Common Bivalves Research Articles

Effects of Lyngbya majuscula blooms on the seagrass Halodule wrightii and resident invertebrates

Cyanobacterial blooms have been increasing worldwide due to increased nutrients associated with urban, industrial, and agricultural development. Blooms that occur in the Indian River Lagoon (IRL), Florida may be increased by nutrient-laden runoff from storm water and non-point sewage pollution due to alterations to the watershed. In the IRL, during the summer of 2006, extensive blooms of the marine cyanobacterium, Lyngbya majuscula, were observed forming mats throughout beds of the seagrass Halodule wrightii in Fort Pierce, Florida. The effects of cyanobacterial blooms were compared to artificial shading of H. wrightii to assess the shading potential of L. majuscula. The combined effects of L. majuscula removal and artificial shading showed increases in the below ground biomass of H. wrightii. However, leaf length increased in the presence of L. majuscula. In response to artificial shading, H. wrightii decreased in density, but showed similar leaf elongation. A common bivalve in our study area, Macoma constricta, increased in density when L. majuscula was removed. Therefore, when L. majuscula blooms occur, light limitation is one of the mechanisms altering H. wrightii density and leaf lengths in the IRL. Loss of H. wrightii biomass due to shading from cyanobacterial mats may further damage the diversity and habitat value of the IRL.

Spatial and temporal distribution of mercury and methylmercury in bivalves from the French coastline

Marine mercury (Hg) concentrations have been monitored in the French coastline for the last half a century using bivalves. The analyses presented in this study concerned 192 samples of bivalves (mussels: Mytilus edulis and Mytilus galloprovincialis and oysters: Crassostrea gigas and Isognomon alatus) from 77 sampling stations along the French coast and in the French Antilles sea. The goals of this study were to assess MeHg levels in various common bivalves from French coastline, and to identify possible geographic, taxonomic or temporal variations of concentrations. We show that the evolution of methylmercury (MeHg) concentrations covary with total mercury (HgT) concentrations. Moreover, in most of the study sites, HgT concentrations have not decreased since 1987, despite regulations to decrease or ban mercury used for anthropic activities.

Abundance distribution patterns of intertidal bivalvesMacoma balthicaandCerastoderma eduleat the Murman coast tidal flats (the Barents Sea)

Density distribution of the common infaunal bivalves,Macoma balthicaandCerastoderma edule, was studied along the Murman Coast of the Barents Sea during 2002–2010. In both species, abundance was generally higher in West Murman in contrast to East Murman. Highest density ofMacoma balthicareaching 1535 ind. m−2was observed in the Kola Inlet.Cerastoderma edulewas less abundant; its density rarely exceeded 10 ind. m−2in all but one site, where 282 ind. m−2was registered. Reconstruction of abundance distribution across the European geographic range ofMacoma balthicarevealed that it does not match an ‘abundant-centre’ pattern, having features of ramped north. On the other hand, distribution ofCerastoderma eduleabundance across the range generally follows an ‘abundant-centre’ pattern but southern edge populations show relatively higher abundances as compared with those at the north edge (the Barents Sea).

Are Acila divaricata and Acila mirabilis One species or two distinct species? Evidence from COI mitochondrial DNA

Acila divaricata (Hinds, 1843) and A. mirabilis (Adams and Reeve, 1850) are common benthic bivalves in China. A number of researchers have proposed that the latter species is a junior synonym of the former species. Because of morphological similarities, it is difficult to distinguish these two species based on visual examination only. For better understanding of their taxonomy, the mitochondrial COI gene fragments of five individuals of A. divaricata from the East China Sea and six individuals of A. mirabilis from the Yellow Sea were sequenced in this study. The phylogenetic relationships of the obtained COI sequences, together with nineteen sequences of three species of the genus Nucula, were analyzed. The pairwise intra- and inter-specific distances for the COI sequences ranged from 0.002 to 0.017 and from 0.128 to 0.134, respectively, and no overlap was found. Phylogenetically, A. divaricata and A. mirabilis form distinct clades and cluster into a sister to all other Nucula species. The results indicated that A. divaricata and A. mirabilis are two distinct species. The differences in the morphology and distribution between the two species were briefly discussed.

Triton's trident: cryptic Neogene divergences in a marine clam (Lasaea australis) correspond to Australia's three temperate biogeographic provinces

The southern coast of Australia is composed of three distinct biogeographic provinces distinguished primarily by intertidal community composition. Several ecological mechanisms have been proposed to explain their formation and persistence, but no consensus has been reached. The marine clam Lasaea australis is arguably the most common bivalve on southern Australian rocky shores and occurs in all three provinces. Here, we tested if this species exhibits cryptic genetic structuring corresponding to the provinces and if so, what mechanisms potentially drove its divergence. Variation in two mitochondrial genes (16S and COIII) and one nuclear gene (ITS2) was assayed to test for genetic structuring and to reconstruct the clam's phylogenetic history. Our results showed that L. australis is comprised of three cryptic mitochondrial clades, each corresponding almost perfectly to one of the three biogeographic provinces. Divergence time estimates place their cladogenesis in the Neogene. The trident-like topology and Neogene time frame of L. australis cladogenesis are incongruent with Quaternary vicariance predictions: a two-clade topology produced by Pleistocene Bass Strait land bridge formation. We hypothesize that the interaction of the Middle Miocene Climate Transition with the specific geography of the southern coastline of Australia was the primary cladogenic driver in this clam lineage. Additional in-depth studies of the endemic southern Australian marine biota across all three provinces are needed to establish the generality of this proposed older framework for regional cladogenesis.

The molluscan bio-fouling community on the Red Sea pearl oyster beds

In the Red Sea, pearl oyster banks occur most extensively around the Dahlak and the Farasan Islands. Pearl oysters (Pinctada, Pteriidae) form extended beds by attaching themselves to hard substrates. Such beds attract a diverse bio-fouling fauna. Most dominant are the molluscs, but little is known about the associated biota of pearl oyster beds, their distributional abundance, and the structure of this community. In this study, the macro-molluscan fauna living on pearl oyster beds in the Red Sea around the Farasan Islands was studied using a quantitative survey of the by-catch left by pearl oyster divers. Bivalvia represented 99.6% of the malaco-fauna on pearl oyster beds around the Farasan Islands, while gastropods and chitons represented only 0.4%. In total, 33 mollusc species were identified (24 bivalves, 7 prosobranch gastropods, one basomatophore gastropod and one chiton), with Brachidontes variabilis, a species which is not found on Arabian Gulf pearl oyster beds, the most common bivalve (71% of all molluscs), and Diodora ruppellii the most common gastropod (0.12% of all molluscs). The results are discussed and compared with the pearl oyster beds from the Arabian Gulf.

Cloning and expression of thiolase enzymes in freshwater molluscs

Many species of freshwater molluscs exist in North America. Among these are the common gastropods Helisoma trivolvis, Physa acuta, and Goniobasis virginica. Additionally, the Asian clam, Corbicula fluminea, which found its way from China to North America some 70 years ago, is a very common bivalve. A considerable gap remains in the knowledge of lipid metabolism and lipid biochemistry in molluscs. The purpose of this research is to clone and express thiolase enzymes in various freshwater molluscs.

Influence of an altered salinity regime on the population structure of two infaunal bivalve species

Hydrological alterations in watersheds have changed the flows of freshwater to many nearshore marine environments. The ensuing alterations to the salinity environment of coastal waters may have implications for species distribution. This study describes the response of two common bivalves to a modified salinity environment imposed by freshwater inputs from a hydroelectric power station in Doubtful Sound, New Zealand. Populations of Austrovenus stutchburyi and Paphies australis inhabiting river deltas near the outflow of the power station in inner Doubtful Sound were more than an order of magnitude smaller in abundance than populations in neighbouring Bradshaw Sound where the salinity regime is unaltered. In addition, there was a lack of small size classes of both species in inner Doubtful Sound, suggesting that these populations are unsustainable over the long term (10–20 years). Laboratory experiments demonstrated that sustained exposure (>30 days) to low salinity (<10) significantly decreased bivalve survivorship; however, both species survived periods of exposure to freshwater up to at least 20 days in duration if followed by a period of return to normal seawater salinity. Examination of the extant salinity regime in light of these results indicates the current salinity environment in Doubtful Sound restricts bivalves to deeper waters (5–6 m depth). The observed discrepancy in the total biomass of these active suspension feeders between altered and control sites has potential implications for the flux of organic matter in the food webs of Fiordland's shallow soft sediment communities.

Bioerosion versus colonisation on Bivalvia: A case study from the Upper Miocene of Cacela (southeast Portugal)

A study of the bioerosion structures and the skeletobionts associated with the most common bivalves (infauna and epifauna) from the classic Upper Tortonian site of Cacela, Algarve region, SE Portugal, revealed 24 different ichnotaxa and five systematic groups of encrusters (Foraminifera, Annelida, Bryozoa, Balanomorpha and Bivalvia). Despite a relatively high ichnodiversity, the percentage of bioerosion in the specimens analysed is quite low (10–12%). This is explained by rapid sedimentation with only short periods of exposure on the sea-floor. The dominant bioerosion structures were linked to the boring activity of nonpredatory organisms. Algal microborings are the most common, followed by annelid borings ( Caulostrepsis-Maeandropolydora), sponge borings ( Entobia) and ctenostome bryozoans ( Pinaceocladichnus). Spatial distribution of bioerosion structures and encrusters allow the reconstruction of three successive stages. The first was restricted to the biosubstrate lifetime, with structures showing a preferred orientation and situated exclusively on the outside of the shells. The second comprises the period immediately after death, with structures that extend outwards and start with the colonization of the interior of the valves, losing their initial orientation. The third stage relates to later postmortem colonisation, with structures on both sides of the valves and without a preferential orientation.

Effect of Sewage Discharge in Spisula subtruncata (da Costa 1778) Populations

Sewage discharge is a common source of pollution in coastal marine waters. Several municipal treatment plants dump treated water in medium to fine sand Spisula subtruncata communities. This bivalve is generally considered a major food source for demersal fishes, and it is important as a dominant species in structuring the macrobenthic community during the spring and summer months. We sampled within five locations affected by sewage discharge along the Castellon coast (northwest Mediterranean Sea) where S. subtruncata (da Costa 1778) is a common bivalve. Van Veen grab samples were obtained for the study of the bivalve population and to characterize the sediment. The sewage discharges studied affect Spisula populations. In the stations near the outfalls, the abundance and the average size of S. subtruncata decreased. However, this effect did not correlate with sediment characteristics, such as granulometry or pH.

Habitat context influences predator interference interactions and the strength of resource partitioning

Despite increasing evidence that habitat structure can shape predator-prey interactions, few studies have examined the impact of habitat context on interactions among multiple predators and the consequences for combined foraging rates. We investigated the individual and combined effects of stone crabs (Menippe mercenaria) and knobbed whelks (Busycon carica) when foraging on two common bivalves, the hard clam (Mercenaria mercenaria) and the ribbed mussel (Geukensia demissa) in oyster reef and sand flat habitats. Because these species co-occur across these and other estuarine habitats of varying physical complexity, this system is ideal for examining how habitat context influences foraging rates and the generality of predator interactions. Consistent with results from previous studies, consumption rates of each predator in isolation from the other were higher in the sand flat than in the more structurally complex oyster reef habitat. However, consumption by the two predators when combined surprisingly did not differ between the two habitats. This counterintuitive result probably stems from the influence of habitat structure on predator-predator interactions. In the sand-flat habitat, whelks significantly reduced their consumption of their less preferred prey when crabs were present. However, the structurally more complex oyster reef habitat appeared to reduce interference interactions among predators, such that consumption rates when the predators co-occurred did not differ from predation rates when alone. In addition, both habitat context and predator-predator interactions increased resource partitioning by strengthening predator dietary selectivity. Thus, an understanding of how habitat characteristics such as physical complexity influence interactions among predators may be critical to predicting the effects of modifying predator populations on their shared prey.

Comparisons of class- and lower taxon-level patterns in naticid gastropod predation, Cretaceous to Pleistocene of the U.S. Coastal Plain

Predation by drilling gastropods provides evidence of predator–prey interactions usually lacking in the fossil record of other systems; the record of gastropod drilling has been used to test hypotheses concerning the role of ecology in evolution. Initial tests of the hypothesis of escalation employed assemblage-level estimates of drilling frequencies. Use of assemblage-level data to estimate predation intensities has been criticized because results based on such data may be confounded by varying relative abundances of prey taxa with different morphologies and adaptive syndromes. We tested the robustness of Cretaceous–Pleistocene temporal patterns previously derived from 28 Atlantic and Gulf Coastal Plain assemblages based on data for eight common bivalve and gastropod prey families and eleven additional long-ranging bivalve taxa of subfamily to species rank. Despite changing relative abundances of taxa through time, the general patterns of temporal change in drilling apparent at the assemblage level also occur within lower taxa. The assemblage-level pattern of fluctuating drilling frequencies, with peaks during the Paleocene to middle Eocene, early Oligocene, and middle Miocene to early Pliocene, was replicated for all families except noetiid bivalves and naticid gastropods. With occasional departures, the bivalve taxa at the subfamily to species rank also paralleled patterns for the assemblage as a whole. Statistically significant or nearly significant correlation coefficients between drilling frequencies of lucinids and crassatellids, arcids and crassatellids, carditids and crassatellaceans, and corbulids and arcids over time also indicate that drilling frequencies for these taxa changed synchronously. In contrast, “prey effectiveness” (effectiveness of prey defenses as measured by number of incomplete drill holes: total attempted holes) for lower taxa generally did not correspond to patterns at the assemblage level. All correlation coefficients for prey effectiveness for pairs of lower taxa were nonsignificant, suggesting that changes in prey effectiveness were not synchronized among taxa. Use of assemblage-level estimates in concert with analyses of lower taxa enables reconstruction of the history of predator–prey interactions and testing of hypotheses in evolutionary paleoecology. Assemblage-level estimates, at least in this study, appear to be reliable indicators of changes in the intensity of drilling predation through time. Changes in prey effectiveness appear to be more individualistic and may be affected by the evolutionary response of particular prey taxa to predators.

Chromium in intertidal sediments of the Clyde, UK: potential for remobilisation and bioaccumulation.

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.

Bioaccumulation of PAHs inVenus Verrucosafrom Ligurian Coast

Abstract Marine organisms exposed to oil spills are able to take up and store hydrocarbons; in particular benthic animals and plants can reach a petroleum concentration in their tissues several orders of magnitude higher than in the surrounding water. The present study was carried out in order to determine the polycyclic aromatic hydrocarbon (PAH) concentrations in a common bivalve of the Mediterranean coasts, Venus verrucosa. The organisms were collected in the area along the Ligurian coast, where the Haven wreckage took place and the 16 EPA priority pollutant PAH compounds were determinated. The PAHs were determined by HPLC with a fluorescent detector; the PAH levels found can be considered moderately high.

A palynological study of surface and suspended sediments on a tidal flat: implications for pollen transport and deposition in coastal waters

This study examines patterns of pollen deposition and resuspension on a tidal flat of the Dollard, a tidal basin near the mouth of the Ems River, at the border of Germany and The Netherlands (Fig. 1). Sediment samples were collected during three sequential low tides at the spring stage of the lunar tidal cycle when the greatest area of the flat would be exposed and, with the exception of storm events, when maximum scour and redeposition would be expected to occur. Fifteen sample stations were selected along a 5 km transect, with paired ripple crest and trough samples collected at three stations. Water samples were collected hourly during two tidal cycles, from a single location on the flat. Both numbers and condition of pollen and spore taxa were determined for all samples. Grain size and LOI of suspended matter were also determined. The same eight types of pollen and spores were important in both water and sediment samples: Ericaceae, Alnus, Betula, Chenopodiaceae, Corylus, Gramineae and Polypodiaceae. In water samples the lack of a relationship between concentrations of some pollen types and mineral fractions is assumed to be evidence that certain pollen types are preferentially incorporated into floccules suspended in local waters. Analysis of tidal flat sediments indicates that pollen concentrations increase in troughs between ripples and at lower elevations where finer grain sizes accumulate. There is minimal evidence of selective sorting of pollen types. Ordination (using Principal Components Analysis) of pollen percentages and concentrations in sediments indicates that both elevation and distance from the estuary mouth influence concentrations of all abundant pollen types. These parameters, however, have minimal influence on pollen percentages. Incorporation of pollen into fecal pellets, which have relatively high settling velocities, is assumed to be a critical control on pollen deposition in this environment. Analysis of stomach contents of locally common bivalves supports this hypothesis. Transport and deposition of individual pollen types cannot be predicted as floccules and pellets have varying densities and settling velocities. Some pollen and spores may be deposited in coarser sediments than would be predicted based on the size and density of individual grains, but in general display predicted patterns of deposition of fine-grained clastic sediments.

Archaeological Evidence for a Former Bay at Seaside, Oregon

Cultural shell middens, a common feature of coastal landscapes, preserve a record of past human use of coastal resources and often provide important paleoenvironmental information. Molluscan remains from two shell midden sites, located 0.7 km from the modern Pacific coast at Seaside, Oregon, suggest the former presence of a small sheltered bay at this locality. The modern sand beaches in the Seaside area, stretching for 30 km southward from the mouth of the Columbia River, are exposed to high-energy surf where razor clams ( Siliqua patula) are today the only common bivalve. By contrast, over 90% of molluscan remains (by weight) recovered from the archaeological sites represent species that favor sheltered water. Geologic studies in the Seaside area have shown that the beach prograded some 2 km over the last 4 millennia. The midden evidence suggests that the progradation was accompanied by the infilling of a former bay.

A new hexactinellid sponge from the Eocene of Kutch, India

A single specimen of the new dictyonine hexactinellid speciesVerrucocoelia biswasiwas collected from the Middle Eocene Fulra Limestone from Lakhpat Fort, Kutch, western India. The euretoid species is broadly bowl-shaped, 7–8 cm wide and 5–6 cm high, with walls of branched to weakly anastomosed tubes that extend upward and outward from a simple, unfluted, walled spongocoel. Skeletal strands diverge upward and outward from near the gastral surface of each tube. The sponge occurs in silty tan marl with abundant alveolinids and less common other large foraminifera, bivalves, and gastropods in sediments thought to have accumulated in a quiet, sheltered environment, possibly a lagoon.

Intertidal bivalves: a guide to the common marine bivalves of Alaska

Intertidal bivalves: a guide to the common marine bivalves of Alaska

Post-larval development of the bivalves Nucula turgida, Venus striatula, Spisula subtruncata and S. elliptica (Mollusca: Bivalvia), (with reference to the late larva)

Detailed studies of post-larval shell, hinge and/or internal morphogenesis, from metamorphosis to the completion of development, are available for a very small number of infaunal bivalves (for review of studies see Webb (1984). This paper continues the description, using scanning electron microscopy (SEM), of the post-larval ontogeny of some common infaunal bivalves from north-west European communities and presents the development of Nucula turgida, Venus striatula, Spisula subtruncata and S. elliptica. The association between larval shell morphology and certain features of development in some protobranch bivalves is examined.

Draney Limestone--Early Cretaceous Lacustrine Carbonate Deposition in Western Wyoming and Southeastern Idaho: ABSTRACT

The Lower Cretaceous Draney Limestone, a lenticular carbonate sequence well exposed throughout the Overthrust belt in western Wyoming and southeastern Idaho, records deposition in an extensive, shallow, low-salinity lacustrine system that minimally covered 30,000 sq km. The predominant lithologies of calcareous mudstone, micrite, intramicrite, and biomicrite contain a lacustrine biota composed predominantly of ostracods and the calcareous alga Chara, with less common bivalves and gastropods. The continuity of the Draney throughout the area indicates that this lake was a more or less continuous body of water throughout deposition. Individual units within the Draney, however, cannot be correlated over large distances; this fact suggests significant local chemical and/or phy ical variations within the lake basin during carbonate deposition. The lake appears to have been relatively shallow throughout its extent, as evidenced by the presence of winnowed sandy biomicrite and the ubiquitous Chara, which in modern systems is restricted to shallow photic zones. Limonitic calcareous mudstones which exhibit well-developed calcite boxwork fabrics and vugs filled with calcite spar indicate infrequent subaerial exposure and alteration of lake sediments. Modern playa systems do not serve as a satisfactory analog to the Draney lake because features indicative of (1) frequent subaerial exposure, (2) deposition in exceedingly shallow water, or (3) coprecipitation of more evaporitic minerals have not been observed in the Cretaceous sections. On the contrary, lithologic, faunal, and floral features of Draney strata are more nearly identi al to those of marl deposits in modern, temperate-region, hardwater lakes. Therefore, Cretaceous carbonate deposition under somewhat similar conditions is suggested. End_of_Article - Last_Page 425------------