John Booker

Program Director at SeaCamp /Newfound Harbor Marine Institute on Big Pine Key, FL.

The majority of nearshore waters within Monroe County are less than 2.5 meters deep. Because sunlight can penetrate to the bottom, life abounds in these shallow waters. The plant and animal life in these waters must cope with a wide variety of environmental fluctuations. Air temperatures and sunlight may radically alter water temperature in localized areas. Rain, storm runoff and evaporation can dramatically change salinities in restricted bays and channels. Wind speed and direction and tidal currents can stir up sediments, which in turn decrease light penetration necessary for photosynthesis. All organisms that live in this changing soup of the shallow waters must be adapted to survive these constantly fluctuating conditions.

As one walks from shore into the sea, differences in bottom type and bottom communities are apparent. Inshore, wave action and currents do not permit sediment buildup (this may also be true anywhere fast currents sweep the bottom), and the limestone rock that forms the Keys is evident. This is termed hardbottom, and is an ecological niche for specific life forms. As one progresses farther towards the sea (or bay), a thin sediment bottom (sediments from 2-10 cm) becomes evident, complete with its own mixed algae communities. As sands and silts become deeper (more than 10 cm), a thick sediment bottom emerges that supports a variety of seagrasses.