Seasonal variability in methane and nitrous oxide fluxes from tropical peatlands in the western Amazon basin

Peer reviewedPublisher PD

Greenhouse gas dynamics in degraded and restored tropical peatlands

Agricultural and other land uses on ombrotrophic lowland tropical peat swamps typically lead to reduced vegetation biomass and water table drawdown. We review what is known about greenhouse gas (GHG) dynamics in natural and degraded tropical peat systems in south-east Asia, and on this basis consider what can be expected in terms of GHG dynamics under restored conditions. Only limited in situ data are available on the effects of restoration and the consequences for peat carbon (C) dynamics. Hydrological restoration seeks to bring the water table closer to the peat surface and thus re-create near-natural water table conditions, in order to reduce wildfire risk and associated fire impacts on the peat C store, as well as to reduce aerobic peat decomposition rates. However, zero emissions are unlikely to be achieved due to the notable potential for carbon dioxide (CO2) production from anaerobic peat decomposition processes. Increased vegetation cover (ideally woody plants) resulting from restoration will increase shading and reduce peat surface temperatures, and this may in turn reduce aerobic decomposition rates. An increase in litter deposition rate will compensate for C losses by peat decomposition but also increase the supply of labile C, which may prime decomposition, especially in peat enriched with recalcitrant substrates. The response of tropical peatland GHG emissions to peatland restoration will also vary according to previous land use and land use intensity.Peer reviewe

Time for responsible peatland agriculture

Letter

Quantifying tropical peatland dissolved organic carbon (DOC) using UV-visible spectroscopy

UV–visible spectroscopy has been shown to be a useful technique for determining dissolved organic carbon (DOC) concentrations. However, at present we are unaware of any studies in the literature that have investigated the suitability of this approach for tropical DOC water samples from any tropical peatlands, although some work has been performed in other tropical environments. We used water samples from two oil palm estates in Sarawak, Malaysia to: i) investigate the suitability of both single and two-wavelength proxies for tropical DOC determination; ii) develop a calibration dataset and set of parameters to calculate DOC concentrations indirectly; iii) provide tropical researchers with guidance on the best spectrophotometric approaches to use in future analyses of DOC. Both single and two-wavelength model approaches performed well with no one model significantly outperforming the other. The predictive ability of the models suggests that UV–visible spectroscopy is both a viable and low cost method for rapidly analyzing DOC in water samples immediately post-collection, which can be important when working at remote field sites with access to only basic laboratory facilities

Soil erosion by aeolian action at an intensively cultivated lowland peatland

Drainage of UK lowland peatlands has been undertaken over the last 400 years in order to exploit the productivity of carbon (C) rich peat soils. Management practices are such that many hectares of drained peatland remain un-vegetated for large periods of the year leaving the peat exposed and vulnerable to erosion and transportation by wind action, in events locally known as ‘fen blows’. The impacts of management activity on peatland C budgets have received much attention in relation to losses of soil C in the form of carbon dioxide (CO₂), whereas transport of C through aeolian pathways has remained largely unquantified. Here, horizontal mass flux of C across an agricultural field is quantified over three years using Big Springs Number Eight (BSNE’s) dust samplers and co-located micrometeorological measurements. Relationships between windblown sediment yield and wind speed and near-surface soil moisture content are assessed in combination with the influences of agricultural land management practices

High permeability explains the vulnerability of the carbon store in drained tropical peatlands

Tropical peatlands are an important global carbon (C) store but are threatened by drainage for palm oil and wood pulp production. The store's stability depends on the dynamics of the peatland water table, which in turn depend on peat permeability. We found that an example of the most abundant type of tropical peatland—ombrotrophic domes—has an unexpectedly high permeability similar to that of gravel. Using computer simulations of a natural peat dome (NPD) and a ditch-drained peat dome (DPD) we explored how such high permeability affects water tables and peat decay. High permeability has little effect on NPD water tables because of low hydraulic gradients from the center to the margin of the peatland. In contrast, DPD water tables are consistently deep, leaving the upper meter of peat exposed to rapid decay. Our results reveal why ditch drainage precipitates a rapid destabilization of the tropical peatland C store

Tiger habitat quality modelling in Malaysia with Sentinel-2 and InVEST

Deforestation is a threat to habitat quality and biodiversity. In intact forests, even small levels of deforestation can have profound consequences for vertebrate biodiversity. The risk hotspots are Borneo, the Central Amazon, and the Congo Basin. Earth observation (EO) now provides regular, high-resolution satellite images from the Copernicus Sentinel missions and other platforms. To assess the impact of forest conversion and forest loss on biodiversity and habitat quality, forest loss in a tiger conservation landscape in Malaysia is analysed using Sentinel-2 imagery and the InVEST habitat quality model. Forest losses are identified from satellites using the random forest classification and validated with PlanetScope imagery at 3–5 m resolution for a test area. Two scenarios are simulated using InVEST, one with and one without the forest loss maps. The outputs of the InVEST model are maps of tiger habitat quality and habitat degradation in northeast Peninsular Malaysia. In addition to forest loss, OpenStreetMap road vectors and the GLC2000 land-cover map are used to model habitat sensitivity to threats from roads, railways, water bodies, and urban areas. The landscape biodiversity score simulation results fall sharply from ~0.8 to ~0.2 for tree-covered land cover when forest loss is included in the habitat quality model. InVEST makes a reasonable assumption that species richness is higher in pristine tropical forests than in agricultural landscapes. The landscape biodiversity score is used to compare habitat quality between administrative areas. The coupled EO/InVEST modelling framework presented here can support decision makers in reaching the targets of the Kunming-Montreal Global Biodiversity Framework. Forest loss information is essential for the quantification of habitat quality and biodiversity in tropical forests. Next generation ecosystem service models should be co-developed alongside EO products to ensure interoperability

Timing of therapy for latent tuberculosis infection among immigrants presenting to a U.S. public health clinic: a retrospective study

<p>Abstract</p> <p>Background</p> <p>In the U.S. more than half of incident tuberculosis (TB) cases occur in immigrants. Current guidelines recommend screening and treatment for latent TB infection (LTBI) within 5 years of arrival to the U.S. This study evaluates the timing of LTBI therapy among immigrants presenting for care to a public health TB clinic.</p> <p>Methods</p> <p>Retrospective chart review of patients prescribed LTBI treatment based on medical records from Prince Georges County Health Department.</p> <p>Results</p> <p>1882 immigrants received LTBI therapy at Prince Georges County Health Department between 1999 and 2004. 417 of these patients were diagnosed with LTBI through contact investigations and were excluded from the analysis. Among the remaining 1465 individuals, median time from arrival to the U.S. until initiation of LTBI therapy was 5 months (range 0–42.4 years). 16% of all immigrants initiated therapy more than 5 years after arrival to the U.S. A logistic regression model using risks identified on univariate analysis revealed that referral for therapy by non-immigration proceedings was the strongest predictor of initiation of therapy more than 5 years after arrival to the U.S. Other factors associated with > 5 year U.S. residence prior to initiation of LTBI therapy included female gender (adjusted odds ratio (AOR) 1.8, 95% CI 1.2–2.6), age ≥ 35 (AOR = 4.1, 95% 2.5–6.6), and originating from Latin American and the Caribbean (AOR = 1.9, 95% CI 1.3–3.0).</p> <p>Conclusion</p> <p>Foreign-born individuals who are not referred for LTBI therapy through immigration proceedings are less likely to receive LTBI therapy within 5 years of arrival to the U.S. These data highlight the need to explore other mechanisms for timely LTBI screening beyond services provided by immigration.</p

Manual Scalp Cooling in Early Stage Breast Cancer: Value of Caretaker Training and Patient-Reported Experience to Optimize Efficacy and Patient Selection

Title: Manual scalp cooling in early stage breast cancer: value of caretaker training and patient-reported experience to optimize efficacy and patient selection Authors: Manaz Rezayee1, BS Nicole Moxon1, RN Staci Mellinger1, RN Amanda Y. Seino1 Nicole E. Fredrich1 Tracy L. Kelly1 Susan Mulligan2, MA Patrick Rossi3, MD Ijeoma Uche1, MD Walter J. Urba1, MD PHD Alison K. Conlin1, MD MPH Janet Ruzich1, DO David B. Page1, MD Background: Alopecia is an emotionally distressing common adverse effect of curative-intent chemotherapy in early stage breast cancer.1–6 Although machine-based scalp cooling is effective for reduction of chemotherapy-associated alopecia in early stage breast cancer, availability is geographically limited.7–11 Manual cold-cap systems may also be effective and are available regardless of geographic location.12–14 We evaluated the feasibility of caretaker-administered cold-cap efficacy following structured standardized training, and utilized patient-reported subjective outcomes to develop a clinical tool to facilitate patient selection. Patients and Methods: A small pilot study (n=10) was conducted to evaluate the feasibility and efficacy of manual cold capping. Key eligibility criteria included: 1) no hair loss at baseline; 2) no pre-existing scalp condition; 3) planned curative-intent chemotherapy for early stage breast cancer and 4) availability of caretaker(s). Participants received standardized training and then performed the cold-cap procedure without assistance. The primary endpoint was post-treatment hair retention using Dean’s alopecia scale, with success defined as Results: Of the evaluable patients, 80% (n=8/10) met the primary efficacy endpoint (Dean’s scale 0-2) with 20% (n=2/10) trial failures due to pre-mature discontinuation. Manual cold-capping was worthwhile to 90% of patients (Was it Worth It? Questionnaire) and associated with favorable PROs. Patient interviews identified a number of themes shared by almost all patients, which were subsequently used to develop a questionnaire to aid patient-directed decision-making on whether to pursue manual cold-capping. Conclusion: This study affirms the safety and efficacy of manual cold-capping to reduce alopecia and demonstrates the importance of proper training and education to maximize efficacy. It also highlights the considerable costs and effort associated with cold-capping. Selected patients with early stage breast cancer may benefit subjectively from cold capping while the proposed clinical instrument can be used to facilitate an informed discussion between patient and provider.https://digitalcommons.psjhealth.org/cancer_institute_fellowships/1000/thumbnail.jp

Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

Carbon sequestration and storage in peatlands rely on consistently highwater tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but withmarked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age