Hidrológiai Közlöny 2000 (80. évfolyam)

5-6. szám - XLI. Hidrobiológus Napok: "Vízi ökoszisztémák (taxonómia, biodíverzitás, biomonitorozás, élőhelyek frakmentációja, inváziós fajok biológiája)" Tihany, 1999 október 6-8.

344 HIDROLÓGIAI KÖZLÖNY 2000. 80. ÉVF. 5. SZ. Köszönetnyilvánítás A munka a T 016303 számú OTKA és a 97-111 3,3 számú AKP anyagi támogatásával készült. A tápanyagterhelési adatokért köszönetünket fejezzük ki a Nyugat-Dunántúli Vízügyi Igazgatóságnak. Köszönjük Horváth Teréziának és Kozma Erikának az egész kutatás során nyújtott pótolhatatlan segítségét. Irodalom Bíró P. (1997) Temporal variation in I.ake Balaton and its fish populations. Ecology of Freshwater Fish 6, 196-216. Collos Y. (1983) Transient situations in nitrate assimilation by marine diatoms. 4. Non-linear phenomena and the estimation of the maximum uptake rate. Journal of Plankton Research 5, 677-691. Dortch Q. (1990) The interaction between ammonium and nitrate uptake in phytoplankton. Mar. Ecol. Prog. Ser. 61, 183-201. Elliott R.J. & Porter .4.0. (1971) A rapid cadmium reduction method for the determination of nitrate in bacon and cunng brines. The Analyst 96, 522-527. Fielt R.J., Hamilton R.D. & Camphell N.E.R. (1976) Aquatic acetylenereduction techniques: solutions to several problems. Canadian Journal of Microbiology, 22, 43-51. Gliben PM.. Garside C„ Fuhrman J.A. & Roman M.R. (1991) Timedependent coupling of inorganic and organic nitrogen uptake and regeneration in the plume of the Chesapeake Bay estuary and its regulation by large heterotrophs. Limnol. Ocecmogr. 36, 895-909. Istvánovics V. & Herodek S. (1995) Estimation of net uptake and leakage rates of ortophosphate from 3

2P-uptake kinetics by linear forceflow model. Linmol. Oceanogr. 40: 17-32. Jolánkai G. (1995) A Balaton 1994. évi tápanyagterhelésének meghatározása. Report of the Balaton Program of Water Resources Research Centre, 713/3156, Budapest Lean D.R.S., Murphy T.P.& Pick F.R. (1982) Photosynthetic response of lake plankton to combined nitrogen enrichment. J. Phycology 18, 509-521 lövell T. (1989) Nutrition and feeding of fish. .41-7 Book 260 pp, Van Nostrand Reinhold, New York. 2. táblázat Siófok 1998 Ammónium Urea Nitrát Siófok 1998 V * max V

d% I

k Sötét % V v max V

d% U Sötét % V v max V

d% Ik Sötét % V„p,C Vopt C/V

ma

> (összes N) Febr. 27. 1.69 51.30 32.26 78.33 1.40 60.75 33.71 77.78 0.29 9.17 148.04 32.50 21.4 6.3 Apr. 2. 3.97 77.21 24 89 90.43 4.71 66.47 50.78 84.80 0.30 35.25 46.19 63.19 57.7 6.4 Máj. 13. 2.41 63.08 34.77 77.97 2.61 66.24 34.33 82.07 0.11 23.88 99.04 44.78 24.3 4.7 Jül. 10. 3.01 66.45 102.16 92.05 0.27 38.76 38.39 88.91 0.23 6.87 59.86 21.05 20.5 5.8 Aug. 5. 3.80 65.00 36.00 85.24 0.50 42.00 45.30 71.37 0.31 8.71 58.20 32.26 17.5 3.8 Aug. 19. 5.50 63.45 34.10 61.65 1.38 52.45 39.30 68.57 0.28 6.00 50.80 12.50 17.6 2.5 Szept. 16. 3.24 64.58 37.23 84.19 1.09 53.76 51.76 78.90 0.23 11.99 57.93 31.28 44.7 9.8 Nov. 10. 0.93 79.93 33.54 92.92 0.38 73.70 44.07 90.49 0.03 31.74 47.21 63.93 9.6 7.2 Keszthely Júl. 13. 966 29.50 49.94 55.52 1.77 6.78 52.70 15.92 0.43 0.00 73.38 0.00 85.8 7.2 Aug. 18. 19.60 31.68 48.85 65.49 4.80 18.00 50.32 47.76 0.80 0.00 82.71 0.00 244.2 9.7 Szept. 22. 3.97 33.75 47.80 61.63 1.75 29.70 47.95 56.90 0.27 0.00 92.00 0.00 61.3 10.2 Nov. 16. 0.55 35.60 37.27 67.26 0.13 43.37 32.67 68.18 0.05 1.10 37.06 25.00 17.0 23.1 V

ml

x = maximális felvételi sebesség, V

D % = Sötétben mért felvételi sebesség amaximális felvételi sebesség %-ában; Ik = fényadaptációs paraméter; Sötét % = A sötétben felvett nitrogén az egész napi felvétel %-ában; V^ C = az optimális megvilágításon mért szénfelvétel sebessége; Nitrogen uptake and the importance of internal nitrogen loading in Lake Balaton 'Présing M, 'Herodek S.

, 'Vörös /_, 2Takátsy A. and 3Kovács Gy. 'Balaton I. imno logical Research Institute of the Hungarian Academy of Sciences, P.O. Boi 35, H-8237 Tihany, Hungary 2Janus Pannonius University, Pécs 3Central-Transdanubian District Water Authority, Balatoni út 6, II-8000 Székesfehérvár, Hungary Abstract: The importance of various nitrogen forms to the nitrogen supply of phytoplankton has been investigated in the mesotrophic eastern and eutrophic western basin of Lake Balaton. Ammonium, urea, nitrate uptake were measured simultaneously along with carbon uptake. The uptake rates were determined using 1

5N and l

4C methodologies, and Nrfixation was measured using the acetylene-reduction method. The light dependence of uptake was described with an exponential saturation equation and used to calculate surface-related daily uptake. The contribution of ammonium, urea and nitrate to the daily nitrogen supply of phytoplankton varied between 11 -80 %, 17-73 % and 1-15%, respectively. N2-fixation was negligible in the eastern basin and varied between 5-30 % in the western region of the lake. The annual external nitrogen load was only 10 % of that utilised by algae. The predominant process supplying nitrogen to the phytoplankton in the lake is the rapid recycling of ammonium and urea in the water column. The importance of the internal nutrient loading is emphasised. Mackereth F.J.H., Heron J. & Talling J.F. (1989) Water analysis: Some revised methods for limnologists. Freshwater Biological Association Scientific Publication No. 36, (Ambleside). Mitamura O. & SaijoY. (1986) Urea metabolism and its significance in the nitrogen cycle in the eutrophic layer of Lake Biwa. IV. Regeneration of urea and ammonium. Arch. Hydrobiol. 107, 425-440. Mitamura 0., Saijo Y„ Hino K. & Barbosa F.A.R. (1995) The significance of regenerated nitrogen for phytoplankton productivity in the Rio Doce Valley Lakes, Brazil. Arch. Hydrobiol. 134, 179-194 Newell B.S., Morgan B. & Candy J. (1967) The determination of urea in seawater. J. Mar. Res. 25: 201-201. Présing A/., Herodek S., Vörös L. & Kóbor I. (1996) Nitrogen fixation, ammonium and nitrate uptake during a bloom of Cylindrospermopsis raciborskii in Lake Balaton Arch. Hydrobiol. 136, 553-562. Présing M., Vörös L., Herodek S. & Abrusán Gy. (1998) The significance of various nitrogen sources for phytoplankton growth in shallow lake and hypertrophic reservoirs. Int. Rev. Hydrobiol. 83, 361-368. Présing M„ Herodek S„ Vörös L, Preston T. & Abrusán Gy. (1999) Nitrogen uptake by summer phytoplankton in Lake Balaton. Arch. Hydrobiol. 145,93-110. Takamura N„ Iwakuma T. & Yasuno M. (1987) Uptake of 1

3C and 1

5N (ammonium, nitrate and urea) by Microcystis in Lake Kasumigaura. J. Plankton Res. 9, 151-165. Tátrai I. (1981) Diurnal pattern of the ammonia and urea excretion of feeding and starved bream, Abramis brama L. Comp. Biochem. Physiol. A: 70, 211-215. Vollenweider R.A. (1969) A manual on methods for measuring primary production in aquatic environments IBP Handbook 12, 123 pp., Blackwell Scientific Publications, Oxford. Vörös L„ V.-Balogh K. & Herodek S. (19%) Microbial food web in a large shallow lake (L. Balaton, Hung). Hydrobiologia, 339, 57-65. Vörös L. & V.-Balogh K. (1998) A Balaton Keszthelyi-medencéjének szénforgalma. Hidrológiai Közlöm. 78, 385-386. Keywords: ammonium-, urea-, nitrate uptake, N,-fixation, rcmineralization