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Titolo:
DIRECT AND INTERACTIVE EFFECTS OF ALLOCHTHONOUS DISSOLVED ORGANIC-MATTER, INORGANIC NUTRIENTS, AND ULTRAVIOLET-RADIATION ON AN ALPINE LITTORAL FOOD-WEB
Autore:
VINEBROOKE RD; LEAVITT PR;
Indirizzi:
UNIV ALBERTA,DEPT BIOL SCI EDMONTON AB CANADA UNIV REGINA,DEPT BIOL,LIMNOL LAB REGINA SK S4S 0A2 CANADA
Titolo Testata:
Limnology and oceanography
fascicolo: 6, volume: 43, anno: 1998,
pagine: 1065 - 1081
SICI:
0024-3590(1998)43:6<1065:DAIEOA>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
FRESH-WATER ECOSYSTEMS; EXPERIMENTAL LAKES AREA; UV-B RADIATION; PRECAMBRIAN SHIELD LAKES; MOUNTAIN-NATIONAL-PARK; BENTHIC ALGAE; ANTARCTIC CYANOBACTERIA; PERIPHYTON ASSEMBLAGES; NORTHWESTERN ONTARIO; COMMUNITY STRUCTURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
96
Recensione:
Indirizzi per estratti:
Citazione:
R.D. Vinebrooke e P.R. Leavitt, "DIRECT AND INTERACTIVE EFFECTS OF ALLOCHTHONOUS DISSOLVED ORGANIC-MATTER, INORGANIC NUTRIENTS, AND ULTRAVIOLET-RADIATION ON AN ALPINE LITTORAL FOOD-WEB", Limnology and oceanography, 43(6), 1998, pp. 1065-1081

Abstract

Allochthonous dissolved organic matter (DOM) may regulate littoral food webs by both modifying nutrient availability and attenuating potentially damaging ultraviolet radiation (UVR). These hypotheses were tested in a three-factor (DOM, inorganic nutrients, and WR) experiment using 24 littoral enclosures in an alpine lake located in Banff National Park, Canada. DOM was extracted from treeline soils and added (3 mg DOM liter(-1)) to +DOM enclosures over 1 month. These amendments were intended to simulate increases in allochthonous inputs that might occur as climate warming promotes the development of treeline soils and vegetation. DOM amendments significantly increased epilithon biomass (as total chlorophyll, carotenoids) but did not affect the abundance of either epipelon or phytoplankton. in addition, natural UV irradiance significantly enhanced the positive effect of DOM on epilithon and directly increased the abundance of epipelon. Threefold amendments of ambientnitrogen (N) and phosphorus (P) (20 N:1 P, by weight) significantly increased epilithon abundance. The positive effects of DOM, NP, and UVRon phytobenthos were primarily attributable to the increased abundance of diatoms, whereas NP affected phytoplankton by increasing chrysophytes and dinoflagellates. DOM amendments did not significantly affect the final abundances of heterotrophic bacteria and protists but did result in significantly higher densities of omnivorous copepod nauplii. These results show that allochthonous DOM is an important resource forlittoral food webs in oligotrophic lakes; however, its effects are mediated by UVR and differ between benthic and planktonic habitats. Our findings suggest that littoral food-web structure in clear, shallow lakes and ponds is altered by fluctuations in allochthonous inputs and UVR exposure arising from droughts and long-term climatic change.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 14:16:57