Stable isotope analyses are often used to calculate relative contributions of multiple food sources in an animal's diet. One prerequisite for a precise calculation is the determination of the diet-tissue fractionation factor. Isotopic ratios in animals are not only affected by the composition of the diet, but also by the amount of food consumed. Previous findings regarding the latter point are controversial. As stable isotope analyses have often been used to investigate aquatic food webs, an experiment with carp (Cyprinus carpioL.) was carried out to test the influence of the feeding level and individual metabolic rate on delta(13)C and delta(15)N values of the whole body. After an initial phase, 49 carp were assigned randomly to four groups and fed the same diet at different levels for 8 weeks. For 15 fish, the energy budget was determined by indirect calorimetry. Feed and individual fish were analysed for their proximate composition, gross energy content and delta(13)C and delta(15)N values. delta(13)C and delta(15)N values differed significantly at different feeding levels. While delta(13)C values of the lipids and delta(15)N values decreased with increasing feeding rate, delta(13)C values of the lipid-free matter showed a non-linear pattern. Data obtained from fish held in the respirometric system revealed a relationship between delta(13)C values and the percentage retention of metabolizable energy. Our results show that reconstructing the diets of fish from the isotopic ratios when the feeding level and individual metabolic rates are unknown would introduce an error into the data used for back-calculation of up to 1 per thousand for both delta(13)C and delta(15)N values and may have substantial effects on the results of calculated diets. As other workers have pointed out, the development and application of stable isotopes to nutritional ecology studies is a field in its infancy and gives rise to erroneous, misleading results without nutritional, physiological and ecological knowledge.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/s00442-003-1429-7 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The return of raptors to Scotland's skies: Investigating the diets of reintroduced red kites and white-tailed eagles using stable isotopes.
PLoS One
January 2025
Department of Biological Sciences, Royal Holloway, University of London, Egham, United Kingdom.
Species reintroductions are increasingly seen as important methods of biodiversity restoration. Reintroductions of red kites Milvus milvus and white-tailed eagles Halieaeetus albicilla to Britain, which were extirpated in the late 19th and early 20th centuries, represent major conservation successes. Here, we measured stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in feather keratin and bone collagen of museum specimens of red kites and white-tailed eagles, which were collected from across Scotland between the 1800s and 2010s.
View Article and Find Full Text PDFSeasonal Water-Column Structure Drives the Trophic Niche of Fish Communities on a Temperate Continental Shelf.
Biology (Basel)
December 2024
School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
In seasonally stratified marine environments, the dynamics of benthic-pelagic coupling plays a crucial role in shaping food web structures and fisheries production. We examined fish food web structures across three distinct shelf areas in the Southern Sea of Korea (SSK) during both stratified (summer) and mixed (spring) water conditions using stable isotopes of carbon (δC) and nitrogen (δN). In spring, fish communities exhibited a broader range of δC values compared with summer, indicating more diverse feeding strategies.
View Article and Find Full Text PDFTrophic Structure and Isotopic Niche of Invaded Benthic Communities on Tropical Rocky Shores.
Biology (Basel)
December 2024
Departamento de Ecologia, IBRAG, Universidade do Estado do Rio de Janeiro, Rua Francisco Xavier 524, PHLC, Sala 220, Rio de Janeiro 20559-900, RJ, Brazil.
When a species is introduced in a new location, it is common for it to establish itself when it finds favorable conditions in the receptor community with regard to interspecific interactions with native species. The azooxanthellate corals coccinea and are invasive species introduced in the Caribbean Sea, the Gulf of Mexico, and the Brazilian Southwest Atlantic. They are successful competitors for space, have multiple reproductive modes, and have high larval dispersion and recruitment, but studies on food and trophic relationships of the genus are still scarce.
View Article and Find Full Text PDFA Strong Link Between Oceanographic Conditions and Zooplankton δC and δN Values in the San Jorge Gulf, Argentina.
Biology (Basel)
November 2024
Biology Department, University of New Mexico, Albuquerque, NM 87131-0001, USA.
Maps of (baseline) δC and δN values of primary producers or consumers near the base of food webs provide crucial information for interpreting patterns in the isotopic composition of consumers that occupy higher trophic levels. In marine systems, understanding how oceanographic variables influence these values enables the creation of dynamic isoscapes across time and space, providing insights into how ecosystems function. The San Jorge Gulf (SJG) in the southwest Atlantic Ocean (45° S-47° S) is an area of particular importance, as it is located on one of the most productive continental shelves in the world, supporting large fisheries and marine mammal and seabird populations.
View Article and Find Full Text PDFTrophic ecology in an anchialine cave: A stable isotope study.
PLoS One
January 2025
Colección Nacional de Crustáceos, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico, Ciudad de México, Mexico.
Article Synopsis
- Carbon and nitrogen stable isotopes (δ13C and δ15N) are valuable tools in ecology for tracing energy flows in food webs, particularly in underexplored ecosystems like anchialine caves.
- Sampling at Cenote Vaca Ha in Mexico revealed insights into the nutrient sources for seven endemic stygobitic species, highlighting that isotopic patterns are consistent over time despite some variation.
- The study identified shrimp Typhlatya pearsei as a crucial species linking chemosynthetic microbial production to the anchialine food web, indicating a stable ecosystem reliant on bacterial sources for energy.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!