This trial was conducted in order to determine the effects of cortisol on salt water acclimation of tilapia Oreochromis niloticus (L.). Tilapia (n=42) were injected intraperitoneally with cortisol and then were directly transferred from freshwater (FW) to 15&#8240; salt water (SW). Changes in plasma osmolality, chloride ion concentration (Cl-), plasma level of cortisol and gill Na+, K+-ATPase activity were measured at 6, 12, 24, 48, 72 and 168 hours after transference to 15&#8240; SW. Plasma osmolality and Cl- increased immediately after transference until 12-24 h. The fish injected with cortisol (F) showed higher plasma levels of cortisol than those from control group (C) that maintained the initial levels during the experiment. Gill Na+, K+-ATPase activity of C fish began to increase at first hours after transference and peak at 48h. The differences between gill Na+, K+-ATPase activity of F and C groups were significant (P<0.05) in FW, which confirm the effect of exogenous cortisol.<br>Este estudo foi realizado com o objectivo de testar os efeitos do cortisol na aclimatação da tilápia Oreochromis niloticus (L.) à água salgada. As tilápias (n=42) foram injectadas intraperitonealmente com cortisol e directamente transferidas de água doce para água salobra (15&#8240;). As alterações da osmolaridade, concentração em cloretos (Cl-), os níveis plasmáticos de cortisol e a actividade branquial da Na+, K+-ATPase foram medidas (6, 12, 24, 48, 72 e 168 horas) após a transferência para água salobra. A osmolaridade e a concentração em Cl- aumentou imediatamente após a transferência até às 12-24h. O grupo injectado com cortisol (F) mostrou níveis plasmáticos de cortisol mais elevados do que o grupo controlo (C) que manteve os níveis iniciais durante a experiência. A actividade branquial da Na+, K+-ATPase dos peixes do grupo C começou às primeiras horas após a transferência e teve um pico às 48h. As diferenças entre a actividade enzimática da Na+, K+-ATPase dos grupos F e C foram significativas (P<0,05) em água doce, o que confirma o efeito exógeno do cortisol.

The availability of fresh water on earth is 3%, which is low considering population growth; together with the mismanagement of water resources are the main problems facing the municipality of Riohacha; Therefore, a technology is needed that satisfies the demand for water using saline water, but currently there are no projects and / or studies on desalination techniques that contribute to improving the conditions of access to water suitable for human use and consumption that are viable in the territory, so it is proposed to determine the viability of a seawater desalination model coupled to a microbial desalination cell for vulnerable communities in Riohacha (Guajira) based on a literature review. Which was developed through a meta-analysis where the information was collected, a statistical analysis was developed, comparison between conventional desalination techniques and microbial desalination cells (CDM) and finally the results were analyzed along with social conditions and environmental of Riohacha. The main result is that the techniques coupled to CDM with bio-cathode that are viable for its implementation in Riohacha are Reverse Osmosis (RO) and Multistage Flash Distillation (MSF). Because they are the most efficient and economical techniques, with high availability worldwide and ease of operation, thus contributing to the fulfillment of the sustainable development objectives, ending poverty, zero hunger, health and well-being, and clean water and sanitation. | Ingeniero Ambiental | Pregrado | La disponibilidad de agua dulce en la tierra es del 3%, lo cual es bajo teniendo en cuenta el crecimiento poblacional; en conjunto con la mala gestión del recurso hídrico son las principales problemáticas que afronta el municipio de Riohacha; por lo que se necesita de una tecnología que satisfaga la demanda de agua empleando agua salina, pero actualmente no se encuentran proyectos y/o estudios sobre técnicas de desalinización que contribuyan a mejorar las condiciones de acceso al agua apta para uso y consumo humano que sean viables en el territorio, por lo que se plantea determinar la viabilidad de un modelo de desalinización de agua de mar acoplado a una celda de desalinización microbiana para comunidades vulnerables en Riohacha (Guajira) a partir de una revisión de literatura. La cual se desarrolló mediante un meta-análisis donde se recolectó la información, se elaboró un análisis estadístico, comparación entre las técnicas de desalinización convencionales y las celdas de desalinización microbiana (CDM) y finalmente se analizaron los resultados junto con las condiciones sociales y ambientales de Riohacha.Dando como principal resultado que las técnicas acopladas a la CDM con bio-cátodo que son viables para su implementación en Riohacha son la Ósmosis Inversa (OI) y Destilación Flash Multietapa (MSF). Por ser las técnicas más eficientes, económicas, de alta disponibilidad a nivel mundial y facilidad de operación, aportando así al cumplimiento de los objetivos de desarrollo sostenible fin de la pobreza, hambre cero, salud y bienestar y agua limpia y saneamiento.