ECOSYSTEM PROCESSES IN THE AGE OF ANTIBIOTICS
In 1928, Alexander Fleming identified the antibiotic properties of penicillin. Since this discovery antibiotics have been a boon for human health as well as for agricultural livestock production. In fact, the latter utilizes 80% of the antibiotics produced in the United States, a staggering 33 million pounds a year. Most of these antibiotics and antibiotic derivatives ultimately enter the environment, leading to the assertion that no environment on earth is free from the influence of agricultural antibiotics. Despite this, little research has examined the environmental influence agricultural antibiotics are likely to have, for example, on soil microbial communities and the ecosystem processes they mediate. This research will determine the effect antibiotics have on soil food webs and ecosystem processes both now and in an uncertain future. While examining the environmental implications of antibiotics, this project will include training at the graduate student and postdoctoral levels, and develop an authentic, expeditionary style curriculum that can be integrated across multiple middle schools which enables students to actively participate in research. This research is building on previous USDA funding via an NSF CAREER award.
Carl working at the S.C.A.R.E. (Soil Carbon Antibiotic Resistance Experiment) site, where we are tracking the cycling of carbon and nitrogen when soils are exposed to antibiotic free manure or manure from cattle given one of two types of antibiotics.
Josh, Steve, and Steffany processing samples during a stable isotope pulse-chase at the S.C.A.R.E. site.
This research is supported by the National Science Foundation under award numbers 1832888 and 1845417. This research was supported by Agricultural and Food Research Competitive grant no. 2013-67019-21363 from the USDA-NIFA.
Steve pulse labeling trees so we can track the carbon from VOCs during decomposition.
VOLATILE ORGANIC COMPOUNDS RELEASED DURING LITTER DECOMPOSITION AND THIER RELEVANCE TO SOIL ECOLOGY
Biotic volatile organic compound production are often thought of as a process carried out by living plants. However, recently it has been shown that VOCs are produced and consumed during leaf litter decomposition. These VOCs could serve as an important component of microbial biomass and potentially carbon sequestration in the soil. We currently using three of the most common VOCs produced during litter decomposition to determine where the carbon in the VOCs go, using a pulse-chase experiment. Additionally, we will be looking at how different microbial communities shape VOC profiles produced during litter decomposition.
This research is supported by the National Science Foundation under award number 1555931.
Effects of top scavenger declines—from microbes to ecosystems
Conceptual model linking resource quality with soil carbon persistence.
Unless first consumed by a predator, all animals enter the carrion pool when they die. Scavengers and microorganisms play a critical role in returning carcass-derived nutrients to the soil where they get recycled and used for plant uptake and growth. The impact of carrion inputs on nutrient cycling, food web dynamics, and ecosystem carbon balance remains a mystery. With global declines of many species including scavengers, it is essential to quantify how the quantity and quality of carrion-derived nutrients shapes plant community structure and ecosystem dynamics. Tasmanian devils are an ideal and charismatic species with which to study the effects of scavenging on ecosystem processes. They are one of a few carnivores worldwide that consume bones. By accelerating the cycling of key plant growth-limiting nutrients that would otherwise remain locked in bone material for years, Tasmanian devils provide a critical ecosystem function. In recent years, the emergence of a highly transmissible cancer — devil facial tumor disease, or DFTD — has dramatically reduced devil population sizes in eastern Tasmania and has spread throughout the island, threatening this iconic species with extinction. Researchers will use this tragic situation to test whether devil-scavenging impacts can be detected on an ecosystem scale and how devil population declines result in a shift in the role of other scavenger species.
This research is supported by the National Science Foundation award 2054716.
Synergistic Response Of Soil Function And Biodiversity To Multiple Soil Health Management Practices
Historically management of agricultural soils has resulted in depletion of soil biodiversity and inefficiencies in biogeochemical cycles. Soil health management strategies have often combated these negative effects, but stakeholders are hungry for information regarding potential synergies between management practices.we will pair a common garden experiment with a stable isotope pulse-chase, while simultaneously quantifying the composition, diversity and function of soil microbial communities, enabling for a better understanding of how soil health management practices interact (i.e., cover crop diversity, intercropping, compost addition, and livestock-crop integration). We will then expose soils to an array of global change factors, using a microcosm approach, to address how resistant/resilient soils are to these perturbations. Together the results of these objectives will illustrate synergies between soil health management practices, and how these practices impact soil biogeochemistry and microbial communities. Additionally, this work will provide critical links between soil health metrics and soil microbial community composition and function while also highlighting the resistance/resilience of these communities to global change.
This research is supported by USDA-NIFA under award number 2021-09118.