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• We found no differences in bulk soil C stocks across treatments. • More C found in mineral-associated organic matter with more intensive management. • Results suggest management intensification could increase soil C persistence. Early thinning of loblolly pine plantations can potentially deliver sustainable feedstocks for biofuel/bioenergy. However, the management intensification for increased productivity and the removal of additional biomass from these plantations could reduce carbon (C) inputs belowground and therefore reduce overall ecosystem C storage. Increased fertilization could also affect C stocks, and their relative distribution between soil organic matter (SOM) fractions. We analyzed soil C stocks as a function of soil type and different pine plantation management systems across the Western Gulf region of the United States. Additionally, we analyzed SOM fractions with inherently different stabilization mechanisms and potential C persistence. We found no significant differences in bulk soil C stocks across management intensities or soil types. The early thinning treatment had no effect on the C distribution across each soil organic matter fraction. However, proportionally more C was found in mineral-associated organic matter and less in particulate organic matter in the more intensive management regime treatment, possibly due to higher below ground nutrient inputs and enhanced microbial activity. Our results suggest that management intensification to support biofuel production from loblolly pine plantations will not affect soil C stocks, but may increase their persistence. This study demonstrates that, from a soil C perspective, early thinning of intensively managed loblolly pine plantations has potential as a sustainable biofuel feedstock. [ABSTRACT FROM AUTHOR]

The Quest Carbon Capture and Storage (CCS) project in Alberta, Canada, is a fully integrated project, as it involves the capture, transport, injection, storage of CO 2 , and a measurement, monitoring and verification (MMV) program. The MMV program has two key objectives: a) to ensure containment and b) to ensure conformance. Prior to the start of CO 2 injection at the end of August 2015, a number of projects were undertaken to gather data from various domains, namely the atmosphere, biosphere, hydrosphere and geosphere, to provide input to the Quest MMV program. The focus of this paper is on monitoring activities undertaken in relation to the atmosphere and biosphere domains. Activities undertaken across the Quest sequestration lease area (SLA) included an eddy covariance system, soil gas probes, soil flux chambers, and walk-over surveys. In conclusion, understanding the spatial and temporal variability of CO 2 levels prior to start of CO 2 injection represents an important activity of a CCS MMV program. It provides technical input to the development of such a program, but also provides knowledge for communication to and awareness of project stakeholders (e.g. landowners) regarding CO 2 levels within the atmosphere and biosphere across a SLA. [ABSTRACT FROM AUTHOR]