气候变化领域集成服务门户(CCPortal): Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems

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DOI	10.1016/j.palaeo.2020.110076
	Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems
	Das S.; Judd E.J.; Uveges B.T.; Ivany L.C.; Junium C.K.
发表日期	2020
ISSN	0031-0182
英文摘要	Nitrogen stable isotopes (δ15N) of organic matter can aid in the reconstruction of food webs and, when applied to fossil systems, may help resolve uncertainty about trophic position and provide tests for hypotheses developed using traditional paleoecological techniques. However, in order to use those values to reconstruct trophic relationships in ecosystems and assess changes in their dynamics, an understanding of the variability of isotopic signatures within individuals and across populations is critical. The purpose of this study is to develop a methodology by which to characterize the variability in nitrogen isotope values within bivalve shells and to propose an approach for effective paleoecological and paleoceanographic studies using such data. Here we present high-resolution sclerochronological and whole-shell δ15N values of shell-associated organic matter derived from modern Spisula solidissima bivalves from three different localities. High-resolution δ15N values vary by about 4‰ over the sampled life history, which reflects the interplay of factors such as diet, physiological change over ontogeny, and background nitrogen isotopic signatures of dissolved nutrient nitrogen. A significant correlation of temporally aligned δ15N with δ18O at different lags suggests that the δ15N has a seasonal control. Furthermore, an enrichment in δ15N following peak primary productivity in the region suggests that seasonal turnover of nutrients is the primary driver of δ15N variability. Unfortunately, the fossil record does not always yield well-preserved whole shells, and working with limited shell fragments is unlikely to capture the full range of variation exhibited within a shell. To this end, we also analyzed a field-collected sub-fossil set of Spisula for whole-shell δ15N. The sample set demonstrates 5‰ of variation in δ15N among individual shells, similar to the range observed within serially-sampled shells. This likely reflects a variation that we might expect to see in a population collected from a single horizon in the fossil record. Studies involving shell-associated nitrogen isotopes in a paleo setting should analyze numerous specimens in a stratigraphic unit to capture the whole range of δ15N values within a population. Moreover, for understanding trophic relationships it is important to analyze and compare the δ15N values of multiple coeval taxa each taxa. © 2020 Elsevier B.V.
英文关键词	Nitrogen; Oxygen; Sclerochronology; Seasonal; Spisula solidissima
语种	英语
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150717
作者单位	Department of Earth and Environmental Science, Syracuse University, Syracuse, NY 13244, United States; Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
推荐引用方式 GB/T 7714	Das S.,Judd E.J.,Uveges B.T.,et al. Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems[J],2020.
APA	Das S.,Judd E.J.,Uveges B.T.,Ivany L.C.,&Junium C.K..(2020).Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems.Palaeogeography, Palaeoclimatology, Palaeoecology.
MLA	Das S.,et al."Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems".Palaeogeography, Palaeoclimatology, Palaeoecology (2020).