This is a picture of water grasses. They are an example of a littoral zone organism. The littoral zone is the part of a body of water closest to the shore. There is actually not a concrete definition of the limits of the littoral zone - different scientists and organizations have their own definitions. However, it is usually defined as either between the high and low tide marks in the ocean, or the part of a non-tidal body of water shallow enough for plants at the bottom to undergo photosynthesis. Littoral zone organisms are organisms that live/grow in the littoral zone, like the marsh grasses pictured.