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

2011 ◽  
Vol 25 (14) ◽  
pp. 2089-2094 ◽  
Author(s):  
Anja Matuszak ◽  
Christian C. Voigt ◽  
Ilse Storch ◽  
Hans-Günther Bauer ◽  
Petra Quillfeldt
Keyword(s):  
Food Web ◽  
Spatiotemporal Variation ◽  
Lake Constance ◽  
Δ13c And Δ15n ◽  
Web Studies

Biokinetics and discrimination factors for δ13C and δ15N in the omnivorous freshwater crustacean, Cherax destructor

2012 ◽  
Vol 63 (10) ◽  
pp. 878 ◽  
Author(s):  
J. Veliscek Carolan ◽  
D. Mazumder ◽  
C. Dimovski ◽  
R. Diocares ◽  
J. Twining
Keyword(s):  
Food Web ◽  
Freshwater Ecosystems ◽  
Discrimination Factor ◽  
Δ13c And Δ15n ◽  
Web Studies ◽  
Cherax Destructor ◽  
Tissue Discrimination ◽  
Order Of Magnitude ◽  
Freshwater Crustacean ◽  
Discrimination Factors

Knowledge and understanding of biokinetics and discrimination factors for carbon-13 (δ13C) and nitrogen-15 (δ15N) are important when using stable isotopes for food-web studies. Therefore, we performed a controlled laboratory diet-switch experiment to examine diet–tissue and diet–faeces discrimination factors as well as the biokinetics of stable-isotope assimilation in the omnivorous freshwater crustacean, Cherax destructor. The biokinetics of δ13C could not be established; however, the δ15N value of C. destructor tissue reached equilibrium after 80 ± 35 days, with an estimated biological half-time for 15N of 19 ± 5 days. Metabolic activity contributed to the turnover of 15N by nearly an order of magnitude more than growth. The diet–tissue discrimination factors at the end of the exposure were estimated as –1.1 ± 0.5‰ for δ13C and +1.5 ± 1.0‰ for δ15N, indicating that a δ15N diet–tissue discrimination factor different from the typically assumed +3.4‰ may be required for freshwater macroinvertebrates such as C. destructor. The diet–faeces discrimination factor for δ15N after 120 days was estimated as +0.9 ± 0.5‰. The present study provides an increased understanding of the biokinetics and discrimination factors for a keystone freshwater macroinvertebrate that will be valuable for future food-web studies in freshwater ecosystems.

scholarly journals The influence of fish cage culture on δ13C and δ15N of filter-feeding Bivalvia (Mollusca)

2013 ◽  
Vol 73 (4) ◽  
pp. 743-746
Author(s):  
E. Benedito ◽  
L. Figueroa ◽  
A.M Takeda ◽  
GI. Manetta
Keyword(s):  
Food Web ◽  
Native Species ◽  
Corbicula Fluminea ◽  
Cage Culture ◽  
Aquatic Food Web ◽  
Δ13c And Δ15n ◽  
Value Analysis ◽  
Fine Powders ◽  
Before And After ◽  
Aquatic Food

The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C) and nitrogen (δ15N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.

scholarly journals The use of DNA barcodes in food web construction—terrestrial and aquatic ecologists unite!

Genome ◽  
2016 ◽  
Vol 59 (9) ◽  
pp. 603-628 ◽  
Author(s):  
Tomas Roslin ◽  
Sanna Majaneva
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Taxonomic Resolution ◽  
Dna Barcodes ◽  
Food Web Structure ◽  
Web Studies ◽  
Web Structure ◽  
Asking Questions ◽  
Web Construction ◽  
Interaction Webs

By depicting who eats whom, food webs offer descriptions of how groupings in nature (typically species or populations) are linked to each other. For asking questions on how food webs are built and work, we need descriptions of food webs at different levels of resolution. DNA techniques provide opportunities for highly resolved webs. In this paper, we offer an exposé of how DNA-based techniques, and DNA barcodes in particular, have recently been used to construct food web structure in both terrestrial and aquatic systems. We highlight how such techniques can be applied to simultaneously improve the taxonomic resolution of the nodes of the web (i.e., the species), and the links between them (i.e., who eats whom). We end by proposing how DNA barcodes and DNA information may allow new approaches to the construction of larger interaction webs, and overcome some hurdles to achieving adequate sample size. Most importantly, we propose that the joint adoption and development of these techniques may serve to unite approaches to food web studies in aquatic and terrestrial systems—revealing the extent to which food webs in these environments are structured similarly to or differently from each other, and how they are linked by dispersal.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

Tracing sewage-derived organic matter into a shallow groundwater food web using stable isotope and fluorescence signatures

2011 ◽  
Vol 62 (2) ◽  
pp. 119 ◽  
Author(s):  
Adam Hartland ◽  
Graham D. Fenwick ◽  
Sarah J. Bury
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Food Web ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Shallow Groundwater ◽  
Organic Pollution ◽  
Food Sources ◽  
Δ13c And Δ15n

Little is known about the feeding modes of groundwater invertebrates (stygofauna). Incorporation of sewage-derived organic matter (OM) into a shallow groundwater food web was studied using fluorescence and stable isotope signatures (δ13C and δ15N). Organic pollution was hypothesised to limit sensitive species’ abundances along the contamination gradient and isotope signatures of stygofauna consuming sewage-derived OM were expected to be enriched in δ15N. Stygofauna communities near a sewage treatment plant in New Zealand were sampled over 4 months and microbial biofilms were incubated in situ on native gravel for 1 month. As anticipated, OM stress-subsidy gradients altered stygofauna composition: the biomass of oligochaetes and Paraleptamphopus amphipods increased in OM-enriched groundwater (higher dissolved organic carbon (DOC) and tryptophan-like fluorescence), whereas other, probably less-tolerant taxa (e.g. ostracods, Dytiscidae) were absent. Isotopic signatures for stygofauna from polluted groundwater were consistent with assimilation of isotopically enriched sewage-N (δ15N values of 7–16‰), but highly depleted in δ13C relative to sewage. Negative 13C discriminations probably occur in Paraleptamphopus amphipods, and may also occur in oligochaetes and Dytiscidae, a finding with implications for the application of δ13C for determining food sources in groundwaters. Organic pollution of groundwaters may have serious repercussions for stygofauna community structure with potentially irreversible consequences.

Use of carbon-13 and carbon-14 natural abundances for stream food web studies

2013 ◽  
Vol 28 (5) ◽  
pp. 759-769 ◽  
Author(s):  
Naoto F. Ishikawa ◽  
Fujio Hyodo ◽  
Ichiro Tayasu
Keyword(s):  
Food Web ◽  
Web Studies ◽  
Carbon 14

An efficient method for collecting large samples of live copepods free from detritus

2010 ◽  
Vol 61 (5) ◽  
pp. 621 ◽  
Author(s):  
Carl J. Svensson ◽  
Glenn A. Hyndes ◽  
Paul S. Lavery
Keyword(s):  
Fatty Acids ◽  
Food Web ◽  
Trophic Levels ◽  
Aquatic Systems ◽  
New Method ◽  
Aquatic Environments ◽  
Web Studies ◽  
Large Samples ◽  
Large Numbers ◽  
Harpacticoid Copepods

Meiofauna are often important in the transfer of organic material to higher trophic levels in aquatic environments. However, in food web analysis the group is frequently pooled or ignored owing to the difficulty in isolating individual components of the assemblage. In this study, we developed and tested a new method for extracting photopositive and detritus-free copepod samples from sediments, and compared this method to a previous technique (Couch 1989). In our initial trials, ∼400 copepods (all orders included) were collected in 15 min compared with 60 copepods using Couch’s method. In subsequent trials that focussed on specific orders of copepods, our method was at least 10 times more efficient than Couch’s method at collecting cyclopoid and harpacticoid copepods from sediments. The new method requires very little supervision and there is no requirement for a particular intensity of light. This method can increase the collection of large numbers of photopositive copepods in aquatic systems, and thereby facilitate the inclusion of this important component into future food web studies, particularly those using biomarkers such as stable isotopes or fatty acids.

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