![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
Abstract
Substrates with a unique stable isotope signature provide researchers with the ability to trace nutrients through food webs. Plant material labeled with carbon (13C) can be produced by exposure to carbon dioxide (CO2) with an isotopic composition that differs from ambient conditions during photosynthesis. Labeling can occur continuously or be repeated over several “pulses.” Each method has a high cost either in the form of expensive control systems or significant time investments. In 2012, we built a large growth chamber and used an inexpensive, open-source ArduinoTM microcontroller to monitor and control interior conditions so that we could produce leaf litter dually enriched in 13C and nitrogen (15N) for future incubation experiments. We performed a labeling experiment on 73 saplings representing seven species in 2012 and repeated the labeling on 30 saplings of one species in 2013. We successfully produced over 1 kg of litter enriched in both isotopes; 15N-enrichment (δ15N: 759.2 ± 133.7‰) was much greater than 13C (δ13C: 11.2 ± 3.4‰). Roots (161.0 ± 8.6‰) were much more enriched in 13C than litter (11.2 ± 3.4‰), indicating significant translocation of newly fixed carbohydrates. Some species allocated more resources toward their leaves as trees with the most enriched litter had the least enriched roots. 13C litter enrichment in 2012 was at the lower end of the range reported by similar studies; however, litter from trees labeled over two seasons achieved a higher level of enrichment (401.4 ± 65.5‰).
