@article{867, keywords = {Soil Science}, author = {Natalie Griffiths and Paul Hanson and Daniel Ricciuto and Colleen Iversen and Anna Jensen and Avni Malhotra and Karis McFarlane and Richard Norby and Khachik Sargsyan and Stephen Sebestyen and Xiaoying Shi and Anthony Walker and Eric Ward and Jeffrey Warren and David Weston}, title = {Temporal and Spatial Variation in Peatland Carbon Cycling and Implications for Interpreting Responses of an Ecosystem-Scale Warming Experiment}, abstract = {We are conducting a large-scale, long-term climate change response experiment in an ombrotrophic peat bog in Minnesota to evaluate the effects of warming and elevated CO2 on ecosystem processes using empirical and modeling approaches. To better frame future assessments of peatland responses to climate change, we characterized and compared spatial vs. temporal variation in measured C cycle processes and their environmental drivers. We also conducted a sensitivity analysis of a peatland C model to identify how variation in ecosystem parameters contributes to model prediction uncertainty. High spatial variability in C cycle processes resulted in the inability to determine if the bog was a C source or sink, as the 95% confidence interval ranged from a source of 50 g C m–2 yr–1 to a sink of 67 g C m–2 yr–1. Model sensitivity analysis also identified that spatial variation in tree and shrub photosynthesis, allocation characteristics, and maintenance respiration all contributed to large variations in the pretreatment estimates of net C balance. Variation in ecosystem processes can be more thoroughly characterized if more measurements are collected for parameters that are highly variable over space and time, and especially if those measurements encompass environmental gradients that may be driving the spatial and temporal variation (e.g., hummock vs. hollow microtopographies, and wet vs. dry years). Together, the coupled modeling and empirical approaches indicate that variability in C cycle processes and their drivers must be taken into account when interpreting the significance of experimental warming and elevated CO2 treatments.}, year = {2017}, booktitle = {Soil Science Society of America Journal}, journal = {Soil Science Society of America Journal}, series = {Soil Science Society of America Journal}, volume = {81}, pages = {1668-1688}, institution = {Wiley}, organization = {Wiley}, publisher = {Wiley}, school = {Wiley}, issn = {0361-5995}, doi = {10.2136/sssaj2016.12.0422}, crossref = {}, editor = {}, }