Dredging, Disposal Management and Impacts on Lake Sediments US Army Corps of Engineers.
Impacts of dredging on Seagrass
Transcript of Impacts of dredging on Seagrass
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