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The diatom genus pseudo-nitzschia (bacillariophyceae)in New South Wales, Australia: Morphotaxonomy, molecular phylogeny, toxicity, and distribution

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Ajani, P and Murray, S and Hallegraeff, GM and Lundholm, N and Gillings, M and Brett, S and Armand, L (2013) The diatom genus pseudo-nitzschia (bacillariophyceae)in New South Wales, Australia: Morphotaxonomy, molecular phylogeny, toxicity, and distribution. Journal of Phycology, 49. pp. 765-785. ISSN 0022-3646

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Abstract

Species belonging to the potentially harmful
diatom genus Pseudo-nitzschia, isolated from 16
localities (31 sampling events) in the coastal waters
of south-eastern Australia, were examined. Clonal
isolates were characterized by (i) light and
transmission electron microscopy; (ii) phylogenies,
based on sequencing of nuclear-encoded ribosomal
deoxyribonucleic acid (rDNA) regions and, (iii)
domoic acid (DA) production as measured by liquid
chromatography–mass spectrometry (LC-MS/MS).
Ten taxa were unequivocally confirmed as Pseudonitzschia
americana, P. arenysensis, P. calliantha,
P. cuspidata, P. fraudulenta, P. hasleana, P. micropora,
P. multiseries, P. multistriata, and P. pungens. An
updated taxonomic key for south-eastern Australian
Pseudo-nitzschia is presented. The occurrence of two
toxigenic species, P. multistriata (maximum
concentration 11 pg DA per cell) and P. cuspidata
(25.4 pg DA per cell), was documented for the first
time in Australia. The Australian strains of
P. multiseries, a consistent producer of DA in strains
throughout the world, were nontoxic. Data from
5,888 water samples, collected from 31 oystergrowing
estuaries (2,000 km coastline) from 2005 to
2009, revealed 310 regulatory exceedances for
“Total Pseudo-nitzschia,” resulting in six toxic
episodes. Further examination of high-risk estuaries
revealed that the “P. seriata group” had highest cell
densities in the austral summer, autumn, or spring
(species dependent), and lowest cell densities in the
austral winter, while the “P. delicatissima group” had
highest in winter and spring.

Item Type: Article
Journal or Publication Title: Journal of Phycology
Page Range: pp. 765-785
ISSN: 0022-3646
Identification Number - DOI: 10.1111/jpy.12087
Additional Information:

2013 Phycological Society of America

Date Deposited: 04 Nov 2013 03:39
Last Modified: 18 Nov 2014 04:56
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