Underwater world of science

The research of the sea is fascinating; it has so many different levels. How many of them are familiar to you?

Hormones from pharmaceuticals in seawater

Pharmaceuticals have become recognized as relevant environmental contaminants. Surface waters receive continuous inputs of hazardous compounds (including synthetic and natural hormones) from pharmaceuticals through waste water treatment plants (WWTP) via sludge or effluent. Marine waters are the final sink of the most persistent compounds, and since the Baltic Sea is a sensitive ecosystem with low salinity, low biodiversity and few trophic levels - organisms are prone to be more sensitive to hazardous substances than in other marine areas.

  • Hormones cause changes in reproductive organs of fish and mollusks (e.g. feminization of male gonads) even at very low concentrations (<10 ng l−1).
  • Neither basic wastewater treatment nor basic drinking water treatment eliminates pharmaceuticals due to the chemical stability of the structures.
  • At present, there are no regulations for the monitoring of pharmaceuticals in the aquatic environment or limit values for treated wastewaters
  • Analyses of seawater for hormones are relatively costly and require low detection limits.


“Background Document on Pharmaceuticals and the Baltic Sea Marine Environment”, HELCOM HOD 43/2013

Geological research

In recent years geoarcheological and marine geological research of the eastern Gulf of Finland coasts and near-shore bottom were undertaken. Main methods included analysis of coastal morphology, results of geological research (GIS relief analyses, ground penetrating radar, drilling, grain-size analyses, radiocarbon dating), geoarcheological studies and geological surveying. Findings have shown that coasts of lagoons in Sestroretskaya Lowland and Narva-Luga Klint Bay were inhabited by Neolithic and Early Metal people. Also, it is possible to assume that several times during Holocene (including preAncylus (11000 cal.BP) and preLittorina (8500 cal.BP) regressions) the sea-water level was lower than nowadays. The discovered widespread occurrence of pockmarks was explained by the suggestions that those located in the central part of the gulf are formed by gas-seepage because of active transformation of organic matter by microbiological processes. The pockmarks of other type, found in Kopora and Vyborg bays, probably are formed because of groundwater discharge.


  • “Holocene development of the eastern Gulf of Finland coastal zone (Baltic Sea)”,
  • “Pockmarks of the eastern Gulf of Finland (Baltic Sea) – geology, morphology and genesis”, A.P.Karpinsky Russian Research Geological Institute (VSEGEI), Department of Regional Geoecology and Marine Geology, St.Petersburg, (2) Winogradsky Institute of Microbiology, Moscow, 2014

Marking fish

Fisheries monitoring can provide biologists with essential information on aquatic resources before, during, and after development project construction to ensure such projects have fewer impacts on fish populations. This includes evaluating whether fish passage structures are working, and whether fish populations are changing in abundance. Maintaining healthy fish populations is necessary for the security of vital food resources, and for protecting the structure and relationships of nature’s ecosystems.

  • Various marking methods include biological (natural), chemical, and physical (mutilation or tags) marks.
  • Temporary marks (lasting from a few weeks to years) are applied to fish to identify at recapture.
  • Recapturing marked fish helps estimate fish population size, migration behavior, and survival rate

More information:

Bird radars

Radar observations are conducted to quantify bird movements in order to estimate potential collision risks with tall constructions (wind turbines, bridges, etc.). Now radars are also used as additional instruments on airports to prevent bird strikes.

  • Radar is a tool for monitoring of the movements of birds or other organisms (bats, insects) in the air during the day, or at night in range of typically up to 10 km.
  • It is also necessary to simultaneously carry out observations with spotting scope and/or binoculars to identify the species and number of birds in the flock.
  • With the laser binoculars also the distance of birds and flying height can be measured.


“Current Stage of Bird Radar Systems”, Felix Liechti & Hans van Gasteren, Swiss Ornithological Institute, Royal Airforce of The Netherlands, 2010

Maritime Spatial Planning

Maritime Spatial Planning (MSP) is a process of analyzing and allocating the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic, and social objectives.

Marine spatial planning can be ecosystem-based, area-based, integrated, adaptive, strategic and participatory. There are a number of useful and innovative tools for implementing MSP. The prototype of one of such planning tools, utilizing the sensitivity of different landscape units and habitats, will be tested for large scale marine spatial planning in protection and management of the nature of the Eastern Gulf of Finland in the framework of TOPCONS project.

More information:

TOPCONS project

Biological diversity

The Baltic Sea, including the Kattegat area, hosts more than 6000 species. These include 1700 phytoplankton species, nearly 1200 zooplankton species, more than 400 species of bottom flora, over 2000 species of bottom fauna, nearly 400 species of parasites of vertebrates, nearly 200 fish species, and 3 seal species. In addition, over 80 water bird species can be encountered on the Baltic Sea. As water salinity of the Baltic Sea decreases towards the Gulf of Finland, the biota here does not include fully marine species that live at the Danish straits, such as the common starfish. At the same time, some freshwater species that are absent in the more saline parts of the Baltic Sea are represented in the Gulf of Finland. Some species live in water of any salinity – these are known as euryhaline species.

Traditional marine sampling. Next to developing new methods, traditional means of sampling have been used in the Gulf of Finland for over half a century. Zooplankton samples are collected with special nets, bottom biota is sampled with bottom grabs, and water chemistry and phytoplankton samples are collected with special chambers. Water transparency is measured using a special white round disk (Secchi disk). Many sampling methods are in principle the same as half a century ago but sampling devices and analysis methods have been further developed. Long-term studies have provided us with data sets that can be used for studying and predicting long-term environmental changes.

Artificial reefs represent an innovative, near-natural and environmentally sustainable technology for improving water quality in water bodies. Artificial reefs are special objects, such as concrete blocks, ropes, etc., placed in water bodies by humans. Artificial reefs serve as attachment substrates for animals that feed by filtering water through their body, thereby cleaning the surrounding environment – e.g. blue mussel (Mytilus trossulus). Over the past decades, artificial reefs have proved to be an efficient means for mitigating human impacts on the sea. They provide additional growth surfaces for bottom fauna and flora, as well as shelter and spawning sites for fish.

Seawater acidification is caused by increased levels of carbon dioxide in the air. Atmospheric carbon dioxide is absorbed by surface layers of the sea and lowers the pH of seawater. Acidification of seawater causes changes in the species composition of aquatic biota and in the development of organisms. Acid water damages the calcium-containing body parts of animals. To obtain a thorough overview of seawater acidification, seawater is sampled and analysed in a laboratory. To date, acidification studies have been carried out mainly in ocean conditions but the issue is becoming increasingly significant also from the Gulf of Finland point of view. In Estonia, seawater acidification is being studied at the Estonian Marine Institute, University of Tartu.