Quantification and analysis of emerging threats studies on freshwater zooplankton (Copepoda, Cladocera and Rotifera) in Brazil from 2014 to 2023

Abstract Aim This study aimed to quantify and analyze research on emerging threats to freshwater zooplankton (Copepoda, Cladocera, and Rotifera) in Brazil, published between 2014 and 2023. The primary focus was to systematically identify the main environmental stressors studied, knowledge gaps, and methodological trends employed in the research. Methods The analysis was conducted through a systematic literature review in the Web of Science, Scopus, and SciELO databases, using specific terms related to zooplankton and emerging threats. Peer-reviewed articles published within the defined period were included. Each study was categorized based on the type of stressor analyzed (e.g., climate change, microplastic pollution, biological invasions), taxonomic groups addressed, and methodological approaches employed, following the PRISMA model. Results A total of 176 articles were initially retrieved from the databases, of which 53 met all inclusion criteria and were selected for analysis in this review. Most of these studies focused on multiple zooplankton groups (e.g., Cladocera and Rotifera) and used laboratory experiments or field studies as the primary methodology. The most analyzed stressors were biological invasions (28%) and climate change (24%), followed by harmful algal blooms and emerging contaminants. Conclusions The review highlights the need to expand studies on the combined impacts of emerging stressors on zooplankton and to integrate more robust methodologies that better reflect natural conditions.