Dinoflagellates

The Dinoflagellates are a type of Phytoplankton. Phytoplankton are tiny floating plants that produce about half the worlds oxygen. Phytoplankton are also the bottom level of the aquatic food web. Dinoflagellates are photosynthetic which means that they are a yellow-green and sometimes even red. These photosynthetic Phytoplankton have 2 flagella which enable them to move more instead of just floating. Of the 2000 species of Dinoflagellates 60 species produce toxins that can be harmful to animals and humans. These phytoplankton are the cause of Red Tide. The toxins that they produce causes pfiesteria, which means death to anything that comes in contact with it. Dinoflagellates are not all bad, they are also mutualistic in corals.

http://cimt.ucsc.edu/habid/Diatom_Dino.html

Sea Turtles

Sea turtles are vertabrates of the Sandy Beach. They can grow up to 5ft long and range from 150-400 lbs. Sea Turtles start as a carnivorous animal eating crabs, mollusk, and shrimp, but as they mature they become herbivores. Unlike a regular turtle, a Sea Turtle cannot retract its head or flippers which make them vulnerable on land. Because of their vulnerability they usually only come on land, during the warmest months of the year, to nest. They nest during high tide using the front flippers to dig a nest that they then lay the eggs in. They will nest at the same beach each year.

Geological Interaction: Seaturtles usually stay in the water, but they use the beaches to nest.

Physical Interaction: Sea turtles use the high tides at night to come onshore to create nests and lay thier eggs.

http://www.seaworld.org/infobooks/seaturtle/home.html