Internal phosphorus loading in Canadian fresh waters: a critical review and data analysis

Abstract

Many physical, chemical, and biological processes in freshwater ecosystems mobilize the nutrient phosphorus (P) from sediments, which in turn may contribute to the formation of harmful algal blooms. Here, we critically reviewed internal P loading in Canadian fresh waters to understand the geographic patterns and environmental drivers of this important process. From 43 publications, we consolidated 618 estimates of internal P loading from Canadian freshwater ponds, lakes, reservoirs, and coastal wetlands (n = 70). Expressed in terms of total P, short-term gross rates in sediment samples (L gross ) ranged from −27 to 54 mg·m −2 ·day −1 (n = 461), while long-term net rates in whole ecosystems (L net ) ranged from −1694 to 10 640 mg·m −2 ·year −1 (n = 157). The main environmental drivers of this variation were oxygen, pH, geology, and trophic state. Internal P loading tended to be higher during the open-water season and most prominent in small prairie lakes. Priorities for future research on internal P loading should include resolving methodological problems, assessing the relative importance of different mechanisms, examining the influence of anthropogenic activities, and quantifying rates in understudied ecosystems. Résumé :De nombreux processus physiques, chimiques et biologiques dans les écosystèmes d'eau douce mobilisent le phosphore (P), un élément nutritif, des sédiments, ce qui peut favoriser la formation de fleurs d'eau néfastes. Nous avons effectué un examen critique de l'apport interne de P dans les plans d'eau douce canadiens afin de comprendre les motifs de répartition géographique et les facteurs environnementaux qui influent sur cet important processus. À la lumière de 43 publications, nous avons colligé 618 estimations de l'apport interne de P d'étangs, de lacs, de réservoirs et de milieux humides littoraux d'eau douce canadiens (n = 70). Exprimés en termes de P total, les taux d'apport de P à court terme pour les échantillons de sédiments (L gross ) vont de −27 à 54 mg·m -2 ·jour -1 (n = 461), alors que les taux nets à long terme à l'échelle de l'écosystème (L net ) vont de −1694 à 10 640 mg·m -2 ·an -1 (n = 157). Les principaux facteurs environnementaux influant sur ces variations sont l'oxygène, le pH, la géologie et l'état trophique. L'apport interne de P tend à être plus élevé durant la période d'eau libre et le plus marqué dans les petits lacs de prairie. La priorité des travaux futurs sur l'apport interne de P devrait porter sur la résolution de problèmes méthodologiques, l'évaluation de l'importance relative de différents mécanismes, l'examen de l'influence des activités humaines et la quantification des taux dans les écosystèmes sous-étudiés. [Traduit par la Rédaction]

Exploring temperature and precipitation impacts on harmful algal blooms across continental U.S. lakes

“…Support for this hypothesis occurs if water or summer air temperature is an important predictor of HABs with a positive drift coefficient. Longer summer : Longer seasons of high temperature increase the opportunity for cyanobacterial growth (Anneville et al ; Deng et al ; Visser et al ). Support for this hypothesis occurs if spring air temperature is an important predictor of HABs with a positive drift coefficient. Internal phosphorus loading : Higher temperature increases the rate of internal phosphorus loading, driving HABs (Jeppesen et al ; Matisoff et al ; Orihel et al ; Ding et al ). Support for this hypothesis occurs if water or summer air temperature is an important predictor of TP with a positive drift coefficient, and TP is an important predictor of HABs with a positive drift coefficient. Load driving : Greater precipitation amounts increase nutrient loading, driving HABs (Reichwaldt and Ghadouani ; Michalak et al ).…”

“…This occurs through increased growth rates of harmful cyanobacterial species relative to other species (Paerl and Huisman ; Carey et al ; Visser et al ), through extending of the summer growing season (Anneville et al ; Deng et al ; Visser et al ) and through increased vertical stratification resulting in greater fitness by cyanobacteria that are able to regulate their buoyancy (Wagner and Adrian ; Carey et al ; Posch et al ; Taranu et al ; Visser et al ). Higher temperature also increases internal phosphorus loading from sediments through increased rates of soil diffusivity and increased rates of soil phosphorus regeneration (Matisoff et al ), and this internal phosphorus source has been shown be a significant proportion of the overall phosphorus budget in some lakes (Jeppesen et al ; Ho and Michalak ; Orihel et al ; Ding et al ). Second, greater overall precipitation and more extreme precipitation events are hypothesized to increase HABs through the generation of greater nutrient runoff (Reichwaldt and Ghadouani ; Michalak et al ), although this could be balanced by greater precipitation flushing nutrient‐rich waters out of the ecosystem prior to bloom formation (Anderson et al ; Reichwaldt and Ghadouani ).…”

Coupling Water Column and Sediment Biogeochemical Dynamics: Modeling Internal Phosphorus Loading, Climate Change Responses, and Mitigation Measures in Lake Vansjø, Norway

“…After decades of sustained external P inputs, lakes have been shown to accumulate legacy P and experience mobilization of P from the sediment (i.e., internal loading), a phenomenon extensively reviewed in the literature (e.g., Orihel et al, ). Internal P load is a significant concern for stakeholders due to continued water quality deterioration, with associated social and economic costs, and despite measures put in place to reduce external P loads (Matisoff et al, ; Mueller et al, ).…”

“…After decades of sustained external P inputs, lakes have been shown to accumulate legacy P and experience mobilization of P from the sediment (i.e., internal loading), a phenomenon extensively reviewed in the literature (e.g., Orihel et al, 2017). Internal P load is a significant concern for stakeholders due to continued Process-oriented lake modeling is a useful tool for guiding and assessing long-term management and water governance strategies.…”

“…The goal is to deliver an open-access tool for the combined modeling of water column and sediment that uses a coherent biogeochemical reaction network. Consequently, we updated Matsetlab with reactions of P, aluminum (Al), calcium (Ca), and MyLake with reactions of N, Fe, Al, Ca, and S (Ahlgren et al, 2011;Canavan et al, 2006;Couture, Shafei, et al, 2010;Dijkstra et al, 2018;Dittrich et al, 2009;Doan et al, 2018;Gudimov et al, 2016;Katsev & Dittrich, 2013;Katsev et al, 2006;Li et al, 2018;Parsons et al, 2017;Testa et al, 2013;Van Cappellen & Wang, 1996).…”