marine research in finland - Baltic Marine Environment Bibliography

1.3. Chemical oceanography
The main emphasis of chemical studies in the Institute is to determine the mass balance of nutrients,
heavy metals and organic compounds in the Baltic Sea. Field studies were extended to
cover the winter season in the early 1980’s. Before that time, information was only available for
the ice-free seasons. Determinations of mass balances require information on sources and sinks,
and the transport of compounds in the water body, as well as their related conceptual models.
Input information on nutrients is available from loading estimates provided by other authorities,
while the main sink in the area is sedimentation. For this reason, during recent years, the study
of recent sediments and their role in the mass balance has become the main focus of chemical
oceanography studies. The Institute participates actively in the Sediment Baseline Study of the
Baltic Sea, which focuses on a quantitative determination of the sedimentation of harmful substances
on the sea bottom. Parameters to be determined are the sedimentation rate, and heavy
metal and organochloride concentrations in the sediments.
Other focal points in chemical oceanography studies are the balances and processes of organoclorides
in the water phase, denitrification processes, and the development of numerical models
for mass balance studies.
1.4. Biological oceanography
Marine biological studies remained under the aegis of the Finnish Society of Sciences and Letters
until they were initiated in the Institute in the late 1950’s. Today, the Institute has available
long time series on the variability of benthic populations and zooplankton, as well as being involved
in several ongoing projects on microbiology, primary and secondary production as well
as macrozoobenthos.
The dynamics of plankton blooms are under study both in coastal stations, jointly with the Universities,
and on the open sea. The intensity and seasonal variability of the plankton blooms is
studied not only on research cruises but also by analysing remote sensing data as well as using
continuously-recording fluorometers on passenger ferries. This combination of observing methods
provides good opportunities to verify the relation between eutrophication and the intensity of
blooms in a statistically significant manner.
During recent years, studies of toxic cyanobacterial blooms have been included in the research
agenda. These studies focus on the hydrodynamic control of the blooms and the trophic web dynamics
of the blooms. Field expeditions which include the participation of physical, chemical
and biological oceanographers provide simultaneous data on frontal processes, the entrainment
of nutrients and the evolution of blooms. The study of trophic interactions include phytoplankton
and bacterial production, nutrient uptake and zooplankton grazing pressure.
During most of the growth season in the northern Baltic Proper, suspended matter exists as aggregates
of organic detritus, micro-organisms and inorganic particles. In addition to microscopic-size
particles, a substantial fraction ranges in size from 500 pm to several centimeters.
The dynamics of these aggregates forms one of the themes in the studies of the Baltic ecosystem.
Their importance in the cycling of inorganic nutrients and carbon, their role in denitrification
processes and their relation to cyanobacterial blooms is one of the priority areas of the Institute.
Studies of zooplankton focus on analysis of the biotic and abiotic factors which regulate the
zooplankton production and population dynamics in the northern Baltic Sea. The traditional approach
is combined with modem field, experimental and statistical methods.
Zooplankton data collected since 1965 at fixed coastal stations provide, jointly with simultaneous
hydrographical data, good opportunities for the analysis of abiotic influences on the dynamics.
These data are used in combination with data from intense study periods on the abundance
and development of the life cycle of the species studied.