Influence of Environmental Parameters on the Spring Phytoplankton Bloom Phenology in the North European Basin

In this study, we assess long-term trends of the spring phytoplankton bloom phenology and abiotic factors affecting its vital activity and photosynthetic capacity in three areas of the North European Basin with the most frequent spring phytoplankton blooms based on remote sensing data in 1998–2022. The phonological parameters remained fairly stable over time in the context of increasing Atlantic water inflow in the Barents Sea. In the Norwegian Sea, phenological characteristics also did not have a pronounced trend over the period under consideration. The duration of the spring bloom decreased (significant negative trend: –0.6 days per year), which could be due to a decrease in wind load on the area over the past decades (–0.05 m/s per year) along the western coast of Spitsbergen. The spring blooms timing had a moderate and strong correlation with water temperature and photosynthetically active radiation (r < –0.50 and r > 0.67, respectively). Spring blooms began earlier with a higher intensity of incoming light and higher water temperature, as well as with strong wind-induced mixing in the studying period.