The influence of soil communities on the temperature sensitivity of soil respiration

Soil respiration represents a major carbon flux between terrestrial ecosystems and the atmosphere, and is expected to accelerate under climate warming. Despite its importance in climate change forecasts, however, our understanding of the effects of temperature on soil respiration (RS) is incomplete. Using a metabolic ecology approach we link soil biota metabolism, community composition and heterotrophic activity, to predict RS rates across five biomes. We find that accounting for the ecological mechanisms underpinning decomposition processes predicts climatological RS variations observed in an independent dataset (n = 312). The importance of community composition is evident because without it RS is substantially underestimated. With increasing temperature, we predict a latitudinal increase in RS temperature sensitivity, with Q10 values ranging between 2.33 ±0.01 in tropical forests to 2.72 ±0.03 in tundra. This global trend has been widely observed, but has not previously been linked to soil communities

Sensitivity of net ecosystem exchange and heterotrophic respiration to parameterization uncertainty

We examine the uncertainty in net ecosystem exchange due to the model treatment ofheterotrophic respiration in a variety of hydroclimatic conditions using a land surfacemodel. Multiple soil temperature-respiration functions and soil moisture-respirationfunctions are incorporated into the Carnegie-Ames-Stanford Approach with Carbon-Nitrogen-Phosphorus (CASA-CNP) biogeochemical model coupled to the CommunityAtmosphere Biosphere Land Exchange land surface model. Every possible combination ofthe newly implemented functions is then used to simulate heterotrophic respiration and netecosystem exchange at 10 different flux towers covering a large range of global vegetationtypes. Results show that a large uncertainty in the simulated net ecosystem exchange isattributable to differences in the soil respiration parameterization. No single combination ofsoil temperature and moisture-respiration functions appears to show superior performanceacross all sites. Large variations in the simulated evolution of soil carbon storagesemphasize the problem that to use an observationally based soil temperature or soilmoisture response function requires a land surface model to capture the observed soiltemperature and soil moisture mean and variability correctly. Land surface models areknown to vary dramatically in their simulation of the soil moisture state and probablyin their simulation of soil temperature. Resolving how to simulate heterotrophic respirationand net ecosystem exchange will therefore require an accurate simulation of temperatureand moisture combined with a realistic soil heterotrophic respiration parameterization,and these cannot be developed and implemented in isolation

Phylogenetic Studies of the Bullous Pemphigoid Antigen-1 Using Human Monoclonal-antibodies

Bullous pemphigoid is an autoimmune skin disorder with production of autoantibodies against bullous pemphigoid antigen 1 (BPAg1) and bullous pemphigoid antigen 2 (BPAg2) which are constitutively expressed in hemdesmosomes. Phylogenetic study of the reactivity of 3 human monoclonal antibodies (HuMabs) specific for BPAg1 was performed using immunohistochemical analysis of skin sections. The serum of the 2 BP patients from which the 3 HuMabs were derived stained the basement membrane zone on skin cryostat section of all species tested including fishes, amphibians, reptiles, birds and mammals. However, of the 3 HuMabs BP1, BP2 and BP3, only BP3 reacted with the skin of reptiles, birds and mammals while Bp1 and Bp2 exclusively bound to mammalian skin. These data provide evidence for the existence of multiple epitopes on BPAg1 able to bind autoantibodies