Fig. 1: Images showing Microcoleus mat development, and plots showing changes in nutrients, toxins and mat communities over the 19-day proliferation event.
a Photographs of biofilm-coated cobbles collected across five timepoints from day 3 to day 19, showing increasing biofilm cover. Biofilms are dark green in color, and the cobble surfaces are yellow. b Water column nutrient and biofilm toxin concentrations throughout the sampling period. Toxins were measured across six timepoints with four to eight replicates per time point. Day 0 indicates the start of the experiment (4th March 2016). Error bars = standard errors of means. Abbreviations: Nitrate (NO3-), Nitrite (NO2-), Ammonium (NH4+), Dissolved reactive phosphorus (DRP), Anatoxin-a (ATX), dihydro-anatoxin-a (dhATX). c NMDS ordination of amplicon data based on Bray-Curtis dissimilarities. Samples are labeled according to the day of collection with replicate number and the font size represented the Shannon diversity index. The final stress value is 0.14 and the vector indicates fitted environmental parameters significantly correlated to NMDS coordinates (p < 0.05, permutations = 999). Letters in black font indicate categorical vectors for Microcoleus relative abundance: low (L, 0 – 33%), medium (M, 33–67%), and high (H, 67–100%).
