The diffusion of sustainable family farming practices in Colombia: an emerging sociotechnical niche?

There is significant potential for family farming to contribute to several dimensions of the Sustainable Development Goals adopted by the United Nations General Assembly in 2015. Our research aims to provide insights to help strengthen sustainable family farming. We focus on initiatives that have advanced sustainable family farming innovations in Colombia and analyse the factors and dynamics that have led to the limited penetration of those innovations across the country. To that aim, a transformative methodology is applied involving representatives of farmers’ associations, supporting organisations and researchers from various disciplinary fields. We analyse the network of initiatives against the conceptual background of sociotechnical niches and identify a stable niche where generic lessons are being systematically identified and used to establish replication projects. However, this niche is still limited in its breadth, which results in a low capacity for expansion and a strong dependency on international donors for reproducing experiences. Specific recommendations are outlined for broadening the type of actors involved in the interpretation and dissemination of lessons from the niche. Moreover, we outline suggestions for further research and conceptualisation in two directions: for exploring effective ways of broadening the niche and translating niche lessons to state policies and for deepening the understanding of interactions between the niche and other levels.     

Inter-annual variability in somatic growth rates and mortality of coastal fishes off central Chile: an ENSO driven process?

The effects of El Niño (EN) and La Niña (LN) events upon marine organisms inhabiting the Eastern Pacific coast have been widely studied in recent years, concentrating primarily on changes in species composition and on population size. In this study, using somatic growth rates as metabolic response variables, we evaluated the mortality rates of coastal fishes inhabiting a central Chilean upwelling marine ecosystem in the South Pacific between 1990 and 2003. Four coastal fish species belonging to different trophic levels (one herbivore, one omnivore, and two carnivores) were analyzed. In all species, the estimated cohort somatic growth rates were low for those recruited during EN and high for those recruited during LN events. Annual cohort mortality rates were highest during EN events and lower during LN and transitional years. We propose that productivity (as a bottom-up driver) acts as a primary exogenous factor upon annual cohort mortality rates. We also propose that a plausible mechanism underlying this process is the negative effect the low somatic growth rates may have on fish ecological attributes such as their competitive abilities, condition factors, and predation risks, which ultimately may affect their fitness.     

Mercury balance in amalgamation in artisanal and small-scale gold mining: identifying strategies for reducing environmental pollution in Portovelo-Zaruma,Ecuador

The gold ore mined by artisanal and small-scale miners in Portovelo-Zaruma, Ecuador, is processed in custom mills. Miners can choose between Chilean-mill processing centers, where the ore is ground, concentrated and amalgamated, or “Chancha” Centers, where the whole ore is amalgamated. By weighing mercury before and after all unit operations involved in the amalgamation process, it was possible to determine mercury losses. Analyses in eight centers indicated that 51–59% of mercury introduced into the amalgamation process is recovered when miners squeeze the excess mercury. Around 29% of total mercury is lost when miners burn amalgam and gold is melted, and 15% is lost with the tailings. When only gravity concentrates are amalgamated, 1.4% of mercury entering the process is lost with tailings, whereas 29.5% is lost when the whole ore is amalgamated. Approximately 1.5 tonnes/annum of mercury is released in Portovelo-Zaruma, from which 70% is evaporated and 30% is released with tailings. Mercury-contaminated tailings are leached with cyanide in agitated tanks. A large majority of the processing centers dispose the final tailings with mercury and cyanide into the Calera River and Amarillo River. Mercury dissolved with cyanide likely becomes more bioavailable than metallic mercury. A campaign for reducing mercury emissions must focus on the use of individual retorts – mercury pollution control devices – and the elimination of whole ore amalgamation.     

Evaluation of the operating performance of conventional versus flocculator secondary clarifiers at the Kuwahee Wastewater Treatment Plant, Knoxville, Tennessee.

The difference in performance of three differently designed circular secondary clarifiers in the same wastewater treatment plant was analyzed in this paper. Data obtained using flocculated suspended solids and disperse suspended solids tests were analyzed using statistical tools. The conventional clarifier showed more variability in the average effluent suspended solids concentration when compared with the flocculator-clarifiers. Furthermore, a difference in performance among the two different flocculator-clarifiers was found.     

Life cycle of the jellyfish <Emphasis Type="Italic">Rhizostoma pulmo</Emphasis> (Scyphozoa: Rhizostomeae) and its distribution,seasonality and inter-annual variability along the Catalan coast and the Mar Menor (Spain,NW Mediterranean)

Rhizostoma pulmo is one of the most abundant scyphomedusae along the Mediterranean coasts. To understand changes in the population densities of the medusa stage and its relationship with the benthic stage, we describe all developmental stages from the life cycle of R. pulmo, from the scyphistoma stage to young medusae reared in the laboratory. Mature scyphistomae showed a mean total body length of 1.7 mm and the average tentacle number was 16. Asexual reproduction occurred by lateral budding, podocyst and pedalocyst production. Each strobila released up to 8 ephyrae that had a mean total body diameter of 3.5 mm. Moreover, we also present data on the temporal and spatial distribution of the species in the Catalan Sea and the coastal lagoon on Mar Menor (NW Mediterranean) during the years 2007–2009. In the Catalan Sea, the presence of adult R. pulmo was recorded as extended along the whole coast, but most of the observation was concentrated in the central area; the highest abundances were recorded during the months of July and August. The highest number of observations was detected in 2008 in coincidence with the inter-annual variation observed in the Mar Menor lagoon.     

Photoelectrocatalytic degradation of camphor on TiO2/RuO2 electrodes

The degradation of camphor using titanium/ruthenium dioxide (TiO₂/RuO₂; 70:30) electrodes was investigated in a photoelectrochemical thin-film reactor under near UV light irradiation. Two different electrolytes (Na₂SO₄ and NaCl) were used in this work. Camphor degradation was monitored by solvent extraction methods and gas chromatography (GC) analysis. Comparative studies between photoelectrochemical, electrochemical, photolytic, and heterogeneous photocatalytical process were carried out. When NaCl was used, the degradation efficiency of camphor was improved, probably on account of electrochemical generation of active chlorine species and their photochemical conversion to chlorine radicals. Under these conditions camphor was completely mineralized at reaction times of 30 min.