Marine In terms of nutrient availability the phototic zone is typically ______________ Below the photoic zone in a body of water is a zone which is At the base of most marine ecosystems are Which of the following is the most common coastal wetland in the tropics? Mangrove swamps are important as _______________________________ The density of seawater increases when _______________________________________ In terms of area, oceans cover approximately ___________ % of the earth’s surface. Gyres in the northern hemispheres tend to move oceanic water is a _________________ direction. The area at the mouth of a river where salt and freshwater mix is termed an _____________ In temperate regions the mudflats of an estuary may be populated by what plants? Eel grass is important in what aspect of an estuary? What ecosystem functions do estuaries serve? Some issues associated with ecological integrity of an estuary may include ______________