JPR Advance Access originally published online on August 18, 2007
Journal of Plankton Research 2007 29(10):895-901; doi:10.1093/plankt/fbm067
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dense sub-ice bloom of dinoflagellates in the Baltic Sea, potentially limited by high pH
1 Finnish Environment Institute, PO Box 140, 00251 Helsinki, Finland 2 Tvärminne Zoological Station, University of Helsinki, 10900 Hanko, Finland
* Corresponding Author: kristian.spilling{at}ymparisto.fi
Received on February 27, 2007; accepted on August 15, 2007
| Abstract |
|---|
The phytoplankton community, carbon assimilation, chlorophyll a (Chl a), pH, light and attenuation and inorganic nutrients were monitored under the ice in the coastal Gulf of Finland, Baltic Sea. Maximum ice and snow thickness was 40 and 15 cm, respectively. Freshwater influence had created a halocline 1–2 m below the ice–water interface, and above this halocline, a dense bloom of dinoflagellates developed (max: >300 µg Chl a L–1). The photosynthetic uptake of carbon dioxide by this "red tide" increased the pH to a maximum of 9.0. The sub-ice phytoplankton community was dominated by the dinoflagellate Woloszynskia halophila (max: 3.6 x 107 cells L–1). The pH tolerance of this species was studied in a monoculture and the results indicate that pH >8.5 limits growth of this species at ambient irradiance. This study shows that primary productivity may raise the pH to growth limiting levels, even in marine, low-light environments where pH normally is not considered important.
Communicating editor: K.J. Flynn