v/4t ywzei Oi/e&c&fr

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1 v/4t ywzei i/e&c&fr DIATMS IN A PSTGLACIAL CRE FRM THE BTTM F THE LAKE GRANE LANGSØ DENMARK NIELS FGED FGED NIELS Diatms in a pstglacial cre frm the bttm f the lake Gråne Langsø. Bull. gel. Sc. Denmark vl. 9 pp Cpenhagen December 7th 969. In 0 samples frm a depth f cm. belw the present bttm f the Jutlandic lake Gråne Langsø 0 diatm frms are shwn t ccur. Frm the eclgical spectra calculated it may be deduced that at the time when the sedimentatin tk place the lake was rather pr in nutritius matter (ligtrphic t slightly eutrphic) with a rather varying ph which was mst alkaline when Samples 9 and 0 frm the greatest depth settled and mst acid when Sample 7 settled in rather acid water. As usual when the envirnment is rather pr in nutritius matter the diatm flra is fairly pr in species. All frms shwn are given in table 8 tgether with their relative frequency. Sme ntable r s far rare species are discussed. The making f preparatins micrscpical analysis and treatment f the results f analyses have taken place in the same way as described in my paper n the cre frm the lake Esrm Sø (Fged 968). The material frm Esrm Sø (Fged 968) and frm Gråne Langsø has kindly been left me fr examinatin by Prfessr Dr Kaj Berg the Freshwater Bilgical Labratry f the University f Cpenhagen Hillerød whm I ffer my mst crdial thanks. The samples examined have in the presentatin belw been numbered -0 in accrdance with their rigin frm the fllwing depths (belw the present bttm f the lake) in the cre: N. 50 cm A ttal f 0 different frms f diatms belnging t 64 species and genera were fund. The flra mainly cnsists f freshwater diatms; nly ne halphilus ne meshalbus and ne plyhalbus frm were fund. Amng these nly the halphilus frm Nitzschia frustulwn var. perpusilla can be

2 8 FGED: Diatms in a pstglacial cre cnsidered certainly autchthnus whereas the meshalbus species Rhpaldia musculus perhaps is allchthnus (nly a single valve fund in ne sample) and the plyhalbus Diplneis cffaeifrmis f which t nly ne valve was fund can with certainty be cnsidered adventive. Thus the flra is prer in species than the ne shwn t ccur in the series frm the bttm f Esrm Sø and it appears frm the fllwing tables and diagrams that with regard t the cmpsitin f the flra there are cnspicuus differences between the tw places. The pssibilities f deducing smething frm halbin and ph spectra and diagrams are fairly restricted. They are shwn in tables and and diagrams 4. In tables and 4 halphbus and acidphilus diatms respectively have been detached frm the list f species in table 8. The halbin spectra hwever indicate a freshwater envirnment rather pr in electrlytes. Sample 7 differs mst frm the ther samples as the halphbus and acidphilus species Melsira distrts amunts t 7.6 % f the valves cunted in this sample. Furthermre the species Tabellaria Qrane Langsø. Diagram I. 0 S % halphbus. indifferent. Diagram. I 0 0 I0 0 W56T069 Species halphbus. indifferent.

3 Medd. Dansk Gel. Fren. København. Bind 9 [969] 9 N<S* -* i'* d ffl «~ S * i rtn^nw^lm i«se>-<-<r; * i-^ ri N l-i "" U^ ^ l*n V ^h c\««^ 00 " t «T t «; p - < P 00 r» m-^-^h \ \ r< \ v M ^ "**" p«"i 9 * \»n M V - ^ - ' t M ' f i n m c ^ ^ H * " vi ^ ^ V * N'nert^' ri " \ " r^ 6 ^ANrin rn ""* V v m d" > N r 'V «5l*00\rl^M'-000 V "^ fi av <s csn\p " «^ 00 ^H 00 \n - \Tj-\r~r*^HTt a a u tj Vi G J5» C E 0 C Vi c Wl : '. N l_ N fcn N fc- N S_ N Ui X q) <U m m Al < r^vir\virivir\vir^vif\vi _. S S'S «"?»'S "S E.>Ej>E.>E.>;E>E.> S «"«" c > a > G? a > a > G > VI *-. > G «e ^5 ^ H.s Vi J G. Vi number f speci ttal t-l " u. S D. ci C H Z " E l / : : ' v\ ;; c/ 4>... Vi..... \ V *s *s x. v \ t-i \ i-. X i_ \ ti \ t-< \ u «i (U u E.> E.> E> E.> E.> ajajrtedc G > G > G > G > G > - - c - «! «!c.. S - E a C - I 9*

4 40 FGED: Diatms in a pstglacial cre Grane Langsø. Diagram acidphilus K> S 60 T indifferent. I0 D % alkaliphilus. M t m s W H w. K> K> 0 0 acidphilus. Diagram * V S 60 T indifferent T 60 Q species a/kaliphiius. fenestrata and T. flcculsa als halphbus and acidphilus amunt t 6.4 and.8 % respectively and hence tgether are mre frequent in sample 7 than in the ther samples. There can hardly be any dubt that during the depsiting f sample 7 there was an envirnment in the lake basin which was rather pr in nutritius matter and which was slightly acid. During the depsiting f sample the tendency must have been in the same directin althugh less prnunced. A cmparisn between the spectra and diagrams f Grane Langsø and the crrespnding nes frm the bttm f Esrm Sø clearly shws that the tw envirnments in questin must have been rather different. In the samples frm Esrm Sø the halphbus diatms thus at a maximum amunt t.4 % f all valves cunted and belng t six species whereas the samples frm Grane Langsø have up t 9.4 % halphbus valves and in tw f the samples frm this lake different halphbus species were fund. In the ph spectra the differences stand ut still mre clearly acidphilus species being extremely rare in the samples frm Esrm Sø whereas in the samples frm Grane Langsø there are up t 9 different acidphilus species and up t 9.4 % acidphilus species cunted in a single sample (n. and n. 7 respectively). In the samples frm Esrm Sø n acidphilus species was fund in fur ut f the seven samples and nly a single acidphilus valve was fund in each f the three ther samples. The number f species f diatms fund als t sme degree is characteristic f the varius lcalities. Usually the number f species will

5 Medd. Dansk Gel. Fren. København. Bind 9 [969] 4 Table. Halphbus diatms Gråne Langsø Valves % in sample n: Amphipleura pellucida 4- Cccneis diminuta Cymbella hebridica Denticula tenuis var. crassula -j- Euntia gracilis - mndn var. bidens - parallela - rbusta - tenella -veneris.0.0 Fragilaria virescens var. elliptica Frustulia rhmbides var. saxnica.. Melsira distans 7.6 Navicula disjuncta (?) - vitabunda (?) - wittrckii..0.4 Nitzschia hantzschiana (?) Pinnularia braunei var. amphicephala.0 - divergens var. elliptica - hemiptera - Iegumen - nbilis.8 - ndsa Tabellaria binalis - fenestrara flcculsa Valves % ttal be largest in lcalities with neutral r slightly alkaline water rich in nutritius matter. In the samples frm Esrm Sø a ttal f 4 different frms f diatms were fund and in the sample richest in species (n. 6) 55 different frms were fund. In the samples frm Gråne Langsø nly 06 different frms f diatms were fund and the sample richest in species (n. 5) cntains 0 different frms nly. This fact thus wuld als pint the way indicated abve. Table 5 shws Centrales: Pennales figures and qutients. The highest qutient calculated n the basis and numbers f valves is 9 in sample 4 the flra f which thus wuld indicate a "mderate" eutrphic envirnment. Sample 5 has the percentage qutient 0.79 n the basis f which I shuld characterise the sample as having been depsited in a slightly eutrphic envirnment. All the ther qutients are s small as undubtedly t indicate a markedly ligtrphic envirnment. The centric genera in table 6 pint the same way. Thus in sample 4 Melsira ambigua and in sample 5 Melsira granulata var. angustissima

6 4 FGED: Diatms in a pstglacial cre Table 4. Acidphilus diatms Gråne Langsø Valves % in sample n: Achnanthes lappnica Cymbella hebridica Euntia mndn var. bidens - parallela - pectinalis var. minr.0 f. impressa -f- - rbusta - tenella -veneris.0.0 Frustulia rhmbides var. saxnica. Melsira distans 7.6 Navicula jarnefeltii Pinnularia divergens var. elliptica Tabellaria binalis - fenestrata Valves % ttal are dminants and bth pint twards a mderately eutrphic envirnment whereas Melsira distans which is the dminant frm in sample 7 fairly clearly pints twards an ligtrphic envirnment. In Nygaard 956 an attempt was made by means f new methds f calculatin n the basis f the diatmaceus flra f giving a characterizatin f the ph envirnment in which the flra lived fr the purpse f estimating the ph f a lcality in the past by a diatmaceus analysis f fssile and subfssile material. As t calculatin f the three indices used reference is made t Nygaard (956 pp ). Table 5. Gråne Langsø Centrales Pennales Centrales Pennales Sample N. number f species valves % number f species valves % species valves %

7 Medd. Dansk Gel. Fren. København. Bind 9 [969] 4 Table 6. Gråne Langsø Cycltella Melsira Stephandiscus Sample N. number f species valves % number f species valves % number f species valves % (Index <x = acid units alkaline units index m alkaline units index s = number f alkaline species) acid units number f acid species In Merilåinen 967 (pp. 5-58) Nygaards methd has been applied t recent material frm 4 Finnish lakes and pnds. The results btained there in the case f all the three indices are in fairly clse agreement with the ph values measured. In table 7 the three indices are calculated fr the ten bttm samples f Gråne Langsø. Frm the table it appears by cmparisn with Merilainen's diagram (967 p. 57) that the a and f indices calculated fr Gråne Langsø crrespndingly give the infrmatin that ph during the depsiting f sample 7 was < 7.0 (the a value accrding t Merilainen's diagram indicates a ph f abut 6.5 and Index w indicates a ph f abut 4.0) whereas indices fr the ther samples indicate ph values > 7.0 (r alkaline envirnment) withut any pssibility f a greater differentiatin. Table 7. Gråne Langsø Index Sample N: a w e

8 44 FGED: Diatms in a pstglacial cre Diagram PH. In diagram 5 which crrespnds t Merilainen's index s diagram the index s values fr the samples -0 f Grane Langsø have been inserted. This diagram shws rather a cnspicuus differentatin between the 0 samples. In accrdance with this diagram Grane Langsø shuld have had mst acid stage (ph between 4 and 6) during the depsiting f sample 7 and the lake shuld have been mst alkaline (ph abut 9.0) during the depsiting f samples 9 and 0. It is nt surprising that Nygaard's indices pint the same way fr the material used in the tw methds f calculatin is the same. The decisive questin is whether these indices mre precisely and surely than the spectra used s far can indicate the ph value f a freshwater envirnment f the past. nly the applicatin f a methd t a future mre cmprehensive material can decide this. In table 8 all the frms f diatms shwn t ccur in the 0 samples are listed. 500 valves have been cunted in each sample. The percentage figures are stated. If a species was fund after the cunting was finished a has been added. All the frms fund enter in the calculatin f spectra and are used at the making f the diagrams. The placing in the halbin and ph systems has als been indicated: halbin rate: halphbus indifferent halphilus meshalbus A' plyhalbus 5. ph-rate: acidphil us indifferent alkaliphilus alkalibintic 4. Amng the mre remarkable species the fllwing shuld be mentined: Achnanthes recurvata Hust. (A. Schmidt's Atlas 409: 4-7). Hustedt 950 p. 44 figs 8-0. A widely distributed actually easily recgnizable species which hwever has rarely been fund. In my wn material I have fund it in many recent samples frm Sweden Nrway Iceland and Ireland. Furthermre in interglacial kieselguhr in Denmark. It is very cmmn n the Varanger peninsula in Nrthern Nrway where the findings suggest that the species has a tendency twards acidphily. In the present paper it has in accrdance with Hustedt been cnsidered indifferent as regards ph. It is nt rare in samples 5 6 and 7.

9 Medd. Dansk Gel. Fren. København. Bind 9 [969] 45 Cymbella thumensis (A. Mayer) Hust. (Hustedt 945 p. 98; 4: 60-6). Syn.: Amphra cffeaefrmis Ag. var. thumensis A. Mayer 99 p. 08; 9: Cymbella parvula Krasske 9 p. 9 fig.. This characteristic small C. species has s far been fund in nly a few places in Nrth Germany in the Balkans and in Sweden. In my wn material I have fund a few specimens in Ireland and Iceland and in interglacial kieselguhr frm Hllerup in Denmark. In the tw deepest samples dealt with here it is rather cmmn. The findings f a number f very small Navicula species which have s far been fund very rarely are als particularly remarkable. In this cnnectin it shuld be nted that all these species have been checked in cllabratin with Mr. Max Møller head dispenser dense t whm I am very much bliged fr valuable assistance thrugh many years. Navicula absluta Hust. (950). Hustedt 950 p. 45; 8: p. 5 fig. 4. Previusly fund nly in Nrth Germany (Hustedt 950) and in Spitzbergen (Fged 964). The species resembles N. vitabunda N. laterstrata and N. disjuncta which all f them are als fund in the present material. All the fur species were fund in typical specimens which are relatively easily distinguished. Fund nly in sample 9 where it is nt rare ( %). Navicula acceptata Hust. (950). Hustedt 950 p. 98; 8: p. 47 fig. 7. A small rather characteristic species which has previusly been fund as recent and fssil in Nrth Germany (Hustedt ) and in Denmark (fssil Fged and subfssil in a drill sample frm Esrm Sø). In the present material it is rare in samples 5 and 8. It is pssible t mistake this species fr N. seminulum Grun. and N. submuralis Hust. nne f which has been fund here. Navicula disjuncta Hust. (90). Hustedt 90 p. 74 fig p. 4 figs 75 a-e. A. Schmidt's Atlas 70: : 5-5. A fairly rarely but widely distributed species which I have shwn t ccur in material frm Denmark (recent and fssil) Sweden Nrway Greenland and Afghanistan. In this material fairly rare in sample 5 ( %). Navicula minusculides Hust. (94). Hustedt 94 p. 68 fig p. 55 fig. 8. S far nly fund in Nrth Germany and very rare (Hustedt 94). Differs clearly frm the tw smewhat similar species N. minuscula Grun. and N. mlestifrmis Hust. In the present material fund but fairly rarely in ns 5 6 and 7.

10 46 FGED: Diatms in a pstglacial cre Navicula pprtuna Hust. (950). Hustedt 950 p. 46; 9:. Previusly nly fund in Nrth Germany and very rare (Hustedt 950) and in Denmark (fssil Fged 96) in Nrway (Fged 960) and in Greenland (Fged 958). In the present material very rare nly fund in sample 8. Navicula paanaensis A. Cleve-Euler (99). A. Cleve-Euler 99 p. 6 fig.. Hustedt 96 p. 74 fig Syn.: N. btusangula Hust. in A. Schmidt's Atlas (96) 40: A fairly characteristic species which has s far been described nly frm Finland (A. Cleve-Euler 99 Hustedt 96). In the present material the species is fairly cmmn in sample 9 (.0 %) and rare in Sample 6. Navicula tackei Hust. (94). Hustedt 94 p. 94 figs p. 77 fig S far nly fund in tw highly plluted lcalities in Nrth Germany (Hustedt 94) and in nest material frm a gray hern lcality in Nrth Funen Denmark (Fged 95). The species is rather cmmn in sample 8. Navicula utermhlii Hust. (96). A. Schmidt's Atlas (96) 404:. Hustedt 96 p. 7 fig. 40. Previusly fund in alkaline lcalities in Nrth Germany (Hustedt 96) and in Yugslavia (Hustedt 945). In the present material fund nly in sample 8 where the species is even very cmmn. A few valves nt determined s far perhaps belng t species which have nt frmerly been described. Dansk sammendrag I 0 prøver fra -f- 50 cm til -~ 40 cm under nuværende bund i Gråne Langsø i Jylland er påvist 06 frskellige diatméarter. Af de beregnede øklgiske spektre fremgår at søen under afsætningen af de 0 prøver har været ret næringsfattig (ligtrf eller svagt eutrf) g at ph har været ret variabel. Mest alkalisk har søen været under afsætningen af de nederste prøver (nr. 9 g nr. 0) g mest sur under afsætning af prøve nr. 7. gså den øverste prøve (nr. ) synes at være afsat i ret surt milieu. Diatméflraen er sm sædvanlig i ret næringsfattigt milieu temmelig artsfattig. Alle de fundne arter er anførte i tabel 8 hvri den enkelte arts halbie- g ph-relatin samt relative hyppighed i de 0 prøver er angivet. Ngle bemærkelsesværdige eller hidtil sjældent fundne arter er mtalte. Aarestrupsvej dense April Uth 969

11 Hal. ph 0 Table 8. Pstglacial diatms frm Grane Langsø Achnanthes clerei Grun exigua Grun flexella (Kiitz.) Brun. var alpestris Brun... lancelata (Bréb.) Grun - var elliptica Cleve - var. rstrata (Østrup) Hust lappnica Hust laterstrata Hust linearis (W. Smith) Grun minutissima Kiitz - var. cryptcephala Grun peragallii Bruun recurvata Hust suchlandtii Hust østrupii (A. Cleve) Hust Amphipleura pellucida Kiitz Amphra valis Kiitz - var. libyca (Ehr.) Cleve - var. pediculus Kiitz sp? /4ne/Møeøne/s «w7«(kiitz.) Cleve /4.r/e/7øfle//a frmsa Hassall Calneis bacillum (Grun.) Mereschk 04? ; I

12 Hal. ph l 0.6 Table 8 (cntd.)» 00 schummaniana (Grun.) Cleve var. bicnstricta Grun silicula (Ehr.) Cleve - var. alpina Cleve - var. truncatula Grun Cccneis diminuta Pant placentula Ehr - var. lineata (Ehr.) Cleve Cycltella cmensis Grun cm/«(ehr.) Kiitz kiitzingiana Thwaites - var. parva Fricke -* var. planetphra Fricke - var. schumanni Grun meneghiniana Ktitz cellata Pant. pseudsteltigera Hust Cymatpleura slea (Bréb.) W. Smith Cymbella affinis Ktitz cistula (Hempr.) Grun ehrenbergii Ktitz gracilis (Ralfs) Cleve hebridica (Greg.) Grun helvetica Kiitz micrcephala Grun # a w a a Vi. r

13 Table 8. (cntd.) Hal. ph naviculifrmis Auerswald btusa Greg reinhardtii Grun sinuata Greg thutnensis (A. Mayer) Hust turgida (Greg.) Cleve ventricsa Kutz fen««kiitz. var crassula (Naeg.) Hust 4 Diplneis cffaeifrmis (A. S.) Cleve 5 culata (Bréb.) Cleve va/w (Hilse) Cleve zeira (Ehr.) Kutz - var. prcellus (Kiitz.) Grun - var. saxnica (Kiitz.) Grun Euntia arcus Ehr frmica Ehr gracilis (Ehr.) Rabh /«nam (Ehr.) Grun - var. subarcuata (Naeg.) Grun mttdn Ehr. var. bidens (Greg.) W. Smith. parallela Ehr pectinalis (Kiitz.) Rabh. var. minr (Kutz.) Rabh f. impressa (Ehr.) Hust rbusta Ralf s

14 Hal. ph # Table 8. (cntd.) tenella (Grun.) Hust veneris (Kiitz.). Miiller Fragilaria bicapitata A. Mayer brevistriata Grun capucina Desmaz cnstruens (Ehr.) Grun - var. bindis (Ehr.) Grun - var. subsalina Hust - var. venter (Ehr.) Grun crtnensis Kittn inflata (Heid.) Hust. var. istvanfyffi (Pant.) Hust intermedia Grun lappnica Grun pinnata Ehr virescens Ralfs - var. elliptica Hust Frustulia rhmbidea (Ehr.) De Tni var. saxnica (Rabh.) De Tni Gmphnema acuminatum Ehr - var. brébissnii (Kiitz.) Cleve - var. trigncephala (Ehr.) Grun angustatum (Kiitz.) Rabh - var. prducta Grun cnstrictum Ehr - var. capitata (Ehr.) Cleve gracile Ehr? w Vi 5 v 8 t/l

15 Hal. ph 0 & Table 8. (cntd.) intricatum Ktitz. var. pumila Grun lngiceps Ehr. var. subclavata Grun. f. gracilis Hust livaceum (Lyngbye) Kutz parvulum Kutz Gyrsigma attenuatum (Kutz.) Rabh Mastglia sp? Melsira ambigua (Grun.). Muller arenaria Mre distans (Ehr.) Ktitz granulata (Ehr.) Ralfs - var. angustissima Mtiller italica (Ehr.) Ktitz. subsp. subarctica. Muller reseana Rabh v> S < s w. circulare Agardh - var. cnstricta (Ralfs) Van Heurck. Navicula absluta Hust acceptata Hust bacillum Ehr car/ Ehr. var. angusta Grun cryptcephala Kutz - var. intermedia Grun cuspidata Kutz (7).4 h>

16 Hal. ph 0 T w 0 D a s in a pstglacial c Table 8 (cntd.) dicephala (Ehr.) W. Smith. disjuncta Hust (?) 4 explanata Hust (?) gastrum Ehr gracilides A. Mayer 4 hustedtii Krasske - var. btusa Hust jarnefeldtii Hust laterstrata Hust (?) minusculides Hust (?) pprtuna Hust? paanaensis A. Cleve-Euler (?) perventralis Hust placentula (Ehr.) Grun. f. rstrata A. Mayer pseudscutifrmis Hust pupula Ktitz - var. capitata Hust - var. rectangularis (Greg.) Grun radisa Kiitz rtunda Hust schnfeldii Hust scutellides W. Smith 4 subrtundata Hust rac&e/ Hust (?) tantula Hust tuscula (Ehr.) Grun. f. m/nr 4 utermhlii Hust varistriata Krasske viridula Kiitz vitabunda Hust wittrckii (Lagst.) A. Cleve-Euler -r

17 Table 8 (cntd.) Hal. ph Neidium affine (Ehr.) Cleve var. amphirhynchus (Ehr.) Cleve bisulcatum (Lagerst.) Cleve iridis (Ehr.) Cleve - f. vernalis Reichelt - var. amphighmphus (Ehr.) Van Heurck. Nitzschia angustata (W. Smith) Grun. var. acuta Grun. acula Hantzsch fnticla Grun 4 frustulum Kutz. var. perpusilla (Rabh.) Grun. hantzschiana Rabh (7) recta Hantzsch pephra martyi Hérib Pinnularia brealis Ehr braunii (Grun.) Cleve var. amphicephala (A. Mayer) Hust (?) dactylusekir divergens W. Smith - var. elliptica Grun gentilis (Dnk.) Cleve gibba Ehr - var. linearis Hust - var. parva (Ehr.) Grun hemiptera (Kutz.) Cleve interrupta W. Smith - f. minutissima Hust

18 Table 8 (cntd.) KJ Hal. ph 0 legumen Ehr mair Kiitz.... meslepta (Ehr.) W. Smith... micrstaurn (Ehr.) Cleve - var. brébissnii (Kutz.) Hust.nbilis Ehr.8 ndsa Ehr subslaris (Grun.) Cleve viridis (Nitzsch.) Ehr Rhpaldia gibba (Ehr.). Muller 4 musculus (Kiitz.). Muller 4 Staurneis anceps Ehr.4 - var. gracilis (Ehr.) Cleve.. - var. hyalina Brun & Perag - var. sibirica Grun kriegeri Patrick phenicentern (Nitzsch) Ehr Stephandiscus astraea (Ehr.) Grun. - var. minutula (Kiitz.) Grun. Surirella angusta Kiitz. linearis W. Smith var. cnstricta (Ehr.) Grun... rbusta Ehr. tenera Greg. - var. nervsa Mayer. '.0 w d p" 5" "

19 Hal. ph BS Table 8 (cntd.) s Synedra parasitica W. Smith var. subcnstricta Grun ulna (Nitzsch.) Ehr.... <? vaucheriae Kutz Tabellaria J binalis (Ehr.) Grun fenestrata (Lyågbye) Kutz flcculsa (Rth) Kutz W TSl - SJ - S

20 56 FGED: Diatms in a pstglacial cre References CJeve-Euler A. 99: Bacilariaceen-Assciatinen im nrdlichsten Finnland. Acta Sc. Se. Fenn. N. S. B. T. (). Helsingfrs. Fged N. 95: Diatméerne i en fiskehejreklni. Flra g Fauna 57 Århus Fged N. 968: Diatméerne i en pstglacial breprøve fra bunden af Esrm Sø Danmark. Meddr dansk gel. Fren piates. Hustedt F. 90: Bacillariphyta (Diatméae). In A. Pascher Die Susswasserflra Mitteleurpas 0 Jena 466 pp. Hustedt F. 97: Die Kieselalgen Deutschlands sterreichs und der Schweiz mit Beriichsichtigung der ubrigen Lander Eurpas swie angrenzenden Meeresgebiete. Dr. L. Rabenhrsts Kryptgamen-Flra vn Deutschland sterreich und der Schweiz 7 () Leipzig 845 pp. Hustedt F. 944: Neue und wenig bekannte Diatméen. Ber. Deut. Bt. Ges Hustedt F. 945: Diatméen aus Seen und Quellgebiete der Balkan-Halbinsel. Arch. Hydrbil pi. ^. Hustedt F. 950: Die Diatméenflra nrddeutscher Seen mit besnderer Beriichsichtigung des hlsteinischen Seengebiets. Arch. Hydrbil pi. -4. Hustedt F. 96: Die Kieselalgen Deutschlands sterreichs und der Schweiz mit Beriichsichtigung der ubrigen Lander Eurpas swie angrenzenden Meeresgebiete. Dr. L. Rabenhrst: Kryptgamen-Flra vn Deutschland sterreich und der Schweiz 7 () Leipzig (86). Merilainen J. 967: The diatm flra and the hydrgen-in cncentratin f the water. Ann. Bt. Fenn. 4 Helsinki Nygaard G. 949: Hydrbilgical Studies n Sme Danish Pnds and Lakes. Bil. Skr. 7 () Vid. Selsk. København -9. Nygaard G. 956: Ancient and Recent Flra f Diatms and Chrysphyceae in Lake Gribsø. Fl. Limnl. Scand Schmidt A : Atlas der Diatmacéenkunde. Aschersleben - Leipzig.