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Nanoflagellates of southern Tasmanian waters : taxonomy, toxicology and distribution

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LeRoi, Jeannie-Marie (2000) Nanoflagellates of southern Tasmanian waters : taxonomy, toxicology and distribution. Research Master thesis, University of Tasmania.

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Abstract

A taxonomic survey of scale-bearing nanoflagellate algae from southern Tasmanian
coastal waters was undertaken. Observations were made on 52 samples collected
from 21 different sites (June 1994 - 1995) and resulting enrichment cultures. Scale
morphology was examined using transmission electron microscopy.
Over 70 species of scale-bearing nanoflagellates from four classes and 17 genera
were illustrated, namely: Chrysophyceae - Apedinella, Chrysolepidomonas,
Meringosphaera, Paraphysomonas (8 spp); Prymnesiophyceae - Chrysochromulina
(32 spp), Corymbellus, Imantonia, Pavlova, Phaeocystis (2 spp), Prymnesium
(2 spp); Prasinophyceae - Dolichomastix (2 spp), Mamiella, Mantomiella,
Pyramimonas (7 spp); Dinophyceae - Heterocapsa; and, of uncertain taxonomic
affinities, Petasaria and Thaumatomastix (3 spp).
Seventeen of the nanoflagellate species found were new records for Australian
waters, specifically: Chrysochromulina acantha, C. ahrengotii, C. aff.
brachycylindra, C. aff. camella, C. mactra, C. aff. scutellum, Pavlova pin guis,
Chrysolepidomonas cf. marina, Paraphysomonas antarctica, P. bandaiensis, P.
foraminfera, P. cf. takahashii, Dolichomastix nummulifera, D. aff. tenuilepis,
Mamiella gilva, Petasaria heterolepsis and Thaumatomastix cf. thomseni. All
species, except one (Chrysochromulina novae-zelandiae), are also known from the
northern hemisphere.
Two known toxic species, Chysochromulina polylepsis and C. leadbeateri,
responsible for massive fish kills in Scandinavia, were found in this survey, as well
as the known fish-killing species, Prymnesium patellife rum, observed from two
important Tasmanian oyster-growing area, and subsequently cultured. The biodiversity of scale-bearing nanoflagellates in Tasmanian waters was
highlighted by the large number of previously unreported scale types seen, including
over 17 Chrysochromulina-like scale types, five prasinophyte box scale types and
five Thaumatomastix-like scale types, but lack of complete cells prevented new
species decriptions. However, sufficient material was available to fully characterise
two new Chrysochromulina species. Full species descriptions will be prepared in the
primary literature in the near future. The biodiversity of scale-bearing nanoflagellates in Tasmanian waters was
highlighted by the large number of previously unreported scale types seen, including
over 17 Chrysochromulina-like scale types, five prasinophyte box scale types and
five Thaumatomastix-like scale types, but lack of complete cells prevented new
species decriptions. However, sufficient material was available to fully characterise
two new Chrysochromulina species. Full species descriptions will be prepared in the
primary literature in the near future. Over 20 unialgal strains, with representatives from each observed class, were isolated
from enrichment cultures and maintained; these included Chrysochromulina
(8 strains), Pavlova (4 strains), Prymnesium (6 strains), Phaeocystis globosa,
Pyramimonas grossii, Heterocapsa rotundata and Chrysolepidomonas cf. marina.
Toxicity testing of 26 scale-bearing nanoflagellate strains was undertaken, using
larval brine shrimp (Artemia) bioassays. Prymnesium patelliferum, was found to be
toxic, with 100% mortality of Artemia nauplii after 24 hours exposure to stationary
phase cultures, and toxicity of this species was enhanced when grown in phosphatedeplete
media. Heterocapsa rotundata caused low percentage mortality (12.5%) of
Artemia nauplii under the same bioassay conditions. This is a novel record of toxicity
for this widespread dinoflagellate, and agrees with recent confirmation of toxicity to
bivalves by the related species, H. circularisquama. None of the other nanoflagellate
strains tested were found to be toxic.
A potential new live food species for aquaculture, Pavlova pin guis, was identified
using a combination of ultrastructural and morphological features. This species is
now used in commercial Tasmanian oyster hatcheries as a valuable algal diet.

Item Type: Thesis (Research Master)
Keywords: Phytoplankton, Toxic marine algae
Copyright Holders: The Author
Copyright Information:

Copyright 2000 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

No copying until 1/9/2002. Thesis (M.Sc.)--University of Tasmania, 2000. Includes bibliographical references

Date Deposited: 19 Dec 2014 02:40
Last Modified: 14 Jul 2017 06:15
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