A bibliometric study on diatom DNA metabarcording for water quality monitoring: a global perspective

Abstract

Aquatic biota have been used for decades in water quality assessment since they reflect the changing physico-chemical conditions of  waterbodies. Among the aquatic organisms used in biological assessment are diatoms. Initially, morphological studies of diatoms were  preferred in monitoring but today the new technique of diatom DNA metabarcoding is gaining preference. This study aimed at (1)  summarising the thematic study areas on diatom DNA metabarcoding for water quality monitoring, (2) identification of past and future  trends of research on diatom DNA metabarcoding for water quality monitoring, and (3) determination of regional and institutional trends  in studies involving diatom DNA metabarcoding for water quality monitoring. We obtained data from the Web of Science (WoS)  using research queries like “Diatoms DNA metabarcoding for water quality monitoring”, “Diatoms DNA metabarcoding for water quality  biomonitoring”, and “Diatoms DNA sequencing for water quality monitoring”. We identified 127 articles that had published on diatoms  DNA metabarcoding in water quality monitoring between the years 2003 and 2022. Our study revealed that the developed nations, led by  France, followed by Germany and USA, dominated the research areas involving the use of diatoms DNA metabarcoding in water quality  monitoring. Additionally, our present study showed that DNA metabarcoding was related to biodiversity assessment, rbcL, species  identification and taxonomy, a finding which is in line with previous studies conducted recently that have revealed that DNA-based  approaches, for example the use of rbcL genes, are more effective in the determination of diatom community structures compared to  morphological methods. Although DNA metabarcoding is rapidly gaining popularity in water biomonitoring, there are biases when  explaining the differences between morphological and molecular based diatom indices, among them the incompleteness of the  reference library such as R-syst::diatom database. To address this disparity, there is need to use environmental sequences from high- throughput sequencing (HTS) runs which can subsequently be related to morphological observations, followed by integration of the  same into the reference libraries after setting up several guidelines and quality criteria. Consequently, the findings of this study present  insights that will contribute globally to the development of water quality monitoring frameworks using diatoms.