Hidrológiai Közlöny 2010 (90. évfolyam)

6. szám - LI: Hidrobiológus Napok: „Új módszerek és eljárások a hidrobiológiában” Tihany, 2009. szeptember 30–október 2.

156 HIDROLÓGIAI KÖZLÖNY 2010. 90. ÉVF. 6.. SZ. The relationship between organic carbon pool, bacterioplankton, and photolytic degradation products of organic substances in shallow lakes K, V.-Balogh'

, B, Németh', Gy, Zs, Keresztes

2, Á, Agyi

3, B, Somogyi' & L, Vörös' Abstract: The aim of this paper is the characterization of the relationship between the organic carbon pool, bacterioplankton, and photolytic degradation products of organic substances in shallow lakes. Underwater UV irradiance depth profiles were obtained in situ, dissolved organic carbon and its photolytic degradation product (hydrogenperoxid), and the quantity of phyto- and bacterioplankton were measured in 17 water bodies in the summer of 2009. The H

20

2 production was higher in CDOM rich waters than in clear waters. A significant relationship was found between H

20

2 concentration and vertical attenuation coefficient (Kj UV-A and UV-B) values. An inverse relationship was found between H

20

2 concentration and bacterioplankton biomass. The H

20

2 concentration increased 2-50 times under the effect of artificial sun irradiance in the presence of dissolved colored organic substances (CDOM), but the H

20

2 was immediately eliminated in the presence of high algal concentration. We have found a complex effect of UV radiation on bacterioplankton: both direct inhibitory and indirect inhibitory and stimulating effects were detected. Our results show that the understanding of the functioning of aquatic microbial assemblages and the aquatic carbon cycle is not possible without the thorough knowledge of the photolysis of CDOM. Key words: shallow lakes, DOC, photolysis, phytoplankton, bacterioplankton 45 40 35 30 cn 25 b O 20 < > h15 10 5 0 • NemAlgaC • AlgaC • DOC JUL •o rá •3 co N — C/3 cn CD CD >, >> c c -0) •a) -Q) '03 >, >, rn CD ^ CD "O CD E a) -C Ol o ro CD •o £ -o CO c o CO j?. tz £ a> -o =o -e CD CT ro CD •CD Q. CD > -O N O S rá "a CD c/} <D o -o M P •3 SO TO "35 ISI m CO m CO OQ 1. ábra. Oldott és partikulált (alga és nem alga) szervesszén frakciók koncentrációja magyarországi sekély tavakban 2009 nyarán 20000 18000 16000 14000 o 12000 b a 10000 O 8000 X' 8000 6000 4000 2000 0 2. ábra. Hidrogénperoxid koncentráció az eredeti tóvízben (szürke oszlop) és három órás Nap-szimulátorban történő besugárzást (fehér oszlop) követően (magyarországi sekély tavak 2009 nyár) (Atlag±SD, n=3)