Supervisors: R.
D. Bardgett (Lancaster), H.
Black (CEH Merlewood), P.
Ineson (York)
This part of the project investigates how below-ground fluxes of carbon are utilized by the soil biota, and will inform how these utilization patterns influence soil biodiversity and consequent feedbacks to the different plants. For the first time, we will be able to link these soil biological responses and feedbacks to detailed plant physiological responses that occur above-ground.
It is becoming increasingly apparent that above-ground plant responses
to elevated carbon dioxide (CO2) may be constrained
by below-ground feedback processes, which are mediated by responses of
soil biota to CO2 enrichment (Jones et al. 1998).
This study, and especially its use of 13C stable isotope natural abundance
techniques, provides a unique opportunity to explore:
(1) how sequential increases in atmospheric CO2
concentration influence soil biota and their trophic relationships;
(2) determine whether these changes are related to plant-derived fluxes
and transfers of carbon below-ground.
Specifically, we will test the hypothesis proposed by Jones et al.
(1998), that soil biotic responses to elevated atmospheric CO2
are related to a pathway of events involving increased plant photosynthesis
and below-ground transport of carbon, leading to increased soil carbon
availability, and consequent changes in the competitive interactions between
soil biota. We will test this hypothesis for different tree species and
determine how these changes in soil biota may feedback to the plants through
altering processes of organic matter decomposition and nutrient recycling.
This studentship contains two phases: (1) the assessment of atmospheric
CO2 enrichment effects on different components of
the soil biota, with respect to their abundance, community structure and
metabolic activity, and (2) the use to stable isotope (delta-13C) measures
in different fractions of the soil biota to quantify the effects of above-ground
CO2 enrichment on below-ground C flux into different
fractions of the soil biota, and to determine their trophic relationships.
Last update: 22/01/2002