Fig. 4

Distribution of the pre-harmonized to harmonized water quality concentration data for all water monitoring sites that measure TN and TP in our retrieved data. The harmonized TN distribution plotted here includes water quality observations that were previously labelled as nitrogen, nitrogen mixed forms, or total nitrogen and are now classified as TN based on our methods. Similarly, water quality observations previously labelled as phosphorus, phosphorus mixed forms, or total phosphorus are now classified as TP based on our methods.