Charophytes collapse beyond a critical warming and brownification threshold in shallow lake systems

Choudhury, Maidul I.; Urrutia‐Cordero, Pablo; Zhang, Huan; Ekvall, Mattias K.; Medeiros, Leonardo Rafael; Hansson, Lars

doi:10.1016/j.scitotenv.2019.01.177

Cited by 37 publications

(14 citation statements)

References 48 publications

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“…Moreover, it is expected that as a result of climate change more DOC will consist of humic substances in the future (Creed et al, 2018). Humic substances can directly negatively affect macrophytes as they diminish light availability to primary producers (Karlsson et al, 2009;Choudhury et al, 2019) and reduce macrophyte colonisation depth (Chambers and Prepas, 1988). Moreover, some humic substances may directly affect macrophytes by entering the plant's cells and causing damage by production of reactive oxygen species (Grigutytė et al, 2009) or by interfering with photosynthesis (Pflugmacher et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Response of Submerged Macrophyte Growth, Morphology, Chlorophyll Content and Nutrient Stoichiometry to Increased Flow Velocity and Elevated CO2 and Dissolved Organic Carbon Concentrations

Reitsema

Wolters

Preiner

et al. 2020

Front. Environ. Sci.

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It is expected that climate change will cause more frequent extreme events of heavy precipitation and drought, changing hydrological conditions in riverine ecosystems, such as flow velocity, evapotranspiration (drought) or runoff (heavy precipitation). This can lead to an increased input of terrestrial organic matter and elevated levels of dissolved organic carbon (DOC) and CO 2 due to degradational processes in water. Consequences for submerged macrophytes, as essential organism group, are still poorly understood. The combined effects of changing flow velocity, DOC and CO 2 have not been studied before, so this was tested in a racetrack flume experiment on the macrophyte Berula erecta using a trait-based approach. The plants were exposed to two different flow velocities, two DOC concentrations and two CO 2 concentrations in a full factorial design. Apart from individual dose-response tests, two climate change scenarios were tested: a wet scenario simulating heavy precipitation and runoff with high flow velocity, high DOC and CO 2 concentrations and a dry scenario simulating evapotranspiration with low flow velocity, high DOC and high CO 2 concentrations. Growth rate, biomass, morphology, chlorophyll and nutrient content (C, N, and P) were measured. B. erecta responded strongly to both scenarios. Biomass and the relative growth rate increased and stems were shorter, especially in the wet scenario, and vegetative reproduction (the number of stolons) decreased. In both scenarios, the N content was lower and P content higher than in conditions without climate change. It can be concluded that climate change effects, especially shading by DOC, strongly influence macrophytes: macrophyte abundance will probably be negatively affected by climate change, depending on the macrophyte species and abundance of epiphytic algae. This may have consequences for other components of the aquatic ecosystem.

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Section: Introductionmentioning

confidence: 99%

Response of Submerged Macrophyte Growth, Morphology, Chlorophyll Content and Nutrient Stoichiometry to Increased Flow Velocity and Elevated CO2 and Dissolved Organic Carbon Concentrations

Reitsema

Wolters

Preiner

et al. 2020

Front. Environ. Sci.

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“…In a number of countries, lake brownification is increasing due to multiple mechanisms such as land use, climate change, and a return to less acidification (Temnerud et al, 2014 [ 118 ]). Higher water color causes reduced growth rates of submerged macrophytes (Reitsema et al, 2020 [ 119 ]), including charophytes (Choudhury et al, 2019 [ 120 ]).…”

Section: (Re)establishment Of Submerged Vegetationmentioning

confidence: 99%

Re-Establishment Techniques and Transplantations of Charophytes to Support Threatened Species

Blindow

Carlsson

Weyer³

2021

Plants

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Re-establishment of submerged macrophytes and especially charophyte vegetation is a common aim in lake management. If revegetation does not happen spontaneously, transplantations may be a suitable option. Only rarely have transplantations been used as a tool to support threatened submerged macrophytes and, to a much lesser extent, charophytes. Such actions have to consider species-specific life strategies. K-strategists mainly inhabit permanent habitats, are perennial, have low fertility and poor dispersal ability, but are strong competitors and often form dense vegetation. R-strategists are annual species, inhabit shallow water and/or temporary habitats, and are richly fertile. They disperse easily but are weak competitors. While K-strategists easily can be planted as green biomass taken from another site, rare R-strategists often must be reproduced in cultures before they can be planted on-site. In Sweden, several charophyte species are extremely rare and fail to (re)establish, though apparently suitable habitats are available. Limited dispersal and/or lack of diaspore reservoirs are probable explanations. Transplantations are planned to secure the occurrences of these species in the country. This contribution reviews the knowledge on life forms, dispersal, establishment, and transplantations of submerged macrophytes with focus on charophytes and gives recommendations for the Swedish project.

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“…Distinct C. aspera populations can show different growth optima depending on the habitat (freshwater and brackish), which is translated by changing photophysiological characteristics at varying salinities (Blindow et al, 2003; Blindow & Schütte, 2007). Likewise, water temperature shapes charophyte populations, which may result in local biomass decreases in C. aspera , C. tomentosa , and C. vulgaris if temperature increases more than 2°C (Auderset Joye & Rey‐Boissezon, 2015; Choudhury et al, 2019). Even our short‐term experiments may confirm these results, as both charophyte species lost most biomass at temperatures above average summer habitat temperatures (>24°C).…”

Section: Discussionmentioning

confidence: 99%

Increases in temperature and freshwater inputs will shift grazing patterns of a coastal mesograzer on foundation species

et al. 2022

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Foundation species, and the roles that they play in structuring ecosystems, are threatened by global change. For example, charophytes are a refuge for zooplankton and stabilize sediments, but they are also a food source for various animal species (water birds, fishes, and invertebrates). Particularly, the introduction of new species, such as Gammarus tigrinus, into the Baltic Sea led to yet not understood changes in the food web. Furthermore, future projections point to increased water temperatures and freshwater inputs affecting species capacity to acclimatize to changing abiotic factors. In this study, we investigated the influence of temperature and salinity on the grazing pressure of G. tigrinus on two charophyte species: Chara aspera and Chara tomentosa. The grazing experiments were conducted in a full‐factorial design with the factors salinity (3–13 g kg−1), temperature (5–30°C), and charophyte species. Grazing rates were determined as mass deviation within 48 h considering biomass changes in the presence and absence of gammarids. Grazing rates were further used to calculate charophyte losses in two coastal lagoons with different salinity concentrations for recent and future time periods. Increasing freshwater inputs can buffer charophyte biomass loss at higher temperatures. Gammarids had a higher grazing impact on C. aspera than on C. tomentosa. The potential grazing peak of about 24°C is not yet reached in these coastal waters but may be reached in the near future as shown by our future projection results. However, a temperature increase and decrease in salinity will cause a shift in seasonal individual grazing patterns from summer to spring and autumn. An increase in temperature and freshwater input can lead to a shift in optimal habitats for G. tigrinus in the future. These interactions between abiotic and biotic factors will affect the future spatial distribution that charophytes can exploit as foundation species.

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Charophytes collapse beyond a critical warming and brownification threshold in shallow lake systems

Abstract: Chara vulgaris had higher growth at +2°C and +100% brownification. • Growth of C. vulgaris declined at +4°C and 200% brownification. • Studied charophyte growth will decline as warming and brownification increased.

Cited by 37 publications

References 48 publications

Response of Submerged Macrophyte Growth, Morphology, Chlorophyll Content and Nutrient Stoichiometry to Increased Flow Velocity and Elevated CO2 and Dissolved Organic Carbon Concentrations

Response of Submerged Macrophyte Growth, Morphology, Chlorophyll Content and Nutrient Stoichiometry to Increased Flow Velocity and Elevated CO2 and Dissolved Organic Carbon Concentrations

Re-Establishment Techniques and Transplantations of Charophytes to Support Threatened Species

Increases in temperature and freshwater inputs will shift grazing patterns of a coastal mesograzer on foundation species

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