Ecosystem-level effects of re-oligotrophication and N:P imbalances in rivers and estuaries on a global scale
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Author
Ibáñez, Carles
Caiola, Nuno
Barquín, José
Belmar, Oscar
Casals, Frederic
Fennessy, Siobhan
Hughes, Joselyne
Palmer, Margaret
Peñuelas, Josep
Romero, Estela
Sardans, Jordi
Williams, Michael
Publication date
2022-11-11ISSN
1354-1013
Abstract
Trends and ecological consequences of phosphorus (P) decline and increasing nitrogen (N) to phosphorus (N:P) ratios in rivers and estuaries are reviewed and discussed. Results suggest that re-oligotrophication is a dominant trend in rivers and estuaries of high-income countries in the last two-three decades, while in low-income countries widespread eutrophication occurs. The decline in P is well documented in hundreds of rivers of United States and the European Union, but the biotic response of rivers and estuaries besides phytoplankton decline such as trends in phytoplankton composition, changes in primary production, ecosystem shifts, cascading effects, changes in ecosystem metabolism, etc., have not been sufficiently monitored and investigated, neither the effects of N:P imbalance. N:P imbalance has significant ecological effects that need to be further investigated. There is a growing number of cases in which phytoplankton biomass have been shown to decrease due to re-oligotrophication, but the potential regime shift from phytoplankton to macrophyte dominance described in shallow lakes has been documented only in a few rivers and estuaries yet. The main reasons why regime shifts are rarely described in rivers and estuaries are, from one hand the scarcity of data on macrophyte cover trends, and from the other hand physical factors such as peak flows or high turbidity that could prevent a general spread of submerged macrophytes as observed in shallow lakes. Moreover, re-oligotrophication effects on rivers may be different compared to lakes (e.g., lower dominance of macrophytes) or estuaries (e.g., limitation of primary production by N instead of P) or may be dependent on river/estuary type. We conclude that river and estuary re-oligotrophication effects are complex, diverse and still little known, and in some cases are equivalent to those described in shallow lakes, but the regime shift is more likely to occur in mid to high-order rivers and shallow estuaries.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
574 - General ecology and biodiversity
Pages
19
Publisher
Wiley
Is part of
Global Change Biology
Citation
Ibáñez, Carles, Nuno Caiola, José Barquín, Oscar Belmar, Xavier Benito-Granell, Frederic Casals, Siobhan Fennessy, Jocelyne Hughes, Margaret Palmer, Josep Peñuelas, Estela Romero, Jordi Sardans, and Michael Williams. “Ecosystem-level effects of re-oligotrophication and N:P imbalances in rivers and estuaries on a global scale”. Global Change Biology. doi:10.1111/gcb.16520
Program
Aigües Marines i Continentals
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- ARTICLES CIENTÍFICS [2555]
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