Hidrológiai Közlöny 2012 (92. évfolyam)
5-6. szám - LIII. Hidrobiológus Napok: „A hidrobiológia szerepe a víz-stratégiákban” Tihany, 2011. október 5–7.
99 The effect of periphyton on pondweeds Viktor R. Tóth Balaton Limnological Institute, Hungarian Academy of Sciences Centre for Ecological Research, Tihany Abstract Submerged rooted macrophytes are highly dependent on the irradiance reaching photosynthetic surface, thus amount of periphyton affects primary production, growth and distribution of plants. Seasonal variation and vertical distribution of periphyton on artificial substrates and its effect on light environment was studied in Lake Balaton. Data showed that after 8.8±0.4 days an average of 4.1±0.4 mg (dry weight) cm-2 of periphyton accumulated on the plastic stripes. Thismass corresponded to 294±30 ng m-2 chl-a of epiphytic algae and blocked 92.3±0.8 % of the depth specific radiation. Moreover, seasonal changes and specific vertical distribution of the periphyton was observed. The most active time of periphyton accumulation corresponded to the early months of the vegetative period (up till middle of June). Later the year (summer and early autumn), amount of periphyton significantly decreased, increasing the photosynthetically available light. The best conditions for periphyton accumulation were at 40 cm depth. Periphyton accumulation via additional light attenuation was able to significantly decrease the production of Potamogeton perfoliatus by 60-80%, increasing the importance of the backscattered light that consequently was able to significantly increase production. Recognizable vertical pattern of depth distribution of periphyton could additionally influence the within-plant morphological and physiological variability of macrophytes, resulting a selective pressure on the broadleaf species of submerged rooted macrophytes. Epiphytic algae were connected to both benthic (dominantly benthic penales) and pelagic (very close seasonal dynamics of pelagic and epiphytic biomass) algae. Keywords: periphyton; vertical distribution; seasonal change; macrophyte production; Lake Balaton; Potamogeton perfoliatus, 1. táblázat. A bevonatképződés dinamikája |(a száraz súlya a 10. napon (sza), és a telítődési sebessége (telítődés)], illetve a bevonat transzmittanciája és kloroFill-a tartalma a kísérlet 10. napján. A számok több mélységben gyűjtött adatok átlaga (± SD) (n=14 tömeg, n=21 transzmittancia és n=7 klorofill esetében). A függőleges számok mutatják a szezonális átlagokat, a különbségek t-próbával ellenőrizve. *** - P <0,001, nsz - nem szignifikáns sza (mg bevonat tömeg cm' 2) telítődés (nap) transzmittancia (%) kl-a ()tg m niárc. 22 6.8±2.9 8.7±0.5 3.9:2.2 402.9±224.0 ápr. 06 6.1 ±2.0 7.7±0.4 0.2±0.0 338.7± 122.3 ápr. 20 4.8±1.1 ö -H vb 10.3±1.3 ö 2.1±1.I © 612.2±213.3 W máj. 04 máj. 18 9.7±1.6 7.6±1.6 ö -H vb 9.1±0.7 10.4±1.2 o" 0.3±0.3 l.0±0.8 •ct; 656.2± 191.0 775.7± 176.1 (N jún. 01 5.3±l.O 10.0±0.6 0.9±0.7 336.3±53.3 jún. 15 2.4±0.8 10.6±1.6 18.8±10.5 302.6± 101.7 júl. 05 2.6±0.6 5.8±0.5 I4.3±5.5 155.1 ±69.4 júl. 20 2.3±0.3 9.3±0.2 1.1 ±0.3 in 159.9±41.6 rr aug. 03 2.2±0.4 ö i rí 7.8±1.0 o -H -r 17.8±4.5 o -H 45.1*12.4 n +1 aug. 17 2.6±0.4 ö i rí 8.8±1.1 o -H -r 7.3±3.3 CÁ 99.2±26.6 OS aug. 31 1.0±0.2 ö i rí 7.0±1.2 22.4±l 1.6 —* 87.5±34.1 szept. 14 2.3±0.3 9.9±1.3 4.0±1.5 271.4±24.4 szept. 28 1.2±0.2 7.5±0.6 13.9±3.8 154.3±45.6 t-teszt 7.1"" 1,6 ns z -4.1'" 5.5"*
