Topic
δ13C
About: δ13C is a research topic. Over the lifetime, 399 publications have been published within this topic receiving 22282 citations. The topic is also known as: delta-C-13 & d13C.
Papers published on a yearly basis
Papers
TL;DR: In this article, the authors developed and discussed methods for generating an isotopic baseline and evaluate the assump- tions required to estimate the trophic position of consumers using stable isotopes in multiple ecosystem studies.
Abstract: The stable isotopes of nitrogen (8'5N) and carbon (8'3C) provide powerful tools for estimating the trophic positions of and carbon flow to consumers in food webs; however, the isotopic signature of a consumer alone is not generally sufficient to infer trophic position or carbon source without an appropriate isotopic baseline. In this paper, I develop and discuss methods for generating an isotopic baseline and evaluate the assump- tions required to estimate the trophic position of consumers using stable isotopes in multiple ecosystem studies. I test the ability of two primary consumers, surface-grazing snails and filter-feeding mussels, to capture the spatial and temporal variation at the base of aquatic food webs. I find that snails reflect the isotopic signature of the base of the littoral food web, mussels reflect the isotopic signature of the pelagic food web, and together they provide a good isotopic baseline for estimating trophic position of secondary or higher trophic level consumers in lake ecosystems. Then, using data from 25 north temperate lakes, I evaluate how 815N and 8'3C of the base of aquatic food webs varies both among lakes and between the littoral and pelagic food webs within lakes. Using data from the literature, I show that the mean trophic fractionation of b'5N is 3.4%o (1 SD = 1%M) and of 8'3C is 0.4%o (1 SD = 1.3%o), and that both, even though variable, are widely applicable. A sen- sitivity analysis reveals that estimates of trophic position are very sensitive to assumptions about the trophic fractionation of '5 N, moderately sensitive to different methods for gen- erating an isotopic baseline, and not sensitive to assumptions about the trophic fractionation of 8'3C when 8'3C is used to estimate the proportion of nitrogen in a consumer derived from two sources. Finally, I compare my recommendations for generating an isotopic baseline to an alternative model proposed by M. J. Vander Zanden and J. B. Rasmussen. With an appropriate isotopic baseline and an appreciation of the underlying assumptions and model sensitivity, stable isotopes can help answer some of the most difficult questions in food web ecology.
6,330 citations
TL;DR: In this paper, the carbon and oxygen isotopic variations of primary carbonates have been used to trace the hydrological history of a basin, the evolution of individual water masses, and to correlate carbonate-bearing sediments from different parts of the basin.
Abstract: Primary carbonates are a common feature of many modern and ancient lacustrine deposits. Carbonates from hydrologically open lakes show little or no correlation between δ13C and δ18O. In short-residence-time open lakes, carbonate oxygen isotopic composition is relatively invariant and typically is closely related to the bulk isotopic composition of inflow waters to the lake. Suites of carbonates which display covarying 13C and 18O compositions precipitate from waterbodies having relatively long residence times. Where the correlation between carbon and oxygen isotopic variations is high (r⪖ 0.7 ), the carbonates have normally precipitated from a closed lake. In addition, because of large changes in water balance, the δ18O of closed-lake carbonates usually varies over a range of several %o. Therefore, the combination of degree of covariance and spread of δ18O-values can be used to discriminate between carbonates produced in hydrologically open and closed basins. Within individual basins, covariant trends may have remarkable long-term persistence despite major environmental changes, indicating considerable stability in basin hydrology. Each closed lake has a unique isotopic identity defined by its covariant trend, which is a function of the basin's geographical and climatic setting, its hydrology, and the history of the waterbody. Any major interruption or realignment of this trend reflects a fundamental change in basin hydrology. Isotopic trends based upon the carbon and oxygen isotopic composition of primary lacustrine carbonates have several applications in palaeolimnology. The oxygen isotopic composition of open-lake carbonates may, with caution, be used as a proxy indicator of the composition of regional rainfall. Covariant trends can be used to trace the hydrological history of a basin, the evolution of individual water masses, and to correlate carbonate-bearing sediments from different parts of a basin.
1,039 citations
TL;DR: In this article, a new, accurately dated 250-kyr δ18O and δ13C record determined from speleothems of the Peqiin Cave, Northern Israel is presented.
973 citations
TL;DR: In this paper, a combination of stable isotopic measurements was used to study food web structure of Georges Bank, an important northwestern Atlantic fishing ground, in order to test δ13C, δ15N and δ34S measurements as trophic-level indicators in offshore systems.
Abstract: A combination of stable isotopic measurements was used to study food web structure of Georges Bank, an important northwestern Atlantic fishing ground. Particulate, invertebrate, and fish samples were analyzed to test δ13C, δ15N, and δ34S measurements as trophic-level indicators in offshore systems. Neither sulfur nor carbon measurements proved valuable. Sulfur isotopic compositions showed little change with trophic level, and an apparent diversity of phytoplankton carbon isotopic inputs at the base of the food web complicated use of δ13C to estimate trophic position. Nitrogen isotopic distributions were, however, robust measures of trophic position and showed four broad trophic levels; unsampled large top carnivores may represent a fifth trophic level.
859 citations
TL;DR: In this article, the authors used ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios.
Abstract: Riverine particulate organic matter (POM) samples were collected bi-weekly to monthly from 40 sites in the Mississippi, Colorado, Rio Grande, and Columbia River Basins (USA) in 1996–97 and analysed for carbon and nitrogen stable isotopic compositions. These isotopic compositions and C : N ratios were used to identify four endmember sources of POM: plankton, fresh terrestrial plant material, aquatic plants, and soil organic material. This large-scale study also incorporated ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios. The ancillary data were especially useful for differentiating between seasonal changes in POM source materials and the effects of local nutrient sources and in-stream biogeochemical processes.
Average values of δ13C and C : N for all four river systems suggested that plankton is the dominant source of POM in these rivers, with higher percentages of plankton downstream of reservoirs. Although the temporal patterns in some rivers are complex, the low δ13C and C : N values in spring and summer probably indicate plankton blooms, whereas relatively elevated values in fall and winter are consistent with greater proportions of decaying aquatic vegetation and/or terrestrial material. Seasonal shifts in the δ13C of POM when the C : N remains relatively constant probably indicate changes in the relative rates of photosynthesis and respiration. Periodic inputs of plant detritus are suggested by C : N ratios >15, principally on the Columbia and Ohio Rivers. The δ15N and δ13C also reflect the importance of internal and external sources of dissolved carbon and nitrogen, and the degree of in-stream processing. Elevated δ15N values at some sites probably reflect inputs from sewage and/or animal waste. This information on the spatial and temporal variation in sources of POM in four major river systems should prove useful in future food web and nutrient transport studies. Published in 2001 by John Wiley & Sons, Ltd.
582 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 36 |
| 2024 | 64 |
| 2023 | 202 |
| 2022 | 328 |
| 2021 | 33 |
| 2020 | 26 |