POPULATION DYNAMICS AND FACIES ASSOCIATION OF RECENT FORAMINIFERA FROM A NEARSHORE MARGINAL MARINE ENVIRONMENT: PLYMOUTH SOUND

Plymouth Sound is an area of shallow marine to marginal marine sea approximately 10km² in size. It is situated on the South coast of England and partially restricted from the open ocean by the Breakwater. Its shallow marine waters are diluted by the outflow from two significant rivers; the Tamar and the Plym. All of these factors combined with the partial restriction of the Breakwater and open channels adjacent the Breakwater have created many different sub-environments within this small region. Very low energy to very high energy conditions are present, which range from normal marine, slightly hyposaline to moderately hyposaline. These varied sub-environments reflect many distinct foraminiferal assemblages, both living and dead. The live foraminiferal assemblages show great variation throughout the year in terms of abundance, diversity and number and style of reproductive events. The dead assemblage is relatively stable throughout the year. The assemblages from the different sub-environments reflect varying degrees of post-mortem alteration. A detailed study of the foraminiferal fauna reveals a complex interplay between energy conditions, sediment type, temperature and salinity which are reflected in the foraminiferal morphology, size and abundance. This is further complicated in the dead assemblages by post-mortem processes. The live assemblages were dominated by Ammonia beccarii batavus (Linne) which reached a maximum abundance of 1200 individuals per 100 cm³ and Elphidium crispum (Linne) which reached a maximum of 450 individuals per 100 cm³, other species were locally important such as Brizalina pseudopunctata (Hoglund) in the muds of the Breakwater (Location 9), which reached a maximum of 1600 individuals per 100 cm³. Production of species was very variable but production was highest during April/May, July and September/October. The dead assemblages are dominated by Cibicides lobatulus (Walker and Jacob), an exotic species, which testifies to considerable post-mortem transport. This species accounts for up to 60% of some assemblages. Ammonia beccarii batavus which accounts for up to 50% of some assemblages and Elphidium crispum which accounts for up to 30% of some assemblages. The vertical distribution of foraminifera within the various sedimentary facies and sub-environments was determined by the retrieval of nine sediment cores from six different facies over two years. The cores revealed that the greatest abundance of live foraminifera occurred in the uppermost centimeter/s of the sediment, particularly within muddy sediments. Cores for isotopic analysis were collected from three areas of the Sound and used to determined the sediment accumulation rate and date sediments down to approximately 50 centimeters. Sedimentation has been dynamic and discontinuous. Sediment accumulation rates range from 0.19 cm/per year to 0.48 cm/per year. In addition to the main foraminiferal study of the Sound the previously unstudied Plym Estuary was sampled. This revealed a typical low diversity calcareous fauna composed of Haynesina germanica (Ehrenberg) and Elphidium williamsoni Haynes which attained very high abundances of 4000 individuals per cm³. This study is the most recent of several spanning almost an entire century. Although the data from previous studies are limited, comparison of these previous studies with the present study indicate little change of foraminiferal species in recent time but potentially large changes, particularly in recent years, of foraminiferal abundance and biomass within the Sound

Draft Genome Sequence of the Siderophore-Degrading Soil Bacterium Mesorhizobium loti Strain LU

Here, we present the draft genome of Mesorhizobium loti strain LU, a soil bacterium capable of degrading the trihydroxamate siderophore deferrioxamine B to its constituent monohydroxamic acids. Genome size was 6,399,828 bp, with a GC content of 61.5%. This draft genome consists of 35 scaffolds, with an N50 of 389,921 bp

Draft Genome Sequence of an Active Heterotrophic Nitrifier-Denitrifier, Cupriavidus pauculus UM1

Here, we present the draft genome sequence of Cupriavidus pauculus UM1, a metal-resistant heterotrophic nitrifier-denitrifier capable of synthesizing nitrite from pyruvic oxime. The size of the genome is 7,402,815 bp with a GC content of 64.8%. This draft assembly consists of 38 scaffolds

Seasonal and spatial variations of saltmarsh benthic foraminiferal communities from North Norfolk, England

Time series foraminiferal data were obtained from samples collected from three sites at Brancaster Overy Staithe, Burnham Overy Staithe and Thornham on the North Norfolk coast over a 1-year period. At each collection point, six environmental variables—temperature, chlorophyll, sand, mud, pH and salinity—were also measured. The principle aim of this study was to examine the benthic foraminiferal fauna in regard to the temporal variability of foraminiferal abundance, seasonal trend, dominant species, species diversity and the impact of environmental variables on the foraminiferal communities in the top 1 cm of sediment over a 1-year time series. The foraminiferal assemblages at the three sites were dominated by three species: Haynesina germanica, Ammonia sp. and Elphidium williamsoni. Foraminiferal species showed considerable seasonal and temporal fluctuation throughout the year at the three investigated sites. The foraminiferal assemblage at the three low marsh zones showed a maximum abundance in autumn between September and November and a minimum abundance observed between July and August. There were two separate peaks in the abundance of Ammonia sp. and E. williamsoni, one in spring and another in autumn. In contrast, H. germanica showed a single peak in its abundance in autumn. A generalized additive modelling approach was used to explain the variation in the observed foraminiferal abundance and to estimate the significant impact of each of the environmental variables on living foraminiferal assemblages, with taxa abundance as the dependent variable. When included in the model as predictors, most of the environmental variables contributed little in explaining the observed variation in foraminiferal species abundance. However, the hypotheses for differences amongst sites, salinity and pH were significant and explained most of the variability in species relative abundance

Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus

Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH)–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus) known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1) was examined for its ability to perform heterotrophic nitrification in the presence of Cu2+ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu2+ or 0.5 mM Ni2+ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu2+ or 0.5 mM Ni2+. The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed