Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica
Crustose coralline algae (CCA) occur from the tropics to the poles in photic benthic environments. Here, we report on some of the world’s southernmost and coldest CCA sites in Terra Nova, Ross Sea, Antarctica at 74°41′ S. The recently described red alga Tethysphytum antarticum is investigated for it...
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ftmdpi:oai:mdpi.com:/2075-163X/13/2/215/ 2023-08-20T04:01:09+02:00 Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica Matthias López Correa Sebastian Teichert Federica Ragazzola Salvador Cazorla Vázquez Felix B. Engel Katrin Hurle Claudio Mazzoli Piotr Kuklinski Giancarlo Raiteri Chiara Lombardi agris 2023-02-02 application/pdf https://doi.org/10.3390/min13020215 EN eng Multidisciplinary Digital Publishing Institute Biomineralization and Biominerals https://dx.doi.org/10.3390/min13020215 https://creativecommons.org/licenses/by/4.0/ Minerals; Volume 13; Issue 2; Pages: 215 crustose coralline algae Antarctica taxonomy phylogeny thallus structure biomineralization geochemistry climate change Text 2023 ftmdpi https://doi.org/10.3390/min13020215 2023-08-01T08:36:06Z Crustose coralline algae (CCA) occur from the tropics to the poles in photic benthic environments. Here, we report on some of the world’s southernmost and coldest CCA sites in Terra Nova, Ross Sea, Antarctica at 74°41′ S. The recently described red alga Tethysphytum antarticum is investigated for its skeletal architecture, its mineralogical and geochemical composition, as well as for its taxonomic classification. A phylogenetic analysis based on molecular genetics and the sequencing of the photosystem II protein D1 (psbA) gave a perfect match with T. antarcticum. Histological sections and micro-CT-scans provide new diagnostic details for the conceptacles (the reproductive organs of the alga). X-ray diffractometry and electron-microprobe measurements yielded a clear high-Mg calcite (~8 mol%) composition of the skeletal parts. Detailed back-scattered electron imaging of polished petrographic thin sections revealed a two-layered thallus (vegetative plant tissue), comprising an organic-rich irregularly calcified basal layer with rectangular cells, overlain by the main thallus. Elemental maps show relatively increased sulphur in the basal layer, clearly tied to organic cell walls. MgCO3 and SrCO3 were targeted with semiquantitative elemental mappings and in an ontogenetic quantitative spot transect. Compared with temperature (−1.95 °C to +1.08 °C), the MgCO3 (mol%) reflects this world’s coldest CCA site temperature with the lowest MgCO3 content of 7.9 ± 1.6 mol%. The along transect variability, however, shows with ~6 mol% a larger MgCO3 variability than expected for the 3 °C intra-annual temperature amplitude in Terra Nova Bay. This implies that in low amplitude settings the biomineralisation control on Mg/Ca ratios can outcompete its temperature sensitivity. Mark-recapture studies, next to the environmental logger station La Zecca are suggested, to perform a detailed growth rate and biomineralisation quantification. Text Antarc* Antarctica antartic* Ross Sea MDPI Open Access Publishing Ross Sea Terra Nova Bay Minerals 13 2 215 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
crustose coralline algae Antarctica taxonomy phylogeny thallus structure biomineralization geochemistry climate change |
spellingShingle |
crustose coralline algae Antarctica taxonomy phylogeny thallus structure biomineralization geochemistry climate change Matthias López Correa Sebastian Teichert Federica Ragazzola Salvador Cazorla Vázquez Felix B. Engel Katrin Hurle Claudio Mazzoli Piotr Kuklinski Giancarlo Raiteri Chiara Lombardi Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
topic_facet |
crustose coralline algae Antarctica taxonomy phylogeny thallus structure biomineralization geochemistry climate change |
description |
Crustose coralline algae (CCA) occur from the tropics to the poles in photic benthic environments. Here, we report on some of the world’s southernmost and coldest CCA sites in Terra Nova, Ross Sea, Antarctica at 74°41′ S. The recently described red alga Tethysphytum antarticum is investigated for its skeletal architecture, its mineralogical and geochemical composition, as well as for its taxonomic classification. A phylogenetic analysis based on molecular genetics and the sequencing of the photosystem II protein D1 (psbA) gave a perfect match with T. antarcticum. Histological sections and micro-CT-scans provide new diagnostic details for the conceptacles (the reproductive organs of the alga). X-ray diffractometry and electron-microprobe measurements yielded a clear high-Mg calcite (~8 mol%) composition of the skeletal parts. Detailed back-scattered electron imaging of polished petrographic thin sections revealed a two-layered thallus (vegetative plant tissue), comprising an organic-rich irregularly calcified basal layer with rectangular cells, overlain by the main thallus. Elemental maps show relatively increased sulphur in the basal layer, clearly tied to organic cell walls. MgCO3 and SrCO3 were targeted with semiquantitative elemental mappings and in an ontogenetic quantitative spot transect. Compared with temperature (−1.95 °C to +1.08 °C), the MgCO3 (mol%) reflects this world’s coldest CCA site temperature with the lowest MgCO3 content of 7.9 ± 1.6 mol%. The along transect variability, however, shows with ~6 mol% a larger MgCO3 variability than expected for the 3 °C intra-annual temperature amplitude in Terra Nova Bay. This implies that in low amplitude settings the biomineralisation control on Mg/Ca ratios can outcompete its temperature sensitivity. Mark-recapture studies, next to the environmental logger station La Zecca are suggested, to perform a detailed growth rate and biomineralisation quantification. |
format |
Text |
author |
Matthias López Correa Sebastian Teichert Federica Ragazzola Salvador Cazorla Vázquez Felix B. Engel Katrin Hurle Claudio Mazzoli Piotr Kuklinski Giancarlo Raiteri Chiara Lombardi |
author_facet |
Matthias López Correa Sebastian Teichert Federica Ragazzola Salvador Cazorla Vázquez Felix B. Engel Katrin Hurle Claudio Mazzoli Piotr Kuklinski Giancarlo Raiteri Chiara Lombardi |
author_sort |
Matthias López Correa |
title |
Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
title_short |
Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
title_full |
Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
title_fullStr |
Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
title_full_unstemmed |
Structural and Geochemical Assessment of the Coralline Alga Tethysphytum antarcticum from Terra Nova Bay, Ross Sea, Antarctica |
title_sort |
structural and geochemical assessment of the coralline alga tethysphytum antarcticum from terra nova bay, ross sea, antarctica |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2023 |
url |
https://doi.org/10.3390/min13020215 |
op_coverage |
agris |
geographic |
Ross Sea Terra Nova Bay |
geographic_facet |
Ross Sea Terra Nova Bay |
genre |
Antarc* Antarctica antartic* Ross Sea |
genre_facet |
Antarc* Antarctica antartic* Ross Sea |
op_source |
Minerals; Volume 13; Issue 2; Pages: 215 |
op_relation |
Biomineralization and Biominerals https://dx.doi.org/10.3390/min13020215 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/min13020215 |
container_title |
Minerals |
container_volume |
13 |
container_issue |
2 |
container_start_page |
215 |
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1774723046366511104 |