Binomial co-occurrence networks for 16S rRNA and rbcL communities, along with environmental quartile categories, in Reservoir 3 across 25 samples during the sampling period. Solid black arrows indicate higher-than-expected relationships between taxa (p ≤ 0.01), while dashed grey arrows represent lower-than-expected relationships (p ≤ 0.01). Green nodes denote Cyanobacteria genera, purple nodes represent T&O-degrading bacteria, and yellow nodes indicate diatoms. Blue triangular nodes represent environmental variables, categorised into quartiles: Q1 (lower quartile, ≤ 0.25), Q2 (lower middle quartile, > 0.25 – ≤ 0.50), Q3 (upper middle quartile, > 0.50 – ≤ 0.75), and Q4 (upper quartile, > 0.75). T&O concentrations are categorised as low, medium, and high.

Binomial co-occurrence networks for 16S rRNA and rbcL communities, along with environmental quartile categories, in Reservoir 2 across 30 samples during the sampling period. Solid black arrows indicate higher-than-expected relationships between taxa (p ≤ 0.01), while dashed grey arrows represent lower-than-expected relationships (p ≤ 0.01). Green nodes denote Cyanobacteria genera, purple nodes represent T&O-degrading bacteria, and yellow nodes indicate diatoms. Blue triangular nodes represent environmental variables, categorised into quartiles: Q1 (lower quartile, ≤ 0.25), Q2 (lower middle quartile, > 0.25 – ≤ 0.50), Q3 (upper middle quartile, > 0.50 – ≤ 0.75), and Q4 (upper quartile, > 0.75). T&O concentrations are categorised as low, medium, and high.

Binomial co-occurrence networks for 16S rRNA and rbcL communities, along with environmental quartile categories, in Reservoir 1 across 32 samples during the sampling period. Solid black arrows indicate higher-than-expected relationships between taxa (p ≤ 0.01), while dashed grey arrows represent lower-than-expected relationships (p ≤ 0.01). Green nodes denote Cyanobacteria genera, purple nodes represent T&O-degrading bacteria, and yellow nodes indicate diatoms. Blue triangular nodes represent environmental variables, categorised into quartiles: Q1 (lower quartile, ≤ 0.25), Q2 (lower middle quartile, > 0.25 – ≤ 0.50), Q3 (upper middle quartile, > 0.50 – ≤ 0.75), and Q4 (upper quartile, > 0.75). T&O concentrations are categorised as low, medium, and high.

Binomial cooccurrence networks for 16S rRNA and rbcL communities with environmental quartile categories present in Reservoir 3 across 23 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed grey arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria and yellow nodes represent diatoms. Blue triangular nodes represent environmental variables organised into categorical quantiles based on the range of values for the variable; Q1 – lower quartile (≤ 0.25), Q2 – lower medium quartile (> 0.25 – ≤ 0.50), Q3 – upper medium quartile (> 0.50 – ≤ 0.75) and Q4 – upper quartile (> 0.75). T&O concentrations remain categorised into low, medium and high categories.

Binomial cooccurrence networks for 16S rRNA and rbcL communities with environmental quartile categories present in Reservoir 2 across 30 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed grey arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria and yellow nodes represent diatoms. Blue triangular nodes represent environmental variables organised into categorical quantiles based on the range of values for the variable; Q1 – lower quartile (≤ 0.25), Q2 – lower medium quartile (> 0.25 – ≤ 0.50), Q3 – upper medium quartile (> 0.50 – ≤ 0.75) and Q4 – upper quartile (> 0.75). T&O concentrations remain categorised into low, medium and high categories.

Binomial cooccurrence networks for 16S rRNA and rbcL communities with environmental quartile categories present in Reservoir 1 across 33 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed grey arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria and yellow nodes represent diatoms. Blue triangular nodes represent environmental variables organised into categorical quantiles based on the range of values for the variable; Q1 – lower quartile (≤ 0.25), Q2 – lower medium quartile (> 0.25 – ≤ 0.50), Q3 – upper medium quartile (> 0.50 – ≤ 0.75) and Q4 – upper quartile (> 0.75). T&O concentrations remain categorised into low, medium and high categories.

Binomial cooccurrence networks for 16S rRNA and rbcL genera present in Reservoir 3 across 23 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S rRNA and rbcL genera present in Reservoir 2 across 30 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S rRNA and rbcL genera present in Reservoir 1 across 33 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent Cyanobacteria genera, purple nodes represent T&O degrading bacteria and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S rRNA and rbcL taxa present in Ridgegate reservoir at WHTM location 3. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S rRNA and rbcL taxa present in Ridgegate reservoir at WHTM location 2. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S rRNA and rbcL taxa present in Ridgegate reservoir at WHTM location 1. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Pontsticill reservoir across 17 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Plas Uchaf reservoir across 22 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Pentwyn reservoir across 30 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Llwyn On reservoir across 19 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Llandegfedd reservoir across 23 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Dolwen reservoir across 6 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.1) and dashed black arrows represent negative relationships between taxa (p ≤ 0.1). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Cefni reservoir across 32 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Alwen reservoir across 7 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.05) and dashed black arrows represent negative relationships between taxa (p ≤ 0.05). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria, and yellow nodes represent diatoms.

Binomial cooccurrence networks for 16S and rbcL genera present in Alaw reservoir across 33 samples during the sampling period. Solid black arrows indicate positive relationships between taxa (p ≤ 0.01) and dashed black arrows represent negative relationships between taxa (p ≤ 0.01). Green nodes represent cyanobacteria genera, purple nodes represent T&O degrading bacteria and yellow nodes represent diatoms.