Open AccessAbrupt climate change and early lake development – the L ateglacial diatom flora at H ässeldala P ort, southeastern S weden
Author(s) -
Ampel Linda,
Kylander Malin E.,
Steinthorsdottir Margret,
Wohlfarth Barbara
Publication year - 2015
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/bor.12081
Subject(s) - diatom , climate change , deglaciation , organic matter , aquatic ecosystem , ecosystem , ecology , geology , oceanography , sediment , environmental science , hydrology (agriculture) , paleontology , biology , holocene , geotechnical engineering
The fossil diatom record from the H ässeldala P ort palaeolake, southeastern S weden, offers an excellent opportunity to investigate how past climatic shifts influenced catchment conditions and early lake development. The record, dating to between 13 900 and 11 200 cal. a BP , covers a climatically dynamic period, starting with deglaciation followed by oscillations between warmer and colder climate states. The stratigraphical changes in the fossil diatom assemblages show a trend of less open‐water taxa and a successively more complex periphytic community as the lake shallows and the aquatic habitat structure develops. A diatom‐based reconstruction of lake water pH indicates a natural acidification trend early in the record from 13 900 to 12 500 cal. a BP . From 12 500 cal. a BP , coincident with the start of climate cooling, to 11 300 cal. a BP this trend is disrupted and lake waters become more alkaline. A cooler and drier climate most likely resulted in reduced soil organic matter build‐up as well as more frozen ground that impeded hydrological flow and decreased the input of dissolved organic matter and organic acids into the lake system. This study demonstrates the importance of the hydrological system as a link between terrestrial and aquatic ecosystems during early lake ontogeny.