Greenhouse conditions in lower Eocene coastal wetlands?-Lessons from Schöningen, Northern Germany

• Published in: PloS one 2021-01, Vol.16 (1), p.e0232861-e0232861
• Main Authors: Lenz, Olaf K, Riegel, Walter, Wilde, Volker
• Format: Article
• Language: English
• Subjects: Aggradation; Biodiversity; Biology and Life Sciences; Carbon; Carbon isotopes; Climate; Climate and vegetation; Climate change; Earth Sciences; Ecological succession; Ecology and Environmental Sciences; Ecosystem; Editing; Eocene; Flora; Fossils; Geology; Germany; Greenhouse Effect; Lignite; Methodology; Mines; Mining; Mining - methods; Museums; North Sea; Outcrops; Paleogene; Paleontology; Peat; Physical Sciences; Plants; Research and Analysis Methods; Runoff; Sea level; Sea level changes; Sediments; Soil; Statistical analysis; Terrestrial environments; Vegetation; Wetlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0232861

The Paleogene succession of the Helmstedt Lignite Mining District in Northern Germany includes coastal peat mire records from the latest Paleocene to the middle Eocene at the southern edge of the Proto-North Sea. Therefore, it covers the different long- and short-term climate perturbations of the Paleogene greenhouse. 56 samples from three individual sections of a lower Eocene seam in the record capture the typical succession of the vegetation in a coastal wetland during a period that was not affected by climate perturbation. This allows facies-dependent vegetational changes to be distinguished from those that were climate induced. Cluster analyses and NMDS of well-preserved palynomorph assemblages reveal four successional stages in the vegetation during peat accumulation: (1) a coastal vegetation, (2) an initial mire, (3) a transitional mire, and (4) a terminal mire. Biodiversity measures show that plant diversity decreased significantly in the successive stages. The highly diverse vegetation at the coast and in the adjacent initial mire was replaced by low diversity communities adapted to wet acidic environments and nutrient deficiency. The palynomorph assemblages are dominated by elements such as Alnus (Betulaceae) or Sphagnum (Sphagnaceae). Typical tropical elements which are characteristic for the middle Eocene part of the succession are missing. This indicates that a more warm-temperate climate prevailed in northwestern Germany during the early lower Eocene.