| Bathymetrically, the environment can be subdivided into four distinct levels: supralittoral, intertidal, infralittoral and circalittoral. |
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| The supralittoral is above the high-tide mark and is usually not under water. |
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| The psammon here means the hygrophilous fauna of the moist sand in supralittoral and above the coastal groundwater. |
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| They build burrows in the supralittoral, from the water level up to the hillside dunes. |
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| The influence of environmental stimuli on the direction of movement of the supralittoral gastropod Littorina irrorata. |
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| Transects extended from the supralittoral to the sublittoral zones to allow all macroalgac present to be sampled. |
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| These three subregions are called, in order, the supralittoral zone, the eulittoral zone and the sublittoral zone. |
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| Some types of periwinkles, Neritidae and detritus feeding Isopoda commonly inhabit the lower supralittoral. |
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| The main habitats for aquatic fauna in the supralittoral level are the small islands and islets distributed along the south shore and along the middle of the estuary. |
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