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Legacies of recent environmental change in the benthic communities of Lake Joyce, a perennially ice‐covered Antarctic lake

Legacies of recent environmental change in the benthic communities of Lake Joyce, a perennially... Many Antarctic lakes provide habitat for extensive microbial mats that respond on various timescales to environmental change. Lake Joyce contains calcifying microbialites and provides a natural laboratory to constrain how environmental changes influence microbialite development. In Lake Joyce, depth‐specific distributions of calcitic microbialites, organic carbon, photosynthetic pigments and photosynthetic potential cannot be explained by current growth conditions, but are a legacy of a 7‐m lake level rise between 1973 and 2009. In the well‐illuminated margins of the lake, photosynthetically active benthic communities colonised surfaces submerged for just a few years. However, observed increases in accumulated organic material with depth from 5 to 20 m (2–40 mg ash‐free dry weight cm−2) and the presence of decimetre‐scale calcite microbialites at 20–22 m depth, apparently related to in situ photosynthetic growth, are inconsistent with the current distributions of irradiance, photosynthetic pigments and mat photosynthetic potential (as revealed by pulse‐amplitude‐modulated fluorometry). The microbialites appeared photosynthetically active in 1986 and 1997, but were outside the depth zone where significant phototrophic growth was possible and were weakly photosynthetically competent in 2009. These complex microbial structures have persisted after growth has ceased, demonstrating how fluctuating environmental conditions and the hysteresis between environmental change, biological response and microbialite development can be important factors to consider when interpreting modern, and by inference ancient, microbially mediated structures. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Geobiology Wiley

Legacies of recent environmental change in the benthic communities of Lake Joyce, a perennially ice‐covered Antarctic lake

Geobiology , Volume 9 (5) – Sep 1, 2011

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References (64)

Publisher
Wiley
Copyright
© 2011 Blackwell Publishing Ltd
ISSN
1472-4677
eISSN
1472-4669
DOI
10.1111/j.1472-4669.2011.00289.x
pmid
21884362
Publisher site
See Article on Publisher Site

Abstract

Many Antarctic lakes provide habitat for extensive microbial mats that respond on various timescales to environmental change. Lake Joyce contains calcifying microbialites and provides a natural laboratory to constrain how environmental changes influence microbialite development. In Lake Joyce, depth‐specific distributions of calcitic microbialites, organic carbon, photosynthetic pigments and photosynthetic potential cannot be explained by current growth conditions, but are a legacy of a 7‐m lake level rise between 1973 and 2009. In the well‐illuminated margins of the lake, photosynthetically active benthic communities colonised surfaces submerged for just a few years. However, observed increases in accumulated organic material with depth from 5 to 20 m (2–40 mg ash‐free dry weight cm−2) and the presence of decimetre‐scale calcite microbialites at 20–22 m depth, apparently related to in situ photosynthetic growth, are inconsistent with the current distributions of irradiance, photosynthetic pigments and mat photosynthetic potential (as revealed by pulse‐amplitude‐modulated fluorometry). The microbialites appeared photosynthetically active in 1986 and 1997, but were outside the depth zone where significant phototrophic growth was possible and were weakly photosynthetically competent in 2009. These complex microbial structures have persisted after growth has ceased, demonstrating how fluctuating environmental conditions and the hysteresis between environmental change, biological response and microbialite development can be important factors to consider when interpreting modern, and by inference ancient, microbially mediated structures.

Journal

GeobiologyWiley

Published: Sep 1, 2011

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