Numbers of heterotrophic bacteria as determined by the heterotrophic plate count (HPC) method, expressed as percentages of the direct total bacterial count (TBC).

SW, seawater samples; BW, ballast-water samples. Asterisk (*) indicates mid-ocean ballast-water exchange on day 5. Heterotrophic bacterial counts are from both freshwater-based medium (HPCfw) and seawater-based medium (HPCsw).

SW为海水样本（seawater samples），BW为压载水样本（ballast-water samples）。星号（*）表示第5日开展了远洋压载水置换。异养细菌计数分别基于淡水基培养基（HPCfw）与海水基培养基（HPCsw）完成测定。