European Directory of Marine Environmental Data (EDMED)

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Data set name

Dataset of integrated chlorophyll-a in the upper water column of the Baltic Sea and Gulf of Riga (since 1999)

Data holding centreLatvian Institute of Aquatic Ecology
CountryLatvia  Latvia
ProjectEffect of climate change on aquatic ecosystems in Latvia(KALME); LIMOD(LIMOD); Innovative approaches for marine biodiversity monitoring and assessment of conservation status of nature values in the Baltic Sea(MARMONI)
Time periodNational monitoring and coupled project data. Ongoing.
Geographical area

Territorial and economic waters of Latvia in the Baltic Sea and Gulf of Riga; In 2013 data from 4 stations in Estonian part of the Gulf Riga and Parnu Bay


Chlorophyll pigment concentrations in water bodies


Sieves and filters; manual biota samplers; spectrophotometers


This dataset contains information about integrated chlorophyll-a concentration (miligrams per cubic metre) in the upper 5 or 10 metres of the water column in the territorial and economic waters of Latvia in the Baltic Sea and Gulf of Riga. The majority of the dataset consists of measurements of chlorophyll-a from the National Marine Monitoring Program since 1999. Additional existing data from monitoring and public projects are incorporate into this dataset. Sampling and measurements were done according to HELCOM COMBINE Guidance (1997, 2013) by personnel from the Latvian Institute of Aquatic Ecology. The sampling and measuring methods were/are accredited by the National Accreditation Bureau (LATAK). Water samples were collected onboard research or naval vessels or self-propelled boat. Water samples for determining integrated chlorophyll-a in the upper layer (5 or 10 metre depth) were taken manually by plastic 5 or 10 metre sampling hoses. Pre-treatment of water samples was done immediately after sampling by filtration on vacuum filtration stands (maximum suction pressure 0.3 bar) and GF/F grade (0.7 µm) glass fibre filters. Filtration time didn’t exceed 30 minutes. Filters were kept in a freezer at temperature – 4 degrees Celsius until analysis. Extraction was achieved with ethanol in the dark and spectrophotometric measurements at 664 nm were used for determination of chlorophyll-a. Data are used for the monitoring of environmental status and assessment of eutrophication in the Baltic Sea and Gulf of Riga.

OriginatorsLatvian Institute of Aquatic Ecology
OrganisationLatvian Institute of Aquatic Ecology
AvailabilitySeaDataNet licence
ContactAtis Labucis

Latvian Institute of Aquatic Ecology
Voleru str.4


Telephone+371 67601995, +371 67614840, +371 67610851
Facsimile+371 67601995
Collating centreLatvian Institute of Aquatic Ecology
Local identifier698_CHLA_HOSE
Global identifier6117
Last revised2015-01-13