Trophodynamics and health risk assessment of toxic trace metals in the food web of a plateau freshwater lake

Trophic Transfer of Halogenated Organic Pollutants in a Wetland Food Web: Insights from Compound-Specific Nitrogen Isotope of Amino Acids and Food Source Analysis

“…These phenomena demonstrate the accuracy of the TP simmr model in quantifying the TP of primary consumers. Furthermore, the significant negative correlation observed between TP AAs and ΔTP (simmr‑AAs) (ΔTP (simmr‑AAs) = TP simmr – TP AAs ) was consistent with past research (Figure S1­(b)), − suggesting that organisms in higher TPs are less affected by β Glu/Phe variation . However, the TP simmr of the top predators (kingfishers, 2.80; amphibians (frogs), 2.06) was not significantly higher than that of their diet (paradisefish, 2.71; insects, 1.81) (Figure (a)).…”

“…In addition, the TP AAs (0.86) of the attached algae in this study were similar to those reported for Sargassum filicinum (TP AAs = 0.9), another nonvascular plant, in a past study . The TP AAs (1.04) of the emerged plants, which were also vascular plants, were similar to those of the emerged plants (TP AAs = 0.94) reported by Yan et al These phenomena demonstrate the accuracy of the TP AAs model for quantifying the TP of primary producers. Furthermore, a significant positive correlation between TP bulk and ΔTP (bulk‑AAs) (ΔTP (bulk‑AAs) = TP bulk – TP AAs ) was observed, which has been reported in past studies, − , supporting that δ 15 N baseline variation may have a greater impact on TP bulk quantification of organisms at higher TPs (Figure S1­(a)).…”

“…The TP AAs of kingfishers (2.11) were significantly lower than those of their prey (paradisefishes, 3.50) (Tables S2 and S4), which may be related to the fact that kingfishers take in some terrestrial food sources (moths) indirectly through the process of food web delivery, making it inappropriate to use β Glu/Phe (3.4‰) to estimate the TP AAs of kingfishers. Additionally, the maximum difference of Δδ 15 N Phe (Δδ 15 N Phe = δ 15 N Phe (MAX) – δ 15 N Phe (MIN)) between all consumers in this study was 9.62‰, which is comparable to the results of past studies in freshwater ecosystems of Δδ 15 N Phe = 8.4‰ and Δδ 15 N Phe = 11.67‰ . However, if the Δδ 15 N Phe of less than 2.00‰ for consumers feeding on the same type of primary producer is used as a criterion for the same food chain, , then the results indicated that multiple food chains existed in the wetland food web.…”

“…The TP AAs (1.04) of the emerged plants, which were also vascular plants, were similar to those of the emerged plants (TP AAs = 0.94) reported by Yan et al These phenomena demonstrate the accuracy of the TP AAs model for quantifying the TP of primary producers. Furthermore, a significant positive correlation between TP bulk and ΔTP (bulk‑AAs) (ΔTP (bulk‑AAs) = TP bulk – TP AAs ) was observed, which has been reported in past studies, − , supporting that δ 15 N baseline variation may have a greater impact on TP bulk quantification of organisms at higher TPs (Figure S1­(a)). The TP AAs of kingfishers (2.11) were significantly lower than those of their prey (paradisefishes, 3.50) (Tables S2 and S4), which may be related to the fact that kingfishers take in some terrestrial food sources (moths) indirectly through the process of food web delivery, making it inappropriate to use β Glu/Phe (3.4‰) to estimate the TP AAs of kingfishers.…”

“…Quantification of the relative contribution of primary producers within consumers based on stable isotope analysis and the relative contribution of food sources in each consumer species was quantized by the quantitative fatty acid signature analysis (the QFASA model). We ran the Bayesian mixing model of SIMMR (the simmr model) (Package SIMMR version 0.4.5) with four isotope indexes of δ 13 C, δ 15 N, δ 15 N Phe , and δ 15 N Glu − and ran the QFASA model (Package qfasar version 1.2.1) with 14 fatty acids (more than 1% of all samples) in RStudio Version 1.3.1093. The parameter settings of the model and the method for trophic position correction are described in Text S1.…”