Analysis of the metals and metalloids concentrations and of the bacterial population in sediments of the Red River Delta, Vietnam.

In this study, we discuss for the first time the relationships between the diversity of the bacterial population and of the metals and metalloids concentrations in the sediments of the Red River Delta, Vietnam. The analysis of the 16S rRNA by the Illumina technology revealed a diversified population and a potential of bioremediation by the microorganisms, notably by the relatively abundant in the Bach Dang estuary, where high metals and metalloids concentrations were highlighted. This work offers new information on the environmental context of the delta and highlights the potential impact that metals and metalloids may have on the bacterial population.

Complete Genome Sequence of sp. Strain 8C15b, Isolated from Bank Sediments of Haiphong Bay, Vietnam.

We report the complete genome sequence of sp. strain 8C15b, isolated from bank sediments of Haiphong Bay, Vietnam. The genome includes a 3,628,320-bp circular chromosome and a plasmid of 38,213 bp.

Amino acids promote black carbon aggregation and microbial colonization in coastal waters off Vietnam.

The combustion of fossil fuels and biomass produces pyrogenic organic matter usually known as 'black carbon' (BC), which are transported across the atmosphere as particulate aerosol, eventually deposited on land and oceans. Soil studies have investigated the potential microbial colonization and remineralization of BC particles, but this process has been seldom studied in marine waters. BC provides a significant input of organic carbon to the oceans, yet its fate and role in biogeochemical cycling remains unknown.

Origins and discrimination between local and regional atmospheric pollution in Haiphong (Vietnam), based on metal(loid) concentrations and lead isotopic ratios in PM.

Southeast Asia is a hotspot of anthropogenic emissions where episodes of recurrent and prolonged atmospheric pollution can lead to the formation of large haze events, giving rise to wide plumes which spread over adjacent oceans and neighbouring countries. Trace metal concentrations and Pb isotopic ratios in atmospheric particulate matter < 10 μm (PM) were used to track the origins and the transport pathways of atmospheric pollutants. This approach was used for fortnightly PM collections over a complete annual cycle in Haiphong, northern Vietnam.

Fate and tidal transport of butyltin and mercury compounds in the waters of the tropical Bach Dang Estuary (Haiphong, Vietnam).

In this work, two field campaigns were performed in July 2008 (wet season) and March 2009 (dry season) to produce original data on the concentration, partition and distribution of mercury and butyltin compounds along the tropical Bach Dang Estuary located in North Vietnam (Haiphong, Red River Delta). The results demonstrate that mercury and butyltin speciation in the surface waters of this type of tropical estuary is greatly affected by the drastic changes in the seasonal conditions. During high river discharge in the wet season, there was a large estuarine input of total Hg and tributyltin, while the longer residence time of the waters during the dry season promotes increasing MMHg formation and TBT degradation.

Contribution of anammox bacteria to benthic nitrogen cycling in a mangrove forest and shrimp ponds, Haiphong, Vietnam.

Mangrove forests are common in subtropical regions, and have received considerable attention as vegetative buffers against anthropogenic N-loading. In this study, we investigated anaerobic ammonium oxidation (anammox) as one of potentially important microbial N-removing pathways in mangrove and shrimp pond sediment in Haiphong, Vietnam. Measurements with (15)N-labeled compounds demonstrated the occurrence of anammox in sediment of mangrove forest and a water channel connecting shrimp ponds to the sea in both 2005 and 2007, and of a semi-intensive shrimp pond in 2005.