ORCID Profile
0000-0002-7014-7054
Current Organisation
Universidad Nacional de Costa Rica
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Publisher: Universidad de Costa Rica
Date: 06-09-2021
DOI: 10.15517/RBT.V69ISUPPL.2.48308
Abstract: Introduction: The Gulf of Papagayo (GP) is a site of socioeconomic importance located in the North Pacific of Costa Rica. The ecosystem services of this site represent a benefit in local communities, and its dynamics are influenced by a coastal upwelling system that affects fishing and commercial activity. Objective: The objective of this study was to characterize the spatio-temporal variability of the main hydrographic parameters through measurements in situ during the period 2017-2019. Methods: Eight measurement c aigns were carried out, where a CTD probe was deployed to perform vertical profiles in 23 stations distributed throughout the GP, to characterize the variations in temperature, salinity, dissolved oxygen and chlorophyll concentration. Results: A minimum in surface and bottom temperature associated with upwelling caused by the wind was found in the first period of the year. The increase in salinity was associated with the decrease in temperature, being its highest value in the first period of the year, decreasing until reaching a minimum in November. The maximum chlorophyll concentration coincided with the lowest surface temperatures and the minimum oxygen values were associated with the minimum bottom temperatures, both occurring during the upwelling season. The parameter distribution was similar on dry and rainy seasons in stations located inside Bahía Culebra, likely attributed to the bathymetry effect. Conclusions: Bathymetry determines a south-north asymmetry for salinity and temperature. Subsurface cooling events coincide with strong wind periods. Upwelling influences the surface and bottom hydrographic dynamic in GP and determines the seasonal variability. The negative ENSO phase of 2018 corresponded with the strongest upwelling period, possibly promoting the interaction of upwelled coastal waters and the Costa Rica Thermal Dome.
Publisher: MDPI AG
Date: 25-08-2021
DOI: 10.3390/W13172324
Abstract: In recent years, the northwestern part of the North Pacific areas of Costa Rica has undergone rapid socioeconomic development. This situation, combined with the scarce available information about the water quality of the Gulf of Papagayo, became the starting point to carry out a study to investigate the spatiotemporal variations of physicochemical and biological parameters of surface waters. Seven s lings were collected during the dry season and the rainy season from October 2016 to February 2018. Water quality parameters such as: temperature, salinity, dissolved oxygen, and chlorophyll a of six analytes: nitrate, nitrite, ammonia, phosphate, silicate and biological oxygen demand were measured. The results showed that phosphate and ammonium levels were lower during the rainy season ( µg P-PO4−3 L−1–9.53 µg P-PO4−3 L−1 and µg N-NH4+ L−1–9.57 µg N-NH4+ L−1) than during the dry season ( µg P-PO4−3 L−1–13.64 µg P-PO4−3 L−1 and µg N-NH4+ L−1–14.43 µg N-NH4+ L−1), which may be related to low rainfall (0, 00–26, 16 mm) during the s ling period. The dry season showed enrichment of ammonium, phosphate, and chlorophyll a due to the influence of the coastal upwelling for the intensification of the Papagayo winds from December to March. The physical, chemical, and biological indicators demonstrated that the Gulf waters had adequate quality. Nonetheless, there are specific areas such as Culebra Bay with conditions that could show deterioration of water quality.
Publisher: Universidad Nacional
Date: 08-06-2019
DOI: 10.15359/CICEN.1.32
Abstract: Centrada en 5°N-87°O, la Isla del Coco (IC) es el punto insular más al sur en el Océano Pacífico de la República de Costa Rica. En este estudio se analizan las principales características de las masas de agua alrededor de la IC, así como los c os de velocidad geostrófica para tres transeptos longitudinales. Para ello se utilizó información obtenida durante un crucero hidrográfico llevado a cabo en julio del 2012 dentro del proyecto denominado “Interacciones océano-atmósfera y la bio ersidad marina de la IC, Costa Rica”.
Publisher: Universidad Nacional de Costa Rica
Date: 21-02-2020
Abstract: A razón de liar el conocimiento sobre la estructura y composición de la ictiofauna demersal en el Pacífico de Centroamérica, se realizó el estudio de muestras obtenidas en 98 puntos de arrastre efectuados con el B/O Miguel Oliver entre el 10 de noviembre y el 16 de diciembre de 2010. Con una red tipo Lofoten, se faenó por 30 minutos sobre los puntos ubicados según estratos y profundidad (máxima 1 600 m). La muestra total (17 507 ejemplares) tuvo representación de peces cartilaginosos y óseos ididos en 77 familias y 158 especies. Dicrolene filamentosa (12.27%) mostró la mayor abundancia, las biomasas más representativas del estudio fueron de Peprilus medius (35.67%) y Peprilus snyderi (12.49%) junto con Rhinoptera steindachneri (9.45%), mientras que las especies más frecuentes fueron Peristedion barbiger y Stomias atriventer (ambas con 2.71%). La costa frente a Costa Rica y Panamá mostró ersidad alta (H':3), mientras que la equidad presentó valores uniformes. Para determinar ensamblajes con respecto a la profundidad, se utilizó un ordenamiento espacial que mostró un agrupamiento de 3 conjuntos (PERMANOVA, R = 0.54, P 0.05) y un análisis canónico de correspondencia, el cual arrojó evidencia suficiente de que las especies fueron influenciadas en su distribución por la salinidad y la temperatura. La ictiofauna encontrada responde a eventos y condiciones ambientales particulares que revisten de gran importancia ecológica los hallazgos. Se resalta lo fundamental de los ensamblajes para evaluar cómo las poblaciones cambian como resultado de las características que exhiben las masas de agua.
Publisher: American Geophysical Union (AGU)
Date: 11-2014
DOI: 10.1002/2014JC010175
Publisher: Universidad Nacional
Date: 08-06-2019
DOI: 10.15359/CICEN.1.56
Abstract: El Área Marina de Manejo de bahía Santa Elena (BSE) es un sitio importante para las comunidades cercanas debido a su potencial turístico y pesquero. El objetivo de este trabajo es comprender algunos aspectos de la hidrografía de BSE. Se establecieron dos transectos transversales al canal principal de la bahía Santa Elena para la medición de corrientes, temperatura, concentración clorofila, oxígeno disuelto, salinidad y turbidez además, se realizó un levantamiento batimétrico del área. El movimiento del agua en BSE está influenciadas por la batimetría y las variaciones en las condiciones meteorológicas pueden provocar cambios en las características físicas, químicas y biológicas del cuerpo de agua. Comprender estos aspectos puede ser de gran ayuda para realizar un mejor uso de la BSE y de esta forma aprovechar de manera sostenible los recursos que ofrece.
Publisher: Universidad Nacional
Date: 08-06-2019
DOI: 10.15359/CICEN.1.58
Abstract: El Golfo de Nicoya (GN) es uno de los estuarios más grandes de América Central. Este cuerpo de agua presenta una dinámica de circulación compleja y representa un área de alta importancia pesquera y comercial. El objetivo de este estudio fue caracterizar la variabilidad intra-anual de parámetros oceanográficos en la región interna del GN, Costa Rica. Se realizaron mediciones de caudal y profundidad utilizando correntímetros acústicos. Se obtuvieron perfiles verticales de salinidad, temperatura, clorofila y oxígeno en estaciones a lo largo de transectos perpendiculares a la costa, tanto en marea de flujo como de reflujo. Los resultados muestran un dominio del forzamiento mareal en la circulación del GN. Se demostró que la intensidad del flujo está determinada por la batimetría, con magnitudes mayores en el flanco este del golfo. Se observó una mayor proporción de agua dulce en el flanco oeste. Estos resultados serán insumo para la calibración y validación de modelos hidrodinámicos del GN.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Universidad Nacional
Date: 07-06-2019
DOI: 10.15359/CICEN.1.28
Abstract: El Golfo de Papagayo (GP) posee una abundante riqueza biológica y debido al acelerado desarrollo turístico es vulnerable al impacto de actividades humanas. Un estudio hidrográfico del GP es fundamental para velar por la buena salud de este ecosistema. Se usaron datos de perfiles verticales de una sonda (CTD) desplegada en 24 estaciones distribuidas en todo el GP para caracterizar las variaciones estacionales de temperatura, salinidad, oxígeno disuelto, concentración de clorofila-a y turbidez para los años 2017 y 2018. Se encontró un mínimo (máximo) de temperatura y un máximo (mínimo) de salinidad, clorofila-a y oxígeno disuelto en superficie en febrero (octubre) asociado a la surgencia (subsidencia) producida por los intensos (débiles) vientos alisios de la estación seca (lluviosa) y la alta (baja) productividad primaria. Esta hidrografía es una herramienta útil para la toma de decisiones en políticas ambientales.
Publisher: Wiley
Date: 05-09-2019
DOI: 10.1002/JOC.5806
Publisher: American Meteorological Society
Date: 30-07-2015
DOI: 10.1175/JCLI-D-14-00700.1
Abstract: Studies of decadal-to-multidecadal ocean subsurface temperature variability are fundamental to improving the understanding of low-frequency climate signals. The present study uses the Simple Ocean Data Assimilation (SODA) version 2.2.4 product for the period 1950–2007 to identify decadal modes of variability that characterize the upper Indo-Pacific Ocean temperature structure (5–466-m depth). An empirical orthogonal function (EOF) analysis of the 10-yr low-pass filtered temperature field applied across four depths shows that the dominant mode is characterized by a long-term temperature trend, with warming at the surface and cooling at the thermocline depth connecting the tropical western Pacific with the southern Indian Ocean via the Indonesian Seas. EOF analysis of the detrended 10-yr filtered temperature data and correlation analyses of the EOF time series with established large-scale climate indices identified the interdecadal Pacific oscillation as EOF1, the North Pacific Gyre Oscillation as EOF2, and the decadal component of El Niño Modoki as EOF3 (respectively, modes 2, 3, and 4 of the nondetrended data). EOF2 identifies the Atlantic multidecadal oscillation when the analysis is applied to sea surface temperature anomalies only, suggesting that the surface is forced dominantly by fluxes associated with global-scale weather patterns, while the subsurface is dominantly forced by internal dynamics of the Pacific Ocean. This paper demonstrates that the decadal-to-interdecadal temperature variability in SODA has a pronounced vertical extension through the upper ocean. The upper thermocline accounts for most of the variance in the analysis. These results reinforce the importance of examining the subsurface ocean in climate dynamics studies that seek to understand the ocean’s role.
Publisher: Springer Science and Business Media LLC
Date: 10-05-2020
Publisher: Springer Science and Business Media LLC
Date: 22-10-2022
DOI: 10.1007/S11356-022-23673-7
Abstract: The estuarine ecosystem of Madre de Dios Lagoon (MDL), in the Caribbean Coast of Costa Rica, is exposed to contamination with pesticide residues coming from the upstream agricultural areas. Biomarkers can provide a better indication of the fitness of biota in real mixture exposure scenarios than traditional lethal dose toxicity measurements. Here, we measured biomarkers of biotransformation, oxidative stress, and neurotoxicity on Astyanax aeneus, an abundant fish species in MDL. Glutathione S-transferase activity (GST), catalase activity (CAT), lipid peroxidation (LPO), and cholinesterase activity (ChE) were measured in fish collected during seven s ling c aigns, carried out between 2016 and 2018. Pesticide residues were analyzed in surface water s les collected every time fish were s led. Residues of 25 pesticides, including fungicides, insecticides, and herbicides, were detected. The biomarkers measured in A. aeneus varied along the s ling moments, with biotransformation and oxidative stress signals showing a coupled response throughout the assessment. Furthermore, significant correlations were established between three biomarkers (GST, LPO, and CAT) and in idual pesticides, as well as between GST and LPO with groups of pesticides with shared biocide action. Among pesticides, insecticide residues had a major influence on the responses observed in fish. This work demonstrates the chronic exposure to pesticide residues in MDL and how such exposure is related to physiological responses in fish that can affect their health and potentially, the trophic networks. This early warning information should be considered to improve the protection of estuarine ecosystems in the tropics.
Publisher: American Geophysical Union (AGU)
Date: 08-2015
DOI: 10.1002/2015JC010933
No related grants have been discovered for José Mauro Vargas-Hernández.