Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis

Abstract

Abstract:Functional-based approaches are increasingly being used to define the functional diversity of aquatic ecosystems. In this study, we proposed the use of δ 13 C and δ 15 N stable isotopes as a proxy of zooplankton functional traits in Lake Maggiore, a large, deep subalpine Italian lake. We analyzed the seasonal pattern of δ 13 C and δ 15 N signatures of different crustacean zooplankton taxa to determine food sources, preferred habitats, and trophic positions of species throughout one year. The cladocerans Daphnia longispina galeata gr., Diaphanosoma brachyurum, and Eubosmina longispina were grouped into a primary consumer functional group from their δ 13 C and δ 15 N isotopic signatures, but while the former two species shared the same food sources, the latter exhibited a more selective feeding strategy. Cyclopoid copepods occupied a distinct functional group from the other secondary consumers, being the most 15 N enriched group in the lake. The δ 15 N signature of calanoid copepods showed trophic enrichment in comparison to Daphnia and Eubosmina and linear mixing model results confirmed a predator-prey relationship. In our study, we have demonstrated that the use of δ 13 C and δ 15 N stable isotopes represented an effective tool to define ecological roles of freshwater zooplankton species and to determine functional diversity in a lake.

Long-Term Changes in the Zooplankton Community of Lake Maggiore in Response to Multiple Stressors: A Functional Principal Components Analysis

“…This result agrees well with analyses of ecological roles of Lake Maggiore freshwater zooplankton by carbon and nitrogen stable isotope analyses. Copepods, particularly cyclopoids, occupy a distinct functional group from the other zooplankton secondary consumers, which is an observation also made in previous studies [54,69,70]. , corresponding to the variance of the scores f 1 j , .…”

Species Richness and Taxonomic Distinctness of Zooplankton in Ponds and Small Lakes from Albania and North Macedonia: The Role of Bioclimatic Factors

“…Here, we made an attempt towards this direction while using crustacean zooplankton. This group of organisms, ubiquitous in lentic habitats, has been recently subjected to renewed interest as an effective bio-indicator of the environmental status of ponds and small lakes [62][63][64][65]. The heuristic procedure was used here to identify minimum adequate models predicting the diversity the crustacean zooplankton assemblages across the 40 waterbodies under analysis provided non-univocal results.…”

Trophic Magnification of Legacy (PCB, DDT and Hg) and Emerging Pollutants (PFAS) in the Fish Community of a Small Protected Southern Alpine Lake (Lake Mergozzo, Northern Italy)

“…Samples were oven-dried for at least 24 h at 60 • C, homogenized and transferred into tin capsules (size = 5 × 9 mm). The isotopic composition of organic carbon and nitrogen was determined by the Ján Veizer Stable Isotope Laboratory at the University of Ottawa (Ontario, Canada), following the method already described in previous studies [46,47], using a CE 1110 Elemental Analyzer (Vario EL III Elementar Analysensysteme GmbH, Hanau, Germany) and a DeltaPlus Advantage isotope ratio mass spectrometer (Delta XP Plus Advantage, Thermo Fisher Scientific, Bremen, Germany) coupled to a ConFlo III interface (ConFlo II, Thermo Fisher Scientific, Bremen, Germany). The standard deviation of the analyses (SD) based on laboratory internal standards (C-55) was <0.2 h for both 13 C and 15 N. Isotope ratios were expressed as the parts per thousand (% ) difference from a standard reference of PeeDee Belemnite for carbon and atmospheric N 2 for nitrogen according to the equation:…”