Xavi Sòria-Perpinyà

University of Valencia | UV · Limnology

The validation of algorithms developed from in situ reflectance to estimate water quality variables has the challenge of atmospheric correction (AC) when applied to satellite images. Estimating water quality variables from satellite images requires an accurate estimation of remote sensing reflectances (Rrs) which vary according to the AC applied. V...

Lakes can be important sources of the potent greenhouse gas nitrous oxide (N2O) to the atmosphere, but to what extent abiotic processes may contribute to lacustrine N2O production remains uncertain. We assessed pathways of N2O production and reduction in the water column of meromictic and iron‐rich Lake La Cruz, Spain, including chemodenitrificatio...

Coastal lagoons are an established priority habitat in the European environment because of the biological communities that inhabit them. Their origin is related to the transport of sediments from a nearby river or the movement of sands by the marine currents that produce the closure of a gulf. Therefore, they are recent geological formations, which...

Sentinel-2 offers great potential for monitoring water quality in inland and coastal waters. However, atmospheric correction in these waters is challenging, and there is no standardized approach yet, but different methods coexist under constant development. The atmospheric correction Case 2 Regional Coast Colour (C2RCC) processor has been recently...

Mar Menor is a Mediterranean Coastal lagoon with high environmental and social value, but has suffered important episodes of contamination in recent years due to heavy rains, sediment dragging and polluting substances mainly from agriculture as well as the entry of mining waste, causing an increase in eutrophication. Water quality variables such as...

Remote sensing is an appropriate tool for water management. It allows the study of some of the main sources of pollution, such as cyanobacterial harmful algal blooms. These species are increasing due to eutrophication and the adverse effects of climate change. This leads to water quality loss, which has a major impact on the environment, including...

Inland waters are very sensitive ecosystems that are mainly affected by pressures and impacts within their watersheds. One of water’s dominant constituents is the suspended particulate matter that affects the optical properties of water bodies and can be detected from remote sensors. It is important to know their composition since the ecological ro...

In the European Water Framework Directive, zooplankton was not included as a Biological Quality Element despite its important place in the aquatic trophic web. In the present study on zooplankton abundances and biomasses, we used several metrics to test their ability to detect differences among trophic statuses and ecological potential levels, and...

Satellite images were used to assess surface water quality based on the concentration of chlorophyll a (chla), light penetration measured by the Secchi disk method (SD), and the Cyanobacteria cells number per mL (cyano). For this case study, six reservoirs interconnected were evaluated, comprising the Cantareira System (CS) in São Paulo State (Braz...

Freshwater quality maintenance is essential for human use and ecological functions. To ensure this objective, governments establish programs for a continuous monitoring of the inland waters state. This could be possible with Sentinel-2 (S2) and Sentinel-3 (S3), two remote sensing satellites of the European Space Agency, equipped with spectral optic...

The Albufera of Valencia is a coastal lagoon located in the western area of the Mediterranean Sea, in the Iberian Peninsula. It has an area of 23.1 km2 and an average depth of only 1 m, with a maximum depth of 1.6 m. This lagoon is the remnants of an original and more extensive wetland of about 220 km2 which is now mostly dedicated to rice cultivat...

p class="p1">Water quality is a subject of intense scientific inquiry because of its repercussion in human’s life, agriculture or even energy generation. Remote sensing can be used to control water masses by analyzing biophysical variables. Chlorophyll-a (Chl-a) and Total Suspended Solids (SS) are a well-known feature of water quality. These variab...

RESUMEN Evolución de la conductividad en la Albufera de Valencia entre 1985 y 2018 La laguna costera de la Albufera de Valencia es una masa de agua oligohalina rodeada de un antiguo marjal, transformado en cultivo del arroz desde hace más de 200 años. La presión de las aportaciones superficiales mantiene la conductividad en valores estables en torn...

p>Transparency or turbidity is one of the main indicators in studies of water quality using remote sensing. Transparency can be measured in situ through the Secchi disc depth (SD), and turbidity using a turbidimeter. In recent decades, different relationships between bands from different remote sensing sensors have been used for the estimation of t...

Eutrophy in Albufera of Valencia (Eastern Iberian Peninsula) is a quite old problem since after the intense eutrophication processes throughout the 1960s. The system shifted to a turbid stable state consolidated by the virtual disappearance of macrophytes by the early 1970s. The lagoon has been studied extensively since the 1980s, but efforts to re...

The atmospheric contribution constitutes about 90 percent of the signal measured by satellite sensors over oceanic and inland waters. Over open ocean waters, the atmospheric contribution is relatively easy to correct as it can be assumed that water-leaving radiance in the near-infrared (NIR) is equal to zero and it can be performed by applying a re...

The Phytoplankton Reservoir Trophic Index (PRTI), based on the relative abundance of phytoplankton in reservoirs, was applied to 62 reservoirs, all in the territorial division of the Ebro River Basin, Spain. We compared the results of the PRTI to the Carlson Trophic State Index (TSI), based on the concentration of chlorophyll a in an integrated wat...

Monitoring the ecological state of a hypertrophic lake (Albufera of València, Spain) using multitemporal Sentinel-2 images Albufera of València, a hypertrophic lake, has been studied extensively since the 1980s, but the efforts to revert the system to a clear water state have not yielded the expected results because pressure on this system is growi...

Albufera of Valencia shallow lagoon experiences water clarification about once a year. This study aimed to observe the timing of water clarity events and to detect the associated flow during these periods. Spatial variation in chlorophyll a along the Albufera was observed using remote sensing images. Due to the lagoon’s spatial complexity and the v...

Chlorophyll a concentration in aquatic ecosystems is strongly related to the phytoplankton community biomass, the growth of which depends on nutrient availability. Thus, chlorophyll a concentration provides information about the system status and is the variable most used in limnology for index calculations related to trophic status. Problems may a...

Chlorophyll-a concentration and Secchi disk depth are two of the most important biophysical parameters used to assess water quality and determine the ecological state of inland waters. The Ocean Color 2 and Dall'Olmo three-band algorithms were used to estimate chlorophyll-a concentration and the calibration of the ratio 490/705 nm was used to produ...

The Albufera of València has been a hypertrophic lake since the 1970s. Extensive efforts to revert the system to a clear water state, such as wastewater treatment and green filters construction, have not yielded the desired results; Albufera is still qualified as “bad” according to the Spanish Water Framework Directive implementation. Currently, th...

This study aims to examine four recently conducted trophic state indices that are based on the density of zooplankton and designed for estimating the trophic state of inland waters. These indices include two with formulations based on quotients or ratios, the Rcla and the Rzoo-chla, which were proposed and validated in the European project ECOFRAME...

La Albufera de Valencia, situada en la costa este de la Península Ibérica, es una laguna costera poco profunda, laguna hace necesario un monitoreo constante, el cual puede realizarse a través de la determinación de de la validación del algoritmo de Dall' Olmo et al. la Albufera entre 2016 y 2017, corregidas atmosféricamente. Los resultados de la va...

Enmarcado dentro del proyecto Ecological Status of AQuatic systems with Sentinel satellites, en este trabajo se ha generado una amplia base de datos (N = 392) de reflectividades de S2 simuladas con un modelo de transferencia radiativa, para diferentes concentraciones de Clorofila-a. A partir de ella se calibraron numerosos índices multiespectrales...

Presentamos los resultados de las 1° y 2ª ediciones del curso Certificado Universitario en Estudio de Contaminación de Aguas mediante Teledetección, que se imparte en línea en la Universitat de València. El curso tiene como objetivo formar en el campo de la calidad y de la gestión del agua y en el tratamiento de la contaminación térmica y de los ve...

Con el objetivo de aumentar la resolución espacial y temporal de medidas de profundidad del disco de Secchi a toda la superficie de embalses y lagos de la cuenca del Ebro, durante los años 2013, 2014 y 2015 se recopilaron datos en 51 puntos de muestreo in situ, coincidentes con 26 imágenes de Landsat 8. La heterogeneidad del conjunto de masas de ag...

La cuenca hidrográfica del Ebro es la segunda en tamaño de España tras la cuenca del Duero, y se ubica en el cuadrante nordeste de la península Ibérica, recorrida por el río Ebro desde la sierra de Híjar en Cantabria hasta su desembocadura en el mediterráneo al sur de Tarragona. En aplicación de la legislación que traspone la Directiva Marco del Ag...

Sabiendo que el fitoplancton es el primer grupo de organismos en responder a un enriquecimiento de nutrientes con un crecimiento excesivo debido a sus elevadas tasas de replicación (p.e. Reynolds, 2006), y que la clorofila a es el principal pigmento fotosintético de los productores primarios (plantas, algas, cianobacterias y bacterias fotosintética...

Shallow lakes have low residence time, therefore in this type of lakes rapid flushing could be a suitable measure to control eutrophication. Albufera of Valencia, a Mediterranean shallow lake, nowadays remains turbid and it is considered a hypertrophic lake. Lake hydrology is regulated by the local water council to meet the needs of the surrounding...

Lakes represent a considerable natural source of methane to the atmosphere compared to their small global surface area. Methanotrophs in sediments and in the water column largely control methane fluxes from these systems, yet the diversity, electron accepting capacity, and nutrient requirements of these microorganisms have only been partially ident...

La concentración de clorofila a es una de las variables más utilizadas en limnología para el cálculo de índices que determinen el estado trófico de los sistemas acuáticos. Esta importancia se ve reflejada en la Directiva Marco del Agua, que establece un marco comunitario de actuación para la evaluación del estado de las masas del agua, utilizando l...

La presa de Margalef se localiza en el término municipal del mismo nombre, Margalef, de la comarca del Priorat, (Tarragona, NE de España) y forma parte del "Parc Natural de la Serra del Montsant". Su construcción finalizó en 1995 y tras una década se iniciaron los estudios de seguimiento de la calidad de sus aguas por parte de la Confederación Hidr...

Desde 1980, la profesora Miracle ha desarrollado una buena parte de su dedicación investigadora al estudio de las aguas de la Albufera de Valencia en todos sus aspectos, con la utilización de variados procedimientos y herramientas de observación y análisis. En los primeros años, los trabajos de campo eran la única posibilidad de seguimiento del est...

During 2010, 32 reservoirs in Ebro Basin have been studied, in order to establish the quality of water bodies according to EC WFD. Light extinction, Photosynthetic pigments, CDOM and phytoplankton are some of the variables considered as indicators and were evaluated with the classical methodology and with modern electronic in situ and laboratory de...