Monitoring of total nitrogen in the Contracting Parties of HELCOM is described on a general level in the HELCOM Monitoring Manual in the sub-programme: Nutrients
Monitoring guidelines specifying the sampling strategy are adopted and published.
The monitoring activities relevant to the indicator that are currently carried out by HELCOM Contracting Parties are described in the HELCOM Monitoring Manual Sub-programme: Nutrients.
Total nitrogen is monitored year-round. Furthermore, TN is already widely assessed by Contracting Parties: according to the questionnaire sent to contracting parties via EUTRO-OPER, total nutrients in open-sea areas are monitored and reported by Denmark, Estonia, Finland, Germany, Germany, Germany, Latvia, Lithuania, Poland, the Russian Federation and Sweden. Guidelines for monitoring these indicators exist in the HELCOM Monitoring Manual. Concentrations of total nutrients are total nutrients measured in situ, both from fixed stations using traditional sampling and with Ferrybox flow-through sampling.
For assessment purposes, at least 15 status observations should be conducted annually during the period January to December in each open-sea assessment unit. The compilation of observations is expected to be distributed spatially within the assessment unit in a non-biased way. In coastal areas, at least monthly sampling of representative stations is desirable.