Sustainable management of lakes requires us to overcome ecological, economic, and social challenges. These challenges can be addressed by focusing on achieving ecological improvement within a multifaceted, co‐beneficial context. In‐lake restoration measures may promote more rapid ecosystem responses than is feasible with catchment measures alone, even if multiple interventions are needed. In particular, we identify restoration methods that support the overarching societal target of a circular economy through the use of nutrients, sediments, or biomass that are removed from a lake, in agriculture, as food, or for biogas production. In this emerging field of sustainable restoration techniques, we show examples, discuss benefits and pitfalls, and flag areas for further research and development. Each lake should be assessed individually to ensure that restoration approaches will effectively address lake‐specific problems, do not harm the target lake or downstream ecosystems, are cost‐effective, promote delivery of valuable ecosystem services, minimize conflicts in public interests, and eliminate the necessity for repeated interventions. Achieving optimal, sustainable results from lake restoration relies on multidisciplinary research and close interactions between environmental, social, political, and economic sectors.This article is categorized under: Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems Water and Life > Conservation, Management, and Awareness

The hypertrophic Swarzędzkie Lake, Poland, is characterized by high species diversity, abundance and biomass of both phytoplankton and zooplankton (up to 99.5 mg WW L⁻¹ and 817.75 μg DW L⁻¹, respectively). The community grazing rate calculated with the use of two empirical models, and based on herbivorous crustaceans, peaked in spring and early autumn up to 150.6% of water filtered per day, and was the lowest during winter. Simple statistics revealed a positive correlation between zooplankton biomass and chlorophyll a concentration (r = 0.404, P = 0.033) and between zooplankton abundance and phytoplankton biomass (r = 0.42, P = 0.028). Canonical statistics indicated, however, that the relationship exists only with size groups and/or living forms of a few taxonomical groups of phytoplankton. Redundancy analysis (RDA) confirmed a positive influence of the community grazing rate on micro- and nanoplanktonic Cryptophyceae, but not on the microplanktonic Cyanobacteria, as was suggested by canonical correlation analysis. RDA also indicated a weak negative influence on nanoplanktonic Euglenophyceae and Chlorophyceae exerted by filtering crustaceans. Some taxonomically diverse flagellated nanoplanktonic algae were grazing sensitive, whereas microplanktonic cryptophytes and coenobial green algae were significantly grazing resistant.

The ribbon type Lake Durowskie (Western Poland) is currently undergoing a sustainable restoration process due to water quality deterioration, manifested in water blooms, low transparency, and oxygen deficits near the bottom sediments. Three restoration methods were applied: (i) hypolimnion aeration using two wind-driven pulverizing aerators installed at the deepest places, (ii) phosphorus inactivation using small doses of iron sulfate and magnesium chloride several times a year, and (iii) biomanipulation using pike fry stocking. Research on the exchange of phosphorus in the sediment-water interphase was conducted in the years 2009–2016 to determine the multiannual changes of internal phosphorus loading from bottom sediments during the restoration process. The sustainable approach resulted in a decrease of internal phosphorus loading and a gradual increase in the sorption capacity of bottom sediments, particularly noticeable in the last 2 years. The content of phosphorus in the sediment and in the interstitial water fluctuated, showing an increase during the first years of restoration and then a gradual decrease. It was proved that the process of sustainable restoration is cheap and does not interfere strongly with the ecosystem, although it is long-lasting. It should be continued for many years, especially in the case of continuous external loading of the lake with nutrients from the catchment area, i.e., until the water quality in the main tributary improves and the lake ecosystem stabilizes.