KONGL SVENSKA VETENSKAPS-AKADEMIENS HANDLINGAR Bandet 35 N:o THE PLANKTON OF THE NORTH SEA AND THE SKAGEHAK IN 1900 BY P T CLEVE COMMIIXICATED DECEMBER KEVISED BY H.I TIIEEL A\D A, 11, (i lilOl NATHORST STOCKHOLM KUXGL BOKTRVCKKHIET I' 1902 A NORSTEDT & SÖNER D 'uriiig inonth, the at 1900 ycar the Måseskär west-coast (or about Sweden, of were collected ragularly, to 58° Lat N.) and Väderöboda (or about 59° Lat saiuples of plankton tiines a on N.), the North Sea, four timcs (February, April, August, No- in vember) by stearaers on different routes and, besides, occasionally, by the Governmentsteamer »Svensksund» in the Skagerak and, in July-August, by a tishing boat off the Shetlands The following account contains the results obtained by the microscopical analj^sis of the samples and has been coinpleted by hydrogi-aphical data, cominunicated by Professor S O Pettersson January 1900 Samples were collected the steamer Svenksund Christiania Fjord) ]\Iost on Måseskär at (1 sample), at Väderöboda (3 samples) and by the route Vinga, Marstrand, Lysekil and Dröbak (mouth of samples were collected from the surface water of the low nity characterizing the Baltic Current, but at sali- Dröbak a sam[)le was hauled from the depth The two were vei-y different, and the temperature of of 30 m in water of 34 p m salinity, so also at 57° 59' N 11° 14' E from 90 m samples from the water of 34 p the water was also different, viz m salinity 7,46 The plankton from Dröbak at Dröbak, but 4,45 in the central Skagerak had a niore oceanic character, but the plankton from Skagerak contained about the same species as the Baltic Current at that season, as be seen from the followinsr list: HoUö-Vinga| IJrưbak Ư7° 59' N (Christiania' fjord) iri4'E Temp Calanus finmarchicus Centropages hamatus Microsetella atlantica 4,45 Hollö-Vinga, Dröbak fu° 59' N (Christiania- iri4'E Temp 7j Temp Sal 34,2, Sal 34,3.v Sal 34,56 90 m 30 m 90 m 30 m Gronyanlax spinifera Biddulphia aarita C decipiens C Plectophora arachnoides C stellaris Codonella Tcntricosa Ceratium longipcs C P divergens Ditylum Brigthwellii Rhizosolenia setigera r r r r Thalassiothrix Francnfeldii C tripos , rr radiatns Thalassiosira gelatinosa macroceros Peridiniam depressum diadema C Coscinodisous polychordus Acanthometron pelluciduni I B mobilensis ChEEtoceros debilis 7,46 Sal 3i,s5 OncEea minnta Temora longicornis fjord) Temp 4,45 i Oithona similis Pseudocalanus elougatus will Halosphaera r + THE PLANKTON OF THE NORTH SEA AND THE SKAGEIiAK CLEVE T P The water of the Baltic Current proved \ery variable as to the salinity At Kalt'- only reached 6,94, and the plankton at that spöt contained abundantly the euryCopepods Acartia longiremis, Centropages hamattis and Temora longicornis, but besides, some fresh-watei- species, as A sterionella gracillima, 2'(thellar{a flocculosa sund colonies of a flagellate At Marstraiid and »Tslandsbergs Hufvud» the water (15, 80 and 18,37 p m s.) was sterile The other saniples from the surface-water of the Baltic Current contaiued a number of species, the most generally distributed of ^vhicb were: sund it haliiie Copepoda Acartia longiremis Centropaxjes n hamatus ', , \ , , rseudocalanus elongatas Temora longicornis } boreal, eui'vhahne forms •' I j Oithona similis; tenaperate, eurvhaline and eurytherni Ciliata Ftyclioci/lis acuta.; arctic, neritic Dinoflagellates Ceratiiun tripos; temperate, eur\'therm, euryhaline Dinopliysis acuta; boreal Chlorophyllacese Halosp>hcera; temperate : j; ,,, • ;.;'( Diatomacese Ti Chcetoceros horealis; boreal and arctic C danicus; temperate C debilis; arctic (.' diadoiia; arctic and boreal and boreal Coscinodiscus concinnus; boreal j Tlialassiothrix Fraucnfeldii; l:)oreal i February 1900 A The North Sea was in the tirst da,ys of February explored by steamers on difThe resiilt of the examination of the plankton-samples coUected by these ferent routes steamers bas been registered in Table '' : - The plankton in the Ndi-th Sea -was N-er\' scarce in February as a rulc and occurred any quantity ordy abo^e the edge of the 50-inetre plateau of the Ijottom, chietiy north of the Dooger Bank in BAND KONGL SV VET AKADEMIENS HANJJLlNGAli rn sallnity, of the Avater of 35 species teristic of 35 p water TIk' p N:i) sal •\vere of Scotland, Avas almost sterile E m 35 Most charac- besides Halonphoera, Acanthonia Miil- Acaniliometron pellucidum, Plectojyhora arachnoides and Chcetoceros decipiens leri, Other from that of 34 p m sal The water of 34 p m salinity contained tripos-plankton, and this planktontype was the ruling kind bet^veen Newcastle and Skagen, and most plentitul uorth of the Dogger Bank, thus above the limit between the 50- and 100-metre plateaii of the bottom species seeiii to have migrated into this kind of water The bank-water west of Scotland contained abundantly Coscmodiscus concinims and which were carried with the 35 p m water i-ound Scotland towards the mouth of the Skagerak The only other characteristic forms which occurred in the bankradiatus, C water Avere Fungella aretica (E of Scotland) and Tintinnopsis heroidea, Biddulphia aurita Along the Dutch coast and Coseinodiccus polychordus (W of Denmark) southern neritic plankton occurred loped In mouth from the place its traces merely of Thus, the typical neritic plankton had not yet deveof the Schelt to the West of SchlesAvig appeared the copepods Teniora longicornis and Pseudoccdanus elongatus, which evidentl}' had spread from the depressions of the bottom The B of salinit}^ water contained soon horeal neritic m This 2nd the 32 things p Skagerali between had, 33 to S Bank and W of the Dogger of the Fisher Bank The water at the two stations, where plankton Avas and 6th of February a teraperature betAvcen 2,i and p sparingly thus considerably higher thau in January m., tripos-plankton, became changed, and sira-plankton there as in mixed A\-ith appeared ^vater of the on JTaloq)ha'ra., collected, 3, o and a This kind of but the condition of the 7th of February at Måseskär temperature — 0,35 and the salinity 22,72 kind of plankton prevailed to the end of the month, both at Måseskär and at V;\deröboda, the temperature varying from — 0,35 to — l,o and the from salinity 21,39 and in one sample only Avere the copepods Acartia longireinis and Temora longicornis found in any amount The diatoms Avere, on the contrary, very abundant, and among them the most important were the folloAvins': 'ö to This kind of plankton 26,96 Avas, as usually, verv poor in animals • ' Biddulphia aurita, Coscinocliscus polychordiis, Chcetoceros debilis Skeletonem.a costatum, C diadem a, C socialis, _ Thalassiosira Nordenskiuldii, Thalassiothrix Frauenfeldii March 1900 ' > Samples were collected ;it Måseskär and by the steamer »Svensksund» in Kattegatt Middelgrundet and 56°33'N r2°16'E.) and at Vinga The temperature of the Avater va-ried from 1,2 to and the salinity from 25, 21 to 33,63 The plankton was everyAvhere (at uniform, or sira-plankton, composed chiefly of diatoms red in skiöldii Besides the species, Avhich occur- February (among Avhich Chcetoceros debilis, C diadema and Thalassiosira Nordenwere very common) the folloAving recurred constantly in almost all samples: b r THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK CLEVE T Rhizosolenia semisjnna, Chcetoeeros borealis, B contortus, C flin c; ,10 rr; "^"/u w '/'? II — Per '^^I'j r; _^lv) c Btw '/t o; Tbalassiosira gravida Cl "/ii — — Stepbanopyxis tnrgida CtREV rr '^^jn « ^^k r; J' R styliformis -*/8 r; ^^/a ; r; r Nitzscbia seriata Cl R — ^'/i ^/s i'/4 r; Ehb — — + "/s ; '^^/s oculns iridis Ehb ^^/lO -'Vio r ''; ''/i ; ^'/é r c 29/1" -"/' 4- '^'^/a r; ^^/w r; e/11 »/lo r; Rbizosolenia o ''• — rr; -^J9 rr '^^/e ^^/s r; — i^io densus Cl — — Graui Cl "/i scolopendra Cl — Cl — -V2 + Laudbr — ^s + rr; Cl — C stellaris rf Gonyaulax spinifera Clap & Lachm Peridinium oceanicum Vanh r; '/9 r; ^'/lä '^J2 rr; ^'/lä '-^"/u 5/-J2 r; r; + V12 Leptocylindrus danicus Cl ^','1 r; -fn Gran constrictus ^*/ii danicus Cl ^/i2 — r ^''/.t -'^/t '>">' Coscinodiscns e.xceutricus r rr Halosphoera viridis Schmitz V" '"''; G similis rr T (bottnicns var.) pelhicidus Cl '^'/ii C — C Cyttarocylis serrata — Cl liystrix Poucheti Lagh rr; ^"/n ,._ ''' — — Stein horologium — Diuobrynm pellncidum Levandbr — Biddulpbia mobilensis Bail — rr; -"/n rr r; ^/i — ^V* rr Xanthidium C — PouCHET r; ^,10 ^/g i5c 8/10 Phseocystis r r Steeustrupii Clap ^U ^/i r; ^s^jj — Pleurobracbia pilens Fabr ^'/s Pyropbacus "^/'o r c '/t Limacina retroversa Flem Araphorella r; ^/d -^/e r; '3 Protoceratiura reticulatum ))' r; ^^/w r; (i ^;6 S ^k rr; ^'/i ^''/w Vs +; 3/9 +; 11/9 - 70 c; "*, C iiitermedius Lilljeb Bergh pellucidum rr; ^^/lo r — Anomalocera Patersoni Templ P ir + ^^/e ằ i^/io ằ-r; i',3 ô 2-' KONGL SV VET AKADEMIENS IIANIJLINGAU BAND 35 37 N:() Species excluded from table VI Väderöboda — ^"/s r; V-i » LOHM /5 ^'/ii ev Amathilla angulosa RathkE ^"/s r Caprella septentrionalis KkưYER ^/a rr; ''/s f Parathemisto oblivia KrƯYER Proto pedata Lbach ^'Vis + -",'10 »; -/i2 Podou intermedius Lilljeb /s + Fritillaiia borealis — — — P — P P ?»- ; Corycaeus anglicus Lubb ~ Boeck Isias clavipes r\ '/ii "/a Euterpe acutifrons Dana 2-1/12 - — Labidocera Wollastonii Lubb Temorella ^^ji2 Pleurobracliia pileus Amphorella -/12 -/o — -" lu •/; " , 10 r — MƯB -Via Brandt ^^'i rr; -^ji + 12, Tintiiinopsis tistularis MưB •''/i r »• Tintinnus bottnicus NORDQurST '7» ''• Gyttarocylis serrata Ptychocylis — acuta iniliaris Dictyocha tibula Ehb Acanthometron 28/10 — Sdrir — -*^ catervatum lu aracbnoides Clap Dinophysis rotuudata Stein D Vanhöffenii OSTF Diplopsalis lenticula — 17/ '", a & Lachm — u ^i -^!w r\ ,., i) Bergh — ''In Gonyaulax spiuifera Clap & Lachm 25/1 — septentrionalis 0str C sirailis CL — — c; ^V^ — Lauder oculus iridis Ehb Shrubsolei Cl '^^/lo — V ' /•; 2S/10 R Stolterfothii ,, ^''/i 'S ' r r r r V12 r r ''/a c; — — CL — ''/a V» — y; ^ '/ii 20; 10 ''Vn '''; '*; '^Vi2 _ v 710 +; 2»/io cc r ''/n r; ^'''/'^ '-• + 26,35 r cc r r r + + + + CCC cc + ccc 23,09 — 10 11 11 29 20 11 28 13 19 27 10,0 9,9 8,3 5,7 5,9 4,0 5,2 29,10 27,38 25,75 + + + r r 9' r r + — 20,01 r ) ccc 21,33 25,10 r + c + + cc ccc c rr + cc r + + r +, r cc c + + c c c r c + c + c r c c + c 12 ? C c T- -^ /\ (i 10 + r + ecc 32,1 ' + r r cc "10 18 + r r cc -g 9- 11 ] 32,27 19,73 18,70 '32,01 22,04 20,79 r " ] H- r r + + + + + + r + + r r + + r + »' r r rr r + c c / \ r 1- + r r / rr + rr r • + + + r r J + c c ccc cc + r r c -f c cc r r + + c rr ccc r T c c r ccc cc c r r- r r ' + -r rr rr r rr r r rr r rr rr + r rr rr rr rr rr + r ccc + + c + c c c ccc cc c c c c + c cc + e c c r r + r cc cc c c c c ccc c c r r c ccc + ccc + ccc + r + r r r + r r r r r cc c c c r + + r r fp Tp fp Nm a TpS Nm Nm a Nm a fp Nm fp Nm fp fp Nm Ns Ns Nm Nm Tp , iV.s Nm Nm Tp Tp c c r r r + + + ' , r • r r r r r + r rr r + r ,, r ': '!' r r cc r r Nm c r r r ccc C + :- r r r r ccc + + c + + c : r r + r + i+'r + c r rr r c c r + cc + • r Ne + rr r + + • r r r c _, r + r c rr Nm Nm Nm Ns r + r e Ns Tp Ns Nm, Ns Ns Nm Nm Tp Tp Ns r r fp ! 48 P CLEVE T THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK Table Month 2 13 25 VI 3 4 T) 19 29 26 12 1,0 1,5 4,0 6,0 7,0 I Day 17 25 I Temperature 0,0 2,0 0,0 3,0 5,1 1,0 i i Salinity i Oikoijleura dioica 19,34 19,17 25,10 33,69 26,9fi 32,(;5i32,20 27,43 28,57 30,r,7 29,83 28,00 Fol Acartia Clausii Giesbr A longiremis Lill.tbb Calanas flnmarcliicus Gitnn Oentropagea hamatus Lilljeb C typicns Kbuyer Oithona similis Claus Paracalanus parvus Claus Pseudocalanus elongatus Boeck Temora longicornis O F Mull Evadni Nordmani Loven + + + I + E spinifera P E MtiLL Sagitta bipunrtata Quoi & Gaim Cyttarocylis denticulata Eiib Tintinnopsis campanula Eitb Distephanus speculum Ehk Halosphiera viridis Schmitz, Ceratium liucephalum Cl furca Duj C fusus Duj C lineatum Ehb C longipes Bail C macroceros Ehb C r ccc + NiTzsCH Dinophysis acuta Ehb Peridinium depressum Bail C tripos P divergens Eiib Biddulphia aurita Lynob B mobilensis Bail Ceratanlina Bergonii H Per ChEetoceros horealis Brtw C v Brightwellii Cl C brevis Schutt C constrictus Gran C contortus Schutt C curvisetus Cl C debi.Us Cl : decipiens C densus Cl C diadema Ehb didymus Ehb laciniosns Schutt Schöttii Cl scolopendra Cl teres Cl C C C C c ccc c / cc + Cl C C Coscinodiscus concinuus cc cc r ) ' W Sm Ehb polychordua Gran radiatiis Ehb ste)laris Ropbr C oxcentricus C C C Ditylum Brightwellii West Eucampia zodiacus Ehb Guinardia Haccida Oastr Lauderia anniilata Cl Leptocy lind rus danicus Cl Rhizosolenia calcar avis Schulze R gracillima Vl R semispina Hbnsen R setigera Brtw Skeletonema fostatum Grev Th.ilassiosira Nordenskiöldii Cl Thalassiothrix Frauenleldii Ctran Plankton-ty])f! + + + + (Tp (Tp Ns) Ns) m Tp Ns ccc + c c c c c cc cc cc Si Si + + Si Si Si T Ne Ns Ne Ns Ne Ns BAND KONGL SV VET AKADEMIENS IIANDLINfiAK 49 n:o 35 Väderöboda 1900 6 19 8,0 12,4 13,0 ; i 6 7 7 16 23 18 27 14,8 16,2 16,0 13,0 16,8 18,0 - •29,89 22,88 22,30' 22,04 22,44' 9 10 10 11 12 20 27 10 17 20 28 17,0 18,0 16,3 16,0 14,5 14,5 11,5 10,5 8,3 ' ' 11 11 12 12 12 17 24 24 8,0 6,0 4,0 3,0 6,0 I ' I 32,92 24,(;3 21,83 27,90 28,82 27,01122,05 22.59 30.94 28,19 29,83 29,98 r 4- c I + c r r + r 4- + r 4- 4- c 4- r 4- + + + + cc c + + cc c cc cc r r + + r rr 4- c 1' 4- + + r 4- 4- r + 4- r + r + + r + + + r 4- r r rr r r rr + r ) rr rr rr r r 4- + c 4- 4- 4- rr rr r cc c c cc c c rr r r r r + r r rr r + r r r r }• r ccc ccc ccc r r r r cc r + c + r c + 4- 4- c C 4- C cc cc r 4- e 4- + + 4- + 4- c c c + + + + r r r + + 4- 4- r r 4- r r + )• c cc cc c r 4- c H- r r r r r + r r + r r r r r r r rr r r + + + c r + + + + + r + + r + + r r r 4- + + c iTp?) Ne r Tp Tp Nma Nm a Tp Nma Nma Tp Nma' Tp Tp Tp Tp Tp Tp Tp liand 35, N:o Tryckt tion 12 april 19112 + + r + + r + Tp Nm Nm Ns Nma K Sv Vet Akad Hanrtl ' c ! Ns + r r + r + + + r r 4- c c Ijp Ntii Tp Tp Tp Nm Nm Nm Nm Tp Ns Ns Ns Ns Ns ... 18,7o to 32,92 in Ije The plankton was partly tripos -plankton and the variety of southern neritic -plankton, which Rhizosolenia gracillima predominates (Nma) If the plankton at both stations compared,... prevailing plankton was tripos -plankton, that had remained from the last month, but at the niore southern station Måseskär this kind of plankton was more or less abundantly interraingled with didymus -plankton, ... Dogger Bank The plankton of this kind of water is totally diflferent from what it was in the appears It Of winter the insignificant traces only remain prevailing tripos -plankton then the plankton eonsists