Stressed, but not defenceless: no obvious influence of irradiation levels on antifeeding and antifouling defences of tropical macroalgae

The production of defence metabolites is assumed to be costly in metabolic terms. If this holds true, low-light stress should reduce the ability of seaweeds to defend themselves chemically against herbivory and fouling. We investigated the effect of energy limitation on the defensive status of seaweeds by assessing their attractiveness to mesograzers and their activity against a bivalve macrofouler in comparison with non-stressed conspecifics. The macroalgae Codium decorticatum (Woodw.) M. Howe, Osmundaria obtusiloba (C. Agardh) R. E. Norris, Pterocladiella capillacea (S. G. Gmel.) Santel. and Hommer., Sargassum vulgare C. Agardh and Stypopodium zonale (Lamour.) Papenf. collected at the southeastern Brazilian coast were exposed to six levels of irradiation (between 1 and 180 μmol photons m⁻² s⁻¹) for 10–14 days. After this period, algae from all treatment levels were: (a) processed as artificial food and offered to an amphipod community dominated by Elasmopus brasiliensis Dana and (b) extracted to test for differences in settlement rates of the fouling mussel Perna perna L. on filter paper loaded with the crude extracts. Generally, photosynthesis rates and growth were reduced under low light conditions. Attractiveness to herbivores and macrofoulers, however, was insensitive to energy limitation. We discuss possible explanations for the observed absence of a relationship between light availability and algal defence including the change in nutritional value of the algal tissue, the allocation of resources towards defence instead of growth and the absence of costs for defence.     

Building resilience to El Niño‐related drought: experiences in early warning and early action from Nicaragua and Ethiopia

Forecast‐based drought early warning/early action has been hampered by both inadequate decision‐making frameworks and a lack of appropriate funding mechanisms. Rural communities in Nicaragua and Ethiopia that have participated in resilience‐building interventions of varying durations demonstrate the value of community‐based actions informed by early warning, forecasts and drought management advice, both before and during the agricultural season. While drought affected all crops negatively, participants were better able to mitigate impacts, were more organised in accessing relief and recovered more effectively. These results are consistent with other research on the cost/benefit of anticipatory actions, use of climate services and appropriate drought management advice. They also confirm the importance of embedding short‐term early action in long‐term resilience‐building. Despite this, formal systems, national and local, remain essentially unimplemented. Systems being developed at global level now need to be operationalised and translated into effective local drought management standard operating procedures for the most vulnerable.     

Agricultural waste from the tequila industry as substrate for the production of commercially important enzymes

Approximately 1 million tons of Agave tequilana plants are processed annually by the Mexican Tequila industry generating vast amounts of agricultural waste. The aim of this study was to investigate the potential use of Agave tequilana waste as substrate for the production of commercially important enzymes. Two strains of Aspergillus niger (CH-A-2010 and CH-A-2016), isolated from agave fields, were found to grow and propagate in submerged cultures using Agave tequilana waste as substrate. Isolates showed simultaneous extracellular inulinase, xylanase, pectinase, and cellulase activities. Aspergillus CH-A-2010 showed the highest production of inulinase activity (1.48 U/ml), whereas Aspergillus niger CH-A-2016 produced the highest xylanase (1.52 U/ml) and endo-pectinase (2.7U/ml) activities. In both cases production of enzyme activities was significantly higher on Agave tequilana waste than that observed on lemon peel and specific polymeric carbohydrates. Enzymatic hydrolysis of raw A. tequilana stems and leaves, by enzymes secreted by the isolates yielded maximum concentrations of reducing sugars of 28.2 g/l, and 9.9 g/l respectively. In conclusion, Agave tequilana waste can be utilized as substrate for the production of important biotechnological enzymes.     

Use of two-surfactants mixtures to attain specific HLB values for assisted TPH-diesel biodegradation

In a surfactant assisted biodegradation process, the choice of surfactant(s) is of crucial importance. The question is: does the type of surfactant(i, e. chemical family) affect the biodegradation process at fixed hidrophillic-lypofillic balance(H/B) values? Microcosm assessments were developed using contaminated soil, with around of 5000 mg/kg of hydrocarbons as TPH-diesel. Mixtures of three nonionic surfactants were employed to get a wide range of specific HLB values. Tween20 and Span20 were mixed in the appropriate proportions to get HLB values between 8.6 and 16.7. Tween/Span60 mixtures reached HLB values between 4.7 and 14.9. Finally,Tween/Span80 combinations yielded HLB values between 4.3 and 1.5. TPH-diesel biodegradation was measured at the beginning, and after 8 weeks, as well as the FCU/grsod, as a measure of microorganisms‘ development during the biodegradation period. A second aim of this work was to assess the use of guar gum as a biodegradation enhancer instead of synthetic products. The conclusions of this work are that surfactant chemical family, and not only the HLB value clearly affects the assisted biodegradation rate. Surfactant‘s synergism was clearly observed. Regarding the use of guar gum, no biodegradation enhancement was observed for the three assessed concentrations,i.e., 2, 20, and 200 mg/kg, respectively. On the contrary, TPH-diesel removal was lower as the gum concentration increased. It is quite possible that guar gum was used as a microbial substrate.     

Creating sustainable communities: skills and learning in Ontario’s small urban municipalities

This article presents the pilot study results of a province-wide survey of skills and learning in sustainable community development in Ontario, Canada. The pilot project focuses on the testing of an online survey to examine skills building for creating sustainable communities in Ontario’s small urban municipalities. The survey examined the generic, technical and specialist skills, whether they are skills already acquired and/or required by professionals and practitioners for creating sustainable communities. The survey targeted 74 small urban municipalities and 300 respondents by profession. Building sustainable communities require ‘upskilling’ of the workforce as it poses a challenge to those hoping to make a real progress and development at the local level.     

Emerging pollutants in sewage, surface and drinking water in Galicia (NW Spain)

A monitoring programme was carried out on wastewater, surface and drinking water on the NW area of Spain during the four seasons of a year period (November 2007-September 2008). This study covered a series of emerging pollutants of different classes, including pharmaceuticals, neutral and acidic organophosphorus flame retardant/plasticizers (OPs), triclosan, phenoxy-herbicides, insect repellents and UV filters. From the total set of 53 compounds, 19 were found in raw wastewater with median concentrations higher than 0.1 μg L⁻¹. Among them, salicylic acid, ibuprofen and the UV filter benzophenone-4 (BP-4) were the most concentrated, exceeding the 1 μg L⁻¹ median value. Subsequently, 11 of these contaminants are not efficiently enough removed in the small WWTPs tested and their median concentrations in effluents still surpassed the 0.1 μg L⁻¹, so that they can spread through surface water. These chemicals are the pharmaceuticals naproxen, diclofenac and atenolol; the OPs tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP), tri-n-butyl phosphate (TnBP), diphenyl phosphate (DPhP) and diethylhexyl phosphate (DEHP); and the sulphonate UV filters BP-4 and 2-phenylbenzimidazole-5-sulphonic acid (PBSA). These OPs were then the dominant emerging pollutants occurring in surface and drinking water, where they are detected in the 20-200 ng L⁻¹ range. Pharmaceuticals and UV filters are typically below the 10 ng L⁻¹ level. Finally, herbicides were only detected in the last sampling campaign under the 100 ng L⁻¹ drinking water European Union limit.     

The Transboundary Nature of the Allende–Piedras Negras Aquifer Using a Numerical Model Approach

The Allende–Piedras Negras (APN) aquifer is located between the states of Texas (United States [U.S.]) and Coahuila (Mexico). The Rio Grande crosses the aquifer, acting as a natural and political divide between the countries. However, it remains unclear whether the APN aquifer can be considered a truly transboundary aquifer flow system, which would potentially require joint management by two different administrative jurisdictions. The main purpose of this study was to evaluate the transboundary nature of this aquifer. This was achieved by developing a detailed hydrogeological model to analyze the direction of volumetric fluxes within the APN aquifer using Visual MODFLOW. The model simulated a spatially averaged cumulative drawdown of 0.76 m for the entire aquifer over an 18‐year modeling period (2000–2017). The flow convergence zone, previously located below the Rio Grande, has shifted to the U.S. side in most locations, driven by higher pumping rates of the wells located near the river. This shift of the convergence zone from one country to the other means that groundwater recharge from one side flows underneath the river to the other side. This qualifies the APN aquifer as a “transboundary groundwater flow system.” The procedure followed in this study may be applied to other aquifers that straddle the U.S.–Mexico border and may motivate future modeling studies on other poorly studied transboundary aquifers around the world and thereby enable bi‐national aquifer management.