| Abstract |
Monitoring of the marine environment is carried out in
order to assess the anthropogenic impact and its effects on the Baltic Sea
ecosystem, as well as to assess the effectiveness of environmental protection
measures. The monitoring program includes a large component of biological
parameters and abiotic parameters. The results obtained in the monitoring are
used both in the national environmental assessments and in order to fulfill
Latvia's international obligations under the EU directives and the Helsinki
Convention.
In accordance with the requirements of the Water
Framework Directive, Latvia's coastal and transitional waters are divided into
four types of coastal waters and one type of transitional waters. In addition,
two types of seawater are distinguished - the open part of the Gulf of Riga and
the open part of the Baltic Sea. In order to be able to statistically reliably
assess the changes in the state of the environment in each of the seawater
types, a representative number of observation stations has been selected. The
specific number of stations in each water body depends on the size, shape and
spatial heterogeneity of the observed water body. A total of about 50
monitoring stations, which are monitored 4 times a year. Seasonal cruises are
scheduled for late February to early March (to obtain information on winter
nutrient pool), May (to obtain information on the final phase of spring bloom
of phytoplankton and to collect macrozoobenthos samples), August (to assess the
state of the environment at the end of summer and to collect samples), November
(autumn bloom of phytoplankton and the final stage of oxygen deficiency in the deep
water layers of the Gulf of Riga). The monitoring station net for hazardous
substances in fish is designed to monitor and obtain statistically correct data
on changes in the level and distribution of anthropogenic pollution of
toxicants (heavy metals) in the open part and coast of the Baltic Sea and the
Gulf of Riga once a year.
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