Status of Biodiversity in the Baltic Sea

Abstract

The brackish Baltic Sea hosts species of various origins and environmental tolerances. These immigrated to the sea 10,000 to 15,000 years ago or have been introduced to the area over the relatively recent history of the system. The Baltic Sea has only one known endemic species. While information on some abiotic parameters extends back as long as five centuries and first quantitative snapshot data on biota (on exploited fish populations) originate generally from the same time, international coordination of research began in the early twentieth century. Continuous, annual Baltic Sea-wide long-term datasets on several organism groups (plankton, benthos, fish) are generally available since the mid-1950s. Based on a variety of available data sources (published papers, reports, grey literature, unpublished data), the Baltic Sea, incl. Kattegat, hosts altogether at least 6,065 species, including at least 1,700 phytoplankton, 442 phytobenthos, at least 1,199 zooplankton, at least 569 meiozoobenthos, 1,476 macrozoobenthos, at least 380 vertebrate parasites, about 200 fish, 3 seal, and 83 bird species. In general, but not in all organism groups, high sub-regional total species richness is associated with elevated salinity. Although in comparison with fully marine areas the Baltic Sea supports fewer species, several facets of the system's diversity remain underexplored to this day, such as micro-organisms, foraminiferans, meiobenthos and parasites. In the future, climate change and its interactions with multiple anthropogenic forcings are likely to have major impacts on the Baltic biodiversity.

Biodiversity gradient in the Baltic Sea: a comprehensive inventory of macrozoobenthos data

“…In a previous study, an attempt was made to merge all the macrozoobenthos data around the Baltic Sea (Ojaveer et al 2010). However, as we have learned during the present study, some areas, especially the highly saline area of the Kattegat and the areas with greater freshwater influence (e.g.…”

“…The HELCOM Benthic Invertebrate Checklist is based on the data of Gerlach (2000), Zettler and Röhner (2004), Zettler et al (2008), Ojaveer et al (2010) and Zettler (2011), including more than 1,400 species altogether. During the HELCOM Red List work, new data for more than 600 species were added, obtained from literature, national marine databases and unpublished sources by the present authors.…”

Using the critical salinity (S crit) concept to predict invasion potential of the anemone Diadumene lineata in the Baltic Sea

“…It hosts over 100 non-indigenous species, of which approximately 70 % have established stable populations (Ojaveer et al 2010). Salinity (next to temperature) has been described as the key limiting factor for the spread of marine organisms into the Baltic Sea (Bonsdorff 2006) and several taxa are restricted to the more saline waters of the Kattegat and Western Baltic Sea (WBS), including native anthozoans (sea anemones) (Leppäkoski et al 2002).…”

Metabarcoding approach for nonindigenous species surveillance in marine coastal waters

“…; Leppäkoski et al 2002) and considered as one of the most intensively studied regional seas in the world (Ojaveer et al 2010), there are still substantial gaps in biodiversity knowledge and relevant surveillance programs. For instance, in routine zooplankton monitoring only dominant species of certain groups and size fractions are identified and Zaiko A., Samulioviene A., Ardura A., Garcia-Vazquez E. 2015.…”

“…Metabarcoding approach for nonindigenous species surveillance in marine coastal waters. Marine Pollution Bulletin, 100:53-59. counted, disregarding many important taxa, particularly small-sized and cryptic forms (Ojaveer et al 2010;Hällfors et al 2013). This and insufficient spatial and temporal resolution of the monitoring programs (Patricio et al 2014) may handicap the environmental status assessments relevant to biodiversity and NIS components.…”