Differences in nitrogen and carbon stable isotopes between planktonic and benthic microalgae

Abstract

We compiled published data on the nitrogen and carbon stable isotope ratios of phytoplankton and benthic microalgae from lentic systems and explored the primary factors determining the isotope values among systems. Also, we investigated seasonal changes in nitrogen stable isotope ratios of phytoplankton and benthic microalgae in the strongly acidic lake, Lake Katanuma, which has only two dominant species, Pinnularia acidojaponica as a benthic diatom and Chlamydomonas acidophila, a planktonic green alga. From the published dataset, it may be concluded that d 13 C of benthic diatoms were more enriched than those of phytoplankton at the same sites, although the nitrogen isotope of phytoplankton and benthic microalgae were similar. This differences in d 13 C between benthic microalgae and phytoplankton could be explained by the boundary layer effect. On the other hand, nitrogen isotope values of both benthic microalgae and phytoplankton were primarily controlled by the same environmental factor, and boundary layer effects are not the primary factor determining the nitrogen isotope values of microalgae. Also, we showed temporal dynamics in nitrogen isotopes of benthic and planktonic microalgae species in Lake Katanuma, and the trends of nitrogen isotopes are similar between benthic and planktonic microalgae, as concluded from the published dataset.

Terrestrial support of aquatic food webs depends on light inputs: a geographically‐replicated test using tank bromeliads

“…Stable isotope values were entered for individual invertebrate groups (families, orders or sub-classes). This algal cultivation procedure was not possible in the other sites, so for these sites, we used previously published δ 13 C and δ 15 N data for periphytic algae from freshwater systems (n = 49): mean δ 13 C − 16.80 ‰ (±SE: 4.42 ‰) and mean δ 15 N 5.10 ‰ (±SE: 4.56 ‰) (Doi et al 2010). Instead, we used two different methods to estimate the stable isotope composition of autochthonous producers (see Table 1).…”

Mechanisms controlling the carbon stable isotope composition of phytoplankton in karst reservoirs

“…Furthermore, δ 13 C values of aquatic biota contain important information about the contributions of different organic carbon sources to food web (Yoshii et al, 1999;Grey et al, 2000). Planktonic, benthic and terrestrial primary producers have distinct δ 13 C values (Finlay et al, 1999;Doi et al, 2010;Milligan et al, 2010) that directly reflects their food sources as there is only a slight isotopic enrichment (<1‰) during the feeding process (Yoshii et al, 1999;Post, 2002). Therefore, carbon stable isotope analysis has been proved to be a powerful tool to study carbon sources in the aquatic ecosystem.…”

Estimating Niche Width Using Stable Isotopes in the Face of Habitat Variability: A Modelling Case Study in the Marine Environment

“…Because simulations are based on the isotopic signatures of the global or site mean of the prey species, when populations of specialist predators are observed a large proportion of the calculated isotopic values will fall outside their mixing space, independent of mixing space width. As variability in δ 13 C and δ 15 N of the primary producers in food webs exist among habitats [57], [58], [59], comparisons of δ 13 C and δ 15 N among habitats will be confounded by isotopic variability of the prey source [3].…”