scholarly journals Sediment as a Potential Pool for Lipophilic Marine Phycotoxins with the Case Study of Daya Bay of China

Marine Drugs ◽  
2019 ◽  
Vol 17 (11) ◽  
pp. 623 ◽  
Author(s):  
Yang Liu ◽  
Peng Zhang ◽  
Sen Du ◽  
Zhuoru Lin ◽  
Yanyan Zhou ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Environmental Pollutants ◽  
Sediment Surface ◽  
Daya Bay ◽  
Toxic Substances ◽  
Sediment Samples ◽  
Tropical Area ◽  
Different Seasons ◽  
Sampling Times

Marine sediments can reserve many environmental pollutants. Lipophilic marine phycotoxins (LMPs) are natural toxic substances widespread in the marine environment; however, evidence of their existence in sediment is scarce. In the present study, in order to explore the occurrence and distribution characteristics of LMPs in sediment, surface sediment samples collected from a tropical area of Daya Bay (DYB) at different seasons, were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS). According to the results, up to six toxin compounds were detected in sediment samples from DYB, OA and DTX1 had the highest levels, followed by PTX2, homo-YTX, AZA2, and GYM. Although AZA2 and GYM were found in most of the sediment, OA, DTX1, homo-YTX, and PTX2 were the predominant toxin compounds, and PTX2 was the most ubiquitous toxin in sediment. The spatial distribution of LMP components in the sediment fluctuated with sampling times, partially according to the physical–chemical parameters of the sediment. There are likely several sources for LMPs existing in surface sediments, but it is difficult to determine contributions of a specific toxin-source in the sediment. Therefore, marine sediments may be a toxin reservoir for LMPs accumulation in benthic organisms via food chains.

scholarly journals Facies Heterogeneity and Lobe Facies Multiscale Analysis of Deep-Marine Sand-Shale Complexity in the West Crocker Formation of Sabah Basin, NW Borneo

2021 ◽  
Vol 11 (12) ◽  
pp. 5513
Author(s):  
Muhammad Jamil ◽  
Numair Ahmed Siddiqui ◽  
Abdul Hadi Bin Abd Rahman ◽  
Noor Azahar Ibrahim ◽  
Mohd Suhaili Bin Ismail ◽  
...  
Keyword(s):  
Conceptual Model ◽  
Marine Sediments ◽  
Multiscale Analysis ◽  
The West ◽  
Submarine Fans ◽  
Marine Sand ◽  
Facies Associations ◽  
Vertical Thickness ◽  
Mudstone Facies

Deepwater lobes constitute a significant volume of submarine fans and are primarily believed to exhibit a simple sheet geometry. However, recent studies interpret the geometries of these deep-marine lobes as distinct with respect to the complexity of the facies and their distribution. Hence, a conceptual model of deep-marine sediments is essential to discuss the deep-marine sediments associated with the fan and lobe architecture. The present study highlights the facies heterogeneity and distribution of various lobe elements at a multiscale level by considering a case study of the West Crocker Formation of Sabah in northwest Borneo. The formation was logged on a bed-to-bed scale from recently well-exposed sections, with a total vertical thickness of more than 300 m. The lithological characteristics, bed geometry, sedimentary textures and structures of individual beds were used to categorize the rock units into nine sedimentary lithofacies: five sandstone lithofacies (S1–S5), one hybrid bed facies (H), two siltstone facies (Si1 and Si2) and one shale or mudstone facies (M). These facies were grouped into four facies associations (FA1–FA4), which were interpreted as lobe axis (FA1), lobe off-axis (FA2), lobe fringe (FA3) and distal fringe to interlobe (FA4) facies associations. This study is applicable for the distribution of lobes and their subseismic, multiscale complexities to characterize the potential of hydrocarbon intervals in deep-marine sand-shale system around the globe.

scholarly journals Impact of Bacterial NO3− Transport on Sediment Biogeochemistry

2005 ◽  
Vol 71 (11) ◽  
pp. 7575-7577 ◽  
Author(s):  
Mikio Sayama ◽  
Nils Risgaard-Petersen ◽  
Lars Peter Nielsen ◽  
Henrik Fossing ◽  
Peter Bondo Christensen
Keyword(s):  
Marine Sediments ◽  
Aerobic Oxidation ◽  
Sediment Surface ◽  
Sediment Biogeochemistry ◽  
Suboxic Zone

ABSTRACT Experiments demonstrated that Beggiatoa could induce a H2S-depleted suboxic zone of more than 10 mm in marine sediments and cause a divergence in sediment NO3 − reduction from denitrification to dissimilatory NO3 − reduction to ammonium. pH, O2, and H2S profiles indicated that the bacteria oxidized H2S with NO3 − and transported S0 to the sediment surface for aerobic oxidation.

scholarly journals The Southern Ocean Radiolarian (SO-RAD) dataset: a new compilation of modern radiolarian census data

2021 ◽  
Vol 13 (11) ◽  
pp. 5441-5453
Author(s):  
Kelly-Anne Lawler ◽  
Giuseppe Cortese ◽  
Matthieu Civel-Mazens ◽  
Helen Bostock ◽  
Xavier Crosta ◽  
...  
Keyword(s):  
Species Diversity ◽  
Data Collection ◽  
Southern Ocean ◽  
Marine Sediments ◽  
Surface Sediment ◽  
Census Data ◽  
Reference Dataset ◽  
Past Climate ◽  
Sediment Samples ◽  
Comprehensive Reference

Abstract. Radiolarians (holoplanktonic protozoa) preserved in marine sediments are commonly used as palaeoclimate proxies for reconstructing past Southern Ocean environments. Generating reconstructions of past climate based on microfossil abundances, such as radiolarians, requires a spatially and environmentally comprehensive reference dataset of modern census counts. The Southern Ocean Radiolarian (SO-RAD) dataset includes census counts for 238 radiolarian taxa from 228 surface sediment samples located in the Atlantic, Indian, and southwest Pacific sectors of the Southern Ocean. This compilation is the largest radiolarian census dataset derived from surface sediment samples in the Southern Ocean. The SO-RAD dataset may be used as a reference dataset for palaeoceanographic reconstructions, or for studying modern radiolarian biogeography and species diversity. As well as describing the data collection and collation, we include recommendations and guidelines for cleaning and subsetting the data for users unfamiliar with the procedures typically used by the radiolarian community. The SO-RAD dataset is available to download from https://doi.org/10.1594/PANGAEA.929903 (Lawler et al., 2021).

Prospects and pitfalls of using feathers as a temporal archive of stress events and environmental pollutants: a review and case study

2018 ◽  
Vol 159 (3) ◽  
pp. 771-783 ◽  
Author(s):  
Kathrin Ganz ◽  
David Jenny ◽  
Thomas Kraemer ◽  
Lukas Jenni ◽  
Susanne Jenni-Eiermann
Keyword(s):  
Environmental Pollutants

Potential Oxygen Consumption and Community Composition of Sediment Bacteria in a Seasonally Hypoxic Enclosed Bay

2021 ◽  
Author(s):  
Fumiaki Mori ◽  
Yu Umezawa ◽  
Ruji Kondo ◽  
Gregory N. Nishihara ◽  
Minoru Wada
Keyword(s):  
Oxygen Consumption ◽  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Sediment Surface ◽  
Tetrazolium Chloride ◽  
Sediment Samples ◽  
Potential Oxygen

Abstract The dynamics of potential oxygen consumption at the sediment surface in a seasonally hypoxic bay were monitored monthly by applying a tetrazolium dye (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride [INT]) reduction assay to intact sediment core samples for two consecutive years (2012–2013). Based on the empirically determined correlation between INT reduction (INT-formazan formation) and actual oxygen consumption of sediment samples, we inferred the relative contribution of biological and non-biological (chemical) processes to the potential whole oxygen consumption in the collected sediment samples. It was demonstrated that both potentials consistently increased and reached a maximum during summer hypoxia in each year. For samples collected in 2012, amplicon sequence variants (ASVs) of the bacterial 16S rRNA genes derived from the sediment surface revealed a notable shift in the bacterial community composition before and after the INT assay incubation. Within the bacterial community that was predominated by the ASVs closely related to Woeseia (Woeseiaceae, Gammaproteobacteria), the relative abundance of ASVs affiliated with Arcobacter (Arcobacteraceae, Campylobacteria), a putative sulfur-oxidizing bacterial genus, increased markedly in the summer samples. These findings have implications not only for the group of bacteria that are consistently responsible for the consumption of dissolved oxygen (DO) year-round in the sediment, but also for those that might grow rapidly in response to episodic DO supply on the sediment surface during midst of seasonal hypoxia.

Developing Biological Endpoints for Defining Virtual Elimination: a Case Study for PCDDs and PCDFs

1999 ◽  
Vol 34 (3) ◽  
pp. 391-422
Author(s):  
M.R. Servos ◽  
J.L. Parrott ◽  
J.P. Sherry ◽  
S.B. Brown
Keyword(s):  
Traditional Approach ◽  
Biological Effects ◽  
Detection Limits ◽  
Analytical Techniques ◽  
Management Policy ◽  
Toxic Substances ◽  
Biological Responses ◽  
Considerable Debate ◽  
Mixed Function Oxygenase

Abstract Defining virtual elimination has created considerable debate. A traditional approach has been to use chemically defined detection limits or levels of quantification that are determined using the best currently available methodologies. Ever increasing improvements in analytical techniques could lead to corresponding pressure to reduce the targets for virtual elimination. The current Toxic Substances Management Policy in Canada recognizes this and clearly states that it is not the intent of virtual elimination to have a moving target or to chase down the last molecule of the chemical of concern. Although it may be possible to reduce a chemical to less than some extremely sensitive detection limit, the chemical may or may not exert biological effects at that level. The chemically defined detection limits may be much lower than background levels in the environment, making it an unrealistic target. Conversely biological responses may result from trace levels of a compound that are not detectable in effluents or selected compartments of the environment (i.e., water) using current chemical techniques. Alternatively, an effect-based approach can establish biologically meaningful endpoints to defining virtual elimination. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are used in this study as an example to evaluate the advantages and limitations of several possible approaches of using biological endpoints to determine the presence of these compounds in the environment and ultimately define virtual elimination. A review of the biological responses to PCDD/PCDFs is included to demonstrate the importance of selecting appropriate biological endpoints. Mixed function oxygenase (MFO) induction, although not recommended at this point, is used as an example of a possible sensitive endpoint that could potentially be used to detect exposure of biota to these chemicals. Three different approaches are explored: (1) measuring MFO induction in a sentinel species in the environment; (2) testing environmental extracts for MFO induction in cell lines; and (3) using biological endpoints (MFO induction) to define chemical targets for virtual elimination. While the use of biological end-points is the most desirable approach to defining virtual elimination, there are significant knowledge gaps which limit our selection and application of this approach.

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