MB: Salt Marshes, seagrass meadows, mangroves

Salt marshes: habitat

• inter-tidal zones in temperate and sub-artic estuaries & sheltered coasts

Salt marshes: zonation (lower and upper boundary)

zonation: distinct plant zones, each dominated by a grass species

• Lower boundary: determined by physiological stress (salinity & flooding)

• Upper boundary: determined by competition among species

Salt marshes: ecosystem roles

• capture and bind sediment flowing off the land

• convert dissolved nutrients into particulate organic materials

Salt marshes: Plant traits

• dominant grasses that propagate clonally via rhizomes

Salt marshes: Consumers

• terrestrial: These organisms live and consume food on dry land (deer)

• aerial: These are animals that spend a significant portion of their lives foraging in the air (birds)

• marine consumers: This category includes organisms that live and feed in ocean or other aquatic environments. Their ecosystems are primarily driven by tiny photosynthetic organisms called phytoplankton. 

Seagrass Meadows: Habitat

• shallow subtidal waters

• temperate and tropical

Seagrass Meadows: Vegetation

• vegetation: few species of true “grasses” live intermingled with each other and macro-algae

• flowering plants with leaves, roots, and rhizomes that form dense, underwater meadows in shallow coastal waters

Seagrass Meadows: Features (zonation, propagation)

• no strict zonation pattern

• Blades are often covered with epiphytes (primarily microalgae)- these epiphytes live directly on the seagrass surface increasing the surface area available for them to grow and obtain nutrients and sunlight. 

• propagation occurs clonally through rhizomes

Seagrass Meadows: ecological issues

0 long and straggly blades are a problematic result of the loss of large herbivores such as green turtles, manatees, and dugongs

Mangroves: Habitat

• intertidal

• tropical and subtropical regions

Mangroves: zonation

• distinct zones, each dominated by single mangrove species

Mangroves: reproduction

• Non-clonal: each new tree arises from a seed

• Vivipary: seeds germinate while still attached to the mother tree

trees- that do not propagate clonally; each needs to sprout from a seed, and the seeds sprout while still on the mother tree

Mangroves: Prop roots

• prop roots are heavily epiphytized, with an extremely species-rich community of invertebrates and plants

• sponges on the roots can protect them from boring crustaceans that can cause death of the trees

Common features across all three ecosystems dominated by vascular plants (7)

1. low species diversity of the structure providing plants

2. high species diversity of the organisms living among the structure providing plants (associated organisms)

3. high productivity

4. few organisms feed directly on the living plant parts

5. serve as sediment and nutrient filters from land runoff

6. important roles in the functioning of adjacent ecosystems: contributing food and shelter during hard times or for vulnerable juvenile life stages- serve as nursery habitats for juvenile marine life

7. under threat from human mismanagement- development, pollution, and habitat destruction