Extant and fossil spongiofauna from the underwater Akademician Ridge of lake Baikal (SE Sibiria)

7 Pages·1999·2.5 MB·English

by  E Weinberg

EXTANT AND FOSSIL SPONGIOFAUNA FROM THE UNDERWATER
ACADEMICIAN RIDGE OF LAKE BAIKAL (SF. SIBTRLA
i
E. WEINBERG, C ECKERT, D. MEHL,J.MUELLER, V. MASUDA \NDS EFR] MOVA
Weinberg, E„ Eckert, C, MehL D., Mueller, I Masuda,Y.fi Efremova, l I
(ant and fossil spongiofauna Irom flte underwater Akadcmician Ridge ol Lab I tit
Sibiria). Memoirsof(heQueensland 657 Brisbane.TSSN 00
i
Sedii .idlnuhi> diversri5iliceousas«tfinhlages Sp<
i
MF>ii ulesanddiaiom frustulesarc both wcL preservedandabundant, A bottom sc< Mil coi
X3C1C 4 Sin long) was taken from (he Academician [lidgt using a gravity core)
studi i i 0< m ^tdisci !- ntcrval \ ledin i istedoi 10-3QVD u .
ofbiogenic silica. Majorcontributorswere diatoms, which arc a good tool fbi stratigr-aphic
.mi h di ti fouled in s|
valuablestratigi phii markerslitLakeBaikal, Inadditiontothen itn
rX3GC reveal at' I ubomirskidae consisi i
igether with - at* red nn
I
(Spongillidae). Spicule abundance and diversity were
:
litrij old inter sis. . . ,,
missing, and abundance and diversity ofother ficanllyd d
rhesi tfd rnorphometric changes ma; b i iplti cl
climaticchangesin Lake Baikal duiinj ocencand and
i
liIcsi ion no the evolution I theit
probable spongilli
vdimems,patacolinmoiog\ Luh Bath Istucen uoeiu
.' nhergfemail .U.i.,ir.k.,ru.) .L.im.nolagicalhvtihutelrk\ • who
RAS. i lun BatoiImktuljUtii ?<'< andMarineResearch* RDPo ,.. ,, , /
Potsdam. Germiitry wversit&.Berk
Paf&mtol Wall \ 2249 Berl\in. Gert'r.mny o tf.<
Kawasaki Wf^OJ,Japan;
i / rww '' tfogicul Jmti '' Sf Peterson y ft ' L/'fl i i .'.. fA#im
1 rfw/g, Russia; 21 January IV99,
Compared to most existing fresh water lakes elements oi'sedimentsorhavecome in irom;ifhci
Lake Baikal has many unique features, one of partsofthetake,
which is its sedimentary fossil fauna. Spicule
siliceous sponges and diatom fruslules are well MATERIAL AND METHODS
preserved and abundant in sediments. In the
Academician Ridge region the biogenic silica SAMPLE COLLECTION, Livingspongeswere
contentofsediments reaches LO-30%byweight, sampled between 1996-1997 from the
the mam part consisting of diatoms which arc Academician Ridge by dragging the lake bed
usingadeepwatertrawlei-.inatranscclcxlc.idmi:
traditionallyused&lpalaeostratigraphicanalyses, ™
eAinocucdsoererdpHeise.'nrlg/i'pVatOro.ttoMsenaworh*fta*iLr*ndasksom.eunb.tBs<.tao1ri9ak3tao6alpbii)anmrseosphnooafnlalgl(oelrwoescspwhhialwcthuaeoltrnees-sr ls|f*pmr»ouoJnmlgJAlefh^sci('wlieJ™lrroe,1mhi5UcPQos/l™holsknepeacoeltncoey(ifdm>GluesrcsnLhis.onatngcloltslhf]lisaeshncktdmaeendttovhbtoiyhde,dsnwos,iuttohlh
RHiodwge*rce.p,rdeiseenstcsdiamesinlLtalrayyebred[o.lOtWhMe A,c5a0d0emmitchiicakn. .mdScadi^mr;cinvi1lvscaomrpe,roosnweboraercdoltlheectRe<VJ Vhcvrheoshxacg,in. a
and the water column height above it is 300m. scientific research vessel from the Limnoloe
The present work was undertaken to find how Institute, Irkutsk. Altogether 9 surlaee
spongespiculeshav—e come into the Academician and a gravity core with a length of480emI 'i.
Ridge sediments if they are autochtonous sampled (see Fig.5). Samplmgwas undertakenat
652 MEMOIRS OF THE QUEENSLAND MUSEUM
sidevk-M topview added to the sample; V i=volume ofthe sample
a M
aliquote; l=length ofthe cover glass; =weight
s
of the freeze dried sample; d^diameter of the
Petri dish).
Thecoefficientofquantity, in thiscase0.3925,
has to be newly determined depending on the
diameter ofeach Petri dish using the following
fl\
formula:
N=(0.5(n,+n2) VH2o (d/2)2 p d2)/(VaIl2Ms)
RESULTS
FIG. 1.Schematic illustrationsofPetridishwithcover
glases forsamplesedimentation.
LIVING SAMPLES. Over the Academician
every 10cm interval ofthe gravity core, i.e. 48 Ridge transect we sampled 38 living sponges
samples forthe entire core. from two species, of which 31 specimens
belonged to a new species Baikalospongia sp.
SAMPLE PREPARATION. 5gofeach sediment nov.I (identified by S. Efremova, inprep.). This
sample was freeze dried for 12hrs, oxidised and species is pillow shaped with a strongly porous
disaggregated on a sample shaker using 100ml surface and very stable consistency. Lateral
3% hydrogen peroxide with a drop of cone. surfaces are covered by a cornea-like layer
NH^OH. The solution was then wet sieved protectingthe spongebody from siltpenetration.
througha32mm mesh. Thefraction<32mm was Size varies from I-5cm. Colour of the upper
taken for further sedimentological analysis, surface is green- blue or brownish.
whereas the fraction >32mm was carefully Baikalospongia sp. nov.1 has spicules of a
washed out from the sieve into PE bottles using characteristic shape: both ends of the spicule
50ml distilled H20, and prepared as follows. have unique crown ofthorns. The sponges grow
Depending on numbers ofsamples several Petri on large, compressed, iron-manganese
dishes (4.9cm diameter) wereputonahorizontal concretions which are embedded abundantly in
base(Fig. 1). Twocoverglasseswereplaced into the silts ofthe Academician Ridge. The spicules
eachdishandthedishesfilledtoapprox. 2/3 with ofthisspecieswerefoundinallsedimentsamples
a gelatine solution (0.06g of 700ml distilled here.
water). After shaking the PE bottles containing Two sponges externally similar to
the >32mm fraction a 1ml aliquot was pipetted Baikalospongia—sp. nov.1, but with different
onto the gelatine solution, slowly stirring with a spicule forms short strongyles 170-2!Sum
pipetteinorderthatthesuspensionwould ideally long, 15-22um—wide, with tiny spines diverging
be distributed evenly within the Petri dish. Petri on all sides may be a subspecies of
dishes were left undisturbed for at least 2hrs to Baikalospongia bacilifera, based on similarities
ensureevensettlementofthesuspendedmaterial. in theirskeletal forms.
Subsequently, prepared filterstripswere inserted Also interesting is the find of5 specimens of
into the Petri dishes with one end touching the
soft, friable, brown-blue sponges, 170-215uxn
bottom and the other end touching the base
long, 15-22um wide, with round oscules and
outside. Thus, due to cohesive attraction, water
unattached to any substratum. In skeletal
from thebasinflowedtothe baseandwaspicked
up with a pipette or absorbing paper. For this structure and spicule morphology this sponge is
purpose, a sedimentation 'stairway' was sdiemsiclraribteodabyvarRieetzyvoofyB.(19in3t6e)rmeasdiamo(rDypbh.a)
constructed at the Alfred Wegener Institute profunclalis. Rezvoynotedthat this variety differs
(Zieiinsky, 1993), making this preparation step
mucheasier. InthePetridishesonlythedrycover from5. intermedia s.s. in its spicule size
(330-470urn long, 20-25urn wide), spicule
glasses remained, with an equally dispersed
>32mm fraction.Thesewereputontoglassslides morphology (consisting of slightly curved
strongylescoveredwithsmall spines,withadense
usina canadabalsam as mounting medium.
NspiCUleS/g=(0.3925(nI+n2)VH2od2)/(Vall2Ms) raocucnumdueldat(biaosnal)ofensdm)a,llanpdoipnotsesdessspiionnesofatwetahke
(whereN=amountofspiculespergram offreeze skeletal structure (with an irregular net-like
driedsediment;nt+ri2=amountofspiculescounted reticulation ofspicules bonded at their ends by
inthepreparation;WU2{^volumeofdistilledwater collagen). This species is previouslyknown only
I
SPONGE FAUNA OF LAKE BAIKAL 653
Lubomirskia Baikalospongia Lubomirskia Baiklospongia SwarlscIicw- Spongillasp. bpliydatiasp.
abietina intermedia asp.1 n.sp. skiasp.
2000 2000 600
,, _i i i i i i i i i i i. i. i. i
Spicules perem ofsediment
FIG. 2. Distribution ofsponge spicules in sedimentscollected from the gravity core STX3GC,
from a single specimen collected in 1932 from abundance of spicules in sediments as water
890m depth. depth increased (Fig. 5).
Thetaxonomyusedhereisbasedonthespicule
classification system ofE. Weinberg which is in
somedetailscontroversalamongtheauthors(e.g. TABLE 1.Distributionofspongespeciesinthecentral
partofLake Baikal.
the differentiation of isolated spicules between
Ephydatia and Spongilla). However, we still Akadem
considerthe spicular signals sufficiently distinct Spongesspecies UshIksany R-iicdigaen Sgurrfoaucnidal STX3GC
to establish the specific ecological response
among the freshwater sponges, Lubomirskiidae 1.BbaaickilalHisfperoangia + - - -
and Spongillidae. 2.B. intermedia + - + +
SUBRECENT AND FOSSIL SAMPLE 3.B.interm. m.profimd. - + - +
sMeAdTiEmeRnItAsLa.mpAlnealryesviesaloefds7liddiefsfeprreenptarsapteicoiness ooff 45..BB.abiakcaiHllsipfoernag,isaspn.sp1. 1 +_ ++ +- ++
Lubomirskiidae. Analysis and description ofthe 6.BaikaHspongiansp.2 + - + +
latter are in progress. The most prevalent and 7.BaikaHspongiansp3 + - + +
widely distributed spicules found in surface 8.BaikaHspongiansp.4 + - - +
sediment samples came from Baikalospongia 9.Lubomirskiaabietina + - + +
intermedia, followed by Lubomirskia abietina, 10.Lubomirskiansp. \ + - - +
Baikalospongia sp. nov.1, Baikalospongia sp. L1.Swartschewskiasp. + - + +
nov.2, Baikalospongia sp. nov.3 and 12.Lubomirskiidaen.G. - - + +
Lubomirskiagen. etsp.nov.,whereas spiculesof n.sp.
Swartschewskia sp. were relatively rare. 13.Spongillasp. + - - +
14.Ephydatia + - - +
seTdihmeenctonscaemnptlraetsiwonasofintvheerssepliycucloersrelinatsedurwfiatche 15.Newspicule 1 - - - +
16.Newspicule2 - - - +
water depth, showing a general decrease in
.
654 MEMOIRS OF THE QUEENSLAND MUSEUM
Watcrcontcnt Spongespicules Diatoms Carbon Nitrogen Sulfur Magnetic
% % %
in°„ total total in in in susceptibility
30 .40i.5iC.6i0.70i.80i.100i.20i0.3i00 400
ij
FIG. 3. Sediment parameters ofthegravity core STX3GC.
Analysisofthegravitycore STX3GCrevealed The intervals, which according to diatom
fourgeneraofLubomirskiidae inninespecies, in stratigraphy (Grachev et al., 1997) can be
addition to mega- and microscleres of classified as glacials and stadials, are charact-
Spongillidae Spongilla sp. and only megascleres erisedbydistinctlylowspiculediversityandtotal
ofEphydatia sp. (Fig.3, Table 1). We also found spicule concentration, perhaps reflecting low
spiculesthatcouldnotbeattributedtoanyknown species diversity and abundance during these
livingspecies. Someofthesewereextraordinarily periods. Spicules of Swartschewskia sp. and
long(360-700um),relativelythin (12-16um)and Spongilla sp. disappear completely duringthese
with small spines spread over the whole rhabd. intervals.
Othershadasmoothsurfaceandarelativelythick
rhabd with a length of225-280um and width of DISCUSSION
24-40iim, and small spines found only on the
The presence ofboth living sponges and their
ends.
spicules in subrecent sediments on the
The abundance ofsponge spicules throughout AcademicianRidge suggestthatsponge spicules
thecoreindicatesthatcyclicenvironmentalchanges are an autochtonous element ofthese sediments.
hadtakenplacebetweenthesesedimentarystrata This opinion is confirmed by the presence of
as indicated by maximum and minimum spicule large numbers ofspicules from Baikalospongia
concentrations. The first maximum concentrat- sp. nov.l inthe surface samples ofST14, located
ionshowedup inHolocene sediments, downtoa near living populations.
depth of about 40cm. It is dominated by Sponges have adapted to life on a loose silty
Baikalospongia intermedia, as for the subrecent substrataindifferentways. Firstly, theymay live
surface sediment samples, and Lubomirskia without a fixed anchorageto the bottom, as seen
abietina. The second maximum concentration in Baikalospongia intermedia morpha
commenced at a sediment depth of 200cm and profitndalis living on the Academician Ridge.
ended at 300cm. This has to be classified as the Rezvoi (1936) described similar examples of
Karginsk interstadial, and is indicated by the sponges living on loose substrata without any
presenceofspiculesofBaikalospongiasp.nov. 1 fixed anchorage. Secondly, sponges may live on
SPONGE FAUNA OF LAKE BAIKAL 655
Lake Baikal
• 1 samplestationsof
surfacialground
4r slationofgravitv core
STX3GC
Scale: 1 ; 1 4000(H)
FIG. 4. Map ofthe study locality in Lake Baikal indicatingstation sites forsurface sediments and gravity core
samples.
ferro-manganese crusts in which they build up a spectra found in the gravity core STX3GC (see
horny layer for protection against sedimentation Table 1). Assuming that prevailing wind
in the muddy environment. This strategy is seen directions have changed from E to NE, these
in Bakalospongia n. sp 1 and Baikalospongia sponge spicules are probably allochthoneous
bacilli/era. Thirdly, sponges may grow on other material brought in from the Barguzin Bay and
sponges, using their homy layer as a substrate. Ushkany Is. Even during periods of more
An example ofthis commensalism was seen in a prevalent SW winds the cyclonic centre remains
specimen ofBaikalospongia sp. nov. 1 covered abovetheUshkany Is. Thus, sedimentmaterial is
by two smaller individuals ofthe same species also transported from near shore areas into
livingonitshornyexternal layer,collectedbyour centralpartsofLakeBaikal.Basedonthesefacts,
expedition tothe Bolshye Koty area in 1998, ata weconsiderthatapartofthespicules foundbyus
waterdepthof100m.TheexpeditionoftheIrkutsk from the Academician Ridge are allochtonous
State University found a similar specimen at whereas the others are autochtonous in origin.
Academician Ridge, kindly providedto us by Dr.
In general sponge spicules are not regularly
V. Takhteev. In this case it is also possible that
the two smaller individuals may be buds ofthe distributed within sediments, showing distinctly
larger 'parent' sponge. different patterns during colder and warmer
periodsofthe Lake. Maximum concentrationsof
Spicules were found in both subrecent and spicules occur in the Holocene and late Pleisto-
fossil sediment samples, including those of cene (Figs 3-4). During this peak there is also a
species living today in near shore areas and maximum concentration of diatoms present in
shallow waters of Lake Baikal. These mainly sediments, demonstrating that it was a period of
concern Spongillidae but also some represent- longer lasting warm weather and high bio-
atives of Lubomirskia. The Recent spectra of productivity. In contrast, sediments laid down
species in the area of the S part of Bolshye during the long lasting Sartan stadial (latest
Ushkany I. is generally comparable with the Pleistocene), a relatively cool period, show
1
656 MEMOIRS OF THE QUEENSLAND MUSEUM
Legend:
Baikalospongiaintermedia
Baikalospongiarecta
Baikalospungian.sp-
Baikalospongiabacillifera
1.ubomirskiaabictina
Rezinkoviasp.
Swartschewskiasp. contentofspiculapergram
100
200
300
400
Station4
FIG. 5. Relative compositionofspongespicules in subrecent sediments in relationto waterdepth.
variable concentrations ofdiatoms ranging from spongefauna, ifany,wouldatworsthave ledtoa
very low to virtually absent (Fig. 4), whereas change intheirsymbiont relationshipswith little
sponge spicules are present, and spicule orno impact on theirgeneral living conditions.
ambauxnidmaunmc,e odufrBianigktahliossppeornigoida. Istp.isnpoovs.si1blies tathaat Not all sponge species were present consis-
thisdeepwaterspeciescanbettersurviveoradapt tently overtime. Spicules ofSwartschewskia sp.
to changing environmental conditions due to 1 andSpongillasp.occuronlyintheconcentration
maxima of the Holocene and the Karginsk
particular nutrient regimes and possession of
interstadial. These species are typical
symbionts, because its growth is not strongly
dependent on the availability oforganic nutrient representatives ofthe littoral environment, and
supplies. A change in water chemistry, resulting are obviously more prone to environmental
changesthandeeperwaterspecies.Thesespecies
in dissolution ofdiatom frustules during colder
are potentially useful palaeomarkers as
climates, ashypothesisedby somescientists(e.g. indicators ofrelatively warm periods.
Grachev et al, 1997), seem unlikely given that
the biogenic silica of sponge spicules and The occurrence of unidentified spicules in
diatoms is identical. Ifthis were so then it would sediments, so far are unknown to any species,
beexpectedthatduringachangeinpHconditions suggest that the Lake Baikal fauna may contain
there would be dissolution of both sponge undescribed species of sponges, particularly in
spicules and diatom frustules. A better the endemic family Lubomirskiidae. Ofspecial
explanationproposedby Back& Strecker(1998) interestinthisregardisourfurtherinvestigations
is that during colderclimates, and largely during of deep drilling cores BDP-96 from the
glacial activity, high amounts of suspended AcademicianRidge,whichcontainsnearly 5m.y.
material were transported into the Lake largely of sedimentary records. Thus, even single
reducing light transmission in surface waters. spicules ofnew species can provide information
This could have led to a distinct decrease in the about the evolution ofLubomirskidae as well as
diatom population, whereas its effect on the theirprobable spongillid ancestry.
SPONGE FAUNA OF LAKE BAIKAL 657
ACKNOWLEDGEMENTS Pleistocene in the sediments of Lake Baikal.
RussianGeologyandGeophysies38(5):927-956.
We are grateful to Mikhail A. Grachev, MARTINSON, G.G. 1936a. Izkopaemaya spongio-
Limnological InstituteofIrkutsk,whosedevoted fauna tretichnych otloshenii Pribaikalya [The
work on Lake Baikal made these international fossil spongiofauna in tertiarnary sediments of
slatsutdireescopvoesrsyi.blWe.eWaelsowitshhanhkiLmB.allMitzhaenbdersotnftosreva 193PP6rabil.beaoiRnkataozllpiaornge]id.yealDe2on1ki(4yl)ea:ds2vp1i2kA-uk2la1d4ge.umb(iioinkRnuvsasus.kk)vaSsShSiRn,e
for help in the mathematical analysis of data. glubokovo bureniya u s. Posolska na Baikale
Thanks to John Hooper ofQueensland Museum (Thedistributionofspongespikulafromadeepth
for organising the Sponge Symposium in drillingcorenearbythevillagePosolskain Lake
Brisbane, foreditingthe proceedingsand forhis, Baikal aera]. Dokladv Akademii nauk SSSR,
and two other anonymous referees, critical Geologiya 21(4): 261-264. (in Russ.)
review ofthe manuscript. 1955. Iskopacmaya presnovodnaya fauna i eye
znachenive diva siratiurafii. Vestnik Akademii
nauk SSSR(12): 32-35(in Russ.).
LITERATURE CITED REZVOI, P.D. 1936. Fauna SSSR. Presnovodnye
BACK,S.&STRECKER,MR 1998.Asymmetriclate gfuabuknia,osferUaS;SSRp,ongfirlelsihdwaaeteirLsupboonmgierss,kifiadmaileie[sThoef
Pleistocene glaciations in the North Basin ofthe Spongillidae and Lubomirskiidae]. P. 104. In
Baikal Rift, Russia. Journal of the Geological Zoologicheskii institut Akademii nauk SSSR.
Society, London 155: 61-69. novaya seriya No.3, izd. (Akademii nauk SSSR:
GRACHEV, M.A., LIKHOSHWAY, E.V. VOROBY- Moskva-Leningrad), (in Russ.)
OVA, S.S.. KHLYSTOV, O.M., BEZRUKOVA ZIELINSKJ, U. 1993. Quantitative Bcstimmung von
E.V., WEINBERG, EA\ GOLDBERG, E.U, Palaoumweltparametern des Arilarklischen
GRANTNA. L.Z., VOLOGINA, E.G., LAZO, F.I., Oberflachenwassers im Spatquartiar anhand von
IJ VINA. O.V., LETUNOVA, P.P.,OTINOV, PA'., Transferfunktionen mit Diatomeen [Quantitative
PIROG. V.V., FEDOTOV. A.P.. YASKEVICH, estimation ofpaleoenvironmental parameters of
SA, BOBROV. VA.. SIJKHORUKOV, F.V., the Antarctic Surface Water in the Late
REZCH1KOV, V.I., FEDOR1N, VI.A., Quarternary using transfer functions with
ZOLOTARYOV, K.V & KRAVCHINSKY, VA. diatoms]. Berichte zur Polarforschung (126):
1997. Signals of the paleoclimates of upper 1-148 (Bremerhaven). (in Germ.).