► Aliphatic hydrocarbons of petroleum origin are absent in most sediment samples. ► Terrestrial higher plants derived hydrocarbons are predominant. ► Terrestrial and marine sources of hydrocarbons ...are variable spatially. ► Terrestrial n-alkanes are atmospherically transported to marine systems off China.
Sediment samples from the marine systems along the coast of China, covering Yellow Sea, inner shelf of the East China Sea (ECS) and the South China Sea (SCS), were analyzed for n-alkanes and organic carbon. The concentrations of Σn–C15–35 were 120–1680ngg−1 dry weight with an average of 560ngg−1. Short-chain n-alkanes (<C21) in Yellow Sea and the SCS were derived from mixed bacteria and planktonic sources, while those in the ECS inner shelf were mainly of planktonic sources. Long-chain n-alkanes (>C21) were mainly derived from terrestrial higher plants. Organic carbon deposited into Yellow Sea and Southeast Hainan within the SCS was mainly of terrestrial (13–110%; mean: 58%) and marine (48–110%; mean: 86%) sources, respectively. On the other hand, organic carbon accumulated in the SCS adjacent to the Pearl River Estuary was derived from both terrestrial and marine sources.
Nitrite-oxidizing bacteria (NOB) are chemolithoautotrophs that catalyze the oxidation of nitrite to nitrate, which is the second step of aerobic nitrification. In marine ecosystems, Nitrospina is ...assumed to be a major contributor to nitrification. To date, two strains of Nitrospina have been isolated from marine environments. Despite their ecological relevance, their ecophysiology and environmental distribution are understudied owing to fastidious cultivation techniques and the lack of a sufficient functional gene marker. To estimate the abundance, diversity, and distribution of Nitrospina in various marine sediments, we used nxrA, which encodes the alpha subunit of nitrite oxidoreductase, as a functional and phylogenetic marker. We observed that Nitrospina diversity in polar sediments was significantly lower than that of non-polar samples. Moreover, nxrA-like sequences revealed an unexpected diversity of Nitrospina, with approximately 41,000 different sequences based on a 95% similarity cutoff from six marine sediments. We detected nxrA gene copy numbers of up to 3.57 × 10⁴ per gram of marine sediment sample. The results of this study provide insight into the distribution and diversity of Nitrospina, which is fundamentally important for understanding their contribution to the nitrogen cycle in marine sediments.
Paenibacillus marinisediminis sp. nov., a bacterium isolated from marine sediment Lee, H.W., Kyung Hee University, Seoul, Republic of Korea; Roh, S.W., Kyung Hee University, Seoul, Republic of Korea; Yim, K.J., Korea Basic Science Institute, Jeju, Republic of Korea ...
The journal of microbiology,
06/2013, Letnik:
51, Številka:
3
Journal Article
Recenzirano
A Gram-negative, nonmotile, endospore-forming, rod-shaped bacterial strain LHW35T, which belonged to the genus Paenibacillus, was isolated from marine sediment collected from the south coast of the ...Republic of Korea. A phylogenetic analysis of 16S rRNA gene sequences indicated that strain LHW35T was most closely related to Paenibacillus taiwanensis G-soil-2-3T (97.2% similarity). The optimal growth conditions for strain LHW35T were 37°C, pH 6.0, and 0% (w/v) NaCl. The main isoprenoid quinone was menaquinone-7 (MK-7) and the major polyamine was spermidine. The diamino acid present in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major fatty acids were anteiso-C15:0 and C16:0. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, unidentified amino-hospholipids, unidentified phospholipids, and unidentified polar lipids. A DNA-DNA hybridization experiment using the type strain of P. taiwanensis indicated 40% relatedness. The DNA G+C content was 45.0 mol%. Based on these phylogenetic, genomic, and phenotypic analyses, strain LHW35T should be classified as a novel species within the genus Paenibacillus, for which the name Paenibacillus marinisediminis sp. nov. is proposed. The type strain is LHW35T (
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•Two different geometrical configurations of anode was compared.•Vertical geometry of anode position was found better.•Nutritional analysis of sediment showed that degradation isn’t ...always certain.•Acidobacteria and Actinobacteria were also played an important role as exoelectrogens apart from Proteobacteria.
A comparative study of an anode position in a benthic microbial fuel cell (BMFC) was performed. Different geometric alignment of anodes having single, vertical and horizontal in sediment to understand the impact of positional changes on power performances was studied. Vertical anode configuration showed 1.2 and 2.56 fold higher power density than horizontal and single anode system respectively. Internal resistance was also found 389, 421 and 668 Ω for vertical, horizontal and single anode system respectively. This suggests that the vertical configuration of anode system performs better than horizontal configuration. Nutritional analysis shows that organic matter was consumed initially at a high rate at anode position than non-anode position and among them; degradation of an organic matter in vertical anode system is higher than horizontal and single configuration. The final increment of organics in the system depicted the accumulation of complex organics which were difficult to oxidize. Microbial community obtained from 16S rRNA found to have the increment of Alpha-, Betaproteobacteria, and Acidobacteria on an anode over time. The dominance of Acidobacteria further reveals the acidic environment formation inside the sediment chamber. It can be concluded that Acidobacteria is also the dominant communities besides Proteobacteria.
Bottom sediments of harbors in the South Korea have been long suspected for metal contamination due to ship-based and urban-based activities for the past several decades. A number of areas have been ...suspected to impair ecosystem services to the local residents and drawn complaints from main stakeholders. Twelve contamination suspected harbors were subject to evaluate the level of contamination of Cr, Ni, Cu, Zn, As, Cd, Pb and Hg. The level of sediment contamination for each metal was evaluated comparing the relative enrichment of a given metal to pollution-insensitive aluminum. Regional background concentration of a given metal was also determined based on its down core measurement and sediment texture. Ecological risk posed by the presence of heavy metals was evaluated using the sediment quality guidelines (SQGs) developed by United States National Ocean and Atmosphere Administration (US NOAA) as benchmarks for evaluating sediment chemistry to aquatic organisms. Cu, Zn, Cd, Pb and Hg in the surface sediment were found to be higher than a factor of 1.5 than background sediments, and the overall metal contaminations of surface sediment can be regarded as medium–high- to high-priority sites in the sense of SQGs.
Biosynthesis of silver nanoparticles has been carried out by using the cell free filtrate of marine sediment fungal species of Southern peninsular coastal region of India and identified based on the ...sequence analysis of Internal Transcribed Spacer region of rRNA genes. Species were identified as Aspergillus flavus SP-3, Trichoderma gamsii SP-4, Talaromyces flavus SP-5, and Aspergillus oryzae SP-6. The phylogenetic relationship between the fungal isolates and other fungal strains was compared. Treatment of silver nitrate with the fungal extract produced stable, predominant, monodispersed and spherical silver nanoparticles. Preliminary characterization revealed that the nano-particles were in the range of 20–60nm in all the fungal isolates. Among all the fungi the silver nano-particles of T. gamsii SP-4 showed an enhanced antimicrobial activity against Gram positive bacteria, Gram negative bacteria and fungi pathogens; an anti-oxidant activity at an effective concentration of 99µg/ml; and a dose dependent cytotoxic activity against HEp2 cell lines at LC50 value of 23µg/ml. Thus, the strains, SP3, SP4, SP5, and SP6 could be used for simple, non-hazardous and efficient synthesis of antimicrobial and HEp2 cytotoxic silver nano-particles.
In coastal marine sediments, denitrification and fermentation are important processes in the anaerobic decomposition of organic matter. Microbial communities performing these two processes were ...enriched from tidal marine sediments in replicated, long term chemostat incubations at 10 and 25°C. Whereas denitrification rates at 25°C were more or less stable over time, at 10°C denitrification activity was unstable and could only be sustained either by repeatedly increasing the amount of carbon substrates provided or by repeatedly decreasing the dilution rate. Metagenomic and transcriptomic sequencing was performed at different time points and provisional whole genome sequences (WGS) and gene activities of abundant populations were compared across incubations. These analyses suggested that a temperature of 10°C selected for populations related to Vibrionales/Photobacterium that contributed to both fermentation (via pyruvate/formate lyase) and nitrous oxide reduction. At 25°C, denitrifying populations affiliated with Rhodobacteraceae were more abundant. The latter performed complete denitrification, and may have used carbon substrates produced by fermentative populations (cross-feeding). Overall, our results suggest that a mixture of competition-for substrates between fermentative and denitrifying populations, and for electrons between both pathways active within a single population -, and cross feeding-between fermentative and denitrifying populations-controlled the overall rate of denitrification. Temperature was shown to have a strong selective effect, not only on the populations performing either process, but also on the nature of their ecological interactions. Future research will show whether these results can be extrapolated to the natural environment.
As the artificial defenses often required for urban and industrial development, such as seawalls, breakwaters, and bund walls, directly replace natural habitats, they may produce population ...fragmentation and a disruption of ecological connectivity, compromising the delivery of ecosystem services. Such problems have increasingly been addressed through “Working with Nature” (WwN) techniques, wherein natural features such as species and habitats are included as additional functional components within the design of built infrastructure. There now exists a convincing body of empirical evidence that WwN techniques can enhance the structural integrity of coastal works, and at the same time promote biodiversity and ecosystem services. While these benefits have often been achieved through modification of the hard surfaces of the coastal defense structures themselves, the desired ecological and engineering goals may often demand the creation of new soft substrates from sediment. Here we discuss the design considerations for creating new sediment habitats in the intertidal zone within new coastal infrastructure works. We focus on the sediment control structures required to satisfy the physiological and ecological requirements of seagrass and mangroves – two keystone intertidal species that are common candidates for restoration – and illustrate the concepts by discussing the case study of soft habitat creation within a major multi-commodity port.
Marine sediment has a great potential to generate electricity with a bioelectrochemical system (BES) like the microbial fuel cell (MFC). In this study, we investigated the potential of marine ...sediment and activated carbon (AC) to generate and store electricity. Both internal and external energy supply was validated for storage behavior. Four types of anode electrode compositions were investigated. Two types were mixtures of different volumes of AC and Dutch Eastern Scheldt marine sediment (67% AC and 33% AC) and the others two were 100% AC or 100% marine sediment based. Each composition was duplicated. Operating these BES's under MFC mode with solely marine sediment as the anode electron donor resulted in the creation of a bio-battery. The recharge time of such bio-battery does depend on the fuel content and its usage. The results show that by usage of marine sediment and AC electricity was generated and stored. The 100% AC and the 67% AC mixed with marine sediment electrode were over long term potentiostatic controlled at -100 mV vs. Ag/AgCl which resulted in a cathodic current and an applied voltage. After switching back to the MFC operation mode at 1000 Ω external load, the electrode turned into an anode and electricity was generated. This supports the hypothesis that external supply electrical energy was recovered via bi-directional electron transfer. With open cell voltage experiments these AC marine bioanodes showed internal supplied electric charge storage up to 100 mC at short self-charging times (10 and 60 s) and up to 2.4°C (3,666 C/m
anode) at long charging time (1 h). Using a hypothetical cell voltage of 0.2 V, this value represents an internal electrical storage density of 0.3 mWh/kg AC marine anode. Furthermore it was remarkable that the BES with 100% marine sediment based electrode also acted like a capacitor similar to the charge storage behaviors of the AC based bioanodes with a maximum volumetric storage of 1,373 C/m
anode. These insights give opportunities to apply such BES systems as e.g.,
bio-battery to store and use electricity for off-grid purpose in remote areas.
In situ identification of prokaryotic cells in subsurface sediments is hampered by the low cellular rRNA contents of the target organisms. Fluorescence in situ hybridization with catalyzed reporter ...deposition (CARD–FISH) has the potential to overcome this limitation, and was therefore optimized for a 40 cm deep sediment core sampled from a tidal sandy flat of the German Wadden Sea. Treatment with methanol and H
2O
2 inactivated endogenous peroxidases and effectively reduced the background signal. Percentage of DAPI stained cells detected with the probe combination EUB(I-III), targeting nearly all the
Bacteria, were comparable for CARD–FISH with a horseradish peroxidase (HRP)-labeled probe and FISH with a fluorescently monolabeled probe in the 2–3 cm depth interval (92% and 82%, respectively), but significantly higher with the HRP-labeled probe at 35–40 cm, the deepest layer sampled (63% with HRP vs. 26% with monolabeled probe). With CARD–FISH
Alphaproteobacteria and the
Desulfobulbaceae group of sulfate-reducing bacteria were detected only in the upper layers. In contrast,
Desulfosarcinales, the
Bacteroidetes group,
Planctomycetes, Betaproteobacteria, and
Gammaproteobacteria were found at all depths. Archaea were detectable with ARCH915-HRP after achromopeptidase treatment. Surprisingly, aggregates of Bacteria and Archaea were found, below 12 cm depth, that strongly resemble consortia involved in anoxic oxidation of methane that have previously been found in sediments near methane hydrate deposits. With the optimized CARD–FISH protocol, microbial populations could also be detected in deeper sediment horizons. Furthermore, the intensity of the CARD–FISH signals improved detection of rare organisms such as Archaea.
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