Geographic distribution of epilithic diatoms (Bacillariophyceae) in&amp;nbsp;Antarctic lakes, South Shetland Islands, Maritime Antarctica Region

Silva, Juliana Ferreira da; Oliveira, Maria Angélica; Alves, Rodrigo Paidano; Cassol, Ana Paula Vestena; Anunciação, Raylane Ribeiro da; Silva, Eduardo Pereira da; Schünemann, Adriano Luís; Pereira, Antônio Batista

doi:10.15560/15.5.797

Cited by 4 publications

(1 citation statement)

References 29 publications

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“…This suggests a high tolerance to salinity, radiation, and aridity. This newly described species had been found in several studies of freshwater samples in maritime Antarctica and identified so far as C. krookiformis (Kopalová et al 2012;Sterken et al 2015;Zidarova et al 2016b;Silva et al 2019). Chamaepinnularia krookiformis was first published as Pinnularia krookiformis by Krammer (1992) from a periodic saline pool in North Rhine-Westphalia (Germany) and was then transferred to Chamaepinnularia by Lange-Bert.…”

Section: Monophyly Of the Genus Chamaepinnulariamentioning

confidence: 96%

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Schimani¹,

Abarca²,

Zimmermann³

et al. 2024

Fottea

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The diatom genus Chamaepinnularia was first published by Lange-Bertalot et Krammer in 1996 to accommodate several small species previously included within Navicula and Pinnularia. Despite its morphological similarity to those two genera, the family-level classification of Chamaepinnularia has been considered incertae sedis since its description almost three decades ago. We provide the first molecular characterisation (18S and rbcL) of the genus based on cultured polar strains and investigated its phylogenetic placement. Molecular data are complemented with observations on living cells, as well as detailed examination of oxidized material with light microscopy and scanning electron microscopy. The 12 investigated strains were morphologically identified as three taxa: two already described species (C. gerlachei, C. krookii) and one here newly described (C. australis sp. nov.). These species formed three separate, well-supported branches in the phylogeny. Our analyses placed Chamaepinnularia as a sister group to members of the Sellaphoraceae for which sequence data exist (i.e. Sellaphora, Fallacia, Rossia and Diprora). Based on the presence of hymenate areolae, a single Hshaped plastid with girdle appressed plates and the results of the phylogenetic trees, we propose the inclusion of Chamaepinnularia within the family Sellaphoraceae, which altogether form a supported monophyletic group.

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Section: Monophyly Of the Genus Chamaepinnulariamentioning

confidence: 96%

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Schimani¹,

Abarca²,

Zimmermann³

et al. 2024

Fottea

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Photosynthetic, Respirational, and Growth Responses of Six Benthic Diatoms from the Antarctic Peninsula as Functions of Salinity and Temperature Variations

Prelle

Schmidt

Schimani

et al. 2022

Genes

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Temperature and salinity are some of the most influential abiotic parameters shaping biota in aquatic ecosystems. In recent decades, climate change has had a crucial impact on both factors—especially around the Antarctic Peninsula—with increasing air and water temperature leading to glacial melting and the accompanying freshwater increase in coastal areas. Antarctic soft and hard bottoms are typically inhabited by microphytobenthic communities, which are often dominated by benthic diatoms. Their physiology and primary production are assumed to be negatively affected by increased temperatures and lower salinity. In this study, six representative benthic diatom strains were isolated from different aquatic habitats at King George Island, Antarctic Peninsula, and comprehensively identified based on molecular markers and morphological traits. Photosynthesis, respiration, and growth response patterns were investigated as functions of varying light availability, temperature, and salinity. Photosynthesis–irradiance curve measurements pointed to low light requirements, as light-saturated photosynthesis was reached at <70 µmol photons m−2 s−1. The marine isolates exhibited the highest effective quantum yield between 25 and 45 SA (absolute salinity), but also tolerance to lower and higher salinities at 1 SA and 55 SA, respectively, and in a few cases even <100 SA. In contrast, the limnic isolates showed the highest effective quantum yield at salinities ranging from 1 SA to 20 SA. Almost all isolates exhibited high effective quantum yields between 1.5 °C and 25 °C, pointing to a broad temperature tolerance, which was supported by measurements of the short-term temperature-dependent photosynthesis. All studied Antarctic benthic diatoms showed activity patterns over a broader environmental range than they usually experience in situ. Therefore, it is likely that their high ecophysiological plasticity represents an important trait to cope with climate change in the Antarctic Peninsula.

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Exploring benthic diatom diversity in the West Antarctic Peninsula: insights from a morphological and molecular approach

Schimani,

Abarca,

Skibbe

et al. 2023

MBMG

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Polar regions are among the most extreme habitats on Earth. However, diatom biodiversity in those regions is much more extensive and ecologically diverse than previously thought. The objective of this study was to add knowledge to benthic diatom biodiversity in Western Antarctic coastal zones via identification by means of morphology, DNA metabarcoding and cultured isolates. In addition, a taxonomically validated reference library for Antarctic benthic diatoms was established with comprehensive information on habitat, morphology and DNA barcodes (rbcL and 18SV4). Benthic samples from marine, brackish and freshwater habitats were taken at the Antarctic Peninsula. A total of 162 clonal cultures were established, resulting in the identification of 60 taxa. The combination of total morphological richness of 174 taxa, including the clones, with an additional 73 taxa just assigned by metabarcoding resulted in 247 infrageneric taxa. Of those taxa, 33 were retrieved by all three methods and 111 only by morphology. The barcode reference library of Antarctic species with the new references obtained through culturing allowed the assignment of 47 taxa in the metabarcoding analyses, which would have been left unassigned because no matching reference sequences were available before. Non–metric multidimensional scaling analyses of morphological as well as molecular data showed a clear separation of diatom communities according to water and substratum types. Many species, especially marine taxa, still have no record in reference databases. This highlights the need for a more comprehensive reference library to further improve routine diatom metabarcoding. Overall, a combination of morphological and molecular methods, along with culturing, provides complementary information on the biodiversity of benthic diatoms in the region.

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Geographic distribution of epilithic diatoms (Bacillariophyceae) in Antarctic lakes, South Shetland Islands, Maritime Antarctica Region

Cited by 4 publications

References 29 publications

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Photosynthetic, Respirational, and Growth Responses of Six Benthic Diatoms from the Antarctic Peninsula as Functions of Salinity and Temperature Variations

Exploring benthic diatom diversity in the West Antarctic Peninsula: insights from a morphological and molecular approach

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Geographic distribution of epilithic diatoms (Bacillariophyceae) in&nbsp;Antarctic lakes, South Shetland Islands, Maritime Antarctica Region

Cited by 4 publications

References 29 publications

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Molecular phylogenetics coupled with morphological analyses of Arctic and Antarctic strains place Chamaepinnularia (Bacillariophyta) within the Sellaphoraceae

Photosynthetic, Respirational, and Growth Responses of Six Benthic Diatoms from the Antarctic Peninsula as Functions of Salinity and Temperature Variations

﻿Exploring benthic diatom diversity in the West Antarctic Peninsula: insights from a morphological and molecular approach

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Product

Resources

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Geographic distribution of epilithic diatoms (Bacillariophyceae) in Antarctic lakes, South Shetland Islands, Maritime Antarctica Region

Exploring benthic diatom diversity in the West Antarctic Peninsula: insights from a morphological and molecular approach