Impacts Of Dredging On Sea grasses

Mohammed Al Eid 0910659

Contents What Is Sea Grass?

Where Is Sea Grass In The World?

Where Does Sea Grass Grow?

Types Of Sea Grasses And Their Location

What Are The Threats To Seagrass

Dredging

The Uses Of Dredging

The Impact Of Dredging On Environmentally And On Sea Grass.

Conclusion

What Is Sea Grass? Flowering plants adapted to

marine habitats. Ribbon-shaped leaves The only true flowering plants

that can live completely underwater.

Provide food and habitat for many creatures such as juvenile sea turtles, manatees, crabs, shrimp, and a variety of juvenile fishes.

Where Is Sea Grass In The World?

Seagrass beds cover less than 10% of the world's shallow coastal waters, but are important nursing grounds for commercial fish species

Greatest diversity: Indo-Pacific region

Located along the coast of all continents except Antarctica

Where Does Sea Grass Grow? Must be fully submerged

Require saltwater to grow

Thrive in warm temperatures: 20-30°C

Require light for photosynthesis

Grow in shallow, coastal waters

Root system needs a stable soft-bottom habitat

Types Of Sea Grasses And Their Location

widgeon grass

Johnson’s grass star grassmanatee grass

shoal grass Turtle grass Paddle grass

Location of Sea Grass Types

Turtle- Florida, Caribbean, Bermuda, area between Gulf of Mexico and Venezuela

Manatee- Florida, Bermuda, Bahamas, Gulf of Mexico, Caribbean Shoal- North Carolina, along the Atlantic, coast of Gulf of Mexico,

Caribbean Johnson’s- Indian River Lagoon Paddle- near Indian River Lagoon, Gulf of Mexico, Caribbean,

Indo-West Pacific Star- Florida, Bahamas, Texas, West Indies Widgeon- Atlantic coast (New Found land-Texas)

What Are The Threats To Seagrass Various human activities threaten the health of sea grass

ecosystems:

1. Pollution from agricultural and industrial sources.

2. Disposal of mining wastes.

3. Overfishing—disruption of ecological interactions.

4. Sediment movement from boat propellers.

5. Dredging of harbors, ports And shipping lanes.

Dredging Dredging is an excavation activity or operation usually carried

out in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location. This technique is often used to keep waterways navigable. It is also used as a way to replenish sand on some public beaches, is also used as a To establish and maintain navigation channels and harbors of sufficient size to accommodate shipping vessels.

The Uses Of Dredging Capital: dredging carried out to create a new harbor, berth or

waterway, or to deepen existing facilities in order to allow larger ships access

Construction - the removal of materials previously undisturbed to facilitate new navigation channels or water projects, e.g., locks and dams.

Maintenance - The periodic and repetitive removal of accumulated sediment from navigation channels and harbors to maintain authorized depths and widths

The Impact Of Dredging On Environmentally And On Sea Grass. Reduction in water clarity both from increased turbidity and increased nutrient

loading.

Physical removal or burial of the vegetation and the indirect effect of increasing sedimentation

Release of toxic chemicals (including heavy metals and PCB) from bottom sediments into the water column.

Short term increases in turbidity, which can affect the amount of light penetrate which affect aquatic species metabolism and interfere with spawning.

Dredging may affect the physical environment by changing the bathymetry, altering current velocities and wave conditions

Disturbance of the substratum

Possible contamination of dredge spoils sites

Changes to the topography by the creation of "spoil islands" from the accumulated spoil

Dredging could cause a Reduction of the dissolved oxygen

Conclusion