Implementation and evaluation of a new methane model within a dynamic global vegetation model: LPJ-WHyMe v1.3.1

For the first time, a model that simulates methane emissions from northern peatlands is incorporated directly into a dynamic global vegetation model. The model, LPJ-WHyMe (LPJ <B>W</B>etland <B>Hy</B>drology and <B>Me</B>thane), was previously modified in order to simulate peatland hydrology, permafrost dynamics and peatland vegetation. LPJ-WHyMe simulates methane emissions using a mechanistic approach, although the use of some empirical relationships and parameters is unavoidable. The model simulates methane production, three pathways of methane transport (diffusion, plant-mediated transport and ebullition) and methane oxidation. A sensitivity test was conducted to identify the most important factors influencing methane emissions, followed by a parameter fitting exercise to find the best combination of parameter values for individual sites and over all sites. A comparison of model results to observations from seven sites resulted in normalised root mean square errors (NRMSE) of 0.40 to 1.15 when using the best site parameter combinations and 0.68 to 1.42 when using the best overall parameter combination

Potential for long-term transfer of dissolved organic carbon from riparian zones to streams in boreal catchments

Boreal regions store most of the global terrestrial carbon, which can be transferred as dissolved organic carbon (DOC) to inland waters with implications for both aquatic ecology and carbon budgets. Headwater riparian zones (RZ) are important sources of DOC, and often just a narrow ‘dominant source layer' (DSL) within the riparian profile is responsible for most of the DOC export. Two important questions arise: how long boreal RZ could sustain lateral DOC fluxes as the sole source of exported carbon and how its hydromorphological variability influences this role. We estimate theoretical turnover times by comparing carbon pools and lateral exports in the DSL of 13 riparian profiles distributed over a 69km2 catchment in northern Sweden. The thickness of the DSL was 36±18 (average ± SD) cm. Thus, only about one-third of the 1-m-deep riparian profile contributed 90% of the lateral DOC flux. The 13 RZ exported 8.7±6.5g C m-2year-1, covering the whole range of boreal stream DOC exports. The variation could be explained by local hydromorphological characteristics including RZ width (R2=0.90). The estimated theoretical turnover times were hundreds to a few thousands of years, that is there is a potential long-lasting supply of DOC. Estimates of net ecosystem production in the RZ suggest that lateral fluxes, including both organic and inorganic C, could be maintained without drawing down the riparian pools. This was supported by measurements of stream DO14C that indicated modern carbon as the predominant fraction exported, including streams disturbed by ditching. The transfer of DOC into boreal inland waters from new and old carbon sources has a major influence on surface water quality and global carbon balances. This study highlights the importance of local variations in RZ hydromorphology and DSL extent for future DOC fluxes under a changing climate

Carbon-nitrogen feedbacks in the UVic ESCM

A representation of the terrestrial nitrogen cycle is introduced into the UVic Earth System Climate Model (UVic ESCM). The UVic ESCM now contains five terrestrial carbon pools and seven terrestrial nitrogen pools: soil, litter, leaves, stem and roots for both elements and ammonium and nitrate in the soil for nitrogen. Nitrogen cycles through plant tissue, litter, soil and the mineral pools before being taken up again by the plant. Biological N<sub>2</sub> fixation and nitrogen deposition represent external inputs to the plant-soil system while losses occur via leaching. Simulated carbon and nitrogen pools and fluxes are in the range of other models and observations. Gross primary production (GPP) for the 1990s in the CN-coupled version is 129.6 Pg C a<sup>−1</sup> and net C uptake is 0.83 Pg C a<sup>−1</sup>, whereas the C-only version results in a GPP of 133.1 Pg C a<sup>−1</sup> and a net C uptake of 1.57 Pg C a<sup>−1</sup>. At the end of a transient experiment for the years 1800–1999, where radiative forcing is held constant but CO<sub>2</sub> fertilisation for vegetation is permitted to occur, the CN-coupled version shows an enhanced net C uptake of 1.05 Pg C a<sup>−1</sup>, whereas in the experiment where CO<sub>2</sub> is held constant and temperature is transient the land turns into a C source of 0.60 Pg C a<sup>−1</sup> by the 1990s. The arithmetic sum of the temperature and CO<sub>2</sub> effects is 0.45 Pg C a<sup>−1</sup>, 0.38 Pg C a<sup>−1</sup> lower than seen in the fully forced model, suggesting a strong nonlinearity in the CN-coupled version. Anthropogenic N deposition has a positive effect on Net Ecosystem Production of 0.35 Pg C a<sup>−1</sup>. Overall, the UVic CN-coupled version shows similar characteristics to other CN-coupled Earth System Models, as measured by net C balance and sensitivity to changes in climate, CO<sub>2</sub> and temperature

Depletion of gaseous polycyclic aromatic hydrocarbons by a forest canopy

Rapid uptake of gaseous polycyclic aromatic hydrocarbons (PAHs) by a forest canopy was observed at Borden in Southern Ontario, Canada during bud break in early spring 2003. High volume air samples were taken on 12 individual days at three different heights (44.4, 29.1, and 16.7 m) on a scaffolding tower and on the forest floor below the canopy (1.5 m). Concentrations of PAHs were positively correlated to ambient temperature, resulting from relatively warm and polluted air masses passing over the Eastern United States and Toronto prior to arriving at the sampling site. An analysis of vertical profiles and gas/particle partitioning of the PAHs showed that gaseous PAHs established a concentration gradient with height, whereas levels of particulate PAHs were relatively uniform, implying that only the uptake of gaseous PAHs by the forest canopy was sufficiently rapid to be observed. Specifically, the gaseous concentrations of intermediate PAHs, such as phenanthrene, anthracene, and pyrene, during budburst and leaf emergence were reduced within and above the canopy. When a gradient was observed, the percentage of PAHs on particles increased at the elevations experiencing a decrease in gas phase concentrations. The uptake of intermediate PAHs by the canopy also led to significant differences in gaseous PAH composition with height. These results are the most direct evidence yet of the filter effect of forest canopies for gaseous PAHs in early spring. PAH deposition fluxes and dry gaseous deposition velocities to the forest canopy were estimated from the concentration gradients

The role of the global cryosphere in the fate of organic contaminants

The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate. Given the complexity of contaminant interactions with the cryosphere and limitations on resources and research capacity, interdisciplinary research and extended collaborations are essential to close identified knowledge gaps and to improve our understanding of contaminant fate under a changing climate

Physical training improves cardiopulmonary functional capacity and increases cytokine IL-10 levels in individuals with Chagas disease

Purpose: To evaluate cardiopulmonary functional capacity and the production of cytokines in patients with and without Chagas disease, and with and without hypertension, after short and long-term exercise.Methods: In a case-controlled study, 56 participants who attended the Chagas Disease Laboratory at the State University of Maringa (LDC/UEM) and Basic Health Units (UBS) in Maringa that agreed to participate. The participants were divided into the following groups: 16 with Chagas disease (CHD group), 21 with systemic arterial hypertension (SAH group) and 19 normal individuals without these morbidities (NI group). Each participant performed the 6-min walk test (6MWT), and a 12-week physical training program. Pro-inflammatory and anti-inflammatory cytokines were measured before and after physical training.Results: The CHD group presented good performance in the 6MWT, with no significant differences in distance traveled or perceived exertion (p > 0.05) compared with the NI group. After physical training, the 6MWT results were significantly better, with significant decreases in systolic and diastolic blood pressure, in the SAH group (p = 0.0409; and p = 0.0377, respectively) and NI group (p = 0.0180; and p = 0.0431, respectively) and a significant increase in the levels of the anti-inflammatory cytokine interleukin-10 (IL-10; p < 0.05) in all three groups. The NI group exhibited a significant increase (p < 0.05) in the serum levels of the pro-inflammatory cytokines IL-6, IL-17 and tumor necrosis factor (all p< 0.05).Conclusion: All of the participants presented improvements in cardiopulmonary functional capacity and good prognosis, indicating the protective effect of IL-10 production and the benefits of physical training.Keywords: Chagas disease, Six-minute walk test, Physical training, Cytokines, Cardiopulmonary function capacity, Hypertensio

From biota to chemistry and climate: Towards a comprehensive description of trace gas exchange between the biosphere and atmosphere

Exchange of non-CO2 trace gases between the land surface and the atmosphere plays an important role in atmospheric chemistry and climate. Recent studies have highlighted its importance for interpretation of glacial-interglacial ice-core records, the simulation of the pre-industrial and present atmosphere, and the potential for large climate-chemistry and climate-aerosol feedbacks in the coming century. However, spatial and temporal variations in trace gas emissions and the magnitude of future feedbacks are a major source of uncertainty in atmospheric chemistry, air quality and climate science. To reduce such uncertainties Dynamic Global Vegetation Models (DGVMs) are currently being expanded to mechanistically represent processes relevant to non-CO2 trace gas exchange between land biota and the atmosphere. In this paper we present a review of important non-CO2 trace gas emissions, the state-of-the-art in DGVM modelling of processes regulating these emissions, identify key uncertainties for global scale model applications, and discuss a methodology for model integration and evaluation

Melatonin activate FIS1, DYN1 and DYN2 Plasmodium falciparum related-genes for mitochondria fission: mitoemerald-GFP as a tool to visualize mitochondria structure

Malaria causes millions of deaths worldwide and is considered a huge burden to underdeveloped countries. The number of cases with resistance to all antimalarials is continuously increasing, making the identification of novel drugs a very urgent necessity. A potentially very interesting target for novel therapeutic intervention is the parasite mitochondrion. In this work we studied in P. falciparum three genes coding for proteins homologues of the mammalian FIS1 (Mitochondrial Fission Protein 1) and DRP1 (Dynamin Related Protein 1) involved in mitochondrial fission. We studied the expression of P. falciparum genes that show ample sequence and structural homologies with the mammalian counterparts, namely FIS1, DYN1 and DYN2. The encoded proteins are characterized by a distinct pattern of expression throughout the erythrocytic cycle of Plasmodium falciparum and their mRNAs are modulated by treating the parasite with the host hormone melatonin. We have previously reported that the knock out of the Plasmodium gene that codes for protein kinase 7 is essential for melatonin sensing. We here show that PfPk7 knockout results in major alterations of mitochondrial fission genes expression when compared to wild type parasites, and no change in fission protein expression upon treatment with the host hormone. Finally we have compared the morphological characteristics(using MitoTracker Red CMX Ros. and oxygen consumption properties of P. falciparum mitochondria in wild type parasites and PfPk7 Knockout strains. A novel GFP construct targeted to the mitochondrial matrix to wild type parasites was also developed to visualize Plasmodium falciparum mitochondria. We here show that, the functional characteristics of P. falciparum are profoundly altered in cells lacking protein kinase 7, suggesting that this enzyme plays a major role in the control of mitochondrial morphogenesis and maturation during the intra erythrocyte cell cycle progression. This article is protected by copyright. All rights reserved

Depletion of gaseous polycyclic aromatic hydrocarbons by a forest canopy

Rapid uptake of gaseous polycyclic aromatic hydrocarbons (PAHs) by a forest canopy was observed at Borden in Southern Ontario, Canada during bud break in early spring 2003. High volume air samples were taken on 12 individual days at three different heights (44.4, 29.1, and 16.7 m) on a scaffolding tower and on the forest floor below the canopy (1.5 m). Concentrations of PAHs were positively correlated to ambient temperature, resulting from relatively warm and polluted air masses passing over the Eastern United States and Toronto prior to arriving at the sampling site. An analysis of vertical profiles and gas/particle partitioning of the PAHs showed that gaseous PAHs established a concentration gradient with height, whereas levels of particulate PAHs were relatively uniform, implying that only the uptake of gaseous PAHs by the forest canopy was sufficiently rapid to be observed. Specifically, the gaseous concentrations of intermediate PAHs, such as phenanthrene, anthracene, and pyrene, during budburst and leaf emergence were reduced within and above the canopy. When a gradient was observed, the percentage of PAHs on particles increased at the elevations experiencing a decrease in gas phase concentrations. The uptake of intermediate PAHs by the canopy also led to significant differences in gaseous PAH composition with height. These results are the most direct evidence yet of the filter effect of forest canopies for gaseous PAHs in early spring. PAH deposition fluxes and dry gaseous deposition velocities to the forest canopy were estimated from the concentration gradients.close13