Quantitative distribution of plant and animal communities of the phytobenthic zone in the Baltic Sea

Source: OAI

ABSTRACT Contributions from the Askö laboratory ; 35 Pages: 80 p. : ill., graphs This paper quantitatively describes flora and fauna communities in the central and northern Baltic Sea, on vegetation covered substrate down to maximum 25 m depth, investigated by SCUBA-technique. In the Holmö area, on the sill between the Bothnian Bay and the Bothnian Sea, biomass was characterized by annual, mainly freshwater algae (e.g. Cladophora spp.) growing on the predominantly hard substrate of boulders, stones and pebbles. Muddy substrate, occurring in the shallow bays, had low biomass of freshwater phanerogams. The fauna biomass was dominated by freshwater molluscs (mainly Theodoxus fluviatilis L.) and the isopod Mesidothea entomon L.. Occasionally, Macoma balthica L. was abundant on sand and mud bottoms. Insect larvae were common but contributed little to total animal biomass.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Within the Gulf of Riga Project, phytobenthic and associated animal communities were sampled in 1995 and 1996 using SCUBA techniques. The aim was to quantitatively describe the phytobenthic communities and their distribution and to evaluate the present status of the phytobenthos in comparison to earlier investigations, as well as its contribution to the ecosystem of the Gulf as a whole. Classification and ordination analysis showed differences among the different areas of the Gulf of Riga, where Saaremaa, the Pärnu area and the middle and the inner part of the Gulf formed distinctive groups. The inner part and the Pärnu Bay area are influenced by the nutrient and pollution load of mainly the rivers Pärnu and Daugava. The intermediate western and eastern coasts of the Gulf of Riga, as well as the northern coasts along the island of Saaremaa seem to hold phytobenthic communities of comparable composition and biomass found elsewhere in clean areas of the Baltic Sea.
    Hydrobiologia 01/1999; 393:191-200. · 1.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the Baltic Sea, abiotic factors are often supposed to explain the distribution of the key species Fucus vesiculosus. Still, in many areas, decline of F.vesiculosus has coincided with mass occurrence of the herbivorous isopod Idotea baltica. The aim of this work was to examine whether, how and at what densities I.baltica can affect the distribution of F.vesiculosus in the central Baltic proper. Both large-scale field surveys and a two-week grazing experiment have been performed.In the field survey there was a correlation between density of I.baltica and reduction in depth penetration of F.vesiculosus. At 80 animals per 100g F.vesiculosus wet weight, the depth penetration of the F.vesiculosus belt was reduced by 2.5m within a year. In the grazing experiment there was a correlation between density of I.baltica and loss of F.vesiculosus biomass and meristems. In the controls biomass and number of meristems increased by 50%, while at 20 animals per 100g of F.vesiculosus there was no net growth of F.vesiculosus. Intensity of grazing did not differ between isopod densities of 20, 40 and 60/100g. At isopod densities of 80 and 100/100g though, biomass and meristems decreased by 50%, indicating a threshold for the survival of F.vesiculosus in the experiment. At all densities the isopods preferred younger tissue to older.Our results indicate that grazing by Idotea baltica is an important structuring factor in the Baltic Fucus vesiculosus populations.
    Aquatic Ecology 08/2000; 34(3):253-260. · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A review is given on available knowledge about the southern Baltic banks situated totally or partially within the Polish Exclusive Economic Zone. Particular concern is given to benthic vegetation and benthic fauna, however ichthyofauna and avifauna are also considered. The southern Baltic banks have a potential for commercial exploitation. Identification and selection of potential off-shore marine protected areas is done following criteria of the International Union for Conservation of Nature and other international organisations. The Slupsk Bank is a unique area within the Polish Baltic banks, worthy of designation as an open sea HELCOM Baltic Sea Protected Areas (BSPA) and as a reference area for phytobenthic studies. The Odra Bank, recognised as an important wintering area for birds, is considered as a second BSPA candidate.
    Hydrobiologia 01/1999; 393:271-277. · 1.99 Impact Factor