Hydrologic Dynamics of the Ground-Water-Dependent Sian Ka’an Wetlands, Mexico, Derived from InSAR and SAR Data

The 5,280 km2 Sian Ka’an Biosphere Reserve includes pristine wetlands fed by ground water from the karst aquifer of the Yucatan Peninsula, Mexico. The inflow through underground karst structures is hard to observe making it difficult to understand, quantify, and predict the wetland dynamics. Remotely sensed Synthetic Aperture Radar (SAR) amplitude and phase observations offer new opportunities to obtain information on hydrologic dynamics useful for wetland management. Backscatter amplitude of SAR data can be used to map flooding extent. Interferometric processing of the backscattered SAR phase data (InSAR) produces temporal phase-changes that can be related to relative water level changes in vegetated wetlands. We used 56 RADARSAT-1 SAR acquisitions to calculate 38 interferograms and 13 flooding maps with 24 day and 48 day time intervals covering July 2006 to March 2008. Flooding extent varied between 1,067 km2 and 2,588 km2 during the study period, and main water input was seen to take place in sloughs during October–December. We propose that main water input areas are associated with water-filled faults that transport ground water from the catchment to the wetlands. InSAR and Landsat data revealed local-scale water divides and surface water flow directions within the wetlands.

Repetitive DNA fragments as taxonomic markers for {\it Penaeus\/} sibling taxa (Decapoda: Dendrobranchiata: Penaeidae) from the southern terminus of the Florida peninsula, U.S.A.

Sympatric populations of P. brasiliensis and P. duorarum from Biscayne Bay, Florida, revealed species-specific satellite DNA organizational patterns with the restriction endonuclease EcoRI. The species-specific satellite DNA patterns can be explained as resulting from differential amplification/deletion events having altered monomer arrays after the divergence of these two species. Two discontinuous populations of P. duorarum (Biscayne Bay and Dry Tortugas) were found to exhibit distinct EcoRI satellite fragment patterns; BamHI repetitive fragments specific to the Dry Tortugas P. duorarum population were also detected. In addition, the evolutionary conservation of the Penaeus (Farfantepenaeus) satellites was investigated. The putative conservation of sequences related to one cloned P. duorarum satellite monomer unit suggests that the FTR satellite DNA family may not only be of use as a genome tag to distinguish between sibling and cryptic Penaeus species but may also serve as a probe to better understand decapod crustacean genome organization and evolution. ^

Benthic foraminiferal record of the Pleistocene uplift of the sedimentary deposits of the Burica Peninsula (Costa Rica-Panama) as a result of Cocos Ridge subduction beneath the Central American Arc

This study used paleobathymetric interpretations from benthic foraminiferal assemblages to determine the timing of the initial subduction of the Cocos Ridge beneath the Costa Rica-Panama Arc and the associated amount of uplift. Forty-seven samples from four stratigraphic sections of the Burica and the Armuelles formations yielded 217 identified species. Foraminiferal paleoecology and cluster analyses indicated paleobathymetric differences within and between the sections. Maximum and minimum uplift rates were calculated from the biochronology, elevation, paleobathymetry and estimated eustatic changes. Large decreases in paleobathymetry were mainly due to the initial middle Pleistocene subduction of the Cocos Ridge in less than 0.5 Ma. Uplift rates were uneven across the Burica Peninsula, as follows: La Vaca 4.5–0.8 m/ky, Rabo de Puerco 2.8–0.7 m/ky, San Bartolo–Chiquito 2.7–0.8 m/ky, and eastern coast 8.0–1.5 m/ky. These differences probably resulted from Cocos Ridge asymmetry and differential uplift of tectonic blocks.

Water for the Wayuu: Procurement and maximization of a limited resource among indigenous pastoralists on the Guajira Peninsula of northern Colombia

For the Wayuu of the Guajira Peninsula of northern Colombia, water procurement has historically been challenging. The ancestral territory of this indigenous pastoral society is windy and arid, with low rainfall, high temperatures and an absence of perennial rivers or streams. In the past, the Wayuu adapted to these environmental conditions by practicing transhumance during the prolonged dry seasons, digging spring wells and artificial ponds and by following guiding principles for water usage. Since the 1930s, the government has made efforts to build additional wind-powered wells and ponds for a growing native population. Notwithstanding, these water solutions have only partly met the necessities; public water sources are limited or unreliable and few attempts are made to generate safe drinking water. Furthermore, the ubiquitous practice of animal husbandry places added pressure on existing sources; livestock consume more water than the human populations in the areas visited. Rapid assessments in four Wayuu areas on the peninsula were conducted by the author and an interdisciplinary team working for the Cerrejón Foundation for Water in La Guajira from 2010 to 2013. The assessments were part of a larger pilot project to design and implement a sustainability plan for reservoir-based water supply systems in the region. This study brings cultural practices and local knowledge to the forefront as key elements for the success of water works and other development projects carried out in Wayuu territory.