The Gulf of Bothnia, The Bothnian Sea and The Bothnian Bay

Nitrogen concentrations in sediment; Carbon concentrations in sediment; Inorganic chemical composition of sediment or rocks

Sediment grabs; atomic absorption spectrometers; spectrophotometers

Gulf of Bothnia: This study has been part of the Gulf of Bothnia year 1991 study. The samples were taken with a gravity corer for soft sediments on board R/V Aranda on different cruises during 1991 - 1992. Some samples near the coastal area were taken on board local boats using Box corers and different kinds of tube samplers used by the local water authorities. Total number of stations were 56; 32 stations in the Bothnian Bay and 24 stations in the Bothnian Sea. The sampling areas in the Gulf of Bothnia include both coastal and open sea areas. The sediment corers were cut into 1 cm subsamples and the five uppermost subsamples were analysed. The total amount of subsamples was 350. The freeze dried and homogenated samples were digested with aqua regia and hydrofluoric acid by microwave oven for elemental analysis. For mercury analyses the samples were digested with nitric acid in an autoclave. 17 elements were analysed by AAS and ICP-AES (including P). C and N were analysed with a carbon-nitrogen analyzer. The quality of analysis were controlled by analysing certified reference materials with the samples. The data set shows the distribution of elements in the sediments in the Gulf of Bothnia. Gulf of Finland: The samples were taken with a gravity corer for soft sediments on board R/V Aranda on different cruises during 1992. Total number of stations were 16. In this study supplementary samples from ICES-HELCOM sediment study 1993; 6 stations. The sediment corers were cut into 1 cm subsamples and the ten uppermost subsamples were analysed. The total amount of subsamples was about 220. The freeze dried and homogenated samples were digested with aqua regia, hydrofluoric acid and boric acid by microwave oven for elemental analysis. For mercury analyses the samples were digested with nitric acid in an autoclave. 17 elements were analysed by AAS and ICP-AES (including P). The quality of analysis were controlled by analysing certified reference materials with the samples. The data set shows the distribution of elements in the sediments in the Gulf of Finland. This is ongoing study which will connect BASYS-study.

Finnish Environment Institute
Latokartanonkaari 11
Helsinki

00790
Finland