Abstract
Long-term data sets from 1979 to 2011 were analysed for trends in spring diatom development. As irregular phytoplankton sampling cannot record phytoplankton blooms completely, diatom growth during spring was estimated by silicate consumption. The spring diatom biomass decreased sharply at the end of the 1980s in the Baltic Proper but not in the neighbouring western Baltic area. The diatoms, mainly Thalassiosira spp. and Chaetoceros spp., reappeared after a series of cold winters. A strong negative correlation between the minimum water temperature and the magnitude of the diatom growth in the southern Baltic Proper confirms that diatom growth has decreased after mild winters, when motile phytoplankton, such as dinoflagellates and Mesodinium rubrum, may form blooms instead of diatoms. Silicate limitation did not occur in the Baltic Proper. Decreased convective mixing after mild winters may hamper diatom growth (stratification hypothesis), but this effect could not be proved. Our study supports the hypothesis that increased selective grazing pressure after mild winters may control diatom spring blooms (feeding hypothesis).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
