Climate change is at the top of the development agenda in Central America. This region, together with the Caribbean, is highly vulnerable to the effects of climate change in Latin America. Climate change is manifesting itself through higher average temperatures and more frequent droughts that result in higher water stress, and through the rising frequency of extreme weather events such as tropical storms, hurricanes, floods and landslides, all of which pose significant challenges in the rural water supply and sanitation sector. The paper starts with a review of the historic data on temperature and precipitation trends in Central America and particularly at the regional level in Nicaragua. The data reveal a clear trend of the growing climate variability, increased water stress for crops, and greater frequency of extreme weather events. The rising intensity and frequency of ex-treme weather events is among the most critical risks to the region's development agenda, and they translate into high economic losses. This paper examines the impacts and implications of potential climate change on water resources in Nicaragua and makes key recommendations to integrate climate change and rural water supply and sanitation policies and programs in a way that increase resilience to current and future climate conditions. | 0

The use of fluidized-bed bioreactors in waste and drinking water treatment has several advantages, the most significant of which is the specific removal rate, which is an order of magnitude higher than that of equivalent activated sludge processes. In this paper, the usual concept of nitrification-denitrification in separated units is replaced by a new concept in which the two processes are performed together in a single high-performance fluidized-bed. Based on the former nitrifying reactor, new equipment was designed. This reactor contained a fluidized bed with separated aerobic and anoxic sections for nitrification and denitri fication respectively. This was accomplished by the use of different-diameter sand as carrier material and appropriate reactor shape, recirculation, feed and aeration conditions. The reactor (20 L fluidized-bed volume) was operated for 3 months. It was fed with synthetic waste water (50 L/h) containing 25-40 mg NH₄ ⁺-N/L. Propionic acid and ethanol in a 1:4 ratio were used as the carbon source (2.3 g C/L) for deni trification, fed in at different points of the reactor. Ammonium removal reached 50%, while denitrification was 75%. The total nitrogen removal rate was 0.8-1.2 kg N/m ³.d. A new simple hydrostatic pressure method was used to monitor biofilm thickness in the fluidized bed. During the experiments the oxidation-reduc tion potential (ORP) was tested as a tool to monitor reactor performance; its use for the control of the process was found to be limited.

The effects of different concentration of flaxseed gum (FG) (0.1–0.5%, w/w) on the stability of soybean oil emulsion were studied by particle size, rheological properties, creaming stability and nuclear magnetic resonance (NMR). Results showed that emulsion particle size decreased significantly with the increase in FG concentration. Rheological measurements showed FG exhibited thickening and gelling properties. Viscosity, storage modulus, and loss modulus increased accordingly with the increase in FG concentrations, and emulsions with 0.5% FG looked like a viscoelastic solid. Emulsions with a higher FG concentration exhibited better creaming stability and structure. With the increase of FG concentration, the ¹H and ¹³C NMR spectra line widths in high field also increased, which confirms that the interaction between FG and oil molecules is enhanced. These results show that FG can substitute for other emulsifiers or stabilizers in emulsions, and is beneficial to the stability of emulsions.

La guía metodológica del Foro Mundial Bananero (FMB) tiene como objetivo brindar una guía práctica para reducir las huellas de agua y de carbono en el sector bananero que permita contribuir a la promoción de prácticas sostenibles en la cadena de valor bananera, independiente del nivel de desarrollo en estos campos de los grupos de interés. La guía integral, la cual cuenta con un enfoque de cadena de valor desde productores a minoristas, será instrumental para medir los indicadores clave en el de sempeño ambiental de las plantaciones y fincas de banano, motivando a las organizaciones en diferentes contextos para que inicien procesos similares y fortaleciendo procesos de gobernanza climática en el sector. La publicación ha sido preparada en colaboración con varios miembros del FMB, GIZ, el Ministerio de Agricultura y Ganadería (MAG) y el Ministerio de Medio Ambiente y Energía (MINAE) de Costa Rica, y varios expertos temáticos externos, dando legitimidad y credibilidad a la publlicación.

New explorations in the desert of northeastern Zacatecas, in central-northern Mexico, revealed dozens of archaeological and geoarchaeological sites. One of them, Ojo de Agua, contains the remains of a Pleistocene spring-fed hydrographic system located at the southeastern end of a large elongated endorheic basin. The locality yielded a particularly dark, highly organic stratigraphic layer commonly known in the Americas as Black Mat (BM), exposed on the natural profiles of a creek, but not associated with cultural materials. Several radiocarbon assessments confirmed the formation of the Ojo de Agua Black Mat during the Younger Dryas chronozone, with ten calibrated results clustering between 12,700–12,100 cal BP. This multi-proxy study confirmed the peculiarity of the deposit and found similarities and differences with other contexts of Younger Dryas age. The Ojo de Agua Black Mat (stratum C2) is far richer in charcoal specks than the related strata, but lacks phytoliths, diatoms or ostracods. No further biological remains were found in it, except for intrusive capillary roots. Clearly water-lain in a shallow pond, the stratum qualifies as a clayey silt with an acidic-to-neutral pH. Rich in heavy metals and with high contents of titanium, the Ojo de Agua Black Mat yielded significant indicators of intense wildfires during the Younger Dryas, but produced no carbon spherules or nanodiamonds supposedly linked to the impact theory.

A set of human pharmaceuticals enables identification of groundwater that is influenced by sewage and provides information on the time of recharge. As the consumption rates of the investigated pharmaceuticals have changed over time, so too has the composition of the sewage. At the study area, south of Berlin (Germany), irrigation was performed as a method of wastewater clean-up at sewage irrigation farms until the early 1990s. Today, treated wastewater is discharged into the surface-water-stream Nuthegraben. Groundwater and surface-water samples were analyzed for the pharmaceutical substances clofibric acid, bezafibrate, diclofenac, carbamazepine and primidone, the main ions and organic carbon. The pharmaceutical substances were detected at concentrations up to microgram-per-liter level in groundwater and surface-water samples from the Nuthegraben Lowland area and from the former irrigation farms. Concentrations detected in groundwater are generally much lower than in surface water and there is significant variation in the distribution of pharmaceutical concentrations in groundwater. Groundwater influenced by the irrigation of sewage water shows higher primidone and clofibric-acid concentrations. Groundwater influenced by recent discharge of treated sewage water into the surface water shows high carbamazepine concentrations while concentrations of primidone and clofibric acid are low.

La gestión sostenible de los recursos forestales requiere la integración de varios valores del bosque en los planes de gestión forestal tanto para controlar los ecosistemas forestales como para satisfacer las necesidades y expectativas de los grupos de interés. Este artículo pretende integrar los valores del agua, el carbono y de la madera en un plan de gestión forestal y explicar sus efectos en la dinámica forestal. Se han desarrollado estrategias de gestión alternativas con una mezcla de objetivos de gestión de maximizar la cantidad de NPV (Valor Actual Neto) de madera, carbono y producción de agua junto a limitaciones como la superficie, el control del volumen y la finalización del inventario. Se ha desarrollado un modelo de programación lineal con un horizonte de planificación de 100 años y períodos de 10 años. Las salidas del modelo tales como el NPV y las cantidades de la madera, el agua y el carbono se usaron como indicadores de comportamiento para analizar la dinámica forestal conforme a varias estrategias de gestión. Los resultados mostraron que las estrategias enfocadas al NPV del agua (*W) proporcionan la mínima producción de madera y el máximo nivel de producción de agua. Además, aunque la estrategia enfocada al NPV de la madera (*T) generan un máximo de NPV como se esperaba, sorprendentemente la máxima producción de madera y carbono las proporcionaron las estrategias dirigidas al NPV de carbono (*C) debido principalmente a la repoblación de grandes áreas abiertas en área del estudio de caso. Los resultados indicaron que el comportamiento de una estrategia de gestión depende mucho de los contenidos de la estrategia así como la de la estructura forestal inicial y de la tasa de crecimiento. | Sustainable management of forest resources requires smart integration of various forest values into forest management plans both to control forest ecosystems and to satisfy the needs and expectations of stakeholders. This research initiative aimed to integrate water, carbon and timber values into a forest management plan and explain their effects on forest dynamics. Alternative management strategies with a mix of management objectives maximizing the amount or NPV (Net Present Value) of timber, carbon and water production along with constraints such as area, volume control and ending inventory were developed. A linear programming model with a planning horizon of 100 years and periods of 10 years was developed. Model outputs as NPV and amounts of timber, water and carbon were used as performance indicators to discuss forest dynamics under various management strategies. The results showed that water NPV aimed strategies (*W) provided the minimum timber production and the maximum water production level. Besides, even though timber NPV aimed strategies (*T) generated maximum NPV of timber as expected, surprisingly maximum timber and carbon production were provided by carbon NPV aimed strategies (*C) due mainly to afforestation of large forest openings in the case study area. The results indicated that the performance of a management strategy depends highly on the contents of a strategy as well as the initial forest structure aside from the growth rate.

Variations in the sedimentary organic matter were documented throughout the Agua de la Mula Member (late Hauterivian) of the Agrio Formation, at a combined section in the type area of the Agrio Formation; the base at Agrio del Medio and the middle to top at Bajada del Agrio. A main organic-rich interval was identified in the basal Agua de la Mula Member, dominated by marine-derived Amorphous Organic Matter (AOM), coinciding with the highest Total Organic Carbon (TOC) content, between 1.4 and 3.8 wt.%, suggesting dysoxic conditions. The rest of the Member is predominantly characterized by terrestrially-derived organic matter, mainly phytoclasts, with low TOC values, around 1% or lower, indicating predominantly oxic depositional settings. By integrating stacking pattern and shell beds analysis, four depositional sequences SQ1–SQ4 were recognized. The organic-rich, finely laminated bituminous black shales of the Spitidiscus riccardii zone constitute a mayor and rapid inundation defining a Transgressive System tract (TST), related to a third order asymmetrical mesosequence dominated by a thick High System Tract (HST). It represents the most widespread and important flooding episode within the Neuquén Basin during the late Hauterivian. Inside sequences of higher frequency (SQ1, SQ2, SQ3, SQ4) of probably fourth order were recognized and analysed including several ammonids zones (Spitidiscus riccardii, Crioceratites schlagintweiti, C. diamantensis and Paraspiticeras groeberi). With the exception of the oxygen-controlled, basinal and outer ramp settings indicated for the TST1, which is equivalent to the TST of a lower order sequence, and the lower TST2, respectively, the prevalence of well oxygenated, inner to middle ramp depositional environments, is suggested for the rest of the sedimentary succession and emphasized in HST of SQ2, SQ3 and SQ4. Thus, a shallowing-upward trend with improved oxygenation is recorded through the Agua de la Mula Member, reflected by decreasing TOC, AOM content and preservation state of the organic matter. Based on the whole rock fluorescence analysis of the two selected organic-rich intervals from the Spitidiscus riccardii and the lowermost Crioceratites diamantensis zones, the presence of hydrocarbons suggests a very early in situ generation.

A aplicação ao solo, dos resíduos dos lagares de azeite, em bruto ou após um pro­cesso de compostagem, poderá assegurar um destino final para estes resíduos e ao mesmo tempo permitir a valorização agríco­la de alguns dos seus componentes. Neste estudo, avaliaram-se os efeitos da aplicação ao solo de uma água-ruça (AR) e de um bagaço (B) provenientes de um lagar com sistema de extracção de três fases, bem como de um composto (C) sobre os teores de azoto total e mineral, de carbono orgâni­co e sobre a relação C/N no solo. Estabeleceram-se dois ensaios em vasos utilizando Hordeum vulgare var. Sereia como cultura teste e dois solos distintos: um Cambissolo calcárico -CMca e um Cambissolo dístrico -CMdy. Os ensaios foram delineados em blocos completos casualizados com três repetições, considerando dez tratamentos experimentais: uma testemunha e três níveis de aplicação de cada um dos três produtos mencionados, equivalentes a 80, 160 e 240 m³/ha. Os resultados obtidos revelaram que a aplicação de B e de C ao solo provocou um aumento significativo (p&#8804;0,05) nos teores de carbono orgânico, de azoto total e também na razão C/N de ambos os solos. A aplicação de AR e de B provocou um decréscimo significativo (p&#8804;0,05) inicial, nos teores de azoto nítrico, no CMca. Tal efeito não se verificou com a aplicação do composto, o que sugere que, a técnica da compostagem poderá ser benéfica relativamente àqueles subprodutos.<br>Olive mill wastes application to agricultural soils, directly or after composting, could represent a valuable option for their disposal and a good strategy for their valorization. The aim of the experiment was to evaluate the effects of soil application of olive mill wastewater (OMW) and solid olive mill waste (SOMW) from a three phases olive mill, as well of a compost (C) obtained from a mixture of these byproducts with organic matter residues from gardens and croplands, on soil total and mineral nitrogen, on organic carbon and on carbon/nitrogen ratio. Two factorial pot experiments were established using Hordeum vulgare var. Sereia as test crop and two soils - a Calcaric cambisol (CMca) and a Dystric cambisol (CMdy). The experiment was arranged into completely randomized blocks, with three replications, performing ten treatments. Four levels - 0, 80, 160 and 240 m³/ha - of each product were applied. The obtained results showed a significative increase (p&#8804;0,05) on organic carbon, total nitrogen and C/N ratio, in both soils by SOMW and C application. An initial significative decrease (p&#8804;0,05) on NO3-N was verified with the application of OMW and SOMW on the CMca soil. Results showed that composting avoid initial nitrogen immobilization can be a better alternative to those by-products.