The　composition　of　microbial　communities　can　vary　at　the　microspatial　scale　between　free-living　(FL)　and　particle-attached　(PA)　niches.　However,　it　remains　unclear　how　FL　and　PA　bacterial　communities　respond　to　cyanobacterial　blooms　across　water　depths.　Here,　we　examined　the　community　dynamics　of　the　FL　(0.2–3　μm)　and　PA　(＞3　μm)　bacterioplankton　based　on　16S　rRNA　gene　high-throughput　sequencing　in　a　subtropical　stratified　reservoir　under　Microcystis　aeruginosa　bloom　and　non-bloom　conditions.　Both　FL　and　PA　bacterioplankton　communities　showed　different　responses　in　alpha-　and　beta-diversities　to　the　bloom,　suggesting　the　idea　that　the　responses　of　bacterial　community　could　depend　on　lifestyle.　Specifically,　abundant　PA　subcommunities　showed　a　greater　variation　between　bloom　and　non-bloom　groups　than　abundant　FL　ones.　In　contrast,　rare　FL　subcommunities　exhibited　a　stronger　response　to　water　depth　than　rare　PA　ones.　Furthermore,　the　rare　taxa　exhibited　a　preference　for　PA　status,　shaped　and　stimulated　by　the　M.　aeruginosa　bloom.　Our　analyses　also　showed　that　PA　bacterial　communities　were　generally　more　diverse　and　appeared　to　be　more　responsive　to　routinely　measured　environmental　variables　than　FL　bacteria.　Microcystis　blooms　had　a　facilitative　influence　on　specific　bacteria　by　mediating　the　transitions　from　free-living　to　particle-attached　lifestyles.　Altogether,　these　findings　highlight　the　importance　of　bacterial　lifestyle　and　abundance　in　understanding　the　dynamics　of　microbial　community　in　cyanobacterial　bloom　aquatic　ecosystem.　©　2018　Elsevier　B.V.