First data on dissolved black carbon in the coastal Northwestern Mediterranean Sea.

The spatial distribution of dissolved black carbon (DBC) concentrations was investigated using the benzene-polycarboxylic acid (BPCA) method applied to 28 subsurface seawater samples collected in the Rhone-Fos-Marseille area (Northwestern Mediterranean Sea, Southern France), a coastal zone heavily influenced by the Rhone River and maritime traffic. DBC concentrations, ranging from 9 to 27 µg C L, showed clear spatial differences across the sampling sites. Significantly higher concentrations were observed at the mouth of the Rhone River and in the harbour areas.

Interstitial microbial communities of coastal sediments are dominated by .

Microbial communities in subsurface coastal sediments are highly diverse and play an important role in nutrient cycling. While the major fraction of microorganisms in sandy sediments lives as epipsammon (attached to sand grains), only a small fraction thrives in the interstitial porewaters. So far, little is known about the composition of these free-living microbial communities.

Imprint of incomplete combustion processes on the water column of the anthropogenic-pressured Baltic Sea.

This study evaluates the distribution and sources of thermogenic organic matter in the Baltic Sea water column, focusing on polycyclic aromatic hydrocarbons (PAH), dissolved black carbon (DBC), and the imprint of thermogenic organic matter on the dissolved organic matter (DOM) pool. The spatial patterns and complex interactions between land-based and atmospheric sources were assessed from Kiel Bay to Pomeranian Bight within the water column with the combined targeted and untargeted approaches. The findings emphasize the significant influence of terrestrial inputs from the Oder River and autochthonous production composing DOM.

The diatom Thalassiosira rotula induces distinct growth responses and colonization patterns of Roseobacteraceae, Flavobacteria and Gammaproteobacteria.

Diatoms as important phytoplankton components interact with and are colonized by heterotrophic bacteria. This colonization has been studied extensively in the past but a distinction between the bacterial colonization directly on diatom cells or on the aggregated organic material, exopolymeric substances (EPS), was little addressed. Here we show that the diatom Thalassiosira rotula and EPS were differently colonized by strains of Roseobacteraceae and Flavobacteriaceae in two and tree partner treatments and an enriched natural bacterial community as inoculum.

Naturally induced biphasic phytoplankton spring bloom reveals rapid and distinct substrate and bacterial community dynamics.

Phytoplankton spring blooms are typical features in coastal seas and provide heterotrophic bacteria with a rich blend of dissolved substrates. However, they are difficult to study in coastal seas in-situ. Here, we induced a phytoplankton spring bloom and followed its fate for 37 days in four 600 L-mesocosms.

Land-use changes in Amazon and Atlantic rainforests modify organic matter and black carbon compositions transported from land to the coastal ocean.

This study assessed black carbon (BC) dynamics, concentrations, and the organic matter (OM) isotopic carbon composition in northeastern South America drainage basin coastal sediments. Paraíba do Sul (PSR; Atlantic Rainforest, Brazil) coastal sediments displayed more C-enriched values (-22.6 ± 1.

Molecular level characterization of the biolability of rainwater dissolved organic matter.

The atmospheric wet deposition has been recognized as a significant allochthonous source of dissolved organic carbon (DOC) to the ocean. However, few studies have examined the biolability of rainwater dissolved organic matter (DOM) at the molecular level. Rainwater samples were collected and incubated with ambient microbes.

Impact of Quorum Sensing and Tropodithietic Acid Production on the Exometabolome of .

Microbial interactions shape ecosystem diversity and chemistry through production and exchange of organic compounds, but the impact of regulatory mechanisms on production and release of these exometabolites is largely unknown. We studied the extent and nature of impact of two signaling molecules, tropodithietic acid (TDA) and the quorum sensing molecule acyl homoserine lactone (AHL) on the exometabolome of the model bacterium DSM 17395, a member of the ubiquitous marine group. Exometabolomes of the wild type, a TDA and a QS (AHL-regulator) negative mutant were analyzed Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS).

Deciphering the Virus Signal Within the Marine Dissolved Organic Matter Pool.

Viruses are ubiquitously distributed in the marine environment, influencing microbial population dynamics and biogeochemical cycles on a large scale. Due to their small size, they fall into the oceanographic size-class definition of dissolved organic matter (DOM; <0.7 μm).

Natural Asphalt Seeps Are Potential Sources for Recalcitrant Oceanic Dissolved Organic Sulfur and Dissolved Black Carbon.

Natural oil seepages contribute about one-half of the annual petroleum input to marine systems. Yet, environmental implications and the persistence of water-soluble hydrocarbons from these seeps are vastly unknown. We investigated the release of oil-derived dissolved organic matter (DOM) from natural deep sea asphalt seeps using laboratory incubation experiments.

The carbon and nitrogen budget of -a voracious cold-water coral thriving in an acidified Patagonian fjord.

In the North Patagonian fjord region, the cold-water coral (CWC) occurs in high densities, in spite of low pH and aragonite saturation. If and how these conditions affect the energy demand of the corals is so far unknown. In a laboratory experiment, we investigated the carbon and nitrogen (C, N) budget of from Comau Fjord under three feeding scenarios: (1) live fjord zooplankton (100-2,300 µm), (2) live fjord zooplankton plus krill (>7 mm), and (3) four-day food deprivation.

Carbon assimilating fungi from surface ocean to subseafloor revealed by coupled phylogenetic and stable isotope analysis.

Fungi are ubiquitous in the ocean and hypothesized to be important members of marine ecosystems, but their roles in the marine carbon cycle are poorly understood. Here, we use C DNA stable isotope probing coupled with phylogenetic analyses to investigate carbon assimilation within diverse communities of planktonic and benthic fungi in the Benguela Upwelling System (Namibia). Across the redox stratified water column and in the underlying sediments, assimilation of C-labeled carbon from diatom extracellular polymeric substances (C-dEPS) by fungi correlated with the expression of fungal genes encoding carbohydrate-active enzymes.

Sulfurization of dissolved organic matter in the anoxic water column of the Black Sea.

Today's oceans store as much dissolved organic carbon (DOC) in the water column as there is CO in the atmosphere, and as such dissolved organic matter (DOM) is an important component of the global carbon cycle. It was shown that in anoxic marine sediments, reduced sulfur species (e.g.

Diatom fucan polysaccharide precipitates carbon during algal blooms.

The formation of sinking particles in the ocean, which promote carbon sequestration into deeper water and sediments, involves algal polysaccharides acting as an adhesive, binding together molecules, cells and minerals. These as yet unidentified adhesive polysaccharides must resist degradation by bacterial enzymes or else they dissolve and particles disassemble before exporting carbon. Here, using monoclonal antibodies as analytical tools, we trace the abundance of 27 polysaccharide epitopes in dissolved and particulate organic matter during a series of diatom blooms in the North Sea, and discover a fucose-containing sulphated polysaccharide (FCSP) that resists enzymatic degradation, accumulates and aggregates.

Impact of Viral Lysis on the Composition of Bacterial Communities and Dissolved Organic Matter in Deep-Sea Sediments.

Viral lysis is a main mortality factor for bacteria in deep-sea sediments, leading to changing microbial community structures and the release of cellular components to the environment. Nature and fate of these compounds and the role of viruses for microbial diversity is largely unknown. We investigated the effect of viruses on the composition of bacterial communities and the pool of dissolved organic matter (DOM) by setting up virus-induction experiments using mitomycin C with sediments from the seafloor of the Bering Sea.

Improved Mass Accuracy and Isotope Confirmation through Alignment of Ultrahigh-Resolution Mass Spectra of Complex Natural Mixtures.

Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is one of the state-of-the-art methods to analyze complex natural organic mixtures. The precision of detected masses is crucial for molecular formula attribution. Random errors can be reduced by averaging multiple measurements of the same mass, but because of limited availability of ultrahigh-resolution mass spectrometers, most studies cannot afford analyzing each sample multiple times.

Ammonia-oxidizing archaea release a suite of organic compounds potentially fueling prokaryotic heterotrophy in the ocean.

Ammonia-oxidizing archaea (AOA) constitute a considerable fraction of microbial biomass in the global ocean, comprising 20%-40% of the ocean's prokaryotic plankton. However, it remains enigmatic to what extent these chemolithoautotrophic archaea release dissolved organic carbon (DOC). A combination of targeted and untargeted metabolomics was used to characterize the exometabolomes of three model AOA strains of the Nitrosopumilus genus.

Does the Chemodiversity of Bacterial Exometabolomes Sustain the Chemodiversity of Marine Dissolved Organic Matter?

Marine dissolved organic matter (DOM) is a complex mixture of chemical compounds. At 750 Pg C, it is one of the biggest pools of reduced carbon on Earth. It has been proposed that the diversity of DOM is responsible for its recalcitrance.

Cyanate and urea are substrates for nitrification by Thaumarchaeota in the marine environment.

Ammonia-oxidizing archaea of the phylum Thaumarchaeota are among the most abundant marine microorganisms. These organisms thrive in the oceans despite ammonium being present at low nanomolar concentrations. Some Thaumarchaeota isolates have been shown to utilize urea and cyanate as energy and N sources through intracellular conversion to ammonium.

Diversity of bacterial communities and dissolved organic matter in a temperate estuary.

Relationships between bacterial community and dissolved organic matter (DOM) include microbial uptake, transformation and secretion, all of which influence DOM composition. In this study, we explore diversity and similarity metrics of dissolved organic molecules (Fourier-transform ion cyclotron resonance mass spectrometry) and bacterial communities (tag-sequencing of 16S rRNA genes) along the salinity gradient of the Delaware Estuary (USA). We found that even though mixing, discharge and seasonal changes explained most of the variation in DOM and bacterial communities, there was still a relationship, albeit weak, between the composition of DOM and bacterial communities in the estuary.

The Exometabolome of Two Model Strains of the Group: A Marketplace of Microbial Metabolites.

Recent studies applying Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) showed that the exometabolome of marine bacteria is composed of a surprisingly high molecular diversity. To shed more light on how this diversity is generated we examined the exometabolome of two model strains of the group, and , grown on glutamate, glucose, acetate or succinate by FT-ICR-MS. We detected 2,767 and 3,354 molecular formulas in the exometabolome of each strain and 67 and 84 matched genome-predicted metabolites of and , respectively.