Assessing the influence of the carbon oxidation-reduction state on organic pollutant biodegradation in algal-bacterial photobioreactors

The influence of the carbon oxidation-reduction state (CORS) of organic pollutants on their biodegradation in enclosed algal-bacterial photobioreactors was evaluated using a consortium of enriched wild-type methanotrophic bacteria and microalgae. Methane, methanol and glucose (with CORS -4, -2 and 0, respectively) were chosen as model organic pollutants. In the absence of external oxygen supply, microalgal photosynthesis was not capable of supporting a significant methane and methanol biodegradation due to their high oxygen demands per carbon unit, while glucose was fully oxidized by photosynthetic oxygenation. When bicarbonate was added, removal efficiencies of 37¿±¿4% (20 days), 65¿±¿4% (11 days) and 100% (2 days) were recorded for CH(4,) CH(3)OH and C(6)H(12)O(6), respectively due to the additional oxygen generated from photosynthetic bicarbonate assimilation. The use of NO(3)(-) instead of NH(4)(+) as nitrogen source (N oxidation-reduction state of +5 vs. -3) resulted in an increase in CH(4) degradation from 0 to 33¿±¿3% in the absence of bicarbonate and from 37¿±¿4% to 100% in the presence of bicarbonate, likely due to a decrease in the stoichiometric oxygen requirements and the higher photosynthetic oxygen production. Hypothetically, the CORS of the substrates might affect the CORS of the microalgal biomass composition (higher lipid content). However, the total lipid content of the algal-bacterial biomass was 19¿±¿7% in the absence and 16¿±¿2% in the presence of bicarbonat

Biochar as Soil Amendment: Impact on Soil Properties and Sustainable Resource Management

The role of biochar in improving soil fertility is increasingly being recognized and is leading to recommendations of biochar amendment of degraded soils. In addition, biochars offer a sustainable tool for managing organic wastes and to produce added-value products. The benefits of biochar use in agriculture and forestry can span enhanced plant productivity, an increase in soil C stocks, and a reduction of nutrient losses from soil and non-CO2 greenhouse gas emissions. Nevertheless, biochar composition and properties and, therefore, its performance as a soil amendment are highly dependent on the feedstock and pyrolysis conditions. In addition, due to its characteristics, such as high porosity, water retention, and adsorption capacity, there are other applications for biochar that still need to be properly tested. Thus, the 16 original articles contained in this book, which were selected and evaluated for this Special Issue, provide a comprehensive overview of the biological, chemicophysical, biochemical, and environmental aspects of the application of biochar as soil amendment. Specifically, they address the applicability of biochar for nursery growth, its effects on the productivity of various food crops under contrasting conditions, biochar capacity for pesticide retention, assessment of greenhouse gas emissions, and soil carbon dynamics. I would like to thank the contributors, reviewers, and the support of the Agronomy editorial staff, whose professionalism and dedication have made this issue possible

Should I Stay or Should I Go: The Impact of Crossing Migrants in local communities in Mexico

The interactions between migrants and Mexican local communities have positive and negative outcomes. A report by Human Rights First found that more than 630 violent crimes against asylum seekers were reported in the first few months of the “Remain in Mexico” policy. Still, some migrants have been able to assimilate and stay in Mexico, particularly in large cities such as Tijuana, Baja California and Ciudad Juarez, Chihuahua. This research project combines qualitative data collected through interviews with local NGOs between September 2020 to February 2021 and secondary research data. It focuses on the living conditions of migrants who have stayed in Mexico. Particularly, the study looks into the context that these migrants face when crossing, transiting, and establishing in local Mexican communities, either because they are in the process of waiting for their asylum seeking process to take place in the United States or because they decide to definitely stay in Mexico. In the project, I look at the effects of the “Remain in Mexico” policy and the new challenges migrants have faced since the start of the Covid-19 pandemic. Overall, the project finds that migrants in Mexico are exposed to continuous violence, both from the state, from criminal groups, and even from groups that are in charge of their protection. This context increases the vulnerability of migrants and reduces their capacity to access resources that are already scarce. This situation got exacerbated after the start of the pandemic, with the closure of the Southern border. Further research will focus on the interaction between migrant groups and local communities and the violence that emerges from these exchanges

Estudio expeditivo de los suelos del _área prevista para ampliación en la zona negable de "Sierra Boyera"

7 páginas.-- 1 mapa esquemático de suelosEn el presente trabajo se lleva a cabo una definición somera de las unidades de suelo más sobresalientes, y su distribución se acompaña en un mapa esquemático a escala 1/20.000. Se ha programado como una primera aproximación que permita –después de un trabajo futuro de mayor detalle- efectuar una identificación y clasificación más ajustada de los suelos como base para el conocimiento de los problemas de su puesta en riego.N