Robert S. Prezant

Effects of upper-limit water temperatures on the dispersal of the Asian clam Corbicula fluminea.

Temperature is a determinant environmental variable in metabolic rates of organisms ultimately influencing important physiological and behavioural features. Stressful conditions such as increasing temperature, particularly within high ranges occurring in the summer, have been suggested to induce flotation behaviour in Corbicula fluminea which may be important in dispersal of this invasive species. However, there has been no experimental evidence supporting this hypothesis. It was already proven that C. fluminea drift is supported by a mucilaginous drogue line produced by mucocytes present in the ctenidia. Detailed microscopic examination of changes in these cells and quantification of clam flotation following one, two and three weeks of exposure to 22, 25 and 30°C was carried out so that the effects of increasing water temperatures in dispersal patterns could be discussed. Results show that changes in temperature triggered an acceleration of the mucocytes production and stimulated flotation behaviour, especially following one week of exposure. Dilution of these effects occurred following longer exposure periods. It is possible that these bivalves perceive changing temperature as a stress and respond accordingly in the short-term, and then acclimate to the new environmental conditions. The response patterns suggest that increasing water temperatures could stimulate C. fluminea population expansion.

Marine Macroinvertebrate Diversity of St. Catherines Island, Georgia

Abstract St. Catherines Island is one of several barrier islands lining the coast of Georgia, USA. This island is among the least recently anthropogenically impacted of the Georgia Sea Islands, but had not previously been examined in detail for coastal invertebrate macrofauna. From 1992 through late 1998 a coastal survey was conducted that examined the diverse marine invertebrate fauna of St. Catherines Island. Salt marshes, sand flats, mid- to low-energy sand beaches, beach wood debris, tidal creeks, shallow benthos, and artificial hard substrata (including docks) were qualitatively sampled for macroinvertebrates. Over 340 species were identified. Crustaceans composed close to 40% (14% amphipods; 15% decapods), polychaetes 17.5%, and molluscs about 25% of all species recovered. These results are compared to the few other relevant studies from the United States mid-Atlantic Coast.

Freshwater Molluscs of the United States Military Academy Drainages (West Point, NY) and Comparative Regional Biodiversity of Gastropods

Abstract Thirty-four species of molluscs have been found in the drainage systems of the United States Military Academy at West Point, NY. A few rare species were found as well as a single specimen of a presumed new gastropod taxon. Only two species of unionids, Pyganodon cataracta and Elliptio complanata, were found within the drainages. The largest drainage system, Popolopen Brook, contained the highest diversity of molluscs. Species redundancy between drainages aligned well as a function of the extent of lentic and lotic habitats with brooks and streams having a Bray-Curtis similarity index of ≈ 64.0 when compared to lakes and ponds. On the other hand, a number of species collected were found in only a single drainage. Total drainage area did not correspond well with diversity unless determined as total predicted usable habitat. Thus the drainages with the greatest number of discernible lakes, ponds, streams, and creeks, also had the highest molluscan diversity. On the whole, molluscan diversity of these drainages compared favorably to those of other regional New York sites, but relative abundance or population densities varied, with variations reflecting survey effort, time or season of collections, and incorporation of historic museum collections.

Comparative Shell Microstructure of Two Species of Tropical Laternulid Bivalves from Kungkrabaen Bay, Thailand with After-Thoughts on Laternulid Taxonomy

Abstract: The anomalodesmatan family Laternulidae represents a group of bivalves with a very few well-known taxa and many more poorly known taxa. Laternula rostrata (G. B. Sowerby, 1839) and L. anatina (Linnaeus, 1758) occur in close proximity to each other in and along the margins of mangroves of Kungkrabaen Bay, Thailand. Laternula rostrata resides in soft to sandy sediments often within the interstices of mangrove roots located in more open portions of the mangrove mud flat. Laternula anatina lives deeper in the mangrove in more protected environs. Laternula anatina is a smaller bivalve that has a variable shell outline, sometimes a wrinkled shell appearance, thicker periostracum, and frequently extensive umbonal erosion. Both species have high concentrations of external shell spinules anteriorly and closer to the umbos (i.e., in juvenile shell) reflecting functionality in retaining an infaunal position. The larger L. rostrata is thinner shelled and more fragile; has more distinct and longer shell spinules composed of flattened lathes; a glossy external appearance; a longer umbonal slit; and a deeper pallial sinus. Additionally, L. rostrata has a saddle-shaped lithodesma; a lithodesma is absent in L. anatina as is typical of most laternulids. Shell microstructure of both is prismatonacreous, typical of the group, but the prismatic layer is thin and appears truncated into small blocky and/or granular columns in transitional zones. The bulk of the shell is tightly packed sheet nacre. The growth lines in L. rostrata, more pronounced but fewer in number than in L. anatina, appear as shallow rolling “hills” in both the shell and chondrophore. The differences in shell microstructure in these two species are specific to the taxa but based on different habitats and burrowing depths, albeit within the confines of a tropical mangal, could represent biomineralization events that reflect environmental adaptations. Variations in the thickness of the microstructural shell layers of four species of laternulids is compared and we speculate on possible functional and/or environmental relevance of these differences.

Temporal Variation in Molluscan Community Structure in an Urban New Jersey Pond

Abstract Barbours Pond is a 4.45-ha pond located in Garrett Mountain Reservation in Passaic County in northern New Jersey, one of the most densely populated regions in the United States. Despite its small size and surrounding urban sprawl, the shallow waters of this pond hold 18 species of molluscs. Monthly samples from March 2004 through March 2006 found the highest diversity in December 2004, and in January, June, and July 2005. Additional samples were taken in April 2007 and May 2010 to spot-check relative diversity years after the original sampling period. Total molluscan abundance was greatest in July and November 2004, possibly reflecting new late spring and autumn cohorts. Univariate statistics demonstrate that this pond has a temporally stable and diverse malacofauna. Analysis, of basic environmental parameters including temperature and pH, however, showed little correlation with molluscan diversity over time, underscoring the stable yet complex nature of biodiversity of this small urban pond.

Influence of Diphenhydramine HCl and Caffeine on Embryonic Development and Adult Reproductive Success of the Freshwater Gastropod Helisoma trivolvis

Abstract: Diphenhydramine HCl (DH) and caffeine are commonly detected contaminants in waterways and drinking water nationwide (U.S.A.) and yet little is known of their influence on the development of aquatic molluscs. The antihistamine diphenhydramine blocks the chemical effects of histamine by inhibiting the re-uptake of serotonin (5-HT). Caffeine can influence the regulation of calcium (Ca2+) and neurotransmitters, such as 5- HT, by inhibiting the re-uptake of adenosine. Serotonin receptor-mediated signaling is key during embryonic development in the freshwater snail Helisoma trivolvis (Say 1816). Embryonic development rates of H. trivolvis depend upon external conditions such as oxygen concentration and temperature. We examine the effects of diphenhydramine (DH) and caffeine on development and reproductive potential of this common aquatic snail. Concentrations of DH at 40.0, 50.0 and 60.0 µM affect the in-capsule embryonic development and hatching rate. Caffeine at 40.0, 50.0 and 60.0 µM show no influence to the hatching rates; however, these caffeine concentrations influence the in-capsule embryonic rotation rate. Eight-month observations of adult H. trivolvis reproductive activities show no influence in number of egg masses deposited when exposed to test concentrations of DH or caffeine.

In Memoriam Melbourne Romaine Carriker 1915–2007

On February 25, 2007, 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 February 25, 1915 to Melbourne Armstrong Carriker, Jr. andMyrtle Carmella Carriker on the family coffee plantation,Vista Nieve, near SantaMarta, 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, andMel’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. Mel entered Rutgers University in 1935, majoring in agricultural research and minoring in zoology. He graduated with honors and a B.S. in Zoology in 1938, and it wasMel’s aim to become an ornithologist. But in 1938, his undergraduate advisor, ThurlowC. Nelson, persuaded him to begin studying population movements of oyster larvae in Barnegat Bay, New Jersey. In the fall of that year, he entered the University of Wisconsin, joining the graduate student group of Lowell E. Noland and studying Lymnaea stagnalis (Linnaeus, 1758), the snail vector for swimmer’s itch in humans. There he earned a Master of Philosophy and, then, a Doctor of Philosophy degree. Mel’s graduate worked focused on radular and digestive anatomy, physiology and function of L. stagnalis. During 1939 at Wisconsin, Mel met Meriel Roosevelt McAllister, known as Scottie. He completed his doctoral dissertation and graduated in June 1943. During summers from 1938 through 1941, Mel returned to Great Bay, New Jersey, and in Journal of Shellfish Research, Vol. 27, No. 1, 3–12, 2008.

Melbourne Romaine Carriker: 25 February 1915 – 25 February 2007

1 Department of Biological Sciences, Richard A. Henson School of Science and Technology, Salisbury University, Salisbury, Maryland 21801-6861, U.S.A., clcounts@salisbury.edu 2 College of Science and Mathematics, Montclair State University, Montclair, New Jersey 07043, U.S.A., prezantr@mail.montclair.edu 3 Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, Connecticut 06340, U.S.A., evan.ward@uconn.edu