Frank P. Day

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Uncertainty surrounds belowground plant responses to rising atmospheric CO₂ because roots are difficult to measure, requiring frequent monitoring as a result of fine root dynamics and long-term monitoring as a result of sensitivity to resource availability. We report belowground plant responses of a scrub-oak ecosystem in Florida exposed to 11 yr of(More)
Baldcypress saplings were subjected to two flooding regimes of continuous and periodic inundation for three years to allow comparison of annual ring characteristics. Basal stem discs were examined for the number and nature of intra-annual response features, such as false rings. The formation of latewood was also compared for trees from each flooding regime.(More)
Rapid physiological profiling of heterotrophic microbial communities enables intensive analysis of the factors affecting activity in aerobic habitats, such as soil. Previous methods for performing such profiling were severely limited due to enrichment bias and inflexibility in incubation conditions. We tested a new physiological profiling approach based on(More)
Elevated CO2 can increase fine root biomass but responses of fine roots to exposure to increased CO2 over many years are infrequently reported. We investigated the effect of elevated CO2 on root biomass and N and P pools of a scrub-oak ecosystem on Merritt Island in Florida, USA, after 7 years of CO2 treatment. Roots were removed from 1-m deep soil cores in(More)
Fine root biomass and C content are critical components in ecosystem C models, but they cannot be directly determined by minirhizotron techniques, and indirect methods involve estimating 3-dimensional values (biomass/ soil volume) from 2-dimensional measurements. To estimate biomass from minirhizotron data, a conversion factor for length to biomass must be(More)
Restoration efforts and ecologically based management practices for Atlantic white cedar wetlands have recently focused on organic matter aggradation as an ecosystem function critical to this system’s maintenance. The objective of this study was to evaluate environmental and substrate quality factors influencing root decomposition in naturally recovering(More)
Using minirhizotrons, fine root dynamics were compared in two Atlantic white-cedar swamps with contrasting hydroperiods (intermittently and persistently flooded) in order to evaluate the effects of flooding regime on fine root depth, abundance, production, and longevity. Despite the higher mean watertable depth in the persistently flooded, site, no(More)
Belowground processes in forested wetland ecosystems are exceptionally important, yet most attention seems to focus on surface flooding regimes and other aboveground features of these systems. Field studies in the Dismal Swamp and several manipulative experiments examined belowground dynamics in relation to a flood intensity gradient. Generally, more(More)
THRESHOLDS OF CHANGE IN DECOMPOSITION RATES ALONG A DUNE/SWALE TRANSECT ON A VIRGINIA BARRIER ISLAND Dominic J. Graziani Old Dominion University, 2010 Director: Dr. Frank P. Day Aboveground and belowground decomposition rates were determined along a barrier island dune/swale transect located on the Virginia Coast Reserve-Long Term Ecological Research Site(More)
Disturbance affects most terrestrial ecosystems and has the potential to shape their responses to chronic environmental change. Scrub-oak vegetation regenerating from fire disturbance in subtropical Florida was exposed to experimentally elevated carbon dioxide (CO₂) concentration (+350 μl l(-1)) using open-top chambers for 11 yr, punctuated by hurricane(More)