نتایج جستجو برای: marine sediments

تعداد نتایج: 116648  

2010
Qingren Wang Yuncong Li

Purpose The aim of this study was to assess phosphorusretention (Pret) capacities via P adsorption (Pads) and desorption (Pdes) by sediments collected from six different sources associated with various origins, physical, and chemical characteristics. Materials and methods Sediment samples were collected in the State of Florida, the USA, from estuary, marine, wetland, canal, river, and lake, res...

2014
Nicole M. Scott Matthias Hess Nick J. Bouskill Olivia U. Mason Janet K. Jansson Jack A. Gilbert

During hydrocarbon exposure, the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxyg...

2014
Anne K. Steenbergh Paul L. E. Bodelier Caroline P. Slomp Hendrikus J. Laanbroek

Phosphorus release from sediments can exacerbate the effect of eutrophication in coastal marine ecosystems. The flux of phosphorus from marine sediments to the overlying water is highly dependent on the redox conditions at the sediment-water interface. Bacteria are key players in the biological processes that release or retain phosphorus in marine sediments. To gain more insight in the role of ...

2014
Nikki Dijkstra Peter Kraal Marcel M. M. Kuypers Bernhard Schnetger Caroline P. Slomp

Phosphorus (P) is a key nutrient for marine organisms. The only long-term removal pathway for P in the marine realm is burial in sediments. Iron (Fe) bound P accounts for a significant proportion of this burial at the global scale. In sediments underlying anoxic bottom waters, burial of Fe-bound P is generally assumed to be negligible because of reductive dissolution of Fe(III) (oxyhydr)oxides ...

2017
Kenneth Wasmund Marc Mußmann Alexander Loy

Almost the entire seafloor is covered with sediments that can be more than 10 000 m thick and represent a vast microbial ecosystem that is a major component of Earth's element and energy cycles. Notably, a significant proportion of microbial life in marine sediments can exploit energy conserved during transformations of sulfur compounds among different redox states. Sulfur cycling, which is pri...

2018
Julia Klier Olaf Dellwig Thomas Leipe Klaus Jürgens Daniel P. R. Herlemann

Salinity has a strong impact on bacterial community composition such that freshwater bacterial communities are very different from those in seawater. By contrast, little is known about the composition and diversity of the bacterial community in the sediments (bacteriobenthos) at the freshwater-seawater transition (mesohaline conditions). In this study, partial 16S-rRNA sequences were used to in...

Journal: :Applied and environmental microbiology 2013
Hongyue Dang Haixia Zhou Jinying Yang Huangmin Ge Nianzhi Jiao Xiwu Luan Chuanlun Zhang Martin G Klotz

Thaumarchaeota are abundant and active in marine waters, where they contribute to aerobic ammonia oxidation and light-independent carbon fixation. The ecological function of thaumarchaeota in marine sediments, however, has rarely been investigated, even though marine sediments constitute the majority of the Earth's surface. Thaumarchaeota in the upper layer of sediments may contribute significa...

Journal: :Science 1998
J F Quensen S A Mueller M K Jain J M Tiedje

DDT is reductively dechlorinated to DDD and dehydrochlorinated to DDE; it has been thought that DDE is not degraded further in the environment. Laboratory experiments with DDE-containing marine sediments showed that DDE is dechlorinated to DDMU in both methanogenic and sulfidogenic microcosms and that DDD is dehydrochlorinated to DDMU three orders of magnitude more slowly. Thus, DDD does not ap...

Journal: :Frontiers in microbiology 2015
Antje Gittel Johanna Donhauser Hans Røy Peter R. Girguis Bo B. Jørgensen Kasper U. Kjeldsen

Alkanes are major constituents of crude oil and are released to the marine environment by natural seepage and from anthropogenic sources. Due to their chemical inertness, their removal from anoxic marine sediments is primarily controlled by the activity of anaerobic alkane-degrading microorganisms. To facilitate comprehensive cultivation-independent surveys of the diversity and distribution of ...

2017
Atsuyuki Ohta Noboru Imai Yoshiko Tachibana Ken Ikehara Sylvain Ouillon

The compositions and transfer processes affecting coastal sea sediments from the Seto Inland Sea and the Pacific Ocean are examined through the construction of comprehensive terrestrial and marine geochemical maps for western Japan. Two-way analysis of variance (ANOVA) suggests that the elemental concentrations of marine sediments vary with particle size, and that this has a greater effect than...

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