1. Seagrass, Algae, and Coral Reefs
Shallow Seas
Seagrass, Algae, and Coral Reefs

2. Seagrass vs. Algae Seagrasses Algae Found in the plant kingdom
Have actual roots below the mud, transport tubes (xylem and phloem) for transporting nutrients and water around the plant
Algae
Found in Kingdom Protista
Can be multicellular or unicellular
Have structures to attach them to surfaces, but no underground root systems
No transport tubes

3. Seagrass Beds General Characteristics
The only flowering plants that live entirely in the sea

4. Growth of Seagrasses
Grow best in shallow, sandy areas with clear water, like lagoons or enclosed bays
Thrive in tropics
Tolerant of varying salinity levels

5. Structure Roots – (unlike seaweeds)
absorb nutrients from the sediments / mud and anchor the plant
This recycles nutrients that would otherwise be locked up below the surface
Underground Roots are intertwined, wrapped around each other
This helps Stabilize the sand and sediment of the ocean bottom
Protects from erosion
Encourages buildup of sediments
helps other species to gain a foothold in the shifting sand.

6. Structure Leaves Flower
Perform photosynthesis, providing the plant with a source of glucose
Flower
Structure for reproduction

7. Seagrass Bed Communities
Seagrass beds are highly complex
Attracts a high biodiversity of species that live and rely on them

8. Biodiversity in Seagrass Beds
Seaweeds (algae) grow on the leaves or fronds of the seagrasses

9. Biodiversity in Seagrass Beds
Sedentary organisms-
live on the grasses
Ascidians
Hydroids (sea lace)
bryozoans

10. Camoflauge in Seagrass Beds
Some animals live in seagrass beds their entire life, and have evolved to be adapted for it
Seahorses & seadragons
crabs

11. Seagrass Beds as Nurseries
Some species use seagrass beds to raise their young

12. Seagrass Beds as Food Sources
Some animals eat the seagrass plants
dugongs
manatees
Sea urchins

13. Algae – Kelp Forests

14. General Characteristics
Kelp refers to a type of brown seaweed
Kelp forests grow best in cold, nutrient-rich waters, extending into polar regions

15. Kelp Growth
Live attached to rocks in semi-shallow water, top edge of some kelp beds can be seen at the lowest tides.
Grow densely on rocks and rocky slopes down to around feet deep
Need light for photosynthesis
Can grow deeper in clearer water, but sparsely due to less light for photosynthesis

16. Kelp Structure: multilayered environment that different organisms live on
Holdfast- Instead of roots, kelp has a root-like anchor that helps keep the kelp to the rocky bottom
Frond- palm like leaf structure, One stipe, with pneumatocysts (gas bladder) and blades, make up a single frond.
Blade- like a leaf. It extends horizontally in the water to get sunlight for photosynthesis
Gas Bladder- floats on the stem; Gas-filled sections of the stipe, called pneumatocysts, help keep the kelp upright and oriented towards the surface
Stipe-stem or trunk, transports nutrients to the holdfast below and the blades above.

17. Kelp Communities: within the kelp forests the water is calmer
Supports rich marine communities
Used mostly as shelter
Only about 10% of kelp is eaten directly
The rest enters the food chain as detritus or dissolved organic matter.

18. Holdfast Habitats
Small animals hide from predators in the small spaces of the holdfast
Sea urchins and limpets found grazing on the ocean bottom, on the red seaweeds growing on the kelp in deeper water

19. Frond Habitats
Actively growing kelp Fronds are coated in slime for protection from being eaten
as growth slows later in the season, the fronds may become covered with bryozoans, hydroids, and tube worms.
Some species grow or live on the fronds
Reduce the light reaching the fronds for photosynthesis
Kelp shed their fronds to get rid of the pests
sea floor beneath the kelp may be covered with marine growth, or relatively barren if heavily grazed by sea urchins
Bryozoans
Hydroids
Tube worms

20. Seagrass and Kelp Nurseries
Seagrass beds and kelp forests are important refuges for young fish that need to hide from predators until they reach maturity.
Many fish do not live among seagrasses or kelps as adults, but come into these habitats to spawn, giving their young a greater chance at survival.

21. Seagrass and Kelp Nurseries
Small fish find an abundance of small prey in the form of tiny worms, crustaceans, and mollusks among the seagrasses and in the sediment beneath.
These young fish are often camouflaged in shades of green and brown to avoid detection.

22. Seagrass and Kelp Nurseries
Some herbivorous fish from surrounding reefs come into seagrass beds only at night.
Seagrass beds are important nurseries for some commercial invertebrates, including shrimp and cuttlefish
Many young fish are camouflaged for this environment, and look completely different than the adults