What evidence exists on the effectiveness of algae as biomonitors of pollution in estuaries? A systematic map...

Estuarine coastal regions play a critical role in global aquatic ecosystems, providing essential benefits such as diverse marine habitats, support for local economies through fisheries and tourism, and serving as important carbon stocks. Nonetheless, these invaluable, dynamic and complex habitats are under increasing threat from human-induced pressures, including pollution from agricultural runoff to sewage discharge, emphasizing the urgent need for innovative monitoring and mitigation strategies. Traditional biomonitoring methods involve the use of indicator species such as fish and benthic macroinvertebrates; however, these can be limited in their ability to detect pollution at an early stage. As a result, alternative monitoring strategies such as the use of algae have become increasingly popular due to their abundance sensitivity to changes in water quality. Previous research recognizes the capacity of various algae species to accumulate pollutants, thereby serving as reliable indicators of ecological stress and water contamination. Despite the growing acknowledgment of their potential, a comprehensive evaluation of the effectiveness of algae as biomonitors in estuaries remains without a systematic review. This map, therefore, seeks to synthesize existing knowledge on the applicability and reliability of algae for coastal environmental monitoring, aiming to highlight existing knowledge gaps for a future systematic review. By focusing on the utility of algae in estuarine contexts, this study aspires to provide a comprehensive overview of current practices and propose recommendations. Such an endeavor is crucial for directing future research, informing stakeholders, and guiding policy formulation towards more sustainable and effective environmental management of estuaries. This map aims to be a valuable resource for those involved in the management and preservation of estuarine environments, contributing to discussions on sustainable water management and ecological conservation.

The Collaboration for Environmental Evidence Guidelines and Standards for Evidence Synthesis in Environmental Management will be followed to construct the systematic map. By using a tested search string consisting of English keywords and acronyms, we will look through two published databases (Scopus and Web of Science Core Collection) to find pertinent literature. Terms that describe the exposure (chemicals) and the population (algae in estuaries) will be combined in the search string. To this literature obtained so far, we will add more materials sourced from other search mechanisms. We will add to this body of literature with further material from Google Scholar and other internet searches, including sources in Portuguese. Next, adopting specified eligibility criteria, titles, abstracts, and full-texts will be analyzed one by one. A list of predefined variables will then be extracted from full-texts. A database containing all studies included in the map, along with coded metadata, will be generated. The evidence will be presented in a map report that includes text, figures, and tables. A matrix will be created to display the distribution and frequency of the included studies categorized by types of exposure and outcomes, aimed at identifying potential knowledge gaps and clusters.