Systematic review data

The search for related articles was done through Web of Science with access provided by York University. Most of the diatom-related research consisted of the taxonomy, and the biochemistry part of it. To excluded such unrelated research, search terms used were ‘diatom*’, ‘carbon fixation*’, ‘diversity*’, and ‘marine’, all with AND search function. Excluding duplicate results, the database showed 29 search results regarding with the topics. 20 journal articles were selected for qualitative synthesis where remaining 8 articles were excluded. Most of the excluded articles were relatively out of date which were from late 1990s, and on different focus of study other than diatoms such as biochemistry. From the 21 articles that marked relevant, following dataset were extracted in order to observe the trends. (i) How many different diatom species they used for the experiments, (ii) levels of their study on diatoms, such as in species level, population level, community level, or ecosystem level, and (iii) methodology they used for the experiments. These dataset were individually reviewed and categorized for graphical analysis, and to support the objective for the review. To compare the frequency of the studies conducted based on these categories, bar-graph analysis and chi-squared tests were conducted. For chi-squared test the expected values are evenly distributed frequencies for all values, and were done using excel function command CHITEST.