Abstract.We report the results of a study with proton-induced X-ray emissions (PIXE) of the distribution and concentration of 15 chemical elements (Na to Sr in periodic chart) in four microstructural and two mineralogical regions of shell of rapidly growing adult oysters [Crassostrea virginica (Gmelin)]. Hatchery-raised oysters were grown in Broadkill Estuary, Delaware, USA, for 16 wk in summer 1978. Their valve edges were filed as a marker, and the oysters were replaced in the estuary, where they grew rapidly. Shell deposited after marking had a normal microstructure and mineralogy after a narrow zone of disturbance. After 17 d oysters were sacrificed, and different mineralogical and microstructural regions of valves of three oysters, and parts of valves of two oysters, were analyzed for the elements Na to Sr. Quadrats (2.5 x 0.45 mm) included three calcitic groups (prismatic, foliated, chalky) and one aragonitic (myostracal) microstructural group; four quadrats were on the exterior and five on the interior of right and left valves. Inhalant and exhalant margins of valves and ground right and left valves of one oyster were also analyzed. Elemental chemistry of different regions of shell varied among the three microstructural groups within the single calcitic polymorph, between aragonitic and calcitic regions, and between exhalant and inhalant margins of the valves. Elements were most concentrated in the prismatic region of the right valve. Element concentrations were similar in ground right and left valves, except for higher levels of Si, Fe, and Zn in the right valve (corresponding to their high contents in prismatic shell) and of C1 in the left valve (reflecting high concentration in chalky shell, abundant in this valve). Na, Mg, C1, Cr, Cu, Zn and Br were more concentrated in prismatic than in foliated shell. Chalky shell contained higher concentrations of Na than did prismatic shell, and high concentrations (but lower than in prismatic shell) of Mg, C1, Ti, Mn, Fe, Zn and Br. Element concentration in myostracum was approximately the same as, or lower than, in foliated shell, except for Sr, which was higher than that in any other shell group. In the right valve most elements were concentrated in inhalant margins, and on the left valve, in exhalant margins. With increased weathering of the exterior surface of prismatic shell, Mg, Si, and Mn increased in concentration and Na, A1, C1, Ti, Cr, Fe, Br, and Sr decreased.

No abstract

The exotic Asian bivalve, Corbiculafluminea, is reported for the first time from Panama. It is noted that the species is presently exploited commercially by restaurants in Panama City and it is speculated that these bivalves were imported into the country in shipments of the freshwater fish Tilapia sp., imported from the United States, and used as aquaculture stock.

No abstract

our mentor, colleague, and great friend, Melbourne Romaine Carriker died at Lewes, Delaware. It was his ninety-second birthday. He was surrounded by his children and grandchildren.Mel’s life was as eventful and full as his scientific career. He was born 25 February 1915 to Melbourne Armstrong Carriker, Jr. and Myrtle Carmella Carriker on the family coffee plantation, Vista Nieve, near Santa Marta, Colombia. Mel detailed his boyhood experiences on the plantation in his memoir Vista Nieve (Carriker 2000). In 1925, at the age of ten, Mel participated in his first biological expedition accompanying his father, a world-class ornithologist and entomologist, to the eastern slope of the Andes.The plantation was sold in 1927. After the sale, the family moved to Tom’s River, New Jersey, and Mel’s father became a curator of birds at the Academy of Natural Sciences of Philadelphia (ANSP). Mel attended the public schools and graduated from high school in 1934. In 1934 and early 1935, Mel and his father returned to the Andes in Bolivia on another ornithological expedition (Carriker, Jr. 2006). During the steamship trip, Mel demonstrated his remarkable abilities on the dance floor, exhibiting such skill that other dancers stopped to watch him and his partner. These displays were attributed to lessons provided by Mel’s mother in Tom’s River (Castillo and Holyoak 2004). This journey to the Andes was epic with train travel to the Alto Plano, a steamer across Lake Titicaca, and brushes with Bolivian troops fighting a war with Argentina (Carriker 2005, Carriker, Jr. 2006. It was during this expedition that Mel contracted malaria.