Putrescine and spermidine are short-chained aliphatic polyamines (PAs) that are ubiquitously distributed in seawater. These compounds may be important sources of dissolved organic carbon and nitrogen for marine bacterioplankton. Here, we used pyrotag sequencing to quantify the response of bacterioplankton to putrescine and spermidine amendments in microcosms established using surface waters collected at various stations in the South Atlantic Bight in October 2011. Our analysis showed that PA-responsive bacterioplankton consisted of bacterial taxa that are typically dominant in marine systems.Rhodobacteraceae(Alphaproteobacteria) was the taxon most responsive to PA additions at the nearshore site.Gammaproteobacteriaof the familiesPiscirickettsiaceae;Vibrionaceae; andVibrionaceaeandPseudoalteromonadaceae, were the dominant PA-responsive taxa in samples from the river-influenced coastal station, offshore station and open ocean station, respectively. The spatial variability of PA-responsive taxa may be attributed to differences in composition of the initial bacterial community and variations ofin situphysiochemical conditions among sites. Our results also provided the first empirical evidence thatGammaproteobacteriamight play an important role in PA transformation in marine systems.