to 200 years, the back-stocked carbon molecules we belch into the atmosphere will linger long after we stop feeding the ghost.
By reviving the health and productivity of dynamic Earth systems, we feed carbon to life instead of death. A piece of biochar buried in the ground fosters the soil biome, which in turn improves soil aggregation (Steinbeiss, 2009). The porous material increases water retention, benefitting plants within root-reach as well as those protected from flooding runoff. Creatures in carbonrich soil have contingencies during drought, allowing them to feed higher trophic levels in the short term and lower trophic levels when that matter decays. In a sovereign and untilled soil biome, mycorrhizal fungi receive carbohydrates produced by plant’s photosynthesis and convert them to glomalin, creating a liquid carbon pathway (Jones, 2008). The far-reaching fungi retrieve water and nutrients to repay their debt to the plants. Sequestering atmospheric carbon into the soil promotes life cycles at every energy level, creating a life macrocycle. Loss of soil carbon, alas, does not only stunt the life macrocycle; it reverses it. Land undergoing desertification, for example, loses carbon from exposed soils, reducing water holding capacity and increasing susceptibility to erosion. This debilitation ripples throughout the ecosystem as a death macrocycle, creating vulnerability at every trophic level.
May we, the humans, pursue our ecological dharma of symbiosis: to master the macrocycle. By cooperating with fellow earthlings, we could orchestrate mass carbon sequestration and avoid a dire alternative. Wetlands, grasslands, and cities could all work to convert volatile atmospheric carbon dioxide to fertile soil wealth. These strategies of carbon sequestration work simultaneously to mitigate consequences of climate chaos while drawing down the root cause.
Restored, protected, and constructed wetlands capture and store carbon while sustaining rich biodiversity and cleaning contaminated water. Productive wetlands support a rich array of flora and fauna. Carbon captured in biomass decomposes in an anaerobic underwater environment, causing carbon to persist in solid form and store for longer. Fertility and carrying capacity are maintained; wetland species thrive. Organisms perform nitrification-denitrification services to clean contaminated water and mitigate nutrient loading. These mechanisms are also effective at removing pharmaceuticals and other synthetic contaminants (Du, 2014). As climate change ensues, wetlands capture and manage stormwater runoff. Constructed wetlands can be tailored to a host of municipal purposes and are cheaper than conventional infrastructure solutions (Wu, 2014). Promoting wetland ecosystems harnesses a life macrocycle built on carbon sequestration and water retention.
Grasslands could be managed to sequester considerable amounts of carbon. Forty percent of the earth’s surface is drying and becoming desert; these lands contain over half of the world’s soil carbon. The expansive plains of every habitable continent thrive on mollisols, the most carbon-dense of all soil types. These mollisols support the breadbaskets that feed the world. Evolutionary symbiosis between grazing herds and vast grasslands is paramount to the persistence of valuable mollisols. While many are under the misimpression that sheer number of animals causes land degradation, in fact mollisols did not begin to develop until enormous grazing herds of megafauna evolved to help cycle nutrients (Retallack, 2014). Native plains grasses are unique in their expansive and deep root systems. When animals graze the aboveground vegetation, the plants are unable to support such large root systems, and slough a proportional volume of roots directly into the soil. This traps organic matter underground, where it decays into bioavailable carbon. Nitrogen, phosphorous, and methane from animals resuscitate soils while dense hoof impact improves aeration and infiltration. Livestock managed to mimic this relationship harnesses the same potential, creating a niche for humans that is both financially and ecologically viable. If harnessed, the life macrocycle of grasslands could restore water and food security to vulnerable species, human and otherwise.
Cities are vital catalysts of life macrocycles. More than half of the human population already resides in cities and the growth proceeds unabated. The environmental disruption of cities sprawls at a similar pace. Heat island effect, increased stormwater, reduced surface permeability, water and air pollution, and reduced habitat for flora and fauna all feed each other to create a death macrocycle, increasing everyone’s vulnerability to climate chaos. By capturing the carbon that is lost to the waste steam, cities can offset their emissions and build environmental resilience. Food waste can be collected by adapting municipal trash pick-up to involve composting. Plastics and other carbon-based trash can be recovered using pyrolytic conversion to biochar (Johnson, 2010). Metals can be sorted and recycled using this process, while off-gassing is captured in a closed-loop cycle. Carbon-dense compost and biochar capture carbon in a form that is an asset to soil fertility rather than an ecological mar. When buried, this carbon increases water retention, reducing stormwater runoff and promoting vegetative habitat. The inputs increase crop yield, allowing cities to produce more food and reduce future emissions from trucking. Thriving vegetation cools cities and improves air and water quality. In doing so we complete the macro-circuit of life-giving carbon.
Carbon has been fundamental to life since the birth of our planet. It’s the source of all wealth and the conduit of all joy. Carbon cycles amongst and between billions of interconnected earthlings, whose fates teeter on the element’s return trip to the soil. In the absence of symbiosis, each of us is limited by the reach of her arm. Only the generous reciprocity inherent to life macrocycles can restore abundance and harmony to the planet of the living. May we celebrate a happy Anthropocene, anointed in water rather than oil and blood.
Joanna Brown is a MS Candidate at the Tufts Friedman School of Nutrition Science and Policy in the Agriculture, Food, and Environment Program. She is also conducting research on the impact of livestock at the Africa Center for Holistic Management, a SavoryHub in Victoria Falls, Zimbabwe through a Tufts Institute for the Environment Research Fellowship. Her interest in soil carbon stemmed from seeking a leverage point in alleviating food and water insecurity.