A.Y.A. AlKindi

Bacterial flora and antibiotic resistance from eggs of green turtles Chelonia mydas: An indication of polluted effluents

Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.

Ultrastructural features and elemental distribution in eggshell during pre and post hatching periods in the green turtle, Chelonia mydas at Ras Al-Hadd, Oman

Eggshells were randomly collected from turtle nests immediately after oviposition and at the end of incubation to examine the ultrastructural features using scanning JSM-5600LV microscopy. Three layers were recognized; an outer calcareous, a middle multistrata and an inner membrane. The calcareous layer had loose nodular units varying in shape and size without interlocking attachments. In freshly laid eggs, each nodular unit had spicules arranged in folded stacks. The spicules became unfolded during incubation, to form radiating configurations. Elemental composition and mapping of the layers were analyzed using energy dispersive spectroscopy (EDS). The elements were unevenly distributed throughout the eggshell and Ca(2+) decreased significantly after hatching. X-ray diffraction was used to identify the crystals of the eggshells. It revealed that nodular units of the calcareous were made up of CaCO(3), as aragonite (91%), calcite (6%) and vaterite (3%). The middle layer consisted of organic amorphous material with aragonite (89%) and calcite (11%). The shell membrane consisted of reticular fibers with crystals predominantly of NaCl halite. Thermogravimetry analysis of the calcareous layer indicated a complete evaporation of bonded H(2)O at 480 degrees C and CO(2) at 830 degrees C. Using the differential thermal analysis (DTA), aragonite was transformed to stable calcite at 425 degrees C.

The Effect of Physical and Human Factors on Beach Selection by Green Turtles (Chelonia mydas) at Ras Al-Hadd Reserve, Oman

ABSTRACT Beaches at Ras Al-Hadd Reserve, Oman, share common physical features ideal for nesting green turtles (Chelonia mydas). However, human activities related to commercial fishing and coastal development impact nesting. Beaches with hills as a backdrop and with minimal human activities were the primary nesting sites at the reserve. During peak nesting season (monsoon/wet period), the mean number of excavation attempts was equal between oviposited and nonoviposited turtles. During nonpeak season (dry period), the mean number of excavation attempts was significantly higher in nonoviposited turtles than in oviposited turtles, and insufficient sand moisture frequently resulted in one or several nest collapses and oviposition failure.

Emergence pattern of the Green Turtle, Chelonia mydas, hatchlings under laboratory and natural conditions

Abstract Green Turtle eggs were collected at random from 5 different nests from the Ras Al-Hadd Reserve in Oman. They were incubated 16hr after oviposition at constant temperatures set at 30–31°C for female producers and at 26–27° for male producers. Standard histological procedure of the gonads was performed for sex determination. Despite the constant temperatures set in the incubators, there were differences among the incubated eggs. This is similar to the natural condition, where an asynchronous pattern of emergence is common. Pipping occurs when the eggshell has a slit and hatching is when the head and one flipper are outside the eggshell. Emergence occurs when the hatchling is completely free from the extraembryonic membranes and eggshell. There was no correlation between the pipping-hatching and hatching-emergence intervals in the female, but in males the two intervals were significantly correlated (P<0.01). Hatchling weights were: 28.22 g (±0.83) for females and 25.74 g (±0.58) for males. In both sexes, hatchling weight did not influence the duration of the two intervals. The duration between pipping emergence was significantly (P<0.01) longer in females than in males. Natural and incubator observations showed that the hatchlings remained in the nest after emergence for at least 48hr until the umbilical swelling had subsided before attempting their emergence escape. While the hatchlings remain inside the eggshell after pipping attached to chorioallontoic/amniotic membranes, they are occasionally vulnerable to injury by nesting turtles, micro-organisms or early-emerged hatchlings inside the nest.

X-Ray Microanalysis and Image Mapping of Elements from Eggshells of Freshly Laid Eggs of Green Sea Turtles Chelonia mydas

Green turtle Chelonia mydas eggs were taken at oviposition for X-ray microanalysis and image. Untreated eggshells were analyzed for elemental composition and image mapping with an Oxford energy dispersive x-ray spectrometer (EDS) operating at 20kV and a working distance (WD) of 20mm. This involved qualitative, quantitative and area analysis. Qualitative analysis of characteristic X-rays (elements) distribution was displayed as a spectrum. SEM Quant (Oxford Instruments Ltd.) was used for quantitative analysis with ZAF internal standardardization (5 iterations), all elements and element composition expressed as weight percent. Representative sites were chosen for area analysis or image mapping of element distribution.