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001-es BibID:	BIBFORM126219
035-os BibID:	(WoS)001382457400001 (Scopus)85212092273
Első szerző:	Szabó Sándor (biológus)
Cím:	Submerged macrophytes can maintain stable dominance over free-floating competitors through high pH / Sándor Szabó, Noémi Fedor, Gergő Koleszár, Mihály Braun, János Korponai, Aleksandra Kočić, Sabine Hilt, Viktor Oláh
Dátum:	2025
ISSN:	0046-5070 1365-2427
Megjegyzések:	1. Submerged and free-floating macrophytes are the two main vegetation types that can alternatively dominate in small shallow ponds and ditches. Submerged macrophytes provide more aquatic ecosystem services and cause fewer problems with anoxia and greenhouse gas emissions than free-floating plants, but are inferior competitors for light. High pH values have been proposed as a contributor to submerged plant dominance, but threshold values for pH-induced growth reduction of floating plants by submerged macrophytes are not known. 2. In this study, we conducted laboratory experiments to test whether submerged plants (Ceratophyllum demersum) can effectively limit the growth of free-floating competitors (Lemna gibba) by exceeding a critical threshold pH value. We used field data to test if and when such pH values can be achieved within dense submerged macrophyte stands. 3. The pH values that caused 50% reduction in fresh weight- and chlorophyll-based growth of L. gibba were 9.6 and 9.8, respectively, and the growth was negligible above pH 10.0. The photochemical efficiency of photosystem II and chlorophyll content of the floating plants declined rapidly above pH 9 and 9.5, respectively. Similarly, phosphorus concentration decreased and dry matter content increased sharply in L. gibba fronds above pH 9.5, respectively. We thus expect a critical pH threshold for L. gibba at around 9.5. 4. Our mesocosm and field data show that the critical pH threshold for L. gibba growth is regularly exceeded within dense stands of bicarbonate-using submerged macrophytes in lentic water-bodies. Such conditions can be prevalent in the upper water layer during most of the day (12 h) in summer. 5. The literature showed that many duckweed species (and other common free-floating plants) in temperate and tropical water bodies show growth inhibition above pH 8. Therefore, high pH created by submerged macrophytes that use HCO3? in photosynthesis can be a major mechanism by which dominance over free-floating competitors is maintained in densely vegetated lentic eutrophic water bodies. We propose that alternative stable states occur between free-floating and submerged macrophytes along a pH gradient. Active management of pH may, thus, help in maintaining the desired state
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Ceratophyllum competition inhibition Lemna stable state
Megjelenés:	Freshwater Biology. - 70 : 1 (2025), p. 1-11. -
További szerzők:	Fedor Noémi (biológus) Koleszár Gergő Braun Mihály (1966-) (vegyész, analitikus) Korponai János (1964-) (biológus) Kočić, Aleksandra Hilt, Sabine Oláh Viktor (1980-) (biológus)
Pályázati támogatás:	FK134296 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM016488
Első szerző:	Szabó Sándor (biológus)
Cím:	Strong growth limitation of a floating plant (Lemna gibba) by the submerged macrophyte (Elodea nuttallii) under laboratory conditions / Sándor Szabo, Marten Scheffer, Rudi Roijackers, Beata Waluto, Mihaly Braun, Peter T. Nagy, Gabor Borics, Luis Zambrano
Dátum:	2010
ISSN:	0046-5070
Megjegyzések:	The asymmetric competition for light and nutrients between floating and submerged aquatic plants is thought to be key in explaining why dominance by either of these groups can be stable and difficult to change. Although the shading effect of floating plants on submerged plants has been well documented, the impact of submerged plants on floating plants has been poorly explored hitherto. Here, we used laboratory experiments to examine how submerged plant (Elodea nuttallii) alter nutrient conditions in the water column and how this affects the growth of floating plants (Lemna gibba). We demonstrate that, at higher nutrient concentrations, Lemna is increasingly likely to outcompete Elodea. Under low nutrient concentrations (0.1-2 mg N L-1) Elodea can strongly reduce the growth of Lemna. Growth of floating plants virtually stopped in some of the experiments with Elodea. Extremely reduced tissue N, Mn, chlorophyll and elongated roots indicated that the growth inhibition of Lemna by Elodea was predominantly caused by the latter's impact on the nutrient conditions for floating plants. These results strengthen the hypothesis that submerged plants can prevent colonization of a lake by floating plants.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban competition duckweed nutrient limitation submerged plants shallow urban lakes aquatic macrophytes azolla-filiculoides phosphorus sources catastrophic loss waste-water duckweed competition vegetation algae
Megjelenés:	Freshwater Biology. - 55 : 3 (2010), p. 681-690. -
További szerzők:	Scheffer, Marten Roijackers, Rudi Waluto, Beata Braun Mihály (1966-) (vegyész, analitikus) Nagy Péter Tamás (1970-) (vegyész) Borics Gábor (biológus) Zambrano, Luis
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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