RESUMEN
The impact of meteorological phenomena on ecosystem communities of karst subterranean estuaries (KSEs) remains unknown. KSEs are characterized by vertically stratified groundwater separated by a halocline and host endemic aquatic cave-adapted fauna (stygobionts). In October 2015, 8 days of heavy precipitation caused the first recorded mortality event in the KSE. This event was marked by a halocline shift 5 m deeper. The present study aimed to provide insights into resilience of KSEs faunal communities to temporal shifts in temperature and precipitation. Cave water temperature decreased on average 0.0068°C per mm of accumulated precipitation over 4 days, which can add up to, and surpass, the interannual temperature variation in cases of heavy precipitations. Biological surveys (2012-2021) conducted within cave systems El Aerolito and La Quebrada, in Cozumel, indicated that change in community structure was not detected and stygobionts were resilient; however, marine species inhabiting the caves were impacted. Overall, the faunal community at KSEs remains resilient within short-term meteorological phenomena despite shifts of non-stygobionts.
El impacto de fenómenos meteorológicos en las comunidades de los ecosistemas de estuarios subterráneos kársticos (KSE, por sus siglas en inglés) sigue siendo desconocido. Los KSE se caracterizan por aguas subterráneas estratificadas verticalmente separadas por una haloclina, y albergan fauna acuática endémica adaptada a la vida en cuevas (estigobiontes). En octubre de 2015, ocho días de fuertes precipitaciones causaron el primer evento de mortandad registrado en un KSE. Este evento estuvo marcado por un desplazamiento de la haloclina, resultando en una haloclina 5 m más profunda. El presente estudio tuvo como objetivo proveer información sobre la resiliencia de las comunidades faunísticas de los KSE a cambios temporales en la temperatura y la precipitación. La temperatura del agua de la cueva disminuyó en promedio 0.0068°C por mm de precipitación acumulado durante cuatro días, lo cual puede alcanzar, e incluso superar, la variación interanual de la temperatura debido a fuertes precipitaciones. Los estudios biológicos (20122021) realizados dentro de los sistemas de cuevas El Aerolito y La Quebrada, en Cozumel, indicaron que no se detectó un cambio en la estructura de la comunidad y que los estigobiontes fueron resilientes, sin embargo, las especies marinas que habitan las cuevas se vieron afectadas. En general, la comunidad de fauna de KSEs se mantiene resiliente a los fenómenos meteorológicos a corto plazo a pesar de los cambios en la fauna no estigobia.
RESUMEN
Porifera has been relatively well studied from underwater caves worldwide. However, sponges in Mexico are only known from two anchialine caves: La Quebrada and El Aerolito, both in Cozumel Island. An ecological study found that sponges have the second highest species richness and density in La Quebrada. The aim of the present work is to describe the sponge biodiversity inhabiting the dark zone of La Quebrada anchialine cave. A total of ten species were found and are described herein, six are new species to science vis. Calyx maya n. sp. a thinly branched sponge; Haliclona (Reniera) stygobia n. sp. globe-shaped with the thinnest diameter of oxeas in its group; Haliclona (Halichoclona) chankanaabiis n. sp. tubular habit with the smallest oxeas in its group; Neosiphonia microtriaeneae n. sp. characterized by very small dichotriaenes; Svenzea germanyanezi n. sp. a lone conical shape; and Diplastrella cozumella n. sp. for its tri to multilobed tylostyles. The other four species are previously known from open reefs or deep-sea: Discodermia adhaerens, Siphonidium ramosum, Cinachyrella kuekenthali, and Plakinastrella onkodes. This is the only inventory of Porifera in Mexican caves up to now, thus the species here described are the first stygobiont sponges from Mexico with an endemism rate of Porifera in this anchialine cave of 60%. Conservation programs are needed to preserve this unique and special ecosystem.
Asunto(s)
Cuevas , Haliclona , Animales , Biodiversidad , Ecosistema , MéxicoRESUMEN
Anchialine caves are characterized by high levels of endemism and extreme conditions. However, few ecological studies have been conducted in these ecosystems. This study integrates biotic and abiotic parameters of two sets of cave systems with contrasting high and low species richness. Seven ecological patterns are used to explain the expected species richness and density in an anchialine cave. In addition, the population size for conspicuous macrofauna was estimated. The high impact that single-events have on anchialine fauna are also reported. These findings reinforce the conclusions of previous studies of the high extinction risk of anchialine cave fauna, and substantiate the necessity of ad hoc conservation strategies for anchialine caves.
Asunto(s)
Biodiversidad , Cuevas , Modelos BiológicosRESUMEN
El documento presenta una síntesis editada de largas entrevistas que se mantuvieron con los líderes que presenta el libro, el informe se realiza una interpretación desde la perspectiva del desarrollo humano de las entrevistas, el analisis de los lideres tiene la intencion de rastrear las orientaciones centrales de la elite politica y social, pero a la vez es una manera de interrogarse sobre el por que de estos lideres, que contienen sus palabras y sus propuestas que hacen que la gente se adhiera a su discurso y los coloque en el lugar en el que están.(au)
