Historic overview of algal blooms in marine and estuarine waters of New South Wales, Australia

22 Pages·2001·9.4 MB·

by  P Ajani

Historic Overview ofAlgal Blooms in Marine and
Estuarine Waters of New South Wales, Australia
PenelopeAjani1 Gustaaf Hallegraeff 2and Tim Pritchard1
,
'Water Science Section, Environment ProtectionAuthority, New SouthWales, PO Box
A290 Sydney South, NSW, 1232,Australia
2School ofPlant Science, University ofTasmania, GPO Box 252-55, Hobart,
Tasmania, 7001,Australia
Ajani, P., Hallegraeff, G. and Pritchard, T. (2001). Historic overview ofalgal blooms in
marine and estuarine waters ofNew South Wales, Australia. Proceedings ofthe
LinneanSocietyofNewSouth Wales 123, 1-22.
AcompendiumofalgalbloomreportsformarineandestuarinewatersofNewSouth
Wales,Australia,fortheperiod 1890-1999ispresented.Themajorityofbloomshavebeen
harmlesswaterdiscolourationspredominantlycausedbythelargeheterotrophicdinoflagellate
Noctilucascintillans,orthefilamentouscyanobacteriumTrichodesmiumerythraeum.Other
harmless species thathavebloomed includethe dinoflagellates Gymnodinium sanguineum
(=Akashiwosanguined)andProrocentrumminimum,thesurfdiatomAnaulusaustralis,the
coccolithophoridGephyrocapsaoceanicaandtheciliateMesodinium rubrum. Speciesthat
have produced blooms and are potentially harmful to marine organisms include the
silicoflagellate Dictyocha octonaria, the dinoflagellates Gonyaulax polygramma and
Scrippsiellatrochoideaandthediatoms Thalassiosiraspp. andChaetocerosspp.Thetoxic
raphidophyte species Heterosigma akashiwo, Chattonella cfglobosa andHaramonas sp.,
the dinoflagellates Gymnodinium galatheanum (= Karlodinium micrum), Dinophysis
acuminataandAlexandriumcatenella,andthediatomsPseudo-nitzschiamultiseriesandP.
australishavealsobeenidentifiedasbloom-formingspeciesinthesewaters.
Reportsofalgalbloomshaveapparentlyincreasedconsiderablysince 1990but
thedatamaybebiasedbecauseoftheadhocnatureofthesereports.Forthisreasonitis
difficulttoidentifythecause(s)ofthisapparentincreaseinbloomfrequency.Contributing
factorsmayincludetheexpansionincoastalsettlements,anincreaseinawarenessof
environmentalissuessuchaswaterquality,possiblechangesinanthropogenicnutrient
inputand/ortheeffectsoflarge-scaleoceanographicphenomenaand/orclimatechange.
Manuscriptreceived22August2001,acceptedforpublication24October2001.
KEYWORDS: algalbloom,ciliate,coccolithophorid,cyanobacterium,diatom,
dinoflagellate,estuaries,raphidophyte,silicoflagellate.
INTRODUCTION
Fluctuations in the nutrient status ofcoastal waters, either ofnatural origin or
associated with anthropogenic disturbances, can lead to changes in species composition
and abundance ofmarine andestuarine microalgae. This mayresultin algal blooms that
threatenfishresources,humanhealthandecosystemfunctionandtherecreationalamenity
ofbeaches andembayments. Otheralgalblooms are simplyharmless, transientpulsesin
responsetoepisodicnutrientenrichmentsuchasfromcoastalupwellingevents (Smayda
1997). Whatever factors affect theirformation, the focus on algal blooms is increasing.
Proc.Linn. Soc.N.S.W., 123.2001
2 ALGALBLOOMSINN.S.W.
Globalevidenceis emerging ofanapparentincreaseinthedistributionandfrequency
of algal blooms (Hallegraeff 1993).
Eutrophication can lead to enhanced phytoplankton growth (including
nuisance and/or toxic algal blooms) or a change in the species composition of
phytoplankton and other organisms (Oviatt et al. 1989; Graneli and Moreira 1990;
Riegman etal. 1992; Pan and Rao 1997). Hallegraeffreviewedharmful algal blooms
in the Australian region in 1992 and suggested that from the 1970s to the 1990s
there had been an escalation ofharmful blooms inAustralian marine and estuarine
waters. Consequently, algal blooms have been targeted as a key environmental
indicator for long term monitoring in Australian waters (Ward et al. 1998). There
is, however, no systematic reporting of algal blooms in New South Wales (NSW)
marine and estuarine waters.
The NSWcoastline is 1,900kmin length andranges from warm subtropical
inthenorthto cooltemperateinthe south (Fig. 1). Ithas approximately 700beaches;
with large sandy beaches in the north and smallerpocketbeaches boundedbyrocky
headlands in the south. It is naturally divided into three regions based on broad
oceanographic characteristics and the geological structure of the coastline (EPA
1995). The northern region is under the dominant influence of the warm East
Australian Current, while the coolerwaters and currents from Bass Strait influence
the southern region. The central region is a mixed zone. The majority ofthe human
population (6.3 million) is concentrated in the central zone in three major cities,
Sydney, Newcastle andWollongong, and all ofthese cities are associated with major
NSW
estuaries. Increasedpressures on the entire coastal zone (population increase
and coastal development, tourism, water quality and sewage disposal) mean that
thepotential foralgal blooms is increasing. TheNSWaquaculture industry,presently
worth $42-45 million, is projected to increase to $250 million by 2010.
A three-year ocean nutrient and phytoplankton study carried out by the
New SouthWalesEnvironmentProtectionAuthority (NSWEPA) hasbeencompleted
recently (1995-1998). That study characterised ambientnutrientconcentrations and
more specifically, identifiedthe relative significance ofvarious sources ofnutrients
in NSWoffshore coastal waters. The focus ofthe investigation was on the extent of
slope water intrusions and their associated nutrient concentrations, comparing this
to anthropogenic nutrientinputs, including the three majordeepwaterocean outfalls
and estuarine discharges. Phytoplankton blooms at various locations along coastal
NSW were related to this information. As part of this study the Commonwealth
Scientific and Industrial Research Organisation (CSIRO) long-term 100m coastal
station off Port Hacking was revisited in 1997-98 to investigate phytoplankton
patterns and their hydrological environment and to compare these patterns to
previous investigations atthe same location (Ajaniet al. 2001). Itis useful to discuss
recorded algal blooms in light ofthese data, as well as the links found between the
environmental variables (factors which may promote algal blooms) and the
phytoplankton community composition.
Three types of algal blooms can be distinguished - those that are harmless
water discolourations, potentially harmful to marine organisms (although non-toxic)
orpotentially toxic tohumans. Human illness associated with harmful algae is due to
the naturally occurring toxins which are transferred to humans through the
consumption ofseafood products. Themostsignificantpublic healthproblemscaused
by harmful algae are Amnesic Shellfish Poisoning (ASP), Ciguatera Fish Poisoning
CCFP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP)
and Paralytic Shellfish Poisoning (PSP). Each of these syndromes is the result of
different causative organisms that produce a range of toxins and risks to humans.
These have been discussed by various authors (Taylor 1990; Hallegraeff 1991, 1992,
1993; Smayda 1997). Except for ASP (which is caused by diatoms), all other
syndromes are caused by biotoxins synthesised by dinoflagellates.
Proc.Linn. Soc. N.S.W., 123. 2001
P.AJANI,G.HALLEGRAEFFANDT.PRITCHARD
Figure 1.MapofNewSouthWalescoastalzone
CentralCoasif
HawkesburyRiver«
SydneyHafbotUfParamatfaRiver
PortHacking*
Woitongong*
200 km
Potentially toxic phytoplankton arenotalways toxicinevery situation andit
is anticipated that in the future other phytoplankton species may prove to be toxic
undercertain conditions (UNESCO 1995). In addition, the factors thatpromote algal
populations to significantly increase (deviate from their normal cycle of biomass,
i.e. to 'bloom') are varied.Arange ofphysical, chemical andbiological variables are
involved andthere may be quite different bloom determinants depending on the type
and location ofthe water body (eg estuarine versus offshore waters).
Methods and DataAssessment
This paper discusses visible bloom events that have been recorded in NSW
NSW
marine (coastal and offshore) and estuarine waters. Various government
agencies, localcouncils, waterauthorities, universities andthepublichavecontributed
tothesedata. Publishedreferencestothesebloomshavebeenusedwhereverpossible.
NSW
Otherdatahavebeencollatedfrom EnvironmentProtectionAuthority [formally
theStatePollutionControl Commission (SPCC)] unpublishedfilereports and similar
reports from Australian Water Technologies (AWT). Suitably qualified scientific
officers (including the authors) identified the causative organisms in these bloom
incidents. Blooms listed as "unidentified" were not examined by scientific officers
forvariousreasons suchasno samplewascollectedorbecauseofsampledeterioration
prior to examination. Other potentially harmful species have also been identified in
these waters but have not yet reached bloom proportions. These are also referenced
and discussed.
Proc.Linn. Soc.N.S.W., 123.2001
ALGALBLOOMSINN.S.W.
Table 1. HarmlessalgalbloomsrecordedinNew SouthWales'smarine(M)andestuarine(E)waters
Date Location Bloom Taxa
July-Aug30-32 SydneyHarbour(E) Gymnodiniumsanguineum^
Oct-72 TareeandCoffsHarbour(M) Trichodesmium sp3
Dec-72 PalmBeachtoCronulla(M) Trichodesmiumsp3
Oct-80 AlexandraCanal(CooksRiver, Sydney)(E) Gymnodiniumsanguineum3
Oct-81 LaneCoveRiver(Sydney)(E) Gymnodiniumsanguineum3
Aug-82 LakeMacquarie(CentralCoast)(E) Noctilucascintillans3
Dec-83 Newcastle,Narrabeen,Foster,BondiBeach(M) Trichodesmiumsp3
Apr-84 LaneCoveRiver(Sydney)(E) Mesodiniumrubrum3
Nov-84 LaneCoveRiver(Sydney)(E) Mesodinium rubrum3
Dec-84 SydneytoWollongong(M) Trichodesmiumsp3
Feb-86 LaneCoveRiver(Sydney)(E) Mesodiniumrubrum3
Jan-89 SydneycoastalwatersandJervisBaytoUlladulla(M) Trichodesmium sp3
Aug-92 LakeMacquarie(CentralCoast)(E) Noctilucascintillans3
Sep-92 BerowraCreek(HawkesburyRiver)(E) N. scintillans/G. sanguineum3
Dec-92 JervisBay(M) Gephyrocapsaoceanica2
Jan-93 SydneybeachesandPortKembla(M) Noctilucascintillans3
Jun-93 LakeIllawarra(E) Noctilucascintillans4
1994 BerowraCreek(HawkesburyRiver)(E) Gymnodiniumsanguineum4
Feb-94 Sydneynorthernbeaches (M) Noctilucascintillans4
Apr-94 Ham&ChickenBay(E) Noctilucascintillans3
Jul-94 BerowraCreek(HawkesburyRiver)(E) Pseudonitzschiapungens4
Nov-94 Sydneynorthernbeaches(M) Noctilucascintillans4
Nov-94 OffshorefromPortHackingandWollongong(M) Noctilucascintillans4
Nov-94 NarrabeenLakes(Sydney)(E) Noctilucascintillans4
Dec-94 NewcastleBeach(M) Noctilucascintillans4
Dec-94 JervisBay(M) Noctilucascintillans4
Mar-95 PearlBeach(Sydney)(M) Noctilucascintillans4
Mar-95 BerowraCreek(HawkesburyRiver)(E) Prorocentrumminimum4
Aug-95 NorthHarbour(Sydney)(M) Gymnodiniumsanguineum4
Sep-95 OffshorefromSydneyHeads(M) Noctilucascintillans4
Oct-95 OffshorefromBoatHarbourandAnnaBay(M) Trichodesmiumerythraeum4
Feb-96 StanwellParktoAstinmer(M) Noctilucascintillans4
Feb-96 WamberalBeach(CentralCoast) (M) Noctilucascintillans4
Mar-96 SussexInlet(E) Noctilucascintillans4
Mar-96 ParadiseBeach(StGeorgesBasin)(E) Noctilucascintillans4
Mar-96 HymansBeach(JervisBay) Noctilucascintillans4
Mar-96 SussexInlet(E) Noctilucascintillans4
Aug-96 ShelleyBeach(Manly)(M) Mesodiniumrubrum4
Aug-96 GreenwichBaths(ParramattaRiver)(E) Mesodiniumrubrum4
Oct-96 OffshorefromBoatHarbourandAnnaBay(M) Trichodesmiumerythraeum4
Oct-96 PortStephenstoBroughton Island(M) Trichodesmiumerythraeum4
Oct-96 Manly(Sydney)(M) Noctilucascintillans4
Jan-97 SydneyBeaches(WarriewoodtoManly) (M) Noctilucascintillans4
Jan-97 Evans HeadandCoffsHarbour(M) Trichodesmiumerythraeum4
Jan-97 StGeorgesBasin andJervisBay (M) Noctilucascintillans4
Jan-97 ToowoonBayandsouthtoBateau Bay (M) Noctilucascintillans4
Jan-97 PortStephens(M) Noctilucascintillans4
Feb-97 Centra] Coast (M) Noctilucascintillans4
Feb-97 JervisBay (M) Noctilucascintillans4
Feb-97 SydneyBeaches (CollaroytoCoogee)(M) Noctilucascintillans4
Feb-97 ColedaletoAstinmer(M) Noctilucascintillans4
Feb-97 Manly (Sydney)(M) Noctilucascintillans4
Proc.Linn. Soc. N.S.W., 123. 2001
P.AJANI,G.HALLEGRAEFFANDT.PRITCHARD
Feb-97 Warriewood(Sydney)(M) Noctilucascintillans4
Feb-97 Vincentia(JervisBay)(M) Noctilucascintillans4
Feb-97 BerowraCreek(HawkesburyRiver)(E) Pseudonitzschiapungens4
Apr-97 FrenchmansBay (BotanyBay)(E) Noctilucascintillans4
Apr-97 LakeMacquarie(E) Noctilucascintillans4
Jul-97 StocktonBighttoBirubiPoint(M) Anaulusaustralis4
Aug-97 BassPoint(Sydney)(M) Noctilucascintillans4
Sep-97 St. George'sBasinBeach(E) Noctilucascintillans4
Sep-97 OtfordandWerrong(RoyalNationalPark)(M) Noctilucascintillans4
Oct-97 Newcastle(M) Noctilucascintillans4
Dec-97 IllawarraRegion(M) Noctilucascintillans4
Dec-97 SydneynorthernbeachesandPortStephens(M) Noctilucascintillans4
Jan-98 SydneynorthernbeachesandCentralCoast(M) Noctilucascintillans4
Jan-98 BoatHarbourtoBoulderBay (M) Trichodesmiumeiythraeum4
Jan-98 StanwellParktoKiama(M) Noctilucascintillans4
Jan-98 CronullaandIllawarraRegion(M) Noctilucascintillans4
Jan-98 BatemansBay(M) Noctilucascintillans4
Feb-98 Cronulla(M) Noctilucascintillans4
Feb-98 Clifton(Illawarraregion)(M) Noctilucascintillans4
Feb-98 WhaleBeach(Sydney)(M) Noctilucascintillans4
Feb-98 CollaroyBeach(Sydney)(M) Noctilucascintillans4
Mar-98 SydneybeachesandBonnieHill(CoffsHarbour)(M) Noctilucascintillans4
Mar-98 CoffsHarbour(M) Trichodesmiumerythraeum4
Mar-98 EvansHead(M) Trichodesmiumerythraeum4
Apr-98 WollongongandBatemansBay(M) Trichodesmiumerythraeum4
Apr-98 RichmondRiver(Ballina)(M) Trichodesmiumeiythraeum4
May-98 WallagaLake(E) Noctilucascintillans4
Aug-98 StGeorgesBasin(E) Noctilucascintillans4
Sep-98 LakeMacquarie(E) Noctilucascintillans4
Sep-Oct-98 GudgenCreek(Kingscliff,Grafton)(E) Trichodesmiumerythraeum4
Oct-98 BerowraCreek(HawkesburyRiver)(E) Pseudo-nitzschia4
pseudodelicatissima4
Dec-98 IllawarraRegion(ThirroulandCoalcliff)(M) Noctilucascintillans4
Dec-98 NorthCoastNSW(variousreports)(M) Trichodesmiumeiythraeum4
Dec-98 LakeIllawarra(E) Noctilucascintillans4
Jan-99 NorthCoastNSW(variousreports)(M) Trichodesmiumerythraeum4
Mar-99 OffshorefromJervisBay Trichodesmiumerythraeum4
Oct-99 RichmondRiverE Trichodesmiumerythraeum4
Nov-99 LakeIllawarra(E) Noctilucascintillans4
Nov/Dec-99 SevenMileBeach(Gerringong)(M) Anaulusaustralis4
Dec-99 Sydneynorthernbeaches(M) Noctilucascintillans4
DakinandColefax 1933,2BlackburnandCresswell 1993,3Hallegraeff 1995,4EPAunpublished
RESULTS
HarmlessAlgal Blooms
The majority ofvisible algal blooms in NSW coastal waters havebeen harmless
water discolourations (Table 1). Mostofthese blooms were ofthe large (200-800|im cell
diameter)heterotrophicdinoflagellateNoctilucascintillans 'Redtides' ofthisspecieshave
beenreportedin offshore, coastal andestuarine waters including coastal lagoons ofNSW.
Themajorityofbloomsoccurredin springandsummerandespeciallyafterheavyrainfall.
Alsothe resultanthigh ammoniacontentreleased aftercell lysis may irritatefishthatwill
generally avoidthebloom area (Okaichi andNishio 1976).
Proc.Linn.Soc.N.S.W., 123. 2001
ALGALBLOOMSINN.S.W.
Figure 2a. LM. Filamentous cyanobacterium Trichodesmium erythraeumproducing raft-like bundles, up to
750(imlong;b.LM. Balloon-shaped,colourlessdinoflagellateNoctilucascintillans, 200-500pmdiameter;
c.SEM.DinoflagellateGonyaulaxpolygramma,showingornamentedcelluloseplateswithlongitudinalridges,
cells 29-66 pm long; d. LM. Large, 50-80 |lm long, unarmoured dinoflagellate Gymnodinium sanguineum
("sanguineum"=blood);e.SEM.CalcareousnanoplanktonGephyrocapsaoceanica, 15pmdiameter;f.SEM.
Triangular, armoured dinoflagellatecells, 10-15 pm wide, ofProrocentrum minimum, covered with minute
spinules; g. TEM. weakly silicified cell ofthecentric diatom Thalassiosirapartheneia, 10 pm diameter; h.
TEM.PennatediatombloomofPseudo-nitzschiapseudodelicatissima. Cells57to 150pmlong.
Proc.Linn-. Soc.N.S.W., 123. 2001
P.AJANI,G.HALLEGRAEFFANDT.PRITCHARD 7
NSW
N. scintillans ( Fig. 2b) has long been present in waters with its earliest
record being related to its bioluminescent properties which were observed in Sydney
Harbour by Bennett in 1860. In 1933 Dakin and Colefax referred to this species as a
relatively minor component of the phytoplankton community in NSW coastal waters.
Hallegraeff (1995) collated an historic overview of visible algal blooms in Australian
waters with the first visible bloom ofN. scintillans recorded in NSW waters inAugust
1982 (Lake Macquarie, central NSW). Since then, N. scintillans blooms appear to have
increasedinfrequencyandintensity(maximumcelldensityrecordedas5 x 104cells/Lin
Jervis Bay February 1997). Over a one year sampling period fromApril 1997 to April
1998attheCSIROlong-termcoastalstationoffPortHacking,Ajanietal. (1999)observed
N. scintillans in 61% ofsamples and was absent from avery few samples in the autumn
andwintermonths.Thehighfrequencyofoccurrenceforthis specieswasunprecedented
inthesewaters.Thisincreasecomparedtoearlierstudiesreinforcestheneedtoinvestigate
theglobalpotentialofNoctiluca as an indicatorofcoastaleutrophication (Porumb 1992;
Qi et al. 1993; Lu et al. 1994; Huang and Qi 1997).
The cyanobacterium Trichodesmium erythraeum ( Fig. 2a) is also a common
NSW
'red tide' organism in coastal waters. This tropical/subtropical species produces
episodic blooms that were historically reported as 'sea sawdust' during Captain Cook's
voyage through the Coral Sea (Cribb 1969). The filaments of this alga are united into
smallbundlesthatarejustvisibletothenakedeye (~lmm). Blooms aremostcommonly
seeninnorthernNSWwatersinspring,summerandearlyautumnwhentheEastAustralian
Current (EAC) transports these algal masses into NSWfrom Queensland waters. These
blooms can appearyellow-grey in theirearly stages, while laterthey become areddish-
brown. Recentreports (Hahn andCapra 1992; Endean etal. 1993) suggestthatthis alga
can produce compounds with a mouse intraperitoneal potency but this requires further
investigation.
Various T. erythraeumbloomshaveoccurredinNSWwaterswithaparticularly
large bloom recorded on the south coast (Batemans Bay - south coast NSW) in early
April 1998. Satellite imagery from NSW at his time showed unusually warm water
NSW
throughout the south coast area. This suggested that a strong manifestation ofthe
EAC transported and conceivably triggered the extensive-71 erythraeum bloom in
Batemans Bay (ClydeRiverestuary). The annual distribution ofthis species as reported
byAjanietal. (1999)fromthePortHacking 100mstationalsoshowspeakconcentrations
ofthis species in the coastal waters offSydney in mid-April when surface waters were
>~22°C.
Gymnodiniumsanguineum ( Fig. 2d), alarge non-toxic dinoflagellate, has producedred
NSW
waterdiscolourations in estuarine waters on several occasions (Hallegraeff 1991).
Dakin and Colefax (1933) reported the first blooms in Sydney Harbour in July-August
1930, 1931 and 1932. Furtherblooms ofthis species have occurred in the Cooks River/
AlexandraCanal (Sydney)in October 1980,LaneCoveRiverin October 1981, Berowra
Creek (a tributary of the Hawkesbury River estuary) in 1992 and 1994, and in North
Harbour, Sydney inAugust 1995. This species has recently been renamed asAkashiwo
sanguinea (Daugbjerg et al. 2000)
Another dinoflagellate that is common in the plankton ofAustralian waters is
Prorocentrum minimum ( Fig. 2f). This small ovate species can form extensive blooms
andalthoughithasbeencircumstantiallylinkedwithashellfish-poisoningeventinNorway
in 1979 (venerupin poisoning), no toxic events have occurred in Australia to date
(Hallegraeff 1991). In March 1995, this species bloomed in Berowra Creek. Each year
this species becomes a dominant component of the phytoplankton in this reach of the
Hawkesbury River. In offshore waters, maximum concentrations of this species have
been observedin October (Ajani et al. 2001).
Ararelyreported 'surfdiatom',Anaulusaustralis, wasreported as causing oily
slicks along Stockton Beach to Birubi Point (Hunter region) in July 1997 and again in
Proc.Linn. Soc.N.S.W., 123.2001
8 ALGALBLOOMSINN.S.W.
November/December 1999 at Seven Mile Beach (Gerringong). These cells are able to
rise to the surface and form dense accumulations by attaching themselves to wave-
generatedbubblesinhigh-energysurfzones.Inmostcasestheseaccumulationsdisappear
atnightandreappeareachmorning.Thisspecieshadonlypreviouslybeenreportedalong
thesoutherncoastsofSouthAfricaandAustralia (McLachlan andHesp 1984; Campbell
1996).
Beginning in December 1992, the NSW coastal embayment ofJervis Bay was
impacted for four weeks by an unprecedented, mono-specific bloom ofthe small (<10
|Lim) cosmopolitan coccolithophorid Gephyrocapsa oceanica ( Fig. 2e). It has been
proposedthatthecombinationofupwelledcoolnutrient-richslopewaterandaninfluxof
warm EAC waters, providing enhanced upper layer temperatures and an oceanic algal
seed,wastheinitialmechanismcausingthemilkygreenbloom(BlackburnandCresswell
1993). The maximum cell density of2 x 107 cells/L (EPA unpublished) is greater than
any previously recorded ofthis species inAustralian waters.
Deeppurple,redormuddylookingbloomsoftheciliateprotozoanMesodinium
rubrum (=Myrionectra rubrum) ( Fig. 3d) are common in estuarine waters or sheltered
embayments.Theseorganismscontaincryptomonadalgalsymbionts.Bloomshaveusually
been found to coincide with periods of warm and calm weather although no harmful
effects have everbeenrecorded from such blooms (Bary 1953).
Potentially HarmfulAlgal Blooms- Species harmful to marine organisms
Some algal blooms can become so dense that they can cause death to fish and
invertebrates due to either oxygen depletion orby abrasion damage to their gills (Table
2). A silicoflagellate Dictyocha octonaria ( Fig. 3h) was implicated as the causative
organismin afishkill whichoccurredincoastal waters offNewcastleinFebruary 1993.
Dead fish (especially Caranx sp.) were seen on beaches between Burwood Beach and
Redhead and floating up to 3km offshore. While silicoflagellates are regularly seen in
these waters in the spring and summer months (Ajani et al. 2001), abloom event ofthis
NSW
magnitude had neverpreviously beenrecorded in waters (Hallegraeff 1991).
The non-toxic dinoflagellate Gonyaulax polygramma ( Fig. 2c) also has the
potentialtodevelopharmfulanoxic 'redtides'. BloomsinNSWhaveoccurredinSydney
Harbour(MiddleHead,July 1984),DarlingHarbour(January 1993),BateBay(February
1993) and the mostrecent in Lake Macquarie in October 1993.
Both colony-forming diatoms, Thalassiosira partheneia ( Fig. 2g) and T.
weissflogii, havebloomedinNSWcoastalwaters. T.partheneiabloomedinNSWcoastal
watersfromAugusttoSeptember 1985 andwasthedominantbloomspeciesencountered
duringweeklysamplingatthePortHacking 100mstation(Ajanietal.2001). T. weissflogii
bloomed in theAlexandraCanal inFebruary 1986.An unidentified species belonging to
the genus Thalassiosira bloomed at three locations in the Hawkesbury River in March
1999 - BerowraCreek(3 x 106cells/L), Calabash Bay (3 x 106cell/L) andNeverfail (5 x
105cell/L). Despiteoysterleasesbeingnearby, noeconomiclosswasreportedfromthese
blooms. InTokyo Bay in 1951 asimilarspecies, T. mala, bloomedanddamagedthegills
ofcultured bivalves resulting in significant economic loss (Takano 1956).
Red-brownbloomsofthedinoflagellate,Scrippsiellatrochoidea(Fig. 3a),have
NSW
beenreportedin coastalwatersasearlyasthe 1890s(Whitelegge 1891).Thisspecies
has alsocausedwaterdiscolourationsintheHawkesburyRiverinMarch 1991 andJervis
Bay in 1994. Although non-toxic, this commonly occurring species can cause
deoxygenation ofthe water and subsequent fish kills when it blooms in sheltered bays
(Hallegraeff 1991).
A bloom of Chaetoceros spp. occurred in January 1998 in Gunnamatta Bay,
Port Hacking. No harmful effects were observed from this bloom, however large
concentrations ofsome Chaetoceros spp. can potentially damage the gills offish, which
in turnproducemucusthat induceshypoxia(oxygendeficiency inthebody'stissues)and
Proc.Linn. Soc.N.S.W., 123.2001
P.AJANI,G.HALLEGRAEFFANDT.PRITCHARD 9
hypercapnia (excessive amount of carbon dioxide to the blood) (Rensel 1993). The
estuarine bloom coincided with maximum cell densities of this genus at the long-term
station offshore from Port Hacking (Ajani et al. 2001).
Figure 3a. SEM. Red-waterdinoflagellateScrippsiella trochoidea, 16-36 urnlong. Notetube-shapedapical
poreontopofthecellandnearlyequatorial(notdisplaced)girdlegroove;b.LM.Chain-formingdinoflagel-
lateAlexandrium catenella, causative organism ofparalytic shellfish poisoning. Individual cells 20-22 urn
long.;c.SEM.RedwaterdinoflagellateAlexandriumminutum,causativeorganismofparalyticshellfishpoi-
soning.Individualcells24-29amdiameter.Notethehook-shapedapicalporeontopofthecellandcharacter-
isticshapeoftheconnectingfirstapicalplate.;d.LM.CiliateMesodiniumrubrum,30Jimdiameter,withtwo
systems ofcilia arising from the waist region.; e. LM."Raspberry"-like cell of the fish-killing flagellate
Heterosigmaakashiwo("akashiwo"=redtide),containingnumerousdisc-shapedchloroplasts.Cell 11-25um
long.; f.LM. Undescribed flagellate resembling Haramonas. The cell surface is covered by numerous mu-
ccaouussa-tpirvoeduocrignagnivsesmicolfesd.iaCrerlhlesti3c0s-h4e0llufimshlopnogi.so;ng.inSgE.MC.elSlmsa3l8l-a5r8muoumrelodngd.i;nohf.laSgEelMl.atSeiDliincoeopuhsyssikselaectuomnionfattah,e
silicoflagellateDictyochaoctonaria, 10-20umdiameter;i.SEM. Smallunarmoured,fish-killingdinoflagel-
lateGymnodiniumgalatheanum, 15 umdiameter.
Proc.Linn.Soc.N.S.W., 123. 2001
1 ALGALBLOOMSINN.S.W.
Table2.AlgalbloomsrecordedinNewSouthWales'smarine(M)andestuarine(E)waters-
potentiallyharmfultomarineorganisms
Date Location Bloom Taxa
1890 SydneyHarbour(E) Scrippsiellatrochoidea'
July-84 MiddleHead, SydneyHarbour(E) Gonyaulaxpolygramma2
Aug-85 NSWCoast(M) Thalassiosirapartheneia?
Feb-86 AlexandraCanal (CooksRiver, Sydney)(E) Thalassiosiraweissflogii4
Mar-91 HawkesburyRiver(E) Scrippsiellatrochoidea4
Jan-93 DarlingHarbour(Sydney)(E) Gonyaulaxpolygramma"'
Feb-93 BurwoodBeachtoRedhead(Newcastle)(M) Dictyochaoctonaria4
Feb-93 BateBay(M) Gonyaulaxpolygramma4
Oct-93 LakeMacquarie(E) Gonyaulaxsp5
Mar-95 LakeIllawarra(E) Gymnodiniumcf.
mikimotoi5
Jan-98 GunnamattaBay(PortHacking,Sydney)(E) Chaetocerosspp5
Mar-99 BerowraCreek,CalabashBayandNeverfail Thalassiosirasp5
(HawkesburyRiver)(E)
Dec-99 KiangaLake,NSWSouthcoast(E) Chaetocerosspp.5
1Whitelegge 1890,2SPCCunpublished,3Hallegraeff1991,4Hallegraeff1995,5EPAunpublished
Potentially HarmfulAlgal Blooms - Toxic species
Various algal species arepotentiallytoxictofish andhumans (Fig. 3 andTable
3). Heterosigma akashiwo (= H. carterae) ( Fig. 3e) a toxic raphidophyte, bloomed in
SalamanderBay,PortStephens (1980),BerowraCreek(November 1991,July 1995) and
Sydney Harbour (November and December 1995). These potato-shaped cells contain
numerous ejectosomes that readily discharge (especially upon preservation) making
microscopic identification difficult. The toxicity ofthis species to fish was illustrated in
the Puget Sound (USA) area where fishkills resulted in aconsiderable monetary loss to
the salmonoid aquaculture industry (Rensel et al. 1989). The toxic mechanism of this
species is still underinvestigation although data suggestthat itis through the disruption
ofthe fish gill lamellae. Hypotheses forthis toxicity includepossibleproduction ofhigh
concentrations of superoxide radicals (Yang et al. 1995), the presence ofheterotrophic
bacteriawhichmayexplainthecell'shightoxinvariability(Carrasquero-Verde 1999),or
thepresenceofaneurotoxin whichis similarto,butnotidenticalto,brevetoxin(Kahnet
al 1998)
Another toxic raphidophyte, Chattonella cf. globosa, bloomed sporadically in
Canada Bay, Sydney Harbour, from November 1996 to March 1997. Blooms ofrelated
species have caused significant mortality of cultured yellowtail and red sea bream in
Japanese inland seas (Okaichi 1985) and implicated in the mass mortality of farmed
bluefin tuna in Boston Bay, South Australia in 1996 (Marshall and Hallegraeff 1999).
The production ofsuperoxide radicals as the major mechanism offish mortality is also
hypothesised for this genus. Evidence for brevetoxin-like production is still being
investigated.
A raphidophyte flagellate, Haramonas dimorpha was identified and described
from the mouth of the Daintree River, northeast Australia by Horiguchi in 1996. This
genus is distinguished from other raphidophytes by the cell shape, the possession of a
tubular invagination and a unique arrangement of chloroplasts. In December 1998, a
closely related but as yet undescribed Haramonas species ( Fig. 3f), was implicated in a
fishkill in MorrisonsBay,ParramattaRiver. Rainfall andproximitytoamajorstormwater
canal were possibly contributing factors to bloom development in these waters.
Anothermicroalgaassociatedwith toxicitytofishisGymnodiniumgalatheanum
( Fig. 3i). Between June andJuly 1991 this species was implicated in two extensive fish
Proc.Linn. Srx:.N.S.W., 123. 2001