Distribution of Organisms on the Seashore

Abstract

Marine organisms are found on various types of seashores. The shore features often change gradually according to their degree of exposure to wave action. With decreasing exposure, the substratum changes from rocks in the most exposed/open regions to silts/clays in very sheltered conditions. Some organisms, called ecosystem engineers or foundation species, form biogenic habitats such as mussel beds, oyster reefs, salt marshes, mangrove forests, seagrass meadows, kelp forests, and coral reefs. Marine organisms have latitudinal limits. The climate in Japan ranges from sub-arctic to subtropical, and includes most temperate climatic zones; thus, the distribution of marine organisms depends on the climatic zones present. Biogenic habitats are also influenced by climate; for instance, intertidal salt marsh in a temperate zone is normally replaced by mangrove forest in a subtropical region. Likewise, kelp forest in sub-arctic/temperate zones is replaced by coral reefs in tropical regions. This section briefly describes typical seashore habitats for marine organisms, with a focus on rocky/sediment shores and biogenic habitats, such as kelp forests, salt marshes, mangrove forests, seagrass beds, and coral reefs.