Laboratório de Ecologia Aquática, Departamento de Biologia/Programa de Pós-Graduação em Ecologia e Conservação e Programa de Pós-Graduação em Ciência e Tecnologia Ambiental da Universidade Estadual da Paraíba, Rua Baraúnas n°, 351 - Complexo Três Marias, Prédio de Biologia, Térreo - sala 10. Universitário, CEP 58.429-500, Campina Grande, Paraíba, Brazil.
Laboratório de Ecologia de Bentos, Departamento de Biologia/Programa de Pós-Graduação em Ciência e Tecnologia Ambiental/ Programa de Pós-Graduação em Ecologia e Conservação da Universidade Estadual da Paraíba, Rua Baraúnas n°, 351 - Complexo Três Marias, Prédio de Biologia, Térreo - sala 8. Universitário, CEP 58.429-500, Campina Grande, Paraíba, Brazil.
Water Res. 2023 Nov 1;246:120691. doi: 10.1016/j.watres.2023.120691. Epub 2023 Oct 3.
Anthropogenic activities have led to excessive loading of phosphorus and nitrogen into water bodies, leading to eutrophication and promoting the growth of cyanobacteria, posing a threat to the health of humans and aquatic animals. Techniques such as Floc & Lock have been developed to mitigate eutrophication by reducing phosphorus concentrations in water and preventing algal blooms. However, little attention has been given to the impact of phosphorus resuspension by sediment-associated organisms such as benthic macroinvertebrates, on the effectiveness of this technique. Here, we experimentally evaluated whether the presence of snails Melanoides tuberculata (Müller, 1774) and larvae of Chironomus sancticaroli (Strixino and Strixino, 1981) affects the efficiency of the Floc & Lock technique. Snails and chironomid larvae are benthic macroinvertebrates commonly found in high abundance in eutrophic reservoirs. Specifically, we tested the hypotheses that (i) the presence of benthic macroinvertebrates reduces the efficiency of coagulants and clays in removing phosphorus and algal biomass from the water column, and (ii) this effect is species-dependent, as some organisms such as the snails, revolve the substrate and resuspend sedimented particles, while other ones, such as chironomid larvae, aid in the removal of phosphorus from the water column by depositing them in the sediment. Our findings revealed that the impact of benthic macroinvertebrates on the effectiveness of the Floc & Lock technique is species-dependent. Chironomid larvae positively influenced the efficiency of the technique by aiding in the removal of total phosphorus, soluble reactive phosphorus, and algal biomass from the water column, depositing them in the sediment. In contrast, the presence of snails had the opposite effect, resulting in increased phosphorus concentration and algal biomass in the water. Surprisingly, the snails consumed the flocs formed by the coagulant and clay within a short time interval of 72 h, raising concerns due to the presence of toxic cyanobacterial biomass in these flocs. Our study emphasizes the importance of considering benthic macroinvertebrates and their impact on the effectiveness of eutrophication management techniques.
人为活动导致磷和氮过度负荷到水体中，导致富营养化，并促进蓝藻的生长，对人类和水生动物的健康构成威胁。已经开发出一些技术，如 Floc & Lock，通过降低水中的磷浓度和防止藻类大量繁殖来减轻富营养化。然而，对于沉积物中与生物体相关的磷再悬浮对该技术有效性的影响，人们关注甚少。在这里，我们通过实验评估了蜗牛 Melanoides tuberculata (Müller, 1774) 和摇蚊幼虫 Chironomus sancticaroli (Strixino and Strixino, 1981) 的存在是否会影响 Floc & Lock 技术的效率。蜗牛和摇蚊幼虫是富营养化水库中常见的底栖大型无脊椎动物，数量丰富。具体来说，我们检验了以下两个假设：(i) 底栖大型无脊椎动物的存在会降低混凝剂和粘土去除水柱中磷和藻类生物量的效率，以及 (ii) 这种影响是物种依赖性的，因为一些生物体，如蜗牛，会搅动基质并使沉积物颗粒再悬浮，而其他生物体，如摇蚊幼虫，则通过将磷沉积到沉积物中来帮助从水柱中去除磷。我们的研究结果表明，底栖大型无脊椎动物对 Floc & Lock 技术有效性的影响是物种依赖性的。摇蚊幼虫通过帮助从水柱中去除总磷、可溶反应性磷和藻类生物量并将其沉积到沉积物中来提高技术效率。相比之下，蜗牛的存在则产生了相反的效果，导致水中的磷浓度和藻类生物量增加。令人惊讶的是，蜗牛在 72 小时的短时间间隔内消耗了混凝剂和粘土形成的絮体，由于这些絮体中存在有毒的蓝藻生物量，这引起了人们的关注。我们的研究强调了考虑底栖大型无脊椎动物及其对富营养化管理技术有效性的影响的重要性。
