Seasonal changes of trophic transfer efficiencies in a plankton food web derived from biomass size distributions and network analysis

Abstract

The trophic transfer efficiencies in the planktonic food web of large, deep, and mesoeutrophic Lake Constance were derived independently from biomass size distributions and from mass-balanced carbon flow diagrams based on comprehensive data for biomass, production, and food web structure. The main emphasis was on the transfer of primary production to herbivores since this process dominates the flow of matter within the food web. Biomass size distributions offer an ecosystem approach which relies only on measurements of biomass and a few general assumptions, whereas network analysis is predominantly based on production estimates and requires more detailed knowledge of the ecosystem. Despite these differences, both approaches give consistent results for both the absolute values of the transfer efficiencies and seasonal trends. Estimates of the seasonally averaged transfer efficiency (dominated by the utilization of primary production by herbivores) range from 0.20 to 0.27. They are considerably lower in late winter and spring (0.05 to 0.2l) than in summer and autumn (0.25 to 0.38, extreme values: 0.20 and 0.42).

Trophic Structure and Carbon Flow Dynamics in the Pelagic Community of a Large Lake

“…A comparison of these efficiencies with those derived from network analysis establishes a link between size-dependent and trophic level-based food web descriptions. Both approaches gave consistent results for absolute values and seasonal trends of the trophic transfer efficiencies from phytoplankton to herbivores (Gaedke and Straile, 1994b).…”

Use of size-based production and stable isotope analyses to predict trophic transfer efficiencies and predator-prey body mass ratios in food webs

“…Trophic transfer efficiency (TE) describes the proportion of prey production that is converted to predator production (TE = P c /P p , where P c is predator production and P p is prey production). Since body mass is correlated with specific production (Banse & Moser 1980), biomass size-spectra can be parameterised to give production by body-mass class (Platt & Denman 1978, Gaedke & Straile 1994, Duplisea & Kerr 1995. If mean predator-to-prey mass ratios can be estimated, then trophic transfer efficiency can be determined from the slope of the production size spectrum (e.g.…”

“…If mean predator-to-prey mass ratios can be estimated, then trophic transfer efficiency can be determined from the slope of the production size spectrum (e.g. Gaedke & Straile 1994). However, if trophic level at body mass is known, TE could be calculated without knowing the mean predator-prey body-mass ratio.…”

Energy flow of a boreal intertidal ecosystem, the Sylt-Rømø Bight

“…In many of these studies, network analysis, a set of algorithms derived from input/output analysis, trophic and cycle analysis, has been used to compute several ecosystem properties such as the structural complexity of the ecosystem, the structure and magnitude of the cycling of energy and material, the efficiency of energy transfer within the system, rates of energy assimilation and dissipation, trophic structure, system activity, growth and development (cf. Ulanowicz 1986, Baird & Ulanowicz 1989, Gaedke & Straile 1994, Heymans et al 2002. Results from network analysis thus provide significant insight into the fundamental functioning of the ecosystem , Baird 1999.…”