Ecology of Aquatic Ecosystems and the Importance of the Element Iron (Fe) – Theoretical Aspects and Guide for Practical Laboratory Activity to measure the concentration of Iron (Fe) in aqueous solution Alexandre Almeida da Costa Lucas, Walter Barrella

Abstract

This article's main objective is to develop theoretically and practically fundamental concepts of ecology, biology and chemistry. With the artifice of a practical activity in the laboratory that consists of determining the concentration of the element iron (Fe) in an aqueous solution of fresh water. The relevance of freshwater is observed holistically, considered as a determining and strategic factor in the distribution of civilization that traditionally develops in places close to freshwater reserves. Aquatic ecosystems are seen as a connecting interface between large aquatic systems, formed by lakes and seas, and terrestrial ones, containing various mineral resources essential in various biological processes. Taking into account that iron is relatively more important in maintaining the life of aquatic plants in relation to maintaining the life of freshwater fish, a reference is made to topics related to macrophytes, showing that science interconnects many concepts depending on the degree of abstraction. These plant species are capable of bringing many ecological benefits to aquatic ecosystems, playing an important role in maintaining resilience in the face of industrial waste dumping, allowing and helping the occurrence of some invertebrate species, some gastropods, for example. Keeping the theme of practical activity as a theoretical reference, the article cites discrete and specific aspects related to iron, such as its elementary use by aquatic plants, natural and anthropogenic sources of iron, its importance in industry and the chemical and physical properties in iron metabolism. man. The four basic forms in which iron occurs in aquatic environments are highlighted. The proposed practical activity basically uses potassium permanganate, potassium thiocyanate and nitric acid, which together develop a specific color depending on the amount of iron in the water sample, which is later compared to a color scale, thus obtaining an estimate of the concentration. of iron in the solution. Note that this activity is very useful as a contingency to replace field, external activities, in case of bad weather, for example. A series of questions are proposed to the student after the conceptual explanation and development of the activity have been completed, thus verifying the understanding and fixation of the topics presented.