Use of 13C and 15N Plant Label Near Natural Abundance for Monitoring Carbon and Nitrogen Partitioning

1994 ◽  
Vol 21 (2) ◽  
pp. 133 ◽  
Author(s):  
E Deleens ◽  
JB Cliquet ◽  
JL Prioul

Tracing with stable isotopes by using naturally or weakly labelled compounds has become a reliable approach in metabolic studies due to the high precision of isotope measurement by mass spectrometers fitted for natural range. Rapid and numerous isotope ratio determinations are now possible due to the recent automation of analyses. Three methods of analysis of carbon and nitrogen partitioning are reviewed from experiments on maize plants: (a) use of natural differences in organ isotope composition; (b) labelling with industrial CO2 naturally depleted in 13C; (c) double C and N labelling with CO2 and NO3 slightly enriched in 13C and 15N. For method (c) which is the most precise, the obtaining of plant matter with 13C and 15N label near their natural isotope abundance (1.1% for C and 0.36% for N) as well the principles of exposure and apparatus for feeding plants are described. Calculations of distribution parameters (relative specific allocation, RSA, and partitioning, %P) are presented and compared with their use in high-enrichment experiments. The precision of parameters and the theoretical or practical limitations of the methods are discussed. We show that the use of stable isotopes near their naturally occurring concentrations allows the tracing of new C or N input with precision, and is suitable for monitoring long-term partitioning. The significant advantages of this method with respect to precision, security and cost of handling compared with high abundance or radioactive tracing are discussed.

2010 ◽  
Vol 61 (3) ◽  
pp. 302 ◽  
Author(s):  
Matthew D. Taylor ◽  
Debashish Mazumder

Carbon and nitrogen stable isotope ratios were analysed for hatchery-reared, recaptured and wild mulloway, Argyrosomus japonicus, to investigate temporal and growth-related changes in isotopic composition for stocked fish after release, and to evaluate changes in isotopic composition in terms of ontogenetic dietary switches. δ13C and δ15N values decreased and increased, respectively, after release. The isotope composition of released fish was distinct from wild fish until 200 days after release, but after 200 days post-release fish did not differ significantly from wild fish of similar or greater sizes. Abrupt dietary transitions from crustaceans to teleost fish (>50 cm total length (TL)) were evident in a rapid δ13C and δ15N change in wild mulloway, and δ15N was significantly greater in wild fish >65 cm TL compared with wild fish <50 cm TL. Multivariate carbon and nitrogen isotopic data were suitable for separating stocked and wild fish for up to 200 days after release, but did not separate wild fish grouped according to dietary composition. Carbon and nitrogen isotopic composition closely reflected dietary transitions and rapid adaptation by stocked mulloway to wild diets, which was evident in a high tissue turnover rate of up to 0.017 day–1. Stable isotopes are a useful tool for examining the integration of released fish into stocked ecosystems and can be used to describe convergence in the diets of wild and released fish.


2011 ◽  
Vol 89 (10) ◽  
pp. 892-899 ◽  
Author(s):  
D.K. Kristensen ◽  
E. Kristensen ◽  
M.C. Forchhammer ◽  
A. Michelsen ◽  
N.M. Schmidt

The use of stable isotopes in diet analysis usually relies on the different photosynthetic pathways of C3 and C4 plants, and the resulting difference in carbon isotope signature. In the Arctic, however, plant species are exclusively C3, and carbon isotopes alone are therefore not suitable for studying arctic herbivore diets. In this study, we examined the potential of both stable carbon and nitrogen isotopes to reconstruct the diet of an arctic herbivore, here the muskox ( Ovibos moschatus (Zimmermann, 1780)), in northeast Greenland. The isotope composition of plant communities and functional plant groups was compared with those of muskox faeces and shed wool, as this is a noninvasive approach to obtain dietary information on different temporal scales. Plants with different root mycorrhizal status were found to have different δ15N values, whereas differences in δ13C, as expected, were less distinct. As a result, our examination mainly relied on stable nitrogen isotopes. The interpretation of stable isotopes from faeces was difficult because of the large uncertainty in diet–faeces fractionation, whereas isotope signatures from wool suggested that the muskox summer diet consists of around 80% graminoids and up to 20% willows. In conclusion, the diet composition of an arctic herbivore can indeed be inferred from stable isotopes in arctic areas, despite the lack of C4 plants.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Risto Vesala ◽  
Laura Arppe ◽  
Jouko Rikkinen

Abstract Fungus-growing termites of the genus Macrotermes cultivate symbiotic fungi (Termitomyces) in their underground nest chambers to degrade plant matter collected from the environment. Although the general mechanism of food processing is relatively well-known, it has remained unclear whether the termites get their nutrition primarily from the fungal mycelium or from plant tissues partly decomposed by the fungus. To elucidate the flows of carbon and nitrogen in the complicated food-chains within the nests of fungus-growing termites, we determined the stable isotope signatures of different materials sampled from four Macrotermes colonies in southern Kenya. Stable isotopes of carbon revealed that the termite queen and the young larvae are largely sustained by the fungal mycelium. Conversely, all adult workers and soldiers seem to feed predominantly on plant and/or fungus comb material, demonstrating that the fungal symbiont plays a different nutritional role for different termite castes. Nitrogen stable isotopes indicated additional differences between castes and revealed intriguing patterns in colony nitrogen cycling. Nitrogen is effectively recycled within the colonies, but also a presently unspecified nitrogen source, most likely symbiotic nitrogen-fixing bacteria, seems to contribute to nitrogen supply. Our results indicate that the gut microbiota of the termite queen might be largely responsible for the proposed nitrogen fixation.


2020 ◽  
Vol 54 (8) ◽  
pp. 819-824
Author(s):  
P. Yu. Voronin ◽  
V. A. Mukhin ◽  
T. A. Velivetskaya ◽  
A. V. Ignatiev ◽  
Vl. V. Kuznetsov

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e82205 ◽  
Author(s):  
Tatiana Lemos Bisi ◽  
Paulo Renato Dorneles ◽  
José Lailson-Brito ◽  
Gilles Lepoint ◽  
Alexandre de Freitas Azevedo ◽  
...  

2005 ◽  
Vol 19 (14) ◽  
pp. 1937-1942 ◽  
Author(s):  
Bojlul Bahar ◽  
Frank J. Monahan ◽  
Aidan P. Moloney ◽  
Padraig O'Kiely ◽  
Charlie M. Scrimgeour ◽  
...  

2006 ◽  
Vol 86 (6) ◽  
pp. 1443-1447 ◽  
Author(s):  
D. Fourgon ◽  
G. Lepoint ◽  
I. Eeckhaut

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiuroids, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess the potential benefit obtained by the symbiotic Ophiomastix venosa juveniles. A tracer experiment was also carried out to clarify the contribution of algae to the nitrogen uptake amongst the tested ophiuroids. Our results suggest that Ophiocoma scolopendrina adults occupy a higher position in the food web than Ophiomastix venosa and mainly feed on neuston. In contrast, O. venosa adults feed on the alga Sargassum densifolium and on organic matter associated with sediment. Free juveniles and symbiotic juveniles of O. venosa have intermediate δ13C values between both adult species. The high proportion of 13C in the symbiotic juveniles compared to the one in their conspecific adults indicates that their diet slightly differs from the latter and is closer to that of Ophiocoma scolopendrina. This raises the hypothesis that symbiotic juveniles steal neuston from their associated host, O. scolopendrina.


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