Nutrient availability affected shallow-lake ecosystem response along the Late-Glacial/Holocene transition

Autor: Petra Houfková, Anna Tichá, Vlasta Jankovská, Daniel Vondrák, Tomáš Bešta
Rok vydání: 2019
Předmět:
Zdroj: Hydrobiologia. 846:87-108
ISSN: 1573-5117
0018-8158
DOI: 10.1007/s10750-019-04054-7
Popis: Shallow lowland lakes undergo long-lasting natural eutrophication processes, which can be studied through the development of communities of aquatic organisms. However, records showing millennial-scale trophic status variability in these water bodies are rare. Two radiocarbon-dated sedimentary profiles from former (now destroyed by brown coal mining) Lake Komořany (Central Europe, Czech Republic) served for a multi-proxy study of biological remains (diatoms, chironomids, pollen) supplemented by X-ray fluorescence (XRF) and loss-on-ignition (LOI). The age–depth model and palynostratigraphy confirm a continuous Late-Glacial to Early-Holocene record. The results suggest consistent in-lake conditions with high nutrient availability since the lake origin in the Late-Glacial period. A distinct shift at the Late-Glacial/Holocene boundary evidenced by an enhancement in diatom valve concentration and a lithological interface was foregone by a qualitative change in diatom and chironomid assemblages along with rise in LOI. It suggests that a major transformation occurred before the onset of the Holocene. As this qualitative change was characterized by a decrease in relative abundance of nutrient-demanding species, we propose an indirect climatic control by means of nutrient availability as the main driver of the aquatic species composition.
Databáze: OpenAIRE