Challenges in using land use and land cover data for global change studies

Land use and land cover data play a central role in climate change assessments. These data originate from different sources and inventory techniques. Each source of land use/cover data has its own domain of applicability and quality standards. Often data are selected without explicitly considering the suitability of the data for the specific application, the bias originating from data inventory and aggregation, and the effects of the uncertainty in the data on the results of the assessment. Uncertainties due to data selection and handling can be in the same order of magnitude as uncertainties related to the representation of the processes under investigation. While acknowledging the differences in data sources and the causes of inconsistencies, several methods have been developed to optimally extract information from the data and document the uncertainties. These methods include data integration, improved validation techniques and harmonization of classification systems. Based on the data needs of global change studies and the data availability, recommendations are formulated aimed at optimal use of current data and focused efforts for additional data collection. These include: improved documentation using classification systems for land use/cover data; careful selection of data given the specific application and the use of appropriate scaling and aggregation methods. In addition, the data availability may be improved by the combination of different data sources to optimize information content while collection of additional data must focus on validation of available data sets and improved coverage of regions and land cover types with a high level of uncertainty. Specific attention in data collection should be given to the representation of land management (systems) and mosaic landscape

Tracking down carbon inputs underground from an arid zone Australian calcrete.

Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (δ13CDOC, δ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota

Zinc Removal with Lignocellulosic Adsorbents; Interaction Mechanisms, from Biosorbent to Soil Conditioner

Abstract The authors have requested that this preprint be removed from Research Square.</jats:p

Cadmium removal mechanisms from aqueous solution by using recycled lignocelluloses

The three organic residuals of pistachio, peanut, and almond were investigated for the removal capacity and removal mechanism of cadmium ion from aqueous. Adsorption efficiency on reducing cadmium was evaluated with batch experiment parameters, contact time, sorbent dose, pH, and Cd2+ amount. The sorption process of metal ions was defined well with the pseudo-second order kinetic, and Langmuir isotherm model having an adsorption capacity (qemax) of 51.28 mg g−1 of pistachio, 62.11 mg g−1 of peanut, 78.74 mg g−1 of almond. The adsorbent was characterized by SEM, FTIR, and elemental analysis. The characterization study revealed that recycled lignocelluloses are composed of rough and porous surfaces with many active sites, contribute to metal ions removal in many ways, such as electrostatic interaction, ion exchange, complex formation, and physical adsorption. These findings highlighted that the shells can be effectively applied removal of divalent metal from aquatic solution

ASSESSMENT OF METHANOGENIC ACTIVITY AND KINETICS OF ANAEROBIC GRANULAR SLUDGE

The study aims to investigate the specific methanogenic activity (SMA) and kinetic coefficients for anaerobic granular sludge under low temperatures. Activity test can be used to outline the operating condition for the system and a parameter to assess the system performance by giving a better understanding of the system performance and stability. The granular sludge samples for SMA test were taken from a lab scale Anaerobic Sequencing Batch Reactor (ASBR) operating for treatment of the low strength wastewater at low temperature. Microbial activities were determined through methane production from acetate. The activities at temperature 25, 15 and 10 degrees C were found as 0.74 gCOD/gVSSd, 0.70 gCOD/gVSSd, and 0.68 gCOD/gVSSd, respectively. As expected, the activity decreased with decreased temperature. First order kinetic model and Gompertz equation was applied to determine the kinetic constant for methane production at batch study. Methane production rate constants for Gompertz equation are as follows; R=0.327 (mlCH(4)h(-1)), M-max=4.97 (ml), and lambda=0.45 at 25 degrees C, R=0.429 (mlCH(4)h(-1)), M-max=3.95 (ml), and lambda=0.98 at 15 degrees C, and R=0.286 (mlCH(4)h(-1)), M-max=3.56 (ml), and lambda=0.83 at 10 degrees C