Hidrológiai Közlöny 1997 (77. évfolyam)

13 A I„(UE m'

2 s ') 300 • NI I, n NO, LlC 250 ?Ul) 150 10Ü 50 0 B U|iE m"

2 s'

1) 300 • NI I, B NO

3 • C l l ... 250 2 UO 150 100 50 ni Jul 26. Auy 15 Auij 2<J Szopl.26 OKI 25. Jul 26 Aug 15. Aug 29. Szepl.26. Okl.25. 2. ábra A fitoplankton niiunóniiiin-. nitrát- és szénfelvételének ertekéi a Siófoki- (A) és a Keszthelyi-mcdcncébcn (1!) Tlic lighl depeiidencc of niliogcn uplakc liy rito|)laiiklon in lakc linlalun INlályás l'i csing, Sándor Ikrodelt, Lajos Vörös nnd *(,'yula Kovács Dalaton Liinnolugical Rescarch Institutc ofthe llungarrtín Academy of Sciences, Tihany, *Cciilral-Transdanubian District ll'ater Autlwrity, Székesfehcnár Ahsliatl: The dcpciidcncc ofsubslialc saluialcd uplakc of MN11/ nnd "NOj' oii liglil nilcnsily by filoplankton was characlcrizcd in two hasins of Laké Balaton Imin July lo Oclober ni ]')')(>. The sainplcs wcrc kc-pl in an incubation box al laké Icinpcralurc and illuiniiiatcd by while lluoicsicnl lainps al lighl inteiisities of 0, 10, 20, 30, 60. 85, 120, 150, 290 and <160 |iliinstein in Js '. In lliis lange of lighl inlcnsity tlic ammónium and niliale uplakc rates can be desuibed vvilh Ihc cxponcnliul saluralion iclutionship ol Welih el al. (I97<1) adding a daik uplakc leim (V|>) lo Ihc cqualion (Fig. l.).TIic uplakc of luiuuoiuum was less inlluenccd by lighl llian Ihc inlialc uplakc Al Ihc sainc lighl iulcnsilics Ihc uplakc ralcs of anunoniuin ineluding Ihc uplakc in daik wcrc usually liighci lliau in Ihc casc of mlialc (Tahlc 2.) Ihc Ik valucs of anunoniuin uplakc wcrc lowcr and did nol cliangc signilkaullv lioiii July lo Oclobci Willi iucicasing piopoilum of bluc-gieciis in Ihc algal populatiou Ihc k valucs of nitralc dcucuscd ltom .suniinet lo auluuui (lig 2.) Thcsc icsulls stiggcsl a lowcr lighl rcquiiciiicut ofhluc-grcciis. Siuiullancoiisly willi llic expciimciils of li^lil dcpciidcncc Ihc aclual uplakc íalcs of aiiunoiiiuin, nilralc, inorgonic carbon and Nj - lixalion wcic alsó mca.suicd wi Ih mN, "C lccluii(|iics and ucclylcnc icdiiclion niclhod icspcclivcly. Ilic daily uplakc ralcs and lixalion wcic talculalcd pci unil suifaic aica ( lahlc I ). By llicsc rcsulls Ihc majorily of niliogcn was originalcd fiom aiiiiiioniuui uplakc in holli liasins Ihc nilialc uplakc and N2 - lixalion usually coulribulcd onlv 10-20 % lo Ihc lolal niliogcn supply. Whcn Ihc icgcncialcd fotnis of niliogcn wcic nol sullicicnl lo suppotl Ihc algal populatiou niliogcn lixalion did play a 11101c itnpoilanl mlc lliis was Ihc lase in Keszthely hasin 111 Atigusl, wlicn N2 - lixalion coulribulcd 67 pcrccnl lo Uie lolal niliogcn dcinand