title: Species composition and cyanotoxin production in periphyton mats from three lakes of varying trophic status

authors: Wood, Susanna A.

subjects: cyanobacteria

abstract: In lakes, benthic micro-algae and cyanobacteria (periphyton) can contribute significantly to total primary productivity and provide important food sources for benthic invertebrates. Despite recognition of their importance, few studies have explored the diversity of the algal and cyanobacterial composition of periphyton mats in temperate lakes. In this study, we sampled periphyton from three New Zealand lakes: Tikitapu (oligotrophic), Ōkāreka (mesotrophic) and Rotoiti (eutrophic). Statistical analysis of morphological data showed a clear delineation in community structure among lakes and highlighted the importance of cyanobacteria. Automated rRNA intergenic spacer analysis (ARISA) and 16S rRNA gene clone libraries were used to investigate cyanobacterial diversity. Despite the close geographic proximity of the lakes, cyanobacterial species differed markedly. The 16S rRNA gene sequence analysis identified eight cyanobacterial OTUs. A comparison with other known cyanobacterial sequences in GenBank showed relatively low similarities (91–97%). Cyanotoxin analysis identified nodularin in all mats from Lake Tikitapu. ndaF gene sequences from these samples had very low (≤ 89%) homology to sequences in other known nodularin producers. To our knowledge, this is the first detection of nodularin in a freshwater environment in the absence of Nodularia. Six cyanobacteria species were isolated from Lake Tikitapu mats. None were found to produce nodularin. Five of the species shared low (< 97%) 16S rRNA gene sequence similarities with other cultured cyanobacteria.

text: Species composition and cyanotoxin production in periphyton mats from three lakes of varying trophic status In lakes, benthic micro-algae and cyanobacteria (periphyton) can contribute significantly to total primary productivity and provide important food sources for benthic invertebrates. Despite recognition of their importance, few studies have explored the diversity of the algal and cyanobacterial composition of periphyton mats in temperate lakes. In this study, we sampled periphyton from three New Zealand lakes: Tikitapu (oligotrophic), Ōkāreka (mesotrophic) and Rotoiti (eutrophic). Statistical analysis of morphological data showed a clear delineation in community structure among lakes and highlighted the importance of cyanobacteria. Automated rRNA intergenic spacer analysis (ARISA) and 16S rRNA gene clone libraries were used to investigate cyanobacterial diversity. Despite the close geographic proximity of the lakes, cyanobacterial species differed markedly. The 16S rRNA gene sequence analysis identified eight cyanobacterial OTUs. A comparison with other known cyanobacterial sequences in GenBank showed relatively low similarities (91–97%). Cyanotoxin analysis identified nodularin in all mats from Lake Tikitapu. ndaF gene sequences from these samples had very low (≤ 89%) homology to sequences in other known nodularin producers. To our knowledge, this is the first detection of nodularin in a freshwater environment in the absence of Nodularia. Six cyanobacteria species were isolated from Lake Tikitapu mats. None were found to produce nodularin. Five of the species shared low (< 97%) 16S rRNA gene sequence similarities with other cultured cyanobacteria.

year: 2012-02

title: Highly specialized microbial diversity in hyper-arid polar desert

authors: Pointing, Stephen B.

subjects: Antarctica

abstract: The McMurdo Dry Valleys in Antarctica are a cold hyperarid polar desert that present extreme challenges to life. Here, we report a culture-independent survey of multidomain microbial biodiversity in McKelvey Valley, a pristine example of the coldest desert on Earth. We demonstrate that life has adapted to form highly-specialized communities in distinct lithic niches occurring concomitantly within this terrain. Endoliths and chasmoliths in sandstone displayed greatest diversity, whereas soil was relatively depauperate and lacked a significant photoautotrophic component, apart from isolated islands of hypolithic cyanobacterial colonization on quartz rocks in soil contact. Communities supported previously unreported polar bacteria and fungi, but archaea were absent from all niches. Lithic community structure did not vary significantly on a landscape scale and stochastic moisture input due to snowmelt resulted in increases in colonization frequency without significantly affecting diversity. The findings show that biodiversity near the cold-arid limit for life is more complex than previously appreciated, but communities lack variability probably due to the high selective pressures of this extreme environment.

text: Highly specialized microbial diversity in hyper-arid polar desert The McMurdo Dry Valleys in Antarctica are a cold hyperarid polar desert that present extreme challenges to life. Here, we report a culture-independent survey of multidomain microbial biodiversity in McKelvey Valley, a pristine example of the coldest desert on Earth. We demonstrate that life has adapted to form highly-specialized communities in distinct lithic niches occurring concomitantly within this terrain. Endoliths and chasmoliths in sandstone displayed greatest diversity, whereas soil was relatively depauperate and lacked a significant photoautotrophic component, apart from isolated islands of hypolithic cyanobacterial colonization on quartz rocks in soil contact. Communities supported previously unreported polar bacteria and fungi, but archaea were absent from all niches. Lithic community structure did not vary significantly on a landscape scale and stochastic moisture input due to snowmelt resulted in increases in colonization frequency without significantly affecting diversity. The findings show that biodiversity near the cold-arid limit for life is more complex than previously appreciated, but communities lack variability probably due to the high selective pressures of this extreme environment.

year: 2009-11-24

title: Romeo and Tusi: An eclectically musical Samoan/Māori Romeo and Juliet from Aotearoa/New Zealand

authors: Houlahan, Mark

subjects: Romeo and Tusi

abstract: Is there a distinctive New Zealand Shakespeare? What ‘new’ approaches to Shakespeare have originated from New Zealand? This article explores the issue by contextualising a version of Romeo and Juliet staged successfully throughout New Zealand in the late 1990s. The production is set against the background of the history of Shakespeare in New Zealand, which goes back to the arrival of Captain Cook on the Endeavour in 1769.

Pacific Underground's Romeo and Tusi sought a looser and more populist kind of Shakespeare performance. They used the conceit of rehearsing the play at high school, where a Māori Romeo and a Samoan Juliet cross community boundaries. Drawing on several music genres, and performing outdoors, they generated a Shakespeare that audiences from a diverse range of ethnic and cultural communities could enjoy.

text: Romeo and Tusi: An eclectically musical Samoan/Māori Romeo and Juliet from Aotearoa/New Zealand Is there a distinctive New Zealand Shakespeare? What ‘new’ approaches to Shakespeare have originated from New Zealand? This article explores the issue by contextualising a version of Romeo and Juliet staged successfully throughout New Zealand in the late 1990s. The production is set against the background of the history of Shakespeare in New Zealand, which goes back to the arrival of Captain Cook on the Endeavour in 1769.

Pacific Underground's Romeo and Tusi sought a looser and more populist kind of Shakespeare performance. They used the conceit of rehearsing the play at high school, where a Māori Romeo and a Samoan Juliet cross community boundaries. Drawing on several music genres, and performing outdoors, they generated a Shakespeare that audiences from a diverse range of ethnic and cultural communities could enjoy.

year: 2009