Food web structure of a shallow eutrophic lake (Lake Taihu, China) assessed by stable isotope analysis

Abstract

Lake Taihu is a large, shallow, and eutrophic lake in China. It has provided local communities with valuable fisheries for centuries, but little is known of the trophodynamics, or of its faunal communities. Carbon and nitrogen isotopic composition was used to assess its trophic pathways and the food web structure [food sources and trophic levels (TL)]. Basal food sources were distinguishable based on their d 13 C values, ranging from -27.2 to -15.2%. Consumers were also well separated in d 13 C (-26.9 to -17.9% for invertebrates and -25.7 to -18.1% for fishes), which allowed for an effective discrimination of carbon sources between these fauna. An average trophic enrichment factor of 3.4% was used to calculate the TLs based on d 15 N of zooplankton, with results indicating a food web having four TLs. Although d 15 N values overlap and cover a large range within trophic compartments, the isotopic signatures of the species assessed revealed a general trend of 15 N enrichment with increasing TL. Stable isotope signatures were also used to establish a general food web scheme in which five main trophic pathways were analyzed.

To What Extent Do Food Preferences Explain the Trophic Position of Heterotrophic and Mixotrophic Microbial Consumers in a Sphagnum Peatland?

“…The increasing sensitivity of analytical tools now makes it possible to study ever-smaller organisms using stable isotope probing [8,12]. Stable isotope ratios of carbon and nitrogen are increasingly used to provide time-integrated information about feeding relationships and food web structure, as showed for aquatic food webs [13][14][15]. By providing a temporally and spatially averaged estimate of carbon and nitrogen that is actually assimilated by organisms [16], stable isotopes can improve our estimates of the major pathways of energy flows through microbial food webs [17].…”

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

“…In recent years, stable isotope analysis of consumer tissues and dietary sources as well as the use of Bayesian Stable Isotope Mixing Models emerged as an alternative but complementary technique to conventional gut/stomach content analysis. Indeed, stable isotopes have increasingly demonstrated their utility in numerous recent food web studies (Fry, 2006;Gu, Schelske, & Waters, 2011;Layman et al, 2011;Mao, Gu, Zeng, Zhou, & Sun, 2012;Mao et al, 2014;Rao, Ning, Zhong, Jeppesen, & Liu, 2015). Stable isotopes are especially useful because they provide time-integrated and spatial differences into trophic relationships among organisms, and thus can be used to develop models of trophic structure (Layman et al, 2011).…”

“…Food web studies employing either ecological models or stable isotopes are relatively insufficient in tropical African aquatic ecosystems (Jepsen & Winemiller, 2002;Kupfer, Langel, Scheu, Himstedt, & Maraun, 2006;Mao et al, 2012;Mavuti, Moreau, Munyadrorero, & Plisnier, 1996). In Ethiopia, food web studies are an emerging field of research interest and stimulating results were obtained for some lakes (Fetahi & Mengistou, 2007;Fetahi, Schagerl, Mengistou, & Libralato, 2011).…”

Zoobenthos are minor dietary components of small omnivorous fishes in a shallow eutrophic lake

“…Recently, the trophic roles of omnivorous fishes in lake food webs have been examined using natural stable-isotope procedures (Vander Zanden and Vadeboncoeur 2002;Jones and Waldron 2003;Kanaya et al 2009;Mao et al 2012). Most of these works have focussed on the roles of large omnivorous fishes (e.g.…”