Se estudian suelos, sedimentos y aguas de tres lagunas situadas en Cantalejo (Segovia), se determinan los contenidos en Zn, Cd, Pb y Cu en los tres medios y se relacionan las concentraciones en suelos con las fracciones granulometricas, materia organica y pH.

El objetivo principal de este trabajo es proponer un índice para el estudio de la calidad fisicoquímica del agua, en un contexto probabilístico. Este índice se utiliza para evaluar la calidad del agua de uso piscícola. La metodología aquí propuesta se aplica a los datos observados en un amplio conjunto de puntos de muestreo ubicados en la cuenca hidrográfica del Júcar. | The aim of this paper is to propose an index for water quality into a probability context. This index is utilized to evaluate the physical-chemical quality of surface fresh water intended for fish life. The methodology proposed here is then applied to the data observed in a set of sampling points of the Júcar river basin district.

Introduction: Worldwide, six genera of the class Hydrozoa are recognized in continental waters: the cosmopolitan Hydra, the colonial Cordylophora and Pachycordyle, the medusae Craspedacusta and Limnocnida and the little polyp Calpasoma. Even though interest in cnidarians has grown in recent years, those restricted to freshwater continue to be relegated and there is even little published information on the ubiquity of certain species. In the Neotropical region, knowledge about its distribution is still very scarce. Methods: We reviewed the global literature on the subject and different online database platforms, presenting in this work a nomenclator, including discussions of the status of some species and provide the most recent identification key.  Results: This analysis reveals that in 15 countries corresponding to the Neotropical region, the finding of freshwater hydrozoans has been reported. Panama, Brazil and Argentina are the countries with the highest number of reports. Conclusions: The heterogenity of environments where these genera have been found (from the Strait of Magellan to Mexico) offers a clear vision of their wide distribution and great adaptability to different environments. This study evidence the knowledge gap that still exists about the Neotropical freshwater hidrozoans and the importance of systematizing the current information about their distribution, biology and ecology, especially for those species considered invasive. | Introducción: A nivel mundial, se reconocen seis géneros de hidrozoos de agua dulce: la cosmopolita Hydra, los pólipos coloniales Cordylophora y Pachycordyle, las medusas Craspedacusta y Limnocnida y el pequeño pólipo Calpasoma. A pesar de que el interés por los cnidarios ha crecido en los últimos años, los grupos restringidos a agua dulce siguen relegados, hay poca información sobre la ubicuidad de ciertas especies, o los datos no han sido publicados oficialmente. En la región Neotropical el conocimiento de la distribución de este grupo zoológico aún continúa siendo escaso. Métodos: Analizamos la literatura mundial específica y diferentes bases de datos en línea, presentando en este trabajo un nomenclador, las calves de identificación más recientes, incluyendo, además, discusiones sobre el estado de algunas especies. Resultados: Este análisis revela que al menos 15 países pertenecientes a la región Neotropical contienen reportes de hidrozoos dulceacuícolas. Panamá, Brasil y Argentina son los países con mayor número de hallazgos. Conclusiones: La disparidad de ambientes donde estos géneros han sido hallados (desde el Estrecho de Magallanes hasta México) ofrece una clara visión de su amplia distribución y su gran adaptabilidad a diferentes ambientes. Revela el vacío de información que aún existe sobre estos organismos dulceacuícolas, y la importancia de retomar esta línea de investigación, para ampliar el conocimiento sobre su distribución, biología y ecología, especialmente para aquellas especies consideradas invasoras.

Observations of water surface elevation (WSE) and bathymetry of the lagoons and cenotes of the Yucatán Peninsula (YP) in southeast Mexico are of hydrogeological interest. Observations of WSE (orthometric water height above mean sea level, amsl) are required to inform hydrological models, to estimate hydraulic gradients and groundwater flow directions. Measurements of bathymetry and water depth (elevation of the water surface above the bed of the water body) improve current knowledge on how lagoons and cenotes connect through the complicated submerged cave systems and the diffuse flow in the rock matrix. A novel approach is described that uses unmanned aerial vehicles (UAVs) to monitor WSE and bathymetry of the inland water bodies on the YP. UAV-borne WSE observations were retrieved using a radar and a global navigation satellite system on-board a multi-copter platform. Water depth was measured using a tethered floating sonar controlled by the UAV. This sonar provides depth measurements also in deep and turbid water. Bathymetry (wet-bed elevation amsl) can be computed by subtracting water depth from WSE. Accuracy of the WSE measurements is better than 5–7 cm and accuracy of the water depth measurements is estimated to be ~3.8% of the actual water depth. The technology provided accurate measurements of WSE and bathymetry in both wetlands (lagoons) and cenotes. UAV-borne technology is shown to be a more flexible and lower cost alternative to manned aircrafts. UAVs allow monitoring of remote areas located in the jungle of the YP, which are difficult to access by human operators.