Evidence of warming effects on phytoplankton productivity rates and their dependence on eutrophication status
2010
Tadonléké, Remy | Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL) ; Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
International audience
اظهر المزيد [+] اقل [-]إنجليزي. Using 31-yr data from measurements in a lake that has experienced change in eutrophication status, I showed that the effects of global warming on chlorophyll a (Chl a)–normalized maximum rates of photosynthesis (Pmax : Chl a) may be positive, nonsignificant, or negative, depending on nutrient availability. The magnitude of Pmax : Chl a change in response to warming showed hyperbolic relationships with phosphorus concentrations; it was positive and constant when total phosphorus (TP) in the lake water exceeded 22 mg P L21 (eutrophic conditions) but was negative when TP was lower (nutrient-poor conditions), indicating direct negative effects of warming on primary productivity (PP) under phosphorus scarcity. Vertically integrated PP responses corroborate those of Pmax : Chl a. These data also showed long-term seasonal variations in the sensitivity of phytoplankton productivity to temperature. The observed hyperbolic curves strongly suggest that the ‘‘limiting-nutrient cell quota’’–based mechanism reported so far only in laboratories (by studies analyzing temperature-nutrient effects on microalgal growth or photosynthesis) operates in nature and plays a key role in determining phytoplankton response to warming of waters. The present findings provide insight on how phytoplankton productivity may respond to future warming in lakes of differing eutrophication status.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
المعلومات البيبليوغرافية
تم تزويد هذا السجل من قبل Institut national de la recherche agronomique