Eutrophication of water bodies markedly reduces their recreational and economic use, which in turn compels those interested to pursuing prompt and effective restoration. This also applies to waters with a moderate pool of biogenic resources which, following temporarily increased nutrient alimentation from the catchment area may become eutrophic. The in-situ experiment tested the impact of chemical restoration on benthic macroalgae (Chara hispida L.) found in meso-eutrophic waters. Commonly used doses of iron sulphate were applied, defined as Low - 10.8 g Fe m-2 and High - 21.6 g Fe m-2. It was presumed that the sudden shift of abiotic conditions of the environment will disturb growth and stoichiometry of the species. Analyses encompassed physicochemical water parameters (e.g. nutrient concentration, light availability), morphological features and elemental composition of the charophytes. Application of the coagulant caused shading of the plants and elimination of bioavailable phosphates from the water. This induced changes of behavioural ecology of the species, manifesting in elongation of the main axis and increase of the assimilation area (growth of branchlets and side-axes) as well as stoichiometric changes. It was found that shortage of phosphates in the water resulted in decreased phosphorus concentration in the thalli due to biological dilution. The increase of assimilation area and phosphorus dilution in the thalli have not been previously reported for charophytes. In this study, the qualitative transformation of the environment following application of iron as part of chemical lake restoration was evinced in significant ecological changes that adversely affected macrophytobenthos. The findings of the experiment can therefore be taken into account while planning restoration procedures, so as to preclude the risk of a negative trend of ecological changes.

中文翻译：

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大型藻类（Characeae，Charophyceae）对铁超载的原位行为响应和生态化学计量调整：对恢复湖泊的影响。

水体的富营养化明显减少了其娱乐性和经济性，这反过来又迫使那些有兴趣进行迅速有效恢复的人们。这也适用于具有适度生物资源的水域，这些水域在集水区暂时增加养分营养后可能变得富营养化。原位实验测试了化学修复对中富营养水域底栖大型藻类（Chara hispida L.）的影响。使用常用剂量的硫酸铁，定义为低-10.8 g Fe m-2和高-21.6 g Fe m-2。据推测，环境中非生物条件的突然变化将干扰该物种的生长和化学计量。分析包括理化水参数（例如营养物浓度，光的可用性），藻类的形态特征和元素组成。混凝剂的使用会导致植物遮光，并从水中消除可生物利用的磷酸盐。这引起了该物种行为生态学的变化，表现为主轴的伸长和同化面积（小枝和侧轴的生长）的增加以及化学计量的变化。发现由于生物稀释，水中磷酸盐的缺乏导致thalli中磷浓度降低。藻类的同化面积增加和磷的磷稀释度以前没有报道。在这个研究中，应用铁作为化学湖泊恢复的一部分后，环境发生了质的变化，这表明对重大底栖生物产生不利影响的重大生态变化。因此，在计划恢复程序时可以考虑到实验的结果，从而避免了生态变化的负面趋势。