30-50 miles off capes of Kaliakra, Galata and Emine, Varna and Burgas bays and Varna and Beloslav lakes

Dissolved oxygen parameters in the water column; Nitrate concentration parameters in the water column; Salinity of the water column; Temperature of the water column; Nitrite concentration parameters in the water column

CTD; spectrophotometers

The main parameters, presented in this data set include - temperature (° C), salinity (ppt), dissolved oxygen (ml/l), NO3 (mmol/m^3), NH4 (mmol/m^3) Additional parameters, studied during the 2000-s include: Si (mmol/m^3), P (mmol/m^3), Inorganic Phosphorus (IP), Inorganic Nitrogen (IN), Total Phosphorus (TP), Suspended Matter (SM) and chlorophyll a (mg/m^3). Two different instrument groups are used to collect the hydrological and hydrochemical data on board. These were: a) Hydrographic casts (Station Data) which measure temperature through the use of reversing thermometers and capture of water samples with various bottle types at different depths for determination of salinity, oxygen, nutrients: N-NO2, N-NO3, permanganate oxidizability, etc.; the hydrographic casts are the data source prior to 2001. b) CTDs (Conductivity/Temperature/Depth probes, Sea&Sun Technology).

Institute of Fishery Resources
4 Primorski Blvd P.O. Box 72
Varna

9000
Bulgaria