Winter-Summer Dynamics of Microbial Plankton in a Small Arctic Estuary: an Association with Environmental Factors
摘要
To elucidate the principal factors governing chlorophyll a concentration (Chl-a), prokaryotic plankton abundance/biomass, and viral abundance/biomass, we conducted a seasonal survey from late winter to early summer 2023 at high tide in Veresova Inlet. Water temperature rose from − 0.4 °C in winter to 8.2 °C in summer, while salinity declined from 15.5 to 5.8. pH remained stable (7.7–8.4). Phosphate and nitrate concentrations decreased slightly, whereas silicate increased. Chl-a was minimal in winter (< 0.9 mg m–3) and peaked in spring (1.23 mg m–3). Prokaryotic plankton abundance/biomass increased from winter to summer (6.5 × 105–28.2 × 105 cells L–1, 14.1 mgC m–3–73.7 mgC m–3), dominated by small and ultra-small morphotypes. Virioplankton abundance/biomass concurrently rose from 6.1 × 106 particles L–1/0.34 µgC m–3) in winter/spring to 14 × 106 particles L–1/0.70 µgC m–3 in summer. Chl-a and prokaryotic abundance correlated positively with rising temperature and negatively with salinity. Nutrient levels were positively associated with Chl-a but inversely related to microbial abundance. Virioplankton abundance and biomass were strongly linked to elevated temperatures. Moreover, prokaryotic abundance and biomass correlated positively with Chl-a, while virioplankton dynamics corresponded to changes in prokaryotic abundance. Seasonal shifts in bacterioplankton size and morphometry suggest the presence of distinct bacterial populations exhibiting adaptations to varying environmental conditions.