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Dieren en planten

Arthropods   Crustaceans   Barnacles   Sacculina carcini   Herring family   Herring   Flatfish   Plaice   Fish biology   Fish diseases   Algae and seaweed   Diatoms   Green seaweed   Ulva   Gutweed   Eelgrass   Fungi, mushrooms   Fungi in the sea   Phytoplankton   Aquatic plants   

Water en land

Sea regions   North Sea (biotope)   

Mens en Milieu

Water   Seawater   Pollution   Marine litter   Coastwatch   

Fungi in the sea

Many small, usually one-celled fungi live in seawater, almost all belonging to the Phycomycetes. They are rarely larger than a tenth of a millimeter and therefore barely visible with the naked eye. A number of these fungi causes diseases and can infect sea fish, crustaceans and seaweed. Some moulds float freely in the water, others attach themselves onto driftwood, shells and sand grains on the bottom. The fungi which float freely in water have unusual protusions for better flotation, just like zooplankton. Fungi are specialized in breaking down materials, including lignine found in driftwood and chitine (an important building material in the external skeleton of crustaceans).

  • Reproduction

    Reproduction takes place via spores. These spores are able to survive for long periods of time on the bottom until they find something appropriate for growing. They often have a tail flagellate, just like sperm cells, allowing them to swim a bit.

  • Distribution of marine fungi

    Marine fungi are found particularly in the vicinity of the coast, up to 2000 spores per liter water. More nutrients are available here, in the form of organic material. Organic material is small pieces of dead plants and animals floating in the water, often originating from land. Many fungi are unable to reproduce in the sea, needing freshwater. Further away from the coast, one only finds 10 spores per liter water.
    Unusual bacteria and one-celled yeast are found in the oxygen-depleted black spots on the tidal flats. They ferment the sugars from organic materials just like their relatives do in bakeries and beer breweries.

  • Fungi are specialists in degradation

    In the days when nets and ropes were made from natural materials, certain fungi caused incredible damage within several weeks or months to the ocean-going shipping and the fisheries. The ropes and nets molded if not dried well. Nor were wooden ship wrecks safe from the fungi. Fungi cannot eat present-day nets made from nylon and other kinds of plastic materials. Unfortunately, lost drifting nets nowadays are also left behind undegraded, with many (negative) consequences for sea fauna.

  • Marine fungi as pathogen

    Some marine fungi can cause fish diseases, such as Ichthyophonus hoferi. While herring and plaice do not survive an infection with this fungi, cod species are usually able to recover. The intestines as well as skin tissue are affected. Fortunately, these fungi cannot survive in mammals.
    Other fungi grow on calcium and even damage, for example, the teeth of wolf-fish by dissolving the material.
    The fungus Labyrinthula infects eelgrass and can cause massive death. This fungus can cause colorless patches on green seaweed. Diatoms can also be infected by this fungus.