Status of water quality at Holbox Island, Quintana Roo State, Mexico

Abstract

Holbox Island (with its coastal lagoon, Yalahau Lagoon) located in the littoral zone at the north-eastern tip of the Yucatan Peninsula, Gulf of Mexico, is a relatively undisturbed ecosystem that is currently under threat from unplanned and intensive urban development. Although other ecosystems in this littoral zone have been studied to determine the basic requirements for sustainable development, little information about Holbox Island exists. Thus far, no data concerning coastal pollution in Yalahau Lagoon have been published. As part of a larger, on-going study, this article reports the results of analyses to determine the temporal and spatial variations of standard physical and chemical parameters and to evaluate the relationships among these parameters. Water and sediment samples collected from 42 stations during two seasons of the year (rainy and dry seasons) were analyzed using standard methods. The results indicate that, in general, the area is relatively undisturbed by human influence. Dissolved oxygen content was lower than 4 ml l−1 and the percentage of oxygen saturation lower than 90%, suggesting that the site supports higher consumption than production of oxygen. Nitrogen is mostly present as ammonium and low concentrations of nitrate; nitrite, and phosphate indicate that eutrophication is not widespread in the area. Sediments are mostly sandy,containing less than 10% organic matter at most stations. The redox potential of sediments was negative for all samples. Water quality at stations in the proximity of boating and dumping activities shows higher degradation than at other stations within the lagoon. These preliminary results provide the opportunity to construct a baseline for coastal water quality,prior to impending urban development, and may serve to determine whether the future natural and development processes have impact on the conditions and health of coastal ecosystems around Holbox Island. In addition, because the area is, as yet, relatively undisturbed, the data reported here allow us to take stock of the extent to which other sites in the Yucatan littoral zone have already been degraded by human development activities.

Morphometric relationships of juvenile Metapenaeopsis goodei (Smith, 1885) (Decapoda, Penaeidae) in the Yucatan Peninsula, Mexico

“…1). In the Yalahau lagoon and its adjacent inshore sublittoral zone (<2 km from the shoreline; <2 m depth) euhaline conditions prevail (salinity between 35 and 40) throughout the year with little seasonal variation (Tran et al, 2002). Three main weather seasons are recognized in this region: (1) dry, with low rainfall and high air temperatures (March-May, 0-30 mm/month, 36-38°C);…”

Spatial and temporal variations in physicochemical characteristics of water and sediment in the Yalahau coastal lagoon, Quintana Roo

“…Es la laguna costera más extensa en la región, con longitud de 30 km, anchura de 8 a 10 km y área de 275 km 2 . El intervalo de marea es micromareal (< 1 m), la profundidad promedio del agua es de 2 m (intervalo: 0.3 a 4 m) y no existe estratificación de la columna de agua (Tran et al, 2002a). Se encuentra rodeada por bosques de manglar, principalmente Rhizophora mangle Linnaeus y Avicennia germinans (Linnaeus) Linnaeus (García-Beltrán, 2006).…”

“…El intercambio de agua entre el mar y la laguna Yalahau ocurre principalmente a través de una boca natural de 5 km de anchura localizada al oeste. La salinidad tiende a incrementarse hacia el interior pasando de condiciones mixoeuhalinas en la boca de comunicación mar-laguna a condiciones hiperhalinas en la zona norte, que presenta una escasa comunicación con el resto de la Laguna, lo que ocasiona menor circulación y alta evaporación (Tran et al, 2002a(Tran et al, , 2002bAguilar-Salazar et al, 2003). En sitios cercanos a la boca de comunicación mar-laguna, el sedimento se compone principalmente de arena (> 80%), mientras que en la zona norte, el limo y la arcilla representan hasta un 50% (Tran et al, 2002b).…”

“…La laguna costera Yalahau presenta condiciones relativamente prístinas (Tran et al, 2002a;May-Kú et al, 2010;Medina-Moreno et al, 2014). Sin embargo, en Holbox al norte de la laguna, el desarrollo turístico se ha incrementado considerablemente en la última década (Tran et al, 2002c).…”

“…El análisis de la heterogeneidad espacial en la laguna Yalahau indica la presencia de seis a ocho zonas hidrológicas. En general, se observan condiciones polihalinas (18-30 ups) en el sur, hiperhalinas (> 40 ups) en el norte y mixoeuhalinas (30-40 ups) en la boca de comunicación mar-laguna (Tran et al, 2002a(Tran et al, , 2002bAguilar-Salazar et al, 2003). Estas zonas también difieren en temperatura del agua, oxígeno disuelto, nutrientes inorgánicos disueltos (e.g., amonio, fosfato, silicato), materia orgánica y textura del sedimento.…”