Application of a Multi-Metal Stable-Isotope-Enriched Bioassay to Assess Changes to Metal Bioavailability in Suspended Sediments

2021 ◽  
Author(s):  
Qiuling Wu ◽  
Tianying Zheng ◽  
Stuart L. Simpson ◽  
Qiao-Guo Tan ◽  
Rong Chen ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Suspended Sediments ◽  
Metal Bioavailability

Variability of sediment source attribution with CSSI over temporal and spatial scales – from soil texture to land-use unit and from event to seasonality.

2020 ◽  
Author(s):  
Axel Birkholz ◽  
Miriam Glendel ◽  
Richard E. Brazier ◽  
Christine Alewell
Keyword(s):  
Land Use ◽  
Stable Isotope ◽  
Soil Texture ◽  
Stable Carbon Isotopes ◽  
Spatial Scales ◽  
Suspended Sediments ◽  
High Temporal Resolution ◽  
Storm Events ◽  
Isotope Data ◽  
Temporal And Spatial

<p>Soil erosion and its accompanying on- and off-site effects represent a serious threat to the environment. Over the last years many studies have been successfully carried out using compound-specific stable carbon isotopes of fatty acids (FA) and <em>n</em>-alkanes to characterize source soils and attribute suspended sediments or sedimentary archives to the characterized sources. One worthy next aim would be the extrapolation to large catchments. Important for this is a deepened knowledge about the variability of the signals over different temporal and spatial scales, which has so far been largely neglected, with the exception of a handful of studies. With this knowledge it should be possible to understand processes better in the catchment and deliver improved interpretation and representation of empirical data, ultimately supporting suitable mitigation actions to minimize sediment transport to aquatic environments.</p><p>In our study we present compound-specific stable isotope data of long-chain FAs from two neighbouring yet distinct (in terms of soils and land use) catchments, Aller and Horner Water (17.6km<sup>2</sup> and 22km<sup>2</sup> respectively), Exmoor, South-west England. To capture the spatial heterogeneity, we analysed possible source soils from different land-uses, including moorland, heather, forest, permanent grassland, arable and ley grassland on different soil textures (clay, loam, and peat) for their FA stable isotope signature. A very interesting outcome is the apparent influence that soil texture has on the stable isotope signal of the FAs of the same land-use units. To consider temporal variability, we present isotope data for FAs of high flow events from the main outlet and 4 sub-catchments of Aller and Horner waters over the course of one year. Three of these events have been sampled at a high temporal resolution of up to 24 sediment samples per event.</p><p>Previous research by our group found a significant importance of the seasonal variability in the suspended sediment origin in the Baldegg Lake catchment, Switzerland.  In addition to such seasonal understanding, this study will allow us to understand the short-term variability in the origin of the transported sediments during storm events and to link it with high spatial resolution of the characterized source soils.</p>

Hydrologic regime and turbidity influence entrance of terrestrial material into river food webs

2015 ◽  
Vol 72 (7) ◽  
pp. 1099-1112 ◽  
Author(s):  
Katherine A. Roach ◽  
Kirk O. Winemiller
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Suspended Sediments ◽  
High Flow ◽  
Low Flow ◽  
Terrestrial Plants ◽  
Terrestrial Organic Matter ◽  
River Wave Concept ◽  
Aquatic Food ◽  
Terrestrial Material

We used stable isotope signatures of deuterium (δD) and a Bayesian stable isotope mixing model to estimate contributions of algae versus terrestrial plants to consumers during different hydrologic phases in three Texas rivers spanning a gradient of turbidity and light penetration. In the two rivers where high-flow pulses increased turbidity, assimilation of source material by consumers varied according to discharge stage. In these rivers, algae made greater contributions to macroinvertebrates and fish biomass following low-flow periods, and terrestrial plants made greater contributions following high-flow pulses. In the river with greatest loads of suspended sediments, contributions of material from terrestrial plants also increased slightly following an extended low-flow period, possibly because of increased abundance of inedible cyanobacteria. During flow pulses, lower algal biomass and production, combined with increased inputs of terrestrial organic matter from watersheds and riparian habitats, can result in greater inputs of terrestrial material into aquatic food chains. These patterns most closely match predictions of the River Wave Concept, which posits that flow is the key process determining the source of organic matter assimilated by higher consumers in rivers. Incorporation of interactions between hydrology and turbidity into river ecosystem models should facilitate more accurate predictions of food web dynamics.

Vitamin A Value of Plant Food Provitamin A - Evaluated by the Stable Isotope Technologies

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang
Keyword(s):  
Stable Isotope ◽  
Vitamin A ◽  
Provitamin A ◽  
Animal Origin ◽  
Plant Food ◽  
Plant Foods ◽  
A Value ◽  
Provitamin A Carotenoids ◽  
Β Carotene

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.

Stable isotope metabolic labeling of a mouse model reveals synaptic biomarkers for anxiety disorders

2009 ◽  
Vol 42 (05) ◽  
Author(s):  
MD Filiou ◽  
YY Zhang ◽  
B Bisle ◽  
E Frank ◽  
MS Kessler ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Mouse Model ◽  
Anxiety Disorders ◽  
Metabolic Labeling
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