scholarly journals The Effect of Storage on the Radiocarbon, Stable Carbon and Nitrogen Isotopic Signatures and Concentrations of Riverine DOM

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1113-1122 ◽  
Author(s):  
P Gulliver ◽  
S Waldron ◽  
E M Scott ◽  
C L Bryant
Keyword(s):  
Stream Water ◽  
River System ◽  
Isotopic Signature ◽  
Health Impacts ◽  
Stable Carbon ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Storage Method ◽  
Baseline Values ◽  
Chemical Preservatives

Chemical preservatives (e.g. mercuric chloride) are routinely added to freshwater samples to prevent biological activity compromising the isotopic signature of dissolved organic matter (DOM) with time. However, alternative preservation methods are needed due to regulations restricting the use of preservatives with potentially adverse environmental and health impacts, rendering such additions unviable. This study investigates whether a non-chemical storage method is sufficient to maintain the radiocarbon and stable carbon and nitrogen signatures of freshwater DOM from a low order river system draining a peaty catchment. Some 50 L of stream water were collected in 1 plastic carbuoy and, within 24 hr, 1-L aliquots were transferred to acid-washed plastic bottles. Five aliquots were analyzed immediately to determine the baseline values for 14C (pMC), δ13C (VPDB‰), δ15N (AIR‰), %C (mg L–1), and %N (mg L–1). Of the remaining subsamples, 20 were frozen and a further 20 refrigerated at <4 °C. After 7, 30, 90, and 180 days, 5 frozen and 5 refrigerated aliquots were analyzed in the same manner as the baseline aliquots. Analysis of the results shows that there is no statistically significant interaction between the variables storage method or length of storage for any of the determinants. Storage method has a statistically significant effect on 14C (pMC) and [C] (mg L–1). Length of storage has a statistically significant effect on δ13C (VPDB‰), [C] (mg L–1), and [N] (mg L–1) values. Neither storage method nor length of storage appear to have a statistically significant effect on 815N (AIR‰) values.

Using natural strontium isotopic signatures as fish markers: methodology and application

2000 ◽  
Vol 57 (11) ◽  
pp. 2280-2292 ◽  
Author(s):  
Brian P Kennedy ◽  
Joel D Blum ◽  
Carol L Folt ◽  
Keith H Nislow
Keyword(s):  
River Basin ◽  
Stream Water ◽  
Spatial Scales ◽  
Fish Tissue ◽  
Isotopic Signature ◽  
Food Sources ◽  
Sr Isotopes ◽  
Connecticut River ◽  
Isotopic Signatures ◽  
Calcified Tissues

To distinguish Atlantic salmon (Salmo salar) populations in tributaries of the Connecticut River, we studied the incorporation and stability of Sr isotopes in juvenile salmon. We established the geologic basis for unique isotopic signatures in 29 salmon sites. Stream-specific Sr isotopic ratios (87Sr/86Sr) were found in calcified tissues of salmon parr within 3 months of stocking. We found little seasonal variation in the Sr signatures of stream water or fish tissue. There were no significant differences among the Sr signatures of otoliths, scales, and vertebrae. For mature salmon raised under constant conditions, 70% of the Sr isotopic signature in calcified tissues was derived from food sources. We developed a criterion for identifying moving fish based upon the isotopic variability of genetically marked fish. Applying this criterion to our streams, 7% of the fish in our study had incorporated Sr from multiple streams. Strontium isotopes distinguished all 8 regions in the White River basin and 7 of the 10 regions in the West River basin. When watersheds are considered together, Sr isotopes differentiated 11 unique signatures from 18 regions. We conclude that Sr isotopes are an effective marking tool and discuss ways in which they can be combined with other marking techniques over larger spatial scales.

How does acid treatment to remove carbonates affect the isotopic and elemental composition of soils and sediments?

2008 ◽  
Vol 5 (1) ◽  
pp. 33 ◽  
Author(s):  
Milena Fernandes ◽  
Evelyn Krull
Keyword(s):  
Organic Carbon ◽  
Isotopic Analysis ◽  
Isotopic Signature ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Isotopic Shifts ◽  
Soils And Sediments ◽  
Significant Difference ◽  
Acid Treatments

Environmental context. The ability to accurately determine the elemental and isotopic composition of soils and sediments has important implications to our quantitative understanding of global biogeochemical cycles. However, the analysis of organic carbon in solid matrices is a time-consuming task that requires the selective removal of carbonates, a treatment that has the potential to significantly alter the composition of the original sample. In the present work, we compare three of the most common acid treatments used for carbonate removal, and critically evaluate their effect on the content and isotopic signature of organic carbon and nitrogen in both soils and sediments. Abstract. In the present work, we compared the efficacy of three acid treatments in removing carbonates from soils and sediments for elemental and isotopic analysis. The methods tested were (1) refluxing with H2SO3; (2) in situ treatment with H2SO3 in silver capsules; and (3) treatment with HCl followed by rinsing with water. Refluxing with H2SO3 led to substantial losses of organic carbon and nitrogen, but comparatively small nitrogen isotopic shifts. The in situ treatment was inadequate for carbonate-rich samples (contents ≥30%) as a consequence of the formation of a mineral precipitate. Treatment with HCl led to substantial losses of nitrogen from carbonate-rich samples, and deviations in nitrogen isotopic signatures (δ15N) of up to 3.7‰. δ15N values showed no significant difference between acid-treated and untreated samples or between treatments, although variability was high and influenced by sample composition. Carbonate-poor samples showed no statistical difference in δ13C values between treatments, whereas carbonate-rich samples tended to be more 13C-depleted when treated with HCl, potentially suggesting the preferential preservation of 13C-depleted compounds (e.g. lipids or lignin).

scholarly journals The Effect of Increased Ozone Levels on the Stable Carbon and Nitrogen Isotopic Signature of Wheat Cultivars and Landraces

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 883
Author(s):  
Melissa Chang-Espino ◽  
Ignacio González-Fernández ◽  
Rocío Alonso ◽  
Jose Luis Araus ◽  
Victoria Bermejo-Bermejo
Keyword(s):  
Stomatal Conductance ◽  
Nitrogen Concentration ◽  
Isotopic Signature ◽  
Ozone Exposure ◽  
Negative Effects ◽  
Strong Negative Correlation ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Grain Nitrogen ◽  
Δ15n And Δ13c

Several studies have highlighted the negative effects of ozone (O3) on wheat development and productivity. The negative effects of O3 are mediated by changes in photosynthetic carbon and nitrogen metabolism, which are difficult and time-consuming to assess and are thus only measured sporadically throughout the plant cycle. Stable isotope measurements in grains can help integrate the effects of chronic O3 exposure over the lifespan of the plant. This particular study focuses on the extent to which the stomatal conductance and productivity of Mediterranean wheat are related to carbon and nitrogen isotopic signatures under chronic O3 exposure. An open top chamber experiment was designed to analyse the effects of the pollutant on 12 Spanish wheat genotypes, which included modern cultivars, old cultivars and landraces. Four O3 treatments were considered. Stomatal conductance (gs) measurements were carried out during anthesis, and yield and nitrogen content parameters were taken at maturity, along with the carbon (δ13C) and nitrogen (δ15N) isotopic composition measured in grains. Modern and old cultivars responded similarly to O3 and were sensitive to the pollutant regarding yield parameters and gs, while landraces were more O3-tolerant. Grain δ13C had a strong negative correlation with grain yield and stomatal conductance across genotypes and O3 conditions, and increased under higher O3 concentrations, showing its capacity to integrate O3 stress throughout the wheat cycle. Meanwhile, a higher nitrogen concentration in grains, coupled with smaller grains, led to an overall decreased grain nitrogen yield under higher O3 concentrations. This nitrogen concentration effect within the grain differed among genotypes bred at different ages, following their respective O3-sensitivity. δ15N showed a possible indirect effect of O3 on nitrogen redistribution, particularly under the highest O3 concentration. The correlations of δ15N and δ13C to the usual effects of ozone on the plant suggest their potential as indicators of chronic ozone exposure.

scholarly journals Trophic structure of the macrobenthic community of Hornsund, Spitsbergen, based on the determination of stable carbon and nitrogen isotopic signatures

Polar Biology ◽  
2014 ◽  
Vol 37 (9) ◽  
pp. 1247-1260 ◽  
Author(s):  
A. Sokołowski ◽  
A. Szczepańska ◽  
P. Richard ◽  
M. Kędra ◽  
M. Wołowicz ◽  
...  
Keyword(s):  
Trophic Structure ◽  
Macrobenthic Community ◽  
Stable Carbon ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen

Stable Carbon- and Nitrogen-Isotope Ratios of Bone Collagen Used to Study Coral-Reef and Terrestrial Components of Prehistoric Bahamian Diet

1988 ◽  
Vol 53 (2) ◽  
pp. 320-336 ◽  
Author(s):  
William F. Keegan ◽  
Michael J. DeNiro
Keyword(s):  
Coral Reef ◽  
Nitrogen Isotopes ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Isotopic Signature ◽  
Bone Collagen ◽  
Food Groups ◽  
Stable Carbon ◽  
Carbon And Nitrogen ◽  
Consumption Practices

Previous studies have demonstrated that stable carbon- and nitrogen-isotope ratios of bone collagen can be used to distinguish marine and terrestrial components of prehistoric human diet. However, when this method was first applied to prehistoric Bahamians, their bone-collagen nitrogen-isotope ratios were found to be outside the ranges observed for other coastal populations that ate substantial quantities of marine foods. This study examines in detail the distributions of stable carbon and nitrogen isotopes in Bahamian food chains. Our results indicate that the unique isotopic signature in bone collagen of prehistoric Bahamians reflects the enrichment of 13C and the depletion of 15N in seagrass and coral-reef communities relative to other oceanic environments. The results also demonstrate that bone-collagen 13C/12C ratios can be used to distinguish marine from terrestrial contributions in the prehistoric Lucayan Taino diet, and that 15N/14N ratios serve to identify the use of certain marine food groups. This approach should prove useful for the study of consumption practices in other tropical coral-reef environments and as a method for evaluating theoretically predicted optimal diets.

scholarly journals Distribution and isotopic composition of lead in bottom sediments from the hydrographic system of Belém, Pará (western margin of Guajará Bay and Carnapijó River)

2016 ◽  
Vol 46 (suppl 1) ◽  
pp. 197-208 ◽  
Author(s):  
Elma Costa Oliveira ◽  
Jean Michel Lafon ◽  
José Augusto Martins Corrêa ◽  
Jully Hellen dos Santos Carvalho
Keyword(s):  
Bottom Sediments ◽  
Suspended Matter ◽  
Human Activities ◽  
River System ◽  
Isotopic Signature ◽  
Average Concentration ◽  
Estuarine System ◽  
Western Margin ◽  
Isotopic Signatures ◽  
Anthropogenic Contribution

ABSTRACT: This study first aimed to evaluate the effect of human activities on the distribution of lead within the estuarine system of Belém, Pará. This was achieved by studying the concentration and isotopic signature of Pb in bottom sediments from the western margin of Guajará Bay and from Carnapijó River, an area removed from the influence of the city of Belém. Secondly, the contribution of suspended matter in the transportation of anthropogenic Pb in Guajará Bay was evaluated. Third, the content and background isotopic signature of Pb in the hydrographic system of Belém was determined. Isotopic signatures of sediments from the western margin of Guajará Bay confirm an anthropogenic contribution of Pb throughout the entire bay. The Pb accumulation process has become more efficient over the last 10 years, and this can be attributed to the rapid population growth of Belém city. Sediments in Carnapijó River are not affected by human activities, and the average concentration values (Pb = 19.6 ± 3.7 mg kg-1) and isotopic signatures (206Pb/207Pb = 1.196 ± 0.004) confirm the background Pb values previously proposed for the river system in the Belém region. The isotopic signatures of suspended matter on the eastern (206Pb/207Pb = 1.188) and western (206Pb/207Pb = 1.174) margins of Guajará Bay show that suspended matter is an efficient Pb transportation mechanism of domestic and industrial wastewater from Belém to the western margin of the Bay due to tidal effects at the confluence with Guamá River.

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