For full methodology, see Roux et al (2016).
Great Lakes methodology:
For each lake, 33 to 45L of water were 0.22 micron m-filtered and viruses were concentrated from the filtrate using iron chloride flocculation followed by storage at 4 degrees C. After resuspension in ascorbic-EDTA buffer (0.1 M EDTA, 0.2 M Mg, 0.2 M ascorbic acid, pH 6.0), viral particles were concentrated using Amicon Ultra 100 kDa centrifugal devices (Millipore), treated with DNase I (100U/mL) followed by the addition of 0.1 M EDTA and 0.1 M EGTA to halt enzyme activity, and extracted with the QIAamp DNA Mini Kit (Qiagen 51304).
Tara Expedition methodology:
20 L of seawater were 0.22 μ m-filtered, and viruses were concentrated from the filtrate using iron chloride flocculation followed by storage at 4°C. After resuspension in ascorbic-EDTA buffer (0.1 M EDTA, 0.2 M Mg, 0.2 M ascorbic acid, pH 6.0), viral particles were concentrated using Amicon Ultra 100 kDa centrifugal devices (Millipore), treated with DNase I (100U/mL) followed by the addition of 0.1 M EDTA and 0.1 M EGTA to halt enzyme activity, and extracted with the QIAamp DNA Mini Kit (Qiagen 51304).
Bermuda BATS methodology:
Approximately 180L of seawater were concentrated using a 100kDa tangential flow filter, 0.22 μ m-filtered, PEG precipitated, cesium chloride purified, and DNA was extracted using formamide.