The relationship between carbon and nitrogen stable isotopes of zooplankton and select environmental variables in low-latitude reservoirs

• Published in: Limnology 2013, Vol.14 (1), p.97-104
• Main Authors: Hou, Wei, Gu, Binhe, Zhang, Huajun, Gu, Jiguang, Han, Bo-Ping
• Format: Article
• Language: English
• Subjects: Aquatic ecosystems; Biomedical and Life Sciences; Carbon; Ecology; Environment; Environmental factors; Eutrophication; Freshwater & Marine Ecology; Life Sciences; Limnology; Nitrogen; Nitrogen sources; Nutrient concentrations; Particulate organic matter; Plankton; Research Paper; Reservoirs; Stable isotopes; Trophic levels; Zooplankton
• ISSN: 1439-8621; 1439-863X
• DOI: 10.1007/s10201-012-0388-2

Cyclopoids were collected from 18 reservoirs in southern China during August (a wet month) and December (a dry month) of 2010 for the analysis of carbon and nitrogen stable isotopes (δ 13 C Zoo and δ 15 N Zoo ). The objectives of this study were to examine whether δ 13 C Zoo and δ 15 N Zoo can be better indicators of primary productivity and trophic state than the stable isotope composition of suspended particulate organic matter (POM), and to evaluate the relationship between δ 13 C Zoo and δ 15 N Zoo and select environmental variables. The δ 13 C Zoo in these reservoirs was enriched in August and depleted in December, and varied significantly along the continuum of trophic levels. By contrast, δ 15 N Zoo was depleted in August and enriched in December, and did not increase significantly with an increase in trophic state. Both δ 13 C Zoo and δ 15 N Zoo were more strongly correlated with environmental factors than δ 13 C POM and δ 15 N POM were. In addition, more environmental factors were significantly correlated with δ 13 C Zoo and the δ 15 N Zoo than with δ 13 C POM and δ 15 N POM . When data from two seasons were pooled, δ 13 C Zoo was strongly correlated with dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP) and the DIN:SRP ratio, while δ 15 N Zoo was weakly correlated with nutrient concentrations. This study indicates that, compared to the stable isotope composition of POM, δ 13 C Zoo is a better indicator of primary productivity and trophic state, while δ 15 N Zoo may be used as a proxy for nitrogen sources in aquatic ecosystems.