Inner Oslofjorden Phytoplankton Database

Study Extent

The database covers several sampling stations in the inner Oslofjorden, with the majority of samples (61%) from Dk1/S1 (N59.814999 E10.569384). Dk1 has been the most sampled station throughout all the years of sampling. Data are available for the years 1896-97, 1916-17, 1933-1934, 1939, 1948, 1957-58, 1962-65, 1972-1974, 1988-1990, 1994-1995 and 1998-2020. From 1998-2004 there are only samples during the summer months (May to Aug) but from 2006 to 2020, there is good seasonal coverage.

Sampling

The inner Oslofjorden Phytoplankton dataset was compiled in 2020, comprising of quantitative phytoplankton cell counts from inner Oslofjorden since 1896. Previously parts of the data has been available as handwritten or printed tables in reports and published sources. Data from 1994 and onwards have been accessed digitally from the NIVA’s databases but are also available from client reports from the monitoring project for inner Oslofjorden. The data already digitalized were compiled from excel files. Other data were manually entered to standard format in MS Excel files. All collected data were then integrated into one excel database.

Quality Control

After compilation, the data were checked for digitalization errors, which could occur during manual digitalization or just the compilation process. Duplicates and zero values were removed. Then taxonomy specialists did perform a taxonomic quality check. The nomenclature in Worms is quality assured by a wide range of taxonomic specialists. We also cross checked the last updated nomenclature in Algaebase to assign species to a valid class name. When Algaebase and Worms were not in accordance, Algaebase taxonomy was usually chosen except in the case of Bacillariophyceae.

Method steps

1. Data was compiled from a range of sources described in "sampling description". After compilation, the original names in our database and matched them to accepted names and Aphia ID using the taxon match tool available in the open-access reference system; World Register of Marine Species (Worms). The data was then formatted to Darwin Core.

Inner Oslofjorden, Norway