Multidecadal Analysis of Beach Loss at the Major Offshore Sea Turtle Nesting Islands in the Northern Arabian Gulf

Undocumented historical losses of sea turtle nesting beaches worldwide could overestimate the successes of conservation measures and misrepresent the actual status of the sea turtle population. In addition, the suitability of many sea turtle nesting sites continues to decline even without in-depth scientific studies of the extent of losses and impacts to the population. In this study, multidecadal changes in the outlines and area of Jana and Karan islands, major sea turtle nesting sites in the Arabian Gulf, were compared using available Kodak aerographic images, USGS EROS Declassified satellite imagery, and ESRI satellite images. A decrease of 5.1% and 1.7% of the area of Jana and Karan islands, respectively, were observed between 1965 and 2017. This translated to 14,146 m2 of beach loss at Jana Is. and 16,376 m2 of beach loss at Karan Is. There was an increase of island extent for Karan Is. from 1965 to 1968 by 9098 m2 but comparing 2017 with 1968, Karan Is. lost as much as 25,474 m2 or 2.6% of the island extent in 1968. The decrease in island aerial extent was attributed to loss of beach sand. The southern tips of the island lost the most significant amount of sand. There was also thinning of beach sand along the middle and northern sections that exposed the rock outcrops underneath the beach. The process of beach changes of both islands was tracked by the satellite imagery from Landsat 1,3,5,7 and Sentinel-2 during 1972 to 2020. Other factors including the distribution of beach slope, sea level changes, as well as wind & current from both northward and eastward components were analyzed to show its impact on the beach changes. The loss of beach sand could potentially impact the quality and availability of nesting beach for sea turtles utilizing the islands as main nesting grounds. Drivers of beach loss at the offshore islands are discussed in the context of sea level rise, dust storms, extreme wave heights and island desertification

Genetic rearrangements in the rfb regions of Vibrio cholerae O1 and O139.

The recent emergence of a pathogenic new non-O1 serotype (O139) of Vibrio cholerae has led to numerous studies in an attempt to identify the origins of this new strain. Our studies indicate that O139 strains have clear differences in the surface polysaccharides when compared with O1 strains: the lipopolysaccharide can be described as semi-rough. Southern hybridization with the O1 rfb region demonstrates that O139 strains no longer contain any of the rfb genes required for the synthesis of the O1 O-antigen or its modification and also lack at least 6 kb of additional contiguous DNA. However, O139 strains have retained rfaD and have a single open reading frame closely related to three small open reading frames of the O1 rfb region. This region is closely related to the H-repeat of Escherichia coli and to the transposases of a number of insertion sequence elements and has all the features of an insertion sequence element that has been designated VcIS1. Transposon insertion mutants defective in O139 O-antigen (and capsule) biosynthesis map to the same fragment as VcIS1. Preliminary sequence data of complementing clones indicate that this DNA encodes a galactosyl-transferase and other enzymes for the utilization of galactose in polysaccharide biosynthesis. We propose a mechanism by which both the Ogawa serotype of O1 strains and the O139 serotype strains may have evolved