Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production
Photosynthetic photon flux density (PPFD), air relative humidity and thallus temperature (TT) were measured in Usnea antarctica over a period of 12 months at a coastal rock on King George Island, South Shetland Islands. TT had an annual amplitude of c. 54 K with the maximum of +27.4°C recorded in De...
Published in: | Antarctic Science |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
1995
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/s0954102095000356 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102095000356 |
id |
crcambridgeupr:10.1017/s0954102095000356 |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/s0954102095000356 2024-06-23T07:46:45+00:00 Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production Schroeter, Burkhard Olech, M. Kappen, L. Heitland, W. 1995 http://dx.doi.org/10.1017/s0954102095000356 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102095000356 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 7, issue 3, page 251-260 ISSN 0954-1020 1365-2079 journal-article 1995 crcambridgeupr https://doi.org/10.1017/s0954102095000356 2024-06-12T04:03:25Z Photosynthetic photon flux density (PPFD), air relative humidity and thallus temperature (TT) were measured in Usnea antarctica over a period of 12 months at a coastal rock on King George Island, South Shetland Islands. TT had an annual amplitude of c. 54 K with the maximum of +27.4°C recorded in December and minimum of −27.3°C in July. Daily maximum TT exceeded 0°C every month except in June and July when they were below −0.4°C and −1.6°C, respectively. Daily minimum temperatures were always below zero. Diel courses of PPFD showed pronounced seasonal differences between summer (more than 2000 μmol m −2 s −1 ) and winter (less than 50 μmol m −2 s −1 in July). Daily sum of PPFD was highest (more than 30 mol m −2 d −1 ) in December and lowest (0.1 mol m −2 d −1 ) in July. A photosynthesis model was used to estimate the potential annual primary production from habitat PPFD and TT. The estimated potential annual carbon balance of U. antarctica was 323 mg CO 2 g −1 dry weight y −1 assuming that the lichen was always at optimal moisture. The potential carbon balance indicates that primary production is severely limited by low PPFD and subzero TT in the austral winter. Nevertheless, the PPFD and TT would allow metabolic activity during winter but with a negative carbon balance during May–August. Spring and autumnal months are revealed as probably the most important periods for lichen primary production because PPFD exceeds photosynthetic light compensation point during the daytime and ambient moisture conditions frequently favour a positive carbon balance. Article in Journal/Newspaper Antarc* Antarctic Antarctic Science Antarctica King George Island South Shetland Islands Usnea antarctica Cambridge University Press Antarctic Austral King George Island South Shetland Islands Antarctic Science 7 3 251 260 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Photosynthetic photon flux density (PPFD), air relative humidity and thallus temperature (TT) were measured in Usnea antarctica over a period of 12 months at a coastal rock on King George Island, South Shetland Islands. TT had an annual amplitude of c. 54 K with the maximum of +27.4°C recorded in December and minimum of −27.3°C in July. Daily maximum TT exceeded 0°C every month except in June and July when they were below −0.4°C and −1.6°C, respectively. Daily minimum temperatures were always below zero. Diel courses of PPFD showed pronounced seasonal differences between summer (more than 2000 μmol m −2 s −1 ) and winter (less than 50 μmol m −2 s −1 in July). Daily sum of PPFD was highest (more than 30 mol m −2 d −1 ) in December and lowest (0.1 mol m −2 d −1 ) in July. A photosynthesis model was used to estimate the potential annual primary production from habitat PPFD and TT. The estimated potential annual carbon balance of U. antarctica was 323 mg CO 2 g −1 dry weight y −1 assuming that the lichen was always at optimal moisture. The potential carbon balance indicates that primary production is severely limited by low PPFD and subzero TT in the austral winter. Nevertheless, the PPFD and TT would allow metabolic activity during winter but with a negative carbon balance during May–August. Spring and autumnal months are revealed as probably the most important periods for lichen primary production because PPFD exceeds photosynthetic light compensation point during the daytime and ambient moisture conditions frequently favour a positive carbon balance. |
format |
Article in Journal/Newspaper |
author |
Schroeter, Burkhard Olech, M. Kappen, L. Heitland, W. |
spellingShingle |
Schroeter, Burkhard Olech, M. Kappen, L. Heitland, W. Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
author_facet |
Schroeter, Burkhard Olech, M. Kappen, L. Heitland, W. |
author_sort |
Schroeter, Burkhard |
title |
Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
title_short |
Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
title_full |
Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
title_fullStr |
Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
title_full_unstemmed |
Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production |
title_sort |
ecophysiological investigations of usnea antarctica in the maritime antarctic i. annual microclimatic conditions and potential primary production |
publisher |
Cambridge University Press (CUP) |
publishDate |
1995 |
url |
http://dx.doi.org/10.1017/s0954102095000356 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102095000356 |
geographic |
Antarctic Austral King George Island South Shetland Islands |
geographic_facet |
Antarctic Austral King George Island South Shetland Islands |
genre |
Antarc* Antarctic Antarctic Science Antarctica King George Island South Shetland Islands Usnea antarctica |
genre_facet |
Antarc* Antarctic Antarctic Science Antarctica King George Island South Shetland Islands Usnea antarctica |
op_source |
Antarctic Science volume 7, issue 3, page 251-260 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102095000356 |
container_title |
Antarctic Science |
container_volume |
7 |
container_issue |
3 |
container_start_page |
251 |
op_container_end_page |
260 |
_version_ |
1802647927167909888 |