Table 1. Sample Descriptions^a.

sample type	sample name	species (strain)	phylum	source and treatment	other information
freshwater algae	wild-type Chlamydomonas reinhardtii	C. reinhardtii (CC-1690)	Chlorophyte	from CRC, cultured in TAP medium	wild-type strain
freshwater algae	mutant C. reinhardtii	C. reinhardtii (CC-5322)	Chlorophyte	from CRC, cultured in TAP medium	vtc4 mutant, does not accumulate polyP
marine algae	Thalassiosira weissflogii	T. weissflogii	Diatom	isolated from Hong Kong coastal waters and cultured in Guildard’s (F/2) Medium
marine algae	Ruttnera sp.	Ruttnera sp. (PLY510A)	Haptophyta	from RCC, cultured in Guildard’s (F/2) Medium
freshwater bacteria	V. perlucida	Vogesella perlucida	Pseudomanodota	isolated from freshwater Kowloon Reservoir and cultured in R2A medium
marine bacteria	Nautella sp.	Nautella sp.	Pseudomanodota	isolated from Hong Kong coastal waters and cultured in 2216E medium
freshwater environment	Kowloon Reservoir	–	–	waters from freshwater Kowloon Reservoir were filtered through 0.2 μm PC membrane filters to collect particles
marine environment	Hong Kong coast	–	–	coastal seawaters were filtered through 0.2 μm PC membrane filters to collect particles

^aAbbreviations: CRC, Chlamydomonas Resource Center, University of Minnesota; ATCC, American Type Culture Collection; RCC, Roscoff Culture Collection.