Nitrogen stable isotope ratios of lake macrophytes in relation to growth form and nutrient-limitation

King, Lydia; Maberly, Stephen C.; Ville, M.M. De; Kitschke, Michaela; Gibson, C. E.; Jones, Roger

doi:10.1127/1863-9135/2009/0175-0307

Cited by 10 publications

(9 citation statements)

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“…Hawassa, Ziway and Koka showed a wide variation in δ 13 C, δ 34 S and δ 15 N values. The δ 15 N values of macrophyte taxa were variable with a range of about 12‰, which, however, is in accordance with several studies (King et al, 2009;and cited therein). Similarly, the δ 13 C of macrophytes were much more variable reaching differences up to 20‰ (Table 1), which appears large as freshwater macrophytes belong to the C3 group of plants (Beer & Wetzel, 1982).…”

Section: Stable Isotope Compositionsupporting

confidence: 92%

“…The nitrogen nutrition of the primary producers in Lake Koka could be

{NH}_{4}^{+}

(162.4 ± 49.4 μg/L, ± SD ), the primary form of nitrogen in the lake, leading to high δ 15 N values in successive trophic levels. In contrary, in phosphorus‐limited system, where N is in excess of demand, plant uptake of N exhibits fractionation against the heavier 15 N isotope leading to lower plant δ 15 N values (King et al., ; Montoya, ), a possible cause for Lake Hawassa lower delta values (Table ; Lake Hawassa soluble reactive phosphorus, 6.00 ± 1.23 μg/L, was low compared to Lake Koka 34.36 ± 5.53 μg/L, ± SD ). Nevertheless, the studied rift valley lakes have high δ 15 N values compared to other lakes (Rao et al., ).…”

Section: Discussionmentioning

confidence: 99%

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Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Fetahi

Rothhaupt

Peeters

2017

Ecology of Freshwater Fish

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Comprehensive analysis of food webs requires identifying dietary sources that support the production of all major organisms within the food web/food chain. Here, we use stable isotope ratios (δ13C, δ34S and δ15N) to assess the relative contribution of different basal carbon sources to the diet of Nile tilapia (Oreochromis niloticus L.) in three tropical lakes Hawassa (also Awasa in literature), Ziway and Koka (Ethiopia). Computations were carried out with Stable Isotope Analysis in R (SIAR) model to quantify the dietary proportion of each prey for the tilapia fish. Basal food sources were distinguishable based on their δ13C, δ34S and δ15N values. In Lake Ziway, macrophytes (64%) were the dominant assimilated diet of tilapia while particulate organic matter (POM) and zooplankton contributed only 20% and 16%, respectively. In parallel, Nile tilapia in Lake Hawassa assimilated macrophytes (35%), POM (33%) and zooplankton (32%) at comparatively equal proportion. The dietary sources of the fish in Lake Koka were POM (49%) and zooplankton (51%). In contrast with earlier studies based on gut content analysis, the present results reveal that macrophytes contributed more and phytoplankton less than previously reported especially in macrophyte‐dominated lakes Ziway and Hawassa. The ecological condition of the lakes might have been predominantly accountable for the diet change of the tilapia. As dietary data are prerequisite for food web/food chain analysis and aquaculture industry, re‐evaluating the diet of aquatic organisms appear relevant.

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Section: Stable Isotope Compositionsupporting

confidence: 92%

“…The nitrogen nutrition of the primary producers in Lake Koka could be

{NH}_{4}^{+}

Section: Discussionmentioning

confidence: 99%

Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Fetahi

Rothhaupt

Peeters

2017

Ecology of Freshwater Fish

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“…Species that exclusively use nitrogen from the water column (e.g., rootless vascular plants such as Utricularia spp. and mosses) show lower average δ 15 N values than species that use nitrogen from the sediment pore water (King et al., ). No differences were seen among functional groups in our dataset due to a lack of species primarily using nitrogen from the water column, since most species also obtained nitrogen from the sediment pore water, and probably to a large and uncoupled δ 15 N variability of DIN in water and pore water.…”

Section: Discussionmentioning

confidence: 99%

“…One reason could be that most samples were from rooted aquatic plants, which mainly used DIN from the sediment pore water (Barko et al, 1991), whose concentration did not necessarily correlate with water column DIN (Gacia, Chappuis, Lumbreras, Riera, & Ballesteros, 2009). The concentration of other nutrients and their stoichiometry can also be important factors (King et al, 2009;Pastor et al, 2013). For example, plants thriving in phosphorus limited ecosystems tend to have a lower demand relative to the nitrogen source and discrimination is likely to occur, which results in low plant d 15 N (King et al, 2009).…”

Section: Variation Of D 15 N In Aquatic Plants From Stagnant Water mentioning

confidence: 99%

Decrypting stable‐isotope (δ¹³C and δ¹⁵N) variability in aquatic plants

et al. 2017

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Variability in C and N stable isotopes has been acknowledged to hinder their use as tracers of food sources in the study of trophic interactions in ecosystems. This is particularly so whenever benthic primary production is substantial (variability in δ13C) and the ecosystem under study is affected by human impacts (variability in δ15N) in aquatic ecosystems. In this study, we aim to better understand the large and often unexplained variability in the natural abundance of δ13C and δ15N signatures of aquatic plants by analyzing the isotopic composition of plants from 81 lentic systems from NE Spain in relation to extrinsic (alkalinity, pH, nutrient concentrations, water body typology and basin land use) and intrinsic (functional group, carbon assimilation metabolism, elemental composition) predictors. We have encountered significant plasticity in isotopic signatures of aquatic plants associated with the variation in local conditions at the regional scale. The δ13C signature varied from −43.1‰ to −7.5‰ (35.7‰ range) and drivers were both intrinsic and extrinsic. The functional group was the most important factor as it is influenced by different carbon sources. Aquatic plants with leaves in contact with the atmosphere (helophytes, free floating and floating attached; −34.8‰ to −14.6‰) responded in a similar way as terrestrial plants. This contrasted with the enriched mean values of rooted submerged plants (−16.7‰ to −10.5‰) that were more enriched than the described terrestrial C3 range (−34‰ to −22‰) and completely overlapped the terrestrial C4 range (−20‰ to −8‰). Concentration of DIC and pH also emerged as important extrinsic factors driving δ13C variability. The δ15N signature ranged from −5.2‰ to 20.1‰ (25.2‰ range) and the variability was mostly associated with extrinsic factors such as water body type and basin land use, as they influence both the δ15N signature and concentration of the dissolved inorganic nitrogen in the aquatic ecosystems. Only one multifactorial model including the functional group (with the largest contribution), DIC and pH was selected as the best model explaining the variability in δ13C signatures of aquatic plants. The final model had a relatively large explained deviance and was consistent with the previous unifactorial results. Two different models were selected as the best models explaining variability in δ15N signatures of aquatic plants. The models included the geomorphological type of water body as the variable with the largest contribution, and the percentage of either natural or agricultural coverage in the basin. These results are summarized in a conceptual model showing the predictors and their range and direction of variation. This study shows that extrinsic factors are of greater importance in influencing the stable‐isotope signatures of aquatic plants compared to terrestrial plants, because of varied sources and an often limited isotopic discrimination.

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“…in ULC and LLC which leads to the assumption that the δ 15 N values are related to differences in nutrient loads. [35] Chara spp. can utilize nitrogen from sediment or from the water column.…”

mentioning

confidence: 99%

Depth‐specific and spatiotemporal variation of δ¹³C and δ¹⁵N in Charophytes of Lake Constance: implications for food web studies

Matuszak

Voigt

Storch

et al. 2011

Rapid Comm Mass Spectrometry

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Macrophytes are at the base of many lake food webs providing essential food resources for animals at higher trophic level, such as invertebrates, fish and waterbirds. However, data regarding the spatiotemporal variation in isotopic composition of macrophytes are generally missing. We measured the carbon and nitrogen stable isotope ratios of Charophytes at Lake Constance, where they constitute a major food source for waterbirds. Our data reveal seasonal and site-specific differences as well as depth-specific variations in isotopic carbon values within the littoral zone. Charophytes were enriched in (13)C at sites of higher productivity: the δ(13)C values were high in summer, at shallow and at relatively nutrient-rich sites, and comparatively low in winter, and in deeper and nutrient-poorer sites. In contrast, no temporal or spatial trend was found to explain the variability in the isotopic nitrogen values. These results imply that the seasonal timing of food intake (relative to turnover rates of consumers tissue) and the potential depth of foraging need to be taken into account when calculating the relative contribution of energy sources to diets of consumers such as waterbirds.

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Nitrogen stable isotope ratios of lake macrophytes in relation to growth form and nutrient-limitation

Cited by 10 publications

References 0 publications

Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Decrypting stable‐isotope (δ¹³C and δ¹⁵N) variability in aquatic plants

Depth‐specific and spatiotemporal variation of δ¹³C and δ¹⁵N in Charophytes of Lake Constance: implications for food web studies

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Nitrogen stable isotope ratios of lake macrophytes in relation to growth form and nutrient-limitation

Cited by 10 publications

References 0 publications

Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Dietary map of Nile tilapia using stable isotopes in three tropical lakes, Ethiopia

Decrypting stable‐isotope (δ13C and δ15N) variability in aquatic plants

Depth‐specific and spatiotemporal variation of δ13C and δ15N in Charophytes of Lake Constance: implications for food web studies

Contact Info

Product

Resources

About

Decrypting stable‐isotope (δ¹³C and δ¹⁵N) variability in aquatic plants

Depth‐specific and spatiotemporal variation of δ¹³C and δ¹⁵N in Charophytes of Lake Constance: implications for food web studies