1. Marine
flowering plants

2. Flowering plants (Angiosperms)
250,000 species. Most are land plants (trees, flowers, shrubs, grasses etc)
Only three groups are adapted to life in coastal areas either totally or partially submerged:
Seagrasses
Mangroves
Salt-marsh plants

3. Seagrass bed
Salt-marsh
Mangroves

4. What are seagrasses? Seagrasses are not “true” grasses
Seagrasses are found totally submerged in shallow coastal waters
Seagrasses provide important habitat for marine organisms
55 different species of seagrasses worldwide
7 species off the coast of Florida

5. Seagrass communities provide habitat for a variety of marine animals.
Some animals feed directly on the plants while others feed on the variety of organisms that live on and among the seagrass
Large predators also visit the seagrass beds in search of prey

6. Classification of Seagrasses
Kingdom PLANTAE
Vascular Plants
Subclass Monocotyldoneae
Family Potamogtonaceae
Family Hydrocharitaceae
Manatee
grass
Turtle grass

7. Seagrasses have stems (rhizomes) which spread horizontally under the sediment.
Leaves and roots grow from the rhizomes and anchor the plant
Flowers are small and inconspicuous
Pollen often released in thread-like strands and transported by the water

8. Examples of Seagrass species
Turtle Grass (Thalassia testudinum)
Most common in Florida and Bahamas
Flat, ribbon-like blades with blunt tips
Blades up to 14 inches long and ½ inch wide

9. Turtle Grass (continued)
Turtle grass typically occurs from low tide level to a depth of 10m (33ft)
Typically found on sandy or rubble-covered bottoms
Name refers to green sea turtles that often graze on large fields of Thalassia

10. Manatee Grass (Syringodium filiforme)
Second most common seagrass in Florida and Bahamas
Blades up to 20 inches long and cylindrical
Roots barely below the substrate
Favorite food of manatee

11. Star Grass (Halophila engelmanni)
Found on sandy or muddy bottoms up to 130 ft deep
Leaves in “star-like” whorl
blades have distinct midribs and veins and fine tooth edges

12. Eel Grass (Zostera marina)
Most widely distributed
Found in shallow, well protected bays and estuaries of cooler North Atlantic and Pacific

13. Zonation and Distribution
Zonation determined by:
Salinity
Light
Air exposure

14. 55 species worldwide
Over half of these off Australia
The most extensive seagrass community in the world is off
South Florida

15. Seagrasses provide: Sediment stabilization Water Clarity
Productivity and Shelter

16. Seagrasses stabilize sediments and prevent erosion
Seagrasses take up dissolved nutrients and trap sediments resulting in high water clarity
The leaves cut down on wave action and decrease turbulence causing fine sediment to be deposited

17. Productivity
Seagrass areas are the most productive communities in the ocean
Herbivores – feed directly on the seagrass
Infauna – organisms that live in the sediment of the seagrass area
Epiphytes – organisms that live on the blades of the seagrass
Epifauna (epibethic organisms)-organisms that live on the surface of the bottom sediments

18. Sea anemone in the turtle grass
Epiphyte on the turtle
grass

19. Queen Conchs in Turtle grass

20. Sea urchin epifauna
Sea cucumber epifauna

21. Lobsters hiding in the seagrass

22. Seagrass beds provide nursery
areas and feeding grounds for
many species of reef fish