The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The kars...The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations;measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.展开更多
Leucoagaricus lilaceus is recorded for the first time in Mexico.This species is characterized by the purplish pileus,whitish to pinkish gills and a wide bulbose base.The next record represents the northernmost distrib...Leucoagaricus lilaceus is recorded for the first time in Mexico.This species is characterized by the purplish pileus,whitish to pinkish gills and a wide bulbose base.The next record represents the northernmost distribution of this species so far in America.Microscopic and macroscopic features are described and illustrated.展开更多
Fishes use environmental resources differently.Snapper ontogenic movements among coastal habitats lead to diverse diets.We investigated the diets of seven snapper species(Lutjanus apodus,L.analis,L.griseus,L.jocu,L.ma...Fishes use environmental resources differently.Snapper ontogenic movements among coastal habitats lead to diverse diets.We investigated the diets of seven snapper species(Lutjanus apodus,L.analis,L.griseus,L.jocu,L.mahogoni,L.synagris,and Ocyurus chrysurus)in three interconnected coastal environments in the western Caribbean:Río Huach channel,Chetumal/Corozal bay,and the adjacent Xcalak reef lagoon.These three encompass all habitats used by the seven species in the study area.Snapper diets were mostly composed of fish and crustaceans,but dominance of either group varied among the studied habitats;for example,fish were the main prey for L.apodus from the reef lagoon zone,but second in the bay.Snappers are piscivorous-invertivorous mesopredators;the species that relied the most on fishes were L.griseus and L.jocu,whereas O.chrysurus preferred crustaceans.Stomach content results revealed a high degree of dietary overlap among species.Our findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas,supporting the hypothesis of niche segregation.Our results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.展开更多
文摘The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations;measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.
文摘Leucoagaricus lilaceus is recorded for the first time in Mexico.This species is characterized by the purplish pileus,whitish to pinkish gills and a wide bulbose base.The next record represents the northernmost distribution of this species so far in America.Microscopic and macroscopic features are described and illustrated.
文摘Fishes use environmental resources differently.Snapper ontogenic movements among coastal habitats lead to diverse diets.We investigated the diets of seven snapper species(Lutjanus apodus,L.analis,L.griseus,L.jocu,L.mahogoni,L.synagris,and Ocyurus chrysurus)in three interconnected coastal environments in the western Caribbean:Río Huach channel,Chetumal/Corozal bay,and the adjacent Xcalak reef lagoon.These three encompass all habitats used by the seven species in the study area.Snapper diets were mostly composed of fish and crustaceans,but dominance of either group varied among the studied habitats;for example,fish were the main prey for L.apodus from the reef lagoon zone,but second in the bay.Snappers are piscivorous-invertivorous mesopredators;the species that relied the most on fishes were L.griseus and L.jocu,whereas O.chrysurus preferred crustaceans.Stomach content results revealed a high degree of dietary overlap among species.Our findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas,supporting the hypothesis of niche segregation.Our results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.
