Since the 1950s, marine macroalgae have been used as biomonitors of pollution (including heavy metals, organic compounds, or radioactive elements, among others). These organisms have the ability to bioconcentrate bioavailable compounds from the environment, and through a chemical analysis of their tissues, are used as indicators of water quality. However, despite their relevance, there is no standardized protocols for their use as a tool in environmental monitoring programmess. The harmonization of protocols is very important because algae are often included in legislative measurements, and the lack of scientifically based protocols can lead to deficiencies in such regulations. Therefore, an exhaustive study of the use of marine macroalgae in biomonitoring, as well as the standardization of some important methodological aspects of the technique, such as the sampling design, the type of sample, etc., has been carried out in this Doctoral Thesis in order to contribute to the standardization of this technique
