Data access is partially supported by JericoNEXT EU-project.

SYKE Alg@line network in the Baltic Sea monitors the state of the sea and detects algal blooms. Several millions of data points are collected annually from the Baltic Sea, using a fleet of ferries operated by shipping companies.

Ferries are equipped with flow-through systems (usually called 'Ferryboxes') with spatial measurement resolution of about 200 m. The data recording has the geo-reference logging from GPS. Ferryboxes incorporate a thermosalinograph, chlorohyll, phycocyanin and CDOM fluorometers, turbidity meter and refrigerated sampling unit providing discrete water samples for laboratory analyses (e.g. microscopy, FlowCAM, nutrients, optical analysis, and experimental work).

Additional flow-through sensors e.g. for primary production (FRRF) and light reflectance are used periodically. New sensors for pH and pCO2 were implemented in 2018. One of the Algaline routes (Helsinki-Stockholm) passes approximately 10 km south of the Atmospheric and Marine Research Station Utö.

Currently 2 ferryboxes are operated by SYKE Marine Research Center, partly in collaboration with Finnish and international parties:

- FINNMAID (Finnlines) cruising between Helsinki-Travemünde twice a week (Partner: IOW, Germany).
- SILJA SERENADE (Tallink) is cruising between Helsinki and Stockholm daily (Partners: City of Helsinki, Finland; Uusimaa Ely Centre, Finland).



Description of Alg@line project.

Alg@line ferrybox data is available through European FerryBox DatabaseEMODnet Physics, EMODnet Chemistry and Copernicus Marine Environment Monitoring Service.

Ferrybox data from Silja Serenade is visualized at FMI server.

State of the Baltic Sea monitored by Alg@line:

- Nutrients and amount of algae in the Baltic Sea

- Algaline ferrybox observations at Lake & Sea Wiki updated once per hour

- Phytoplankton community reports




Contact person:

Dr. Seppo Kaitala
e-mail  firstname.surname (at)
Marine Research Centre, SYKE


FINNMAID: Helsinki - Travemünde
SILJA SERENADE: Helsinki - Stockholm

Currently operational Ferrybox lines