" Still, i l l npit.cr of t'l~tr pt*c*\f~alcucc! of 01-punis~r~ic: rk~ytl~lrlicity, thcrc is
11. Inrbgo l)r*oport,iot~ of l,iolopist,s workirlp tod11.y w h o do n o t rculizo t h a t
(Jl~a~ldtt Ik.rr~a.~~tl'.r c:ottcty~t. of' I ~ o l r ~ o o n t ~ ~ s i s
tts II ~trtligl~t-lint) paradigm
l r ~ ~ t s t ,
IIOW k)(y ~nociifi(\(I t,o tt rIryt,11111ic s[,twis."
J. 1). ~ ' A T . M R R
irr 13row11 el ul. (1!)50)
The interest i~nci implictttions of circadii~n* rhythrr~s in the vegetal
and rirlirnal Itingtlolns (lo not need to be emphasized even by way of
iritrodr~ction; refercncc to some recent books, symposium proceedings
and review articles, whether devoteti to plants or animals or both, and
either including or exclrlding periods other than circadian, should
provide a convincing background: Riianing (1964), Harker (1964),
AschofT (1965), Sollberger (1965), Hirukow and Rensing (1967), Brllsl6
(1 969), Hidberg ( I 969), Sweeney (1 969a), Brown et al. (1970), Enright
( 1970b), Raillattd (1 971) i~11d Vanden Driessche and Reinberg (1972).
Protista have not rcceivt:d less at,tention than Metazoa (see tn-o
roviews on rmicr?llali~r itlgae or protozoa by Varlden Driessche (1970)
and Swcency (1!)72) ) ; ;I yi~rticnli~rl,y flourishing literature is available
011 nlicr-o-orgi~nia~ns grown in sync:l~ronous cultures, a technique initiated
fhr the prilcticul purpose of' provitling physiologists with iL sufficient
an~orlnt of cclls ut i~ given d~v(?loptnel1t,;L1 ~ t i ~ g ~
(Cook, 1961 ; Tamiyct,
1964, I !Mi ; Zcl~tl~rn, I964 ; Soetlcbr, 1965 ; Pirson ilntl Lorenzen, 1966 ;
I,orenzen, 1 !I70 ;~ntl 0t~11er.u).
tlotning to our firltl of intc~rcst, ho~vcver, i t appears that cornparativrly little ~vorl; 11:~s 1 ~ ~ 1
(lolie 011 c:iroatlian changes in phytoplanltton
populi~tions. Only two topics are recognized a t the textbook Jevd : on
the ollt. h:1nc1, the pllotosgntlietic periodicity first described by 1)oty
*Cirnntlin~~, tliurtlr~l or clical? As alrt,ttdy poir~trtl out (Rournia ant1 I"ront,inr, 10fjR or111
ot.hc.rr), " tlir11~11cll ", htrir~g thc! r~pl)~~+it,r, of " nf)cfurnaI ", c c m r ~ ~ ~ t
apply t,o H. 24-ho~lr
cyclt,. hnl orlly to ILII c!vc?nl, which oocnrs hotwcon snnrisc. arid sunnl:t,. '' (~iroft~1i1111 "
(I?. H t t l b t ~ r ~ )
\voultl ht: thc: right worrl for such a cyclo, wore it not, fi)r an arnl~iguity
filnclllg 1)hy.iiologiwts ( a m Wurtrnan, 1!M7 ancl othora): whether. it is ( 1 ) a n y rhythm tho
l)(~rio(l of which i. . i about 24 hours (20 to 28), or (2) among such rhythms, only thoso
which 1)c~rsist rtr~tlcr constant environmc~ntal conditions; tho author is not entitlrrcl to
uottl(~ t.hiu l r ~ ~ ~ t l t ~ .
'' Ijicl " (used only by oceanographeror) has the name meaning as
circt~tlinu-" 1 ". Thus, in this paper, " circatiinti " and " die1 " will he used indiffernrlt,ly for n,rly pt'riotl of about 24 hours, whether endogenous or exogenous. A fourth
worcl. " tl~tily ", t h o ~ ~ g h
it, clearly rnoans " once a day ", or "every day ", hrt. al;o
int,t.otl~~octl sonlo corifusion in the 1it.nmt.ure.
11. Inrbgo l)r*oport,iot~ of l,iolopist,s workirlp tod11.y w h o do n o t rculizo t h a t
(Jl~a~ldtt Ik.rr~a.~~tl'.r c:ottcty~t. of' I ~ o l r ~ o o n t ~ ~ s i s
tts II ~trtligl~t-lint) paradigm
l r ~ ~ t s t ,
IIOW k)(y ~nociifi(\(I t,o tt rIryt,11111ic s[,twis."
J. 1). ~ ' A T . M R R
irr 13row11 el ul. (1!)50)
The interest i~nci implictttions of circadii~n* rhythrr~s in the vegetal
and rirlirnal Itingtlolns (lo not need to be emphasized even by way of
iritrodr~ction; refercncc to some recent books, symposium proceedings
and review articles, whether devoteti to plants or animals or both, and
either including or exclrlding periods other than circadian, should
provide a convincing background: Riianing (1964), Harker (1964),
AschofT (1965), Sollberger (1965), Hirukow and Rensing (1967), Brllsl6
(1 969), Hidberg ( I 969), Sweeney (1 969a), Brown et al. (1970), Enright
( 1970b), Raillattd (1 971) i~11d Vanden Driessche and Reinberg (1972).
Protista have not rcceivt:d less at,tention than Metazoa (see tn-o
roviews on rmicr?llali~r itlgae or protozoa by Varlden Driessche (1970)
and Swcency (1!)72) ) ; ;I yi~rticnli~rl,y flourishing literature is available
011 nlicr-o-orgi~nia~ns grown in sync:l~ronous cultures, a technique initiated
fhr the prilcticul purpose of' provitling physiologists with iL sufficient
an~orlnt of cclls ut i~ given d~v(?loptnel1t,;L1 ~ t i ~ g ~
(Cook, 1961 ; Tamiyct,
1964, I !Mi ; Zcl~tl~rn, I964 ; Soetlcbr, 1965 ; Pirson ilntl Lorenzen, 1966 ;
I,orenzen, 1 !I70 ;~ntl 0t~11er.u).
tlotning to our firltl of intc~rcst, ho~vcver, i t appears that cornparativrly little ~vorl; 11:~s 1 ~ ~ 1
(lolie 011 c:iroatlian changes in phytoplanltton
populi~tions. Only two topics are recognized a t the textbook Jevd : on
the ollt. h:1nc1, the pllotosgntlietic periodicity first described by 1)oty
*Cirnntlin~~, tliurtlr~l or clical? As alrt,ttdy poir~trtl out (Rournia ant1 I"ront,inr, 10fjR or111
ot.hc.rr), " tlir11~11cll ", htrir~g thc! r~pl)~~+it,r, of " nf)cfurnaI ", c c m r ~ ~ ~ t
apply t,o H. 24-ho~lr
cyclt,. hnl orlly to ILII c!vc?nl, which oocnrs hotwcon snnrisc. arid sunnl:t,. '' (~iroft~1i1111 "
(I?. H t t l b t ~ r ~ )
\voultl ht: thc: right worrl for such a cyclo, wore it not, fi)r an arnl~iguity
filnclllg 1)hy.iiologiwts ( a m Wurtrnan, 1!M7 ancl othora): whether. it is ( 1 ) a n y rhythm tho
l)(~rio(l of which i. . i about 24 hours (20 to 28), or (2) among such rhythms, only thoso
which 1)c~rsist rtr~tlcr constant environmc~ntal conditions; tho author is not entitlrrcl to
uottl(~ t.hiu l r ~ ~ ~ t l t ~ .
'' Ijicl " (used only by oceanographeror) has the name meaning as
circt~tlinu-" 1 ". Thus, in this paper, " circatiinti " and " die1 " will he used indiffernrlt,ly for n,rly pt'riotl of about 24 hours, whether endogenous or exogenous. A fourth
worcl. " tl~tily ", t h o ~ ~ g h
it, clearly rnoans " once a day ", or "every day ", hrt. al;o
int,t.otl~~octl sonlo corifusion in the 1it.nmt.ure.