It has been suggested that the populations of planktonic cyanobacteria that occupy the metalimnion of stratified lakes during the summer months may be aestivating between the main periods of growth during entrainment in the epilimnion in spring and summer. We determined the vertical distribution of the biomass and daily integral of photosynthesis of the population of Planktothrix (Oscillatoria) rubescens in Lake Zu$ rich for 136 d from July to November 1995. The population showed an 80-fold increase during the stratified period but it only doubled over the subsequent period of entrainment. During the first eight days, part of the increase was attributed to recruitment of filaments floating up from greater depths but all of the subsequent production could be accounted for by photoautotrophic growth. On sunny days the biomass-specific photosynthesis of this population reached some of the highest values over the whole period despite its depth ( 13 m). On very cloudy days, however, primary productivity was very low and on 4 days, when the mean depth of the population exceeded 15 m, there was no net production. Over the whole period of the study, the accumulated photosynthetic production exceeded the increase in biomass of the population by a factor of 9n5. Although much of this production occurred during the period of entrainment only a small proportion was translated into growth of the population. It is concluded that the growth that takes place in the period of stratification in the metalimnion is essential to subsequent production.

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Zusammenfassung: Hybrideder Romantik: Frankenstein,Olimpia unddas künstli-cheLeben. Dieser BeitraguntersuchtV orstellungen überdie Mçglichkeit derErzeugung künstlicherLebewesen in derZeitder Romantik unddie damitverbundenen ¾ngsteam Beispiel zweier fiktionalerT exte:M aryS helleys Frankenstein undE rnst TheodorA madeus Hoffmanns Sandmann. Dr.Franksteins Monsterund Dr.Spalanzanis Automatverkçrpern -a uf unterschiedliche Weise-dieM çglichkeit einerW endung wissenschaftlicher Produkte undi nsbesonderek ünstlicherH ybride insM onstrçse.I hreG eschichten thematisierendas Grauen,das vomdrohenden Kontrollverlustausgehtund als dermod-ernenW issenschafti nnewohnendeG efahrs elbstn achd er Zerstçrung derm onstrçsen Kreaturenb estehenb leibt. DerB egriff desU nheimlichen, vonE rnst Jentschu nd Sigmund Freudmit Bezugauf Hoffmanns Sandmann formuliert und1970von demjapani-schenR obotiker Masahiro Mori als Phänomen" desu nheimlichenT als" (Uncanny Valley)weiterentwickelt, erlaubtweitere Einblickeindie FragenachkünstlichenLebewesenund ihre Interaktionmit Menschen.Summary: Hybridso ft he Romantic:F rankenstein, Olimpia, andA rtificialL ife. This essayanalyzesfantasies andfears relatedtothe possible creation of artificial humans in twoi nfluential pieces of Romantic literature, namely E.T. A. Hoffmann's DerS andmann andM aryS helley's Frankenstein. Both thea utomaton Olimpiaa nd Dr.F rankenstein'smonster arehybridcreatures.These dystopianfigures representthe Romantic fear of thelossofcontrol over theoutcome of humanendeavour,theysymbolize thedangers immanent in modern sciencea nd technology.A sh ybrids,O limpia andF rankenstein's monstera re capable of breaking apparently unpenetrable boundaries, such as thoseb etweenh umana nd non-human, andb etween life andd eath.A ss uch, thesec reatures become" unheimlich"( uncanny),acritical term developedb yE rnst Jentsch andS igmund Freud, whod irectlyr eferredt oH offmann's Sandman. Thet erm" uncanny"w as furtherdeveloped by theJapaneseroboticistMasahiroMoriinthe 1970s. Mori's investigation of humanr esponses to androids ("UncannyV alley"), showst he persistenceo f doubts andf ears surroundinga rtificialh umans farb eyondt he Romantic times, and opensnew questionsr elated to thei ssueso fcreation, reproduction,hybrids,hubrisa nd gender.

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