Hydrobiologia 143 : 411-416, (1986)© Dr W. Junk Publishers, Dordrecht - Printed in the Netherlands

Ostracod fauna of Duvensee, an ancient lake in Northern Germany

Jutta GuntherSchonbergstrafie 20, D-7812 Bad Krozingen, FRG

Keywords: paleolimnology, Ostracoda, lake development

Abstract

About 4000 ostracod valves have been analysed from a sediment core of a cultivated bog NW of Hamburg .The deepest deposits are sands free of subfossils, the uppermost layers consist of peat . In the sediment inbetween, there are three layers containing undestroyed valves . The ostracod assemblies of the older claygyttja(Late-glacial) and the two younger, fine detritus deposits (Post-glacial) are strikingly different .

Cytherissa lacustris, Candona neglecta, Ilyocypris bradyi, Herpetocyrpis reptans, and two Limnocytherespecies were found in the Late-glacial layers . Changes in abundance of these species indicate alterations inclimate, lake ground, water inflow and waterlevels . Postglacial layers are rich in Metacypris cordata valvesassociated with numerous Candona species, L. inopinata, Darwinula stevensi, and Cyclocypris laevis. Thesespecies are characteristic of a small lake with a large littoral zone . A similar development in ostracod assem-blages is found in middle Europe by Absolon (1973), although the main Candona species is not C. neglectabut C. candida . Ostracod analysis cannot demonstrate an influence of anthropogenic impacts on ostracodsuccessions .

Introduction

Not much is known of sub fossil ostracods of lakedeposits in Schleswig-Holstein . In central Europethe `Candida' fauna of late glacial sediments are su-perseded by the 'Cordata' fauna (Absolon, 1973) .Is a similar succession to be found in NorthernGermany? Duvensee sediments are ideal to answerthe question whether the succession is caused byclimatic alterations or by anthropogenic influences,because settlement signs are found in Pre-Borealand Boreal (Averdieck, 1983) .

Material and methods

Coring, using a Livingstone piston sampler, andpollen analysis were carried out by Averdieck(1983). The sediment core is 6,90 m long . Thelowest metre is composed of marl and coarse sands,

411

and is overlaid by a deposit of limy clay and silt (upto 5 .90 m). It shows increasing amounts of detritus .Above 4.80 m there are organic sediments, contain-ing biogenic lime, laminated in most places . Above1.30 m there are bog deposits, above 1 .00 m culti-vated high moor (see Fig . 1) .

Ostracods were collected and preserved in Frankecells from the sieved fraction > 200 ,um of 10-31 gfresh sediment . Papers from Absolon (1973, 1978)Diebel & Pietrzeniuk (1977), Hiller (1972), Klie(1938), Ohmert (1979), and Petkovski (1977) wereused for identification of the species . They also in-clude information about the ecology of ostracods .

Results

In late-glacial sediments ostracod valves are bet-ter preserved than in postglacial ones, where unde-stroyed valves could only be found in a few samples .

412

As Fig. 1 shows, only 19 of the 30 samples con-

tained any ostracods, and 93% of the total 3629

valves were found in only nine samples. Six belong

to late-glacial layers - Older Dryas and Allerod -

(zone II and III), one to the Atlanticum (zone

VIII), and two to Sub-Boreal (zone IX and X) . For

more details about ostracod material and systemat-

ics see Table 1 and Fig. 3 .

The lowest layers containing subfossils are

characterized by high frequencies of Candona

neglecta Sars, Ilyocypris sp. Brady & Norman, Her-

petocypris reptans (Baird), and Cytherissa lacustris

(Sars). This species assembley - together with

Potamocypris cff villosa Jurine - is found (see

Fig. 1) during the whole late-glacial. These fre-

quencies decrease temporarily from 88% to 18%

QEOVt

Fig . 1. Distribution of ostracods . Occurrence of cladocers, chironomids, molluscs, Chara residues, and charcoal . Candona spp. includesC. candida, C. protzi, C. marchica, and C. compressa. Ilyocypris includes I. sp . and I. bradyi. Cyclocypris includes C. ovum and C. laevis .

favouring Limnocythere `blankenbergensis' Diebel(1968) (see Fig . 3), Cyclocypris ovum Jurine,

Cypridopsis cff vidua Muller. Afterwards the earli-

er species community reasserts itself, although H.

reptans (Baird) and Ilyocypris sp. sensu Brady &

Norman valves decrease in number and Lim-

nocythere inopinata (Baird) (see Fig . 3, G-I) and

Darwinula stevensoni Brady & Robertson arefound in the sediment for the first time C. neglectaSars, Ilyocypris bradyi Sars, C. lacustris Sars, (seeFig. 3) and L . inopinata Baird still constitute more

than 95% of the ostracod valves. In the Allerod C

lacustris (Sars) dominates with a relative abun-dance of almost 70% . The greater number of com-

plete carapaces are remarkable. C. lacustris (Sars)disappears in Younger Dryas (zone IV) .

ao ?

., Limnocythere

Candona ea_w E r

r _ "- 0 o f O°

a•

C n

a0

c

= u • E

aO 'z 00 Cytherissa

o

~„ oa 520 M

' • 0

elacypris o

0 0p N N x Ostracoda a

Iacustris

0

'3 • cordata eo a

0 o T j o- Q oi

8 $a c

ft

g u u ow v u mo

5A xf

rse

Ix

AT

so

VIII

VII

- r • ~- - -

PB . .-

5 YD IV0

00 I -Ch ara

. Charcoal

6 200

400

600 10 10

2 '0 4•0 60

20

20 40

20

10

20 40

10 10 10 10

20 1. special

O

valves /log sediment taxa relative abundance of ostracods findings

5' algae

EM bog

lime sillG`Q ftj

fine

detritus ere fine

sand/~

coarse

peat

1 00 coarse

Table 1 . Ostracoda, found in Duvensee sediments .

LV = left valve, RV = right valve, 1 = length, h = height Y . Dryas = Younger Dryas .

There are obvious differences in the Atlanticum .Here Metacypris cordata Brady and Robertson (seeFig. 3) predominates, associated with Cyclocyprislaevis (Miller) and Cypridopsis cf. vidua (Miller) .The Candona species C. neglecta Sars, C. candida(Miller), C. protzi Hartwig, C marchica Hartwig,and C. compressa (Koch) are also found . In theSub-Boreal the most abundant ostracod is M. cor-data Brady & Robertson, accompanied by highabundance of L. inopinata (Baird) (see Fig . 3,K-M) and an increase of C. neglecta Sars (seeFig. 1) .

4 1 3

Discussion

Looking at the most abundant ostracods(Fig. 2), what can they tell about the ontogeny ofthe ancient waters? H. reptans is most abundant atthe beginning of lake development . It loves diggingin the mud in shallow places near the shore . The oe-cology of L. 'blankenbergensis' the next extremelyhighly abundant species, is not known . It is foundin the samples with high content of HC1-solubleash (determined by Hofmann, Plon, in litt .). If thisLimnocythere belongs to the Limnocythere stapli-

Taxa Number of valves Preservation+well, -bad

Occurrence Dimensions of valvesmm

Candona candida (Miller, 1776) 22 9 , 400 juv . - late-glacial LV, 9, 1 = 1 .02, h = 0 .58

Candona neglecta Sars, 1887 147 9, 410 , - +postglaciallate-glacial LV, 9, 1= 1 . 15, h=0.58

400 juv . postglacial LV, o, , I = 1 .20, h = 0 .67Candona compressa (Koch, 1837) 12 ad ., 8 juv . - Atlanticum LV,

I=0.92, h=0 .56Candona marchica Hartwig, 1899 329, 7o, - + postglacial LV,9, 1=0 .98, h=0 .57

70 juv . RV, O', I = 1 .06, h = 0 .66Candona protzi Hartwig, 1898 63 9, 120' , - postglacial LV, 9, 1=0 .98, h = 0 .46

70 juv . RV, o, , 1=0.96, h=0 .50Cyclocypris laevis (Miller, 1776) 47 - + postglacial RV, 1=0.53, h=0 .35Cyclocypris ovum (Jurine, 1820) 75 - + late-glacial LV, 1=0.49, h=0 .34Cypria cf. opthalmica 3 - Y . Dryas(Jurine, 1820)Cypridopsis cf. vidua 8 ad ., 86 juv . - +

Sub-Boreallate-glacial RV, 1 = 0 .67, h = 0 .39

(Miller, 1776)Cytherissa lacustris (Sars, 1863) 277 ad ., 260 juv. +

postglaciallate-glacial LV, 1=0.88, h=0 .53

Fig . 3, A - C .Darwinula stevensoni 23 ad ., juv . - Allerod LV, 1=0.72, h=0 .24(Brady & Robertson, 1870)Herpetocypris reptans (Baird, 1835) 23 ad., 69 juv . -

postglaciallate-glacial LV, l T 1 .80, h = 0 .83

Ilyocypris bradyi (Sars, 1890) 80 ad ., 162 juv . - + late-glacial LV, 1 = 0.90, h = 0 .47RV, 1=0.89, h=0.45

Ilyocypris sp . sensu 11 ad ., 23 juv . - + late-glacial LV, 1=0.95, h=0 .53Brady & Norman (1889) RV, 1=0.91, h=0 .50Limnocythere 'blankenbergensis' 153 + Older Dryas LV, 1=0.48, h=0 .25Diebel, 1968 (put to L. (L .)staplini(Gutentag & Benson, 1962)non L. staplini Bhatia, 1968 -by Kazmina (1975)), Fig . 3, D-F .Limnocythere inopinata 396 ad ., 46 juv . + late-glacial : LV, I=0.58„h=0.33(Baird, 1843), Fig . 3, G - M . postglacial : LV, 1=0.62, h=0 .34Metacypris cordata Brady & 4619 , a', juv . + postglacial LV, 9 , 1=0.53, h=0 .31Robertson, 1870, Fig. 3, N+O . LV,oa, 1=0 .43, h=0 .28Potamocypris cf. villosa 19 juv . mostly late-glacial LV, 1 = 0 .68, h = 0 .40(Jurine, 1820) RV, 1=0.64, h=0 .44

4 1 4

NielsenZones Over beck

Sediment depth ( cm )

Herpetecypris reptans

Cytherisao lacustris

Jlyocypris

Limnocytherr'blankenbrrgensis'

inopinala

Cand an a (adult)

(iuvOnii)

C cIocyprIs

Cypridopsis

Mstacyprls cordata

Late- glacialOlder Dryas

II

587

577

567

ni group, as Kazmina (1975) assumes, then there aresome hints with regard to its oecology (Delorme,1969; Forrester, 1983), but this still has to be con-firmed . Together with L. `blankenbergensis', Cy-clocypris and Cypridopsis occur in high abun-dancies also. They are known as good swimmers,which love littoral regions, rich in plants . Findingsof Chara (Averdieck, pers . comm.) in the sample(see Fig . 1) supports this. I. bradyi has its predomi-nance next . It likes springs or the areas near them .With the beginning of Allerod high abundancies ofC, lacustris are obvious . It tolerates large sizes andamounts of detritus and prefers cool, deep water .This ostracod succession gives the idea of a lakewith an increasing water level : shallow water, poorin plants - littoral with Chara meadows - waterinflow from springs - profundal .

In the postglacial, the ostracod assemblies showspecies representative of small water bodies, andlakes rich in plants . Differences in abundance ofspecies are due more to the state of preservationthan to alterations of ostracod associations. Theancient lake always has been rich in carbonates, asvalves, shells, and amorphic calcareous layers show.Decomposition of shells seems to correlate with theproductivity of the lake. As most ostracods live on

AllerodIII

557

547

537

PostglacialAtlanticum

Sub-BorealVill

Ix

x385

245

225

Fig. 2. Distribution of the predominant ostracods . Each line denotes a relative abundance > 6% .

the benthos, the oxygen content must have beensufficient . There are signs, however, of a reducedoxygen supply in postglacial . C. ovum predominantin late-glacial, is succeeded by C. laevis, needingless oxygen (Scharf, 1980) .

The development of Duvensee is similar to thatfound in middle European lacustrine sediments byAbsolon (1973) . There a 'Candida' fauna in late-glacial is followed by a `Cordata' fauna . The mostabundant Candona in the late-glacial of Duvenseeis not C candida but C neglecta. The postglacialfindings are in accordance with Absolon's, whereM. cordata exists in high abundance. In North Ger-man sediments (Poolsee, Alt Fresenburg) we alsofind a 'Neglecta' fauna but a 'Cordata' fauna is notalways obvious.

Are the disturbances in the ostracod successioncaused by anthropogeneous influences? Charcoalwas also found in the oldest microfossiliferous lay-ers. If this is a sign of the first period of clearingby fire, then the lake has been influenced since thebeginning of its development by anthropogenic im-pact. During development in the late-glacial, nofurther evidence is given except the development ofCytherissa lacustris with the high population and itsobviously fast fossilisation. At the same time when C.

lacustris disappears, the sediment gets less mineralicand organic matter is increasing as measured by losson ignition, (Hoffman, Plon, in litt .). Here molluscswere found in the sediment for the first time (see Fig .1) . Loffler (1963) assumed, that C. lacustris is an in-dicator species for changes in the lake sediment dueto cultural influences . More likely the disappearanceof C lacustris is caused here by climatic alterations .In the warmer post-glacial climate and the decreas-ing waterbody C. lacustrishad no chance of survival .

4 15

Fig. 3 . Cytherissa lacustris (Sars, 1863) . A: dorsal, B: RV, C: LV. Limnocythere 'blankenbergensis' Diebel 1968 . D: RV, E : LV, F: dorsal .Limnocythere inopinata (Baird 1843). Late-glacial G : dorsal, H : RV, I : LV. Post-glacial K : dorsal, L : RV, M : LV. Metacypris cordata Brady& Robertson, 1870 . N : dorsal, female, 0 : dorsal, male. Scale : - 0.5 mm . Abbreviations as for Table 1 .

Acknowledgments

I am indebted to Mrs . E. Ganl3 and Dr. D. Keyserfor REM photomicrographs and Mr . H. Petersen,Zoologisches Institut and Museum der UniversitatHamburg, Dokumentation, for nomenclature indi-cation and supply of literature, Mr. B. Chandler,Bad Krozingen, for reviewing the manuscript, andDr. W. Ohmert, Geologisches Landesamt Freiburg,for helpful discussions .

416

References

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Absolon, A., 1978 . Die Gattung Candona im Quartar von Euro-pa. Rozpravy Ceskoslovenske Akademie Ved ., RadaMatematickych A Prirodnich Ved, 88 : 3-73 .

Averdieck, F: R ., 1986. Palynogical investigations in sedimentsof ancient lake Duvensee, Schleswig-Holstein . Hydrobiologia,this volume .

Delorme, L . D., 1969. Ostracodes as Quarternary paleoecologi-cal indicators . Can. J. Earth Sci . 6 : 1471-1476 .

Diebel, K., 1968 . Neue Limnocythere-Arten (Ostracoda) ausdem deutschen Pleistozan . Monatsber. deutsch. Akad. Wis-sensch . 10: 519-538 .

Diebel, K . & E . Pietrzeniuk, 1977 . Ostrakoden aus dem Traver-tin von Taubach bei Weimar. Quartarpalaontologie 2 :119-137 .

Forrester, M ., 1983 . Relationship of two lacustrine ostracod spe-cies to solute composition and salinity: Implications forpaleohydrochemistry. Geology 11 : 435-438 .

Hiller, D., 1972 . Untersuchungen zur Biologie and zur Okologielimnischer Ostrakoden aus der Umgebung von Hamburg .Arch . Hydrobiol . Suppl . 40: 400-497 .

Kazmina, T. A., 1975. Stratigrafia i Ostrakody Pliocena iRannego Pleistocena Juga Zapadno-Sibirskoj Ravniny . TrudyInst . Geol . Geofis Sib . Otd. 264 : 1-108 . (In Russian) .

Klie, W., 1938 . Ostracoda, Muschelkrebse. In : Dahl, Die Tier-welt Deutschlands. Jena 34 (3) : 1-230 .

Loffler, H ., 1969 . Recent and subfossil distribution of Cytheris-sa lacustris (Ostracoda) in Lake Constance. Mitt . int . Ver.Limnol . 17: 240-251 .

Ohmert, W., 1979. Die Ostrakoden der Kernbohrung Eurach 1(Rif3-Eem) . Geologica Bavarica 80: 127-158 .

Petkovski, T. K ., 1977 . Ostrakodenfauna des Mindelsees (S.W.Deutschland). Acta Musei Macedonici Scientiarum Naturali-um, Tom. 15, 3 (128) : 49-94.

Scharf, B. W., 1980. Zur rezenten Muschelkrebsfauna der Eifel-maare (Crustacea : Ostracoda) . Mitt . Pollichia 68 : 185-204.

Accepted 18 March 1986 .