The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Karl Ljung

Karl Ljung

Lecturer

Karl Ljung

Holocene environmental changes on Nightingale Island, South Atlantic, based on diatom floristic changes in an infilled pond

Author

  • Sofia Holmgren
  • Karl Ljung
  • Svante Björck

Summary, in English

A Holocene diatom stratigraphy of 2nd Pond, a small, filled pond on Nightingale Island (37 degrees 25 S, 12 degrees 29 W) was analyzed and interpreted to infer paleolimnological changes on Tristan da Cunha, South Atlantic. The diatom assemblage of 2nd Pond has the character of an acidic, oligotrophic wetland and the diatom record suggests that 2nd Pond most likely has been a bog/wetland throughout most of the Holocene. The-flora is largely dominated by Pinnularia viridis, a species typically found in peat bogs. The flora also includes benthic and epiphytic Gomphonema sp, Achnanthes saxonica, Frustulia cf. rhomboides, Staurosira venter as well as Pinnularia cf. divergens var. decrescens and Eunotia paludosa var. paludosa. Peaks of aerophytic diatom (i.e. mostly Diadesmis spp. and Luticola spp.) abundances and concentrations correspond to increased magnetic susceptibility and slightly higher C/N ratios and are interpreted to be the result of increased catchment erosion due to precipitation and following increased in-wash of terrestrial diatoms. The diatom record suggests dry conditions in the early Holocene, followed by recurrent periods of increased precipitation in the region at 8600-5600 cal a BP and at 2200-1700 cal a BP. The main causes for these hydrological changes are probably changes in intensity and/or position of the Southern hemisphere west wind belt. (C) 2013 Elsevier B.V. All rights reserved.

Department/s

  • Quaternary Sciences
  • MERGE: ModElling the Regional and Global Earth system
  • BECC: Biodiversity and Ecosystem services in a Changing Climate

Publishing year

2013

Language

English

Pages

45-51

Publication/Series

Palaeogeography, Palaeoclimatology, Palaeoecology

Volume

378

Document type

Journal article

Publisher

Elsevier

Topic

  • Geology

Keywords

  • Diatoms
  • Holocene
  • South Atlantic
  • Tristan da Cunha

Status

Published

ISBN/ISSN/Other

  • ISSN: 1872-616X