0000000000287599
AUTHOR
Henn Timm
showing 3 related works from this author
Benthic foodweb structure in a large shallow lake studied by stable isotope analysis
2014
The benthic foodweb structure of Lake Võrtsjärv, a large (270 km2), shallow, and turbid Estonian lake, was evaluated based on C and N stable-isotope signatures (δ13C, δ15N). Variation in δ13C between sampling sites was not related to site proximity to the littoral zone or the more vegetated southern part of the lake, but rather appeared to be influenced by in-situ site peculiarities. δ13C was stable temporally and between functional feeding groups, a result implying that the whole benthic food web of the lake relies largely on the same C source admixture, essentially particulate organic matter (POM). Thus, the foodweb composition of Lake Võrtsjärv is remarkably homogeneous given the lake’s …
Chironomid incorporation of methane-derived carbon in plankton- and macrophyte-dominated habitats in a large shallow lake
2018
1. While 13 C-depleted carbon derived from biogenic methane can substantially contribute to the benthic secondary production in deep stratified lakes, its role in shallow lakes is less clear. We investigated the dynamics of δ13 C and δ15 N in the larvae of Chironomus plumosus throughout an annual cycle in two ecologically distinct basins (open-water plankton-dominated and sheltered macrophyte- covered) of a large (270 km2 ), shallow, polymictic and eutrophic lake (Võrtsjärv, Estonia, North Europe). The larval stable isotopic compositions were linked to the presence of methane-oxidising bacteria (MOB) in larval guts and sediments. 2. Molecular detection of MOB revealed their presence in vari…
Biogenic methane contributes to the food web of a large, shallow lake
2013
Summary Biogenic methane as an alternative carbon and energy source for freshwater organisms has been receiving increasing attention, but the phenomenon is still poorly understood for shallow lakes. We measured the carbon and nitrogen stable isotope signatures (δ13C, δ15N) for key groups of pelagic and benthic organisms, including crustacean zooplankton, chironomid larvae, young-of-the-year and adult fish, to assess whether biogenic methane contributes to pelagic and benthic food webs in a large, shallow lake, Lake Vortsjarv, Estonia. In the southern part of the lake, covered by macrophytes, crustacean zooplankton showed strong seasonal variation of δ13C, with the lowest values occurring in…