Cyanobacterial blooms have not been observed in the Finnish sea-areas. The surface temperature is around 12 degrees Celsius in the open Gulf of Finland and the Archipelago Sea. In the Bothnian Sea the temperature is between 9 and 12 degrees, and in the Bothnian Bay between 4 and 9 degrees.
The phytoplankton level in the Gulf of Finland and the Baltic proper is low, which is typical for the early summer. The biomass is below 4 µg/l in the open sea areas. Cyanobacteria is sparse.
In some places pollen is gathered to the surface, and may resemble an algal bloom. Pollen may be distinguished by its yellow-green coulour, and the fact that it rarely is mixed in the water column.
The surface temperature is around 12 degrees Celsius in the open Gulf of Finland and the Archipelago Sea. In the Bothnian Sea the temperature is between 9 and 12 degrees, and in the Bothnian Bay between 4 and 9 degrees.
The temperature is around 10 degrees in the northern Baltic Proper, 12 degrees in the central Baltic Proper and 15 degrees in the southern Baltic Proper.
The phytoplankton spring bloom has utilized nutrients from the surface. The amount of nitrate- and nitrite nitrogen is near zero in the Gulf of Finland and the Baltic Proper. The amount of phosphate-phosporus is near zero in the Gulf of Finland, 1.0 µmol/l in the norhtern Baltic Proper and 0.2 µmol/l in the southern Baltic Proper.
The phytoplankton community is typical for the early summer. Nanoflagellates dominate, larger diatoms, dinoflagellates and blue-green algae occur in small amounts. Colonies of the golden alga Dinobryon balticum are abundant in the western Gulf of Finland and in the northern Baltic Proper, while the haptophycean Chrysochromulina* spp. cells are abundant in the central and southern Baltic Sea. Small sized Gymnodiniales -cells are also common.
Large dinoflagellates of several genera (Dinophysis acuminata* D. norvegica*, Amylax triacantha, Protoperidinium spp., heterotrophic Gymnodiniales spp.) occur in small numbers in all samples. Smaller gymnodinialean cells and Heterocapsa rotundata are relatively common in the central and southern Baltic Proper.
There are still only small amounts of blue-green algae in the water. Single filaments of Aphanizomenon flos-aquae and Nodularia spumigena* occur from the southern Baltic to the Gulf of Finland. Filaments of Nodularia spumigena* have slightly increased in abundance in the southern and central Baltic Proper. Small colonial blue-green algae (Cyanodictyon spp., Lemmermanniella spp., Aphanothece parallelliformis) have become abundant in the southern parts. (*Potentially toxic or harmful species).
The growth of cyanobacteria is inhibited not only by lacking nutrients, but also by low water temperature. Thus cyanobacterial blooms are very likely in the Finnish sea-areas during the following week.
Scientist Vivi Fleming-Lehtinen, SYKE Marine Centre, 'fistname.lastname@ymparisto.fi, tel. +358 400 609 269
Algae species: Scientist Seija Hällfors, SYKE Marine Centre, fistname.lastname@ymparisto.fi, tel. +358 40 1823179
See also:
Time series
Algae information service
