Morphological, molecular and toxigenic characteristics of Namibian Pseudo-nitzschia species – including Pseudo-nitzschia bucculenta sp. nov.


Contact
Bernd.Krock [ at ] awi.de

Abstract

A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P. bucculenta F. Gai, C. K. Hedemand, N. Lundholm & Ø. Moestrup sp. nov. Molecular and morphological diversity of the Namibian Pseudo-nitzschia species is discussed. Most importantly, P. bucculenta is both morphologically and phylogenetically most similar to P. dolorosa differing mainly in valve width and densities of striae, poroids and band striae as well as by four hemi-compensatory base changes in the ITS2. Morphological and molecular differences among the strains of P. decipiens suggest a temperate and a warm water subdivision. The geographical and toxigenic characteristics of the identified Pseudo-nitzschia species are described and compared to previous studies. Initial tests of toxin production in all seven species revealed production of domoic acid (DA) in two species: one strain of P. australis (0.074 pg DA cell−1) and two strains of P. plurisecta (0.338 pg DA cell−1 and 0.385 pg DA cell−1).



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
47348
DOI https://www.doi.org/10.1016/j.hal.2018.05.003

Cite as
Gai, F. F. , Hedemand, C. K. , Louw, D. C. , Grobler, K. , Krock, B. , Moestrup, Ø. and Lundholm, N. (2018): Morphological, molecular and toxigenic characteristics of Namibian Pseudo-nitzschia species – including Pseudo-nitzschia bucculenta sp. nov. , Harmful Algae, 76 , pp. 80-95 . doi: https://www.doi.org/10.1016/j.hal.2018.05.003


Download
[thumbnail of Gai_2018.pdf]
Preview
PDF
Gai_2018.pdf

Download (4MB) | Preview

Share


Citation

Geographical region

Research Platforms
N/A

Campaigns
N/A


Actions
Edit Item Edit Item