Ocean acidification (OA) has potential to affect marine phytoplankton in ways that are partly understood, but there is less knowledge about how it may alter the coupling to secondary producers. We investigated the effects of OA on phytoplankton primary production, and its trophic transfer to zooplankton in a subtropical eutrophic water (Wuyuan Bay, China) under present day (400 μatm) and projected end-of-century (1000 μatm) pCO2 levels. Net primary production was unaffected, although OA did lead to small decreases in growth rates. OA had no measurable effect on micro-/mesozooplankton grazing rates. Elevated pCO2 had no effect on phytoplankton fatty acid (FA) concentrations during exponential phase, but saturated FAs increased relative to the control during declining phase. FA profiles of mesozooplankton were unaffected. Our findings show that short-term exposure of plankton communities in eutrophic subtropical waters to projected end-of-century OA conditions has little effect on primary productivity and trophic linkage to mesozooplankton.

Irrigation with treated waste water (TWW) in combination with plantation of agroforest species was tested in the Kalaât Landelous region for the reclamation of salt affected soils. Five species (Atriplex nummularia, Eucalyptus gomphocephala, Acacia cyanophylla, Casuarina glauca, Pinus halepensis) were cultivated in saline soils that are affected by shallow, saline groundwater and were irrigated with TWW during the summer season. The results after 4 years of experimentation show a distinct decrease in soil pH and salinity accompanied by a decrease in Cl and Na concentrations. Irrigation decreased the heavy metal concentrations in the topsoil but an increase in deeper layers indicate to leaching due to TWW irrigation. The investigated plant species were differently affected in growth performance by salinity and TWW irrigation. Atriplex nummularia appeared to be the most resistant species and Pinus halepensis the most sensitive one to hydro-pedological conditions of the Kalaât Landelous plot. In conclusion, salt-tolerant plant species seem to be good candidates for the reclamation of salt-affected, waterlogged sites in combination with TWW irrigation, as the adaptations of such species seem to operate under different abiotic stress conditions.

Average nitrogen (N) deposition across Europe has declined since the 1990s. This resulted in decreased N inputs to forest ecosystems especially in Central and Western Europe where deposition levels are highest. While the impact of atmospheric N deposition on forests has been receiving much attention for decades, ecosystem responses to the decline in N inputs received less attention. Here, we review observational studies reporting on trends in a number of indicators: soil acidification and eutrophication, understory vegetation, tree nutrition (foliar element concentrations) as well as tree vitality and growth in response to decreasing N deposition across Europe. Ecosystem responses varied with limited decrease in soil solution nitrate concentrations and potentially also foliar N concentrations. There was no large-scale response in understory vegetation, tree growth, or vitality. Experimental studies support the observation of a more distinct reaction of soil solution and foliar element concentrations to changes in N supply compared to the three other parameters. According to the most likely scenarios, further decrease of N deposition will be limited. We hypothesize that this expected decline will not cause major responses of the parameters analysed in this study. Instead, future changes might be more strongly controlled by the development of N pools accumulated within forest soils, affected by climate change and forest management.

Bed sediments and a dated sediment core were collected upstream and downstream from the city of Lyon (France) to assess the spatial and temporal trends of contamination by per- and polyfluoroalkyl substances (PFASs) in this section of the Rhône River. Upstream from Lyon, concentrations of total PFASs (tPFASs) in sediments are low (between 0.19 and 2.6 ng g-1 dry weight - dw), being characterized by a high proportion of perfluorooctane sulfonate (PFOS). Downstream from Lyon, and also from a fluoropolymer manufacturing plant, tPFASs concentrations reach 48.7 ng g-1 dw. A gradual decrease of concentrations is reported at the coring site further downstream (38 km). Based on a dated sediment core, the temporal evolution of PFASs is reconstructed from 1984 to 2013. Prior to 1987, tPFASs concentrations were low (≤ 2 ng g-1 dw), increasing to a maximum of 51 ng g-1 dw in the 1990s and then decreasing from 2002 to the present day (~10 ng g-1 dw). In terms of the PFAS pattern, the proportion of perfluoroalkyl sulfonic acids (PFSAs) has remained stable since the 1980s (~10%), whereas large variations are reported for carboxylic acids (PFCAs). Long chain- (C>8) PFCAs characterized by an even number of perfluorinated carbons represent about 74% of the total PFAS load until 2005. However, from 2005 to 2013, the relative contribution of long chain- (C>8) PFCAs with an odd number of perfluorinated carbons reaches 80%. Such changes in the PFAS pattern likely highlight a major shift in the industrial production process. This spatial and retrospective study provides valuable insights into the long-term contamination patterns of PFAS chemicals in river basins impacted by both urban and industrial activities.

Marine litter is a global concern. Since most of the litter sinks, understanding the composition of benthic marine litter is crucial for addressing this concern. However, high costs of seafloor monitoring inhibit such understanding. Consequently, benthic marine litter in the Baltic Sea has not been comprehensively addressed yet. Here we present data from 2377 hauls, which collected 6828 litter items and 2412 kg on the Baltic seafloor during six years of the Baltic International Trawl Survey (BITS) by seven nations. Our results show lower percentages of plastic (35%) than the widely cited world average (70%) and less fishery-originated litter (2.2–5.6%) than was previously reported for the Baltic Sea (4–24%). Natural products, mostly residuals of burnt coal, were identified as the most common litter category (42–57%) and were largely ignored in the past. Our results highlight the importance of using several evaluation metrics, particularly number of items, weight and encounter probability.

Phase and amplitude of ecosystem-atmosphere fluxes of reactive nitrogen compounds are poorly understood due to a lack of suitable observation methods. Understanding the biophysical controls of the surface nitrogen exchange is essential for the parameterization of process-based and chemical transport models that can be used for the determination of regional or national nitrogen budgets. In this study, we investigated similarities in time series of net total reactive nitrogen (ΣNr) and carbon dioxide (CO2) fluxes above forest with regard to their variability and driving factors. We found corresponding shapes of the mean diurnal summertime patterns of ΣNr and CO2. While ecosystem respiration leads to a net CO2 release at night, ΣNr was on average deposited throughout the entire observation period. Using artificial neural network analysis, global radiation (Rg) was identified to be the main control for both ΣNr and CO2. While the concentration of ΣNr substantially improved the coefficient of determination for ΣNr fluxes when used as a secondary driver, only minor improvements of 2–3% were found for CO2 fluxes when using for example temperature or vapour pressure deficit (VPD) as secondary driver. Considering two dominant drivers, 41 and 66% of the variability in ΣNr and CO2 fluxes, respectively, could be explained. Further data stratification for ΣNr revealed that higher concentrations, higher temperature, and higher VPD as well as dry leaf surfaces tend to favour higher deposition of ΣNr, whereas lower concentrations, lower temperature, and lower VPD as well as wet leaf surfaces mainly correspond to situations when less ΣNr was deposited or even emitted. Our results support the understanding of biosphere-atmosphere interactions, their driving factors, and establish a link between ΣNr and CO2 exchange, which may be beneficial for future developments in state-of-the-art exchange modelling.

La contaminación atmosférica es un problema global, que va ligado al desarrollo económico. Este tipo de contaminación se debe a las emisiones que son generadas por industrias, el transporte o las actividades cotidianas de los humanos. Para la evaluación de la contaminación atmosférica se tienen herramientas como el monitoreo o la simulación de contaminantes atmosféricos. En Colombia se cuenta con redes de monitoreo en las principales ciudades del país, esta medición es efectiva pero costosa. Por otra parte, se han realizado simulaciones de la calidad del aire sin embargo es necesario verificar la calidad de los datos climatológicos para asegurar la confiabilidad de la información generada. Uno de los mayores problemas que presenta la información meteorológica es la falta de datos que son necesarios para la ejecución de modelos de dispersión en el contexto local. Por esto en este proyecto se planteó una evaluación de los datos meteorológicos recopilados en la zona de estudio para su uso en el modelo AERMOD. Estos datos corresponden a datos del IDEAM para la ciudad de Cali. En la evaluación se encontró que, aunque la estación del IDEAM reporta datos anuales, estos no están completo. Dado que se requieren datos hora a hora en el modelo, se propuso una herramienta para completar los datos faltantes y una metodología de comparación entre datos reales y datos agregados, con el fin de evaluar la viabilidad estadística de la propuesta. Con esto se logró determinar que la herramienta de sustituir los datos faltantes por datos del modelo WRF es válida estadísticamente y podría tener mayor aplicación en el futuro. Al ejecutar el modelo AERMOD con cada uno de los paquetes de datos se encontró que estadísticamente estos valores no tenían diferencias significativas y podían ser usadas cualquiera de los 2 paquetes de datos. Finalmente, con todo el proceso realizado durante el trabajo, se planteó una metodología para la revisión de datos meteorológicos y la ejecución del modelo AERMOD que permita futuras aplicaciones para la obtención de calidad del aire | Proyecto de grado (Ingeniero Ambiental)-- Universidad Autónoma de Occidente, 2019 | Pregrado | Ingeniero(a) Ambiental

La cremación de cuerpos humanos es uno de los servicios funerarios que más se ha incrementado, llegando a cerca del 50% en Colombia. Aunque la cremación es una opción viable frente a la carencia de espacio para la instalación de camposantos, a este proceso se asocia la emisión de compuestos como el material particulado, monóxido de carbono, hidrocarburos aromáticos policíclicos, óxidos de nitrógeno y dióxido de azufre, entre otros. Estos compuestos se relacionan con el deterioro en la calidad del aire, lo cual requiere atención, con el fin de controlar y mitigar los impactos al ambiente y por ende la salud humana. Además de los efectos en la salud, la cercanía de hornos crematorios a zonas residenciales causa inconformidades en la comunidad por la posible generación de olores. Con base en lo anterior en este proyecto, se analizó un horno crematorio localizado en la zona urbana de Santiago de Cali. Se consideró el inventario de emisiones reportado al DAGMA para los años 2015, 2016 y 2017. Con base en estos datos se realizó simulación de la dispersión de contaminantes criterio, haciendo énfasis en los óxidos de nitrógeno y dióxido de azufre, los cuales se asocian a la percepción de olores molestos. De acuerdo con el inventario de emisiones, las emisiones provenientes de la operación del horno, están cumpliendo con la norma de emisiones atmosféricas vigente. La simulación de la dispersión se realizó mediante el uso del software AERMOD, permitiendo evidenciar que el aporte del mismo es bajo con respecto a límite de inmisión (Resolución 2254 de 2017). Igualmente se identificó un área de influencia de 221000 m2 aproximadamente, según la variación en la dirección del viento. En cuanto al olor asociado al dióxido de nitrógeno y azufre, el modelo arrojó resultados que no evidencian la influencia del horno en esta zona de estudio. Finamente, al comparar los datos de la simulación con la información de la calidad del aire registrada en las estaciones de la Escuela República de Argentina, la Flora y Base Aérea, mostraron que el aporte del horno representa una fracción pequeña con respecto al total medido en cada estación. Estos resultados pueden ser un indicio de la necesidad de estudiar con mayor detalle las fuentes de emisiones atmosféricas y la dispersión en la zona de estudio | The cremation of human bodies is one of the funeral services that has increased, reaching close to 50% in the main cities of Colombia. Although, cremation is a viable option compared to the lack of space for the installation of cemeteries, this process is associated with the emission of compounds such as particulate matter, carbon monoxide, polycyclic aromatic hydrocarbons, nitrogen dioxides and sulfur dioxides, among others. These compounds are related to the deterioration in air quality, which requires attention in order to control and mitigate the impacts to the environment and therefore human health. In addition to the effects on health, the proximity of crematoria to residential areas causes disagreements in the community due to the possible generation of odors. In this sense, in this project, a crematorium located in the urban area of Santiago de Cali was analyzed. For this furnace, the inventory of emissions reported to the DAGMA for the years 2015, 2016 and 2017 was analyzed. Based on these data, the dispersion of criteria pollutants was simulated, emphasizing the nitrogen and sulfur dioxides, which Associated with the perception of annoying odors. According to the emissions inventory, the furnace operation is complying with the current air emission standard. The simulation of the dispersion was made by using the software AERMOD, allowing to show the contribution of the same is low with respect to the limit of immission (Resolution 2254 of 2017). Likewise, an influence area of approximately 221000 m2 was identified, according to the variation in wind direction. Regarding the odor associated with nitrogen dioxide and sulfur, the model yielded results that do not show the influence of the furnace in this area of study. Finally, when comparing the data of the simulation with the air quality information registered in the stations of the escuela República de Argentina, la Flora and Base Aérea, they showed that the contribution of the furnace represents a small fraction with respect to the total measured in each station. These results may be an indication of the need to study in greater detail the sources of atmospheric emissions and the dispersion in the study area | Pasantía institucional (Ingeniero ambiental)-- Universidad Autónoma de Occidente, 2019 | Pregrado | Ingeniero(a) Ambiental