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Late Holocene environmental history on Tristan da Cunha, South Atlantic, based on diatom floristic changes and geochemistry in sediments of a volcanic crater lake

Holmgren, Sofia LU ; Ljung, Karl LU and Björck, Svante LU (2012) In Journal of Paleolimnology 47(2). p.221-232
Abstract
A late Holocene diatom stratigraphy of Bottom Pond (37050S, 12 70W) was studied and interpreted to infer paleolimnological and climate changes on Tristan da Cunha, South Atlantic. The diatom flora of Bottom Pond is dominated by meroplanktonic Aulacoseira alpigena and A. distans and a benthic/epiphytic flora including Achnanthes spp., Naviculadicta spp., Eunotia taxa and Frustulia rhomboides.

The flora also includes an important terrestrial and aerophytic component, consisting of several Diadesmis spp., Navicula lapidosa, Nitzschia terrestris and some Pinnularia spp., at times dominating the

flora. Peaks of high terrestrial diatom abundances and low abundances and concentrations of Aulacoseira spp., correspond to periods... (More)
A late Holocene diatom stratigraphy of Bottom Pond (37050S, 12 70W) was studied and interpreted to infer paleolimnological and climate changes on Tristan da Cunha, South Atlantic. The diatom flora of Bottom Pond is dominated by meroplanktonic Aulacoseira alpigena and A. distans and a benthic/epiphytic flora including Achnanthes spp., Naviculadicta spp., Eunotia taxa and Frustulia rhomboides.

The flora also includes an important terrestrial and aerophytic component, consisting of several Diadesmis spp., Navicula lapidosa, Nitzschia terrestris and some Pinnularia spp., at times dominating the

flora. Peaks of high terrestrial diatom abundances and low abundances and concentrations of Aulacoseira spp., correspond to periods of increased magnetic susceptibility and are interpreted to be the result of increased catchment erosion and/or precipitation

leading to enhanced in-wash of species living in the soils around the lake. The diatom record of Bottom Pond most likely registers both local responses to increased erosion in the catchment as well as climatic change of a more regional character. Comparisons

with the geochemical record in 2nd Pond on Nightingale Island show a correspondence between the two data sets at 2,000–1,750 cal yrs BP, most likely evidence of increased precipitation in the Tristan da Cunha region. The Tristan da Cunha archipelago is situated at the northern limit of the Southern hemisphere west wind belt and stronger and/ or a northward shift of the westerlies, are probably the main causes of the precipitation changes. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Diatoms, Holocene climate change, South Atlantic, Tristan da Cunha
in
Journal of Paleolimnology
volume
47
issue
2
pages
221 - 232
publisher
Springer
external identifiers
  • wos:000302382200004
  • scopus:84856001779
ISSN
0921-2728
DOI
10.1007/s10933-011-9571-4
project
BECC
MERGE
language
English
LU publication?
yes
id
ad500d91-be27-428a-8b5c-347e4799a9dc (old id 2255729)
date added to LUP
2012-03-29 13:18:42
date last changed
2017-01-01 05:44:28
@article{ad500d91-be27-428a-8b5c-347e4799a9dc,
  abstract     = {A late Holocene diatom stratigraphy of Bottom Pond (37050S, 12 70W) was studied and interpreted to infer paleolimnological and climate changes on Tristan da Cunha, South Atlantic. The diatom flora of Bottom Pond is dominated by meroplanktonic Aulacoseira alpigena and A. distans and a benthic/epiphytic flora including Achnanthes spp., Naviculadicta spp., Eunotia taxa and Frustulia rhomboides.<br/><br>
The flora also includes an important terrestrial and aerophytic component, consisting of several Diadesmis spp., Navicula lapidosa, Nitzschia terrestris and some Pinnularia spp., at times dominating the<br/><br>
flora. Peaks of high terrestrial diatom abundances and low abundances and concentrations of Aulacoseira spp., correspond to periods of increased magnetic susceptibility and are interpreted to be the result of increased catchment erosion and/or precipitation<br/><br>
leading to enhanced in-wash of species living in the soils around the lake. The diatom record of Bottom Pond most likely registers both local responses to increased erosion in the catchment as well as climatic change of a more regional character. Comparisons<br/><br>
with the geochemical record in 2nd Pond on Nightingale Island show a correspondence between the two data sets at 2,000–1,750 cal yrs BP, most likely evidence of increased precipitation in the Tristan da Cunha region. The Tristan da Cunha archipelago is situated at the northern limit of the Southern hemisphere west wind belt and stronger and/ or a northward shift of the westerlies, are probably the main causes of the precipitation changes.},
  author       = {Holmgren, Sofia and Ljung, Karl and Björck, Svante},
  issn         = {0921-2728},
  keyword      = {Diatoms,Holocene climate change,South Atlantic,Tristan da Cunha},
  language     = {eng},
  number       = {2},
  pages        = {221--232},
  publisher    = {Springer},
  series       = {Journal of Paleolimnology},
  title        = {Late Holocene environmental history on Tristan da Cunha, South Atlantic, based on diatom floristic changes and geochemistry in sediments of a volcanic crater lake},
  url          = {http://dx.doi.org/10.1007/s10933-011-9571-4},
  volume       = {47},
  year         = {2012},
}