Large pools and fluxes of carbon, calcium and phosphorus in dense charophyte stands in ponds

Sand‐Jensen, Kaj; Martinsen, Kenneth Thorø; Jakobsen, Anders Lund; Sø, Jonas Stage; Madsen-Østerbye, Mikkel; Kjær, Johan Emil; Kristensen, Emil; Kragh, Theis

doi:10.1016/j.scitotenv.2020.142792

Cited by 14 publications

(19 citation statements)

References 49 publications

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“…Abundant charophyte stands can serve as nutrient sinks (Blindow et al, 2014; Sand‐Jensen et al, 2021). Consequently, they can buffer the pelagic from eutrophication and increased nutrient loading to oligo‐mesotrophic lakes often remains unnoticed (Schneider et al, 2017; Vermaat et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, shifts between clear and turbid conditions in shallow lakes resulting from loss of charophytes have occurred at relatively low TP concentrations (20 μg/L; Hargeby et al, 2007). Significant amounts of nutrients, however, can be stored in charophytes due to uptake from the water column and co‐precipitation of P with CaCO 3 during photosynthesis (Blindow et al, 2014; Sand‐Jensen et al, 2021). Consequently, nutrient loading to oligotrophic lakes can remain undetected in the pelagic zone (Lambert et al, 2008; Schneider et al, 2017; Vermaat et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Periphyton and benthivorous fish affect charophyte abundance and indicate hidden nutrient loading in oligo‐ and mesotrophic temperate hardwater lakes

et al. 2022

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Charophytes are a key group of submerged macrophytes in temperate hardwater lakes, but have declined or been replaced by angiosperms as a result of eutrophication for more than 100 years. At present, this process is continuing in many European lakes despite an overall reduced nutrient loading. In eutrophic lakes, light attenuation by periphyton is a major factor responsible for declining angiosperm abundance. For charophyte declines, the impact of benthivorous and herbivorous fish has been discussed often, yet periphyton shading has been largely neglected. In our study, we investigated 11 temperate oligo‐mesotrophic (total phosphorus [P] concentrations 9–22 μg/L) hardwater lakes along a gradient of charophyte abundances. Charophyte abundance was mapped using underwater cameras or scuba diving, and coverage was estimated in five classes. Periphyton biomass, nutrient stoichiometry and invertebrate grazer abundance were measured twice on artificial substrates exposed inside and outside fish exclosures for 4 weeks in July and August. Fish biomass was sampled once using multi‐mesh gill netting. We analysed the relationships between water chemistry (concentrations of nutrients and dissolved organic carbon), periphyton biomass and nutrient stoichiometry, periphytic invertebrate grazers and fish biomass to test (a) whether periphyton biomass was controlled bottom‐up by nutrient availability or top‐down by an omnivorous fish–invertebrate–grazer cascade and (b) whether charophyte abundance was affected by periphyton biomass, benthivorous and herbivorous fish. Multiple linear regressions revealed that charophyte abundance was significantly predicted by the biomasses of periphyton and benthivorous bream (Abramis brama L.), whereas herbivorous rudd (Scardinius erythrophthalmus L.) had no significant effect in the investigated lakes. Bream biomass and its proportion in the total fish biomass were linearly related to lake total P concentrations. Periphyton biomass in the tested lakes reached 0.1–21 g dry weight/m2 and primarily was controlled bottom‐up by P availability as indicated from stoichiometry and positive correlations with grazer abundance. Top‐down control was found in only three lakes, which had significantly lower periphyton biomass inside fish exclosures as compared to controls. Our data imply that periphyton shading and negative fish impacts on charophytes increase with P loading. Low charophyte abundances at moderate P concentrations in the lake water indicate a high sensitivity of charophytes and/or unnoticed nutrient loading due to nutrient retention by charophyte stands. Management measures thus must focus on reducing nutrient loading and/or benthivorous fish biomass at early stages of impact to preserve charophyte stands in oligo‐mesotrophic hardwater lakes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Periphyton and benthivorous fish affect charophyte abundance and indicate hidden nutrient loading in oligo‐ and mesotrophic temperate hardwater lakes

et al. 2022

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“…However, during spring, the build‐up of the charophyte biomass with dense carbonate crusts on their surfaces causes a net uptake from the water (Andersen et al., 2019; Herbst et al., 2018). The encrusted carbonate is exported to the calcareous sediment upon charophyte senescence (Sand‐Jensen et al., 2021), while DIC and calcium can be replenished by groundwater input and sediment respiration (McConnaughey et al., 1994).…”

Section: Discussionmentioning

confidence: 99%

Ecosystem Metabolism and Gradients of Temperature, Oxygen and Dissolved Inorganic Carbon in the Littoral Zone of a Macrophyte‐Dominated Lake

et al. 2022

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Submerged charophytes and angiosperms attached to the sediment can develop a dense cover in shallow lakes with clear water (Blindow et al., 2014;Sand-Jensen et al., 2019). Many charophyte and angiosperm species have experienced a profound decline during the last 100 years due to drainage reclamation of land for agriculture (Baastrup-Spohr et al., 2013;Sand-Jensen et al., 2000). Moreover, many lakes have experienced excessive eutrophication and phytoplankton blooms, and consequently a loss of submerged macrophytes due to shading (Hilt et al., 2013;Sand-Jensen et al., 2017). Recently, macrophytes have colonized many new habitats that have

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“…(Murphy et al, 1983;Kiyosawa, 2001;Siong & Asada, 2006;Kufel et al, 2013Kufel et al, , 2015Sand-Jensen et al, 2018, 2021, and also in CaCO 3 incrustation on the upper leaf surface of the submerged flowering plant Potamogeton crispus (Liu et al, 2016). The investigation by Sand-Jensen et al (2021) showed that P in the Chara spp. biomass was up to 0.019 mol P m −2 sediment area, that in the sediment was 0.14 mol P m −2 sediment area, and that in the water body was only 0.00016 mol P m −2 sediment area.…”

Section: Calcium Phosphate Incorporation In Extracellular Calcium Car...mentioning

confidence: 99%

“…Sand‐Jensen et al . (2021) suggested that the P in the Chara carbonate encrustation came from efflux of phosphate from the cells in shoot. Wustenberg et al .…”

Section: Calcium Phosphate Incorporation In Extracellular Calcium Car...mentioning

confidence: 99%

Avoiding and allowing apatite precipitation in oxygenic photolithotrophs

Raven

2023

New Phytologist

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Summary The essential elements Ca and P, taken up and used metabolically as Ca2+ and H2PO4−/HPO42− respectively, could precipitate as one or more of the insoluble forms calcium phosphate (mainly apatite) if the free ion concentrations and pH are high enough. In the cytosol, chloroplast stroma, and mitochondrial matrix, the very low free Ca2+ concentration avoids calcium phosphate precipitation, apart from occasionally in the mitochondrial matrix. The low free Ca2+ concentration in these compartments is commonly thought of in terms of the role of Ca2+ in signalling. However, it also helps avoids calcium phosphate precipitation, and this could be its earliest function in evolution. In vacuoles, cell walls, and xylem conduits, there can be relatively high concentrations of Ca2+ and inorganic orthophosphate, but pH and/or other ligands for Ca2+, suggests that calcium phosphate precipitates are rare. However, apatite is precipitated under metabolic control in shoot trichomes, and by evaporative water loss in hydathodes, in some terrestrial flowering plants. In aquatic macrophytes that deposit CaCO3 on their cell walls or in their environment as a result of pH increase or removal of inhibitors of nucleation or crystal growth, phosphate is sometimes incorporated in the CaCO3. Calcium phosphate precipitation also occurs in some stromatolites.

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Large pools and fluxes of carbon, calcium and phosphorus in dense charophyte stands in ponds

Cited by 14 publications

References 49 publications

Periphyton and benthivorous fish affect charophyte abundance and indicate hidden nutrient loading in oligo‐ and mesotrophic temperate hardwater lakes

Periphyton and benthivorous fish affect charophyte abundance and indicate hidden nutrient loading in oligo‐ and mesotrophic temperate hardwater lakes

Ecosystem Metabolism and Gradients of Temperature, Oxygen and Dissolved Inorganic Carbon in the Littoral Zone of a Macrophyte‐Dominated Lake

Avoiding and allowing apatite precipitation in oxygenic photolithotrophs

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