I. Flowering Plants (Anthophyta)

• Few truly marine species• Seagrasses entirely submerged most of the time; other

marine angiosperms intolerant of prolonged immersion

• Secondary “invaders” of marine ecosystems• Expend considerable energy coping with effects of

salt waterA. Seagrasses (66 species)

• Monocots• Not true grasses (related to lilies)• Hydrophytes (usually immersed)• Roots, stems and shoots grow from horizontal rhizome• Flowers typically small and inconspicuous (Why?)

• Pollen carried by water currents (hydrophilous pollination); No need to attract pollinators

• Highest diversity in Indo-West Pacific (lowest in Atlantic)

Fig. 7-15

- Lacunae: Gas transport and buoyancy- Nodes: Growth and lateral branching- Sheath: Protects base of blade- Roots: Root hairs for absorption of minerals

Fig. 7-17

Aerenchyme- Gas transport- Buoyancy

- Liquid not transported bylacunae

Eelgrass (Zostera marina)

Surf Grass (Phyllospadix scouleri)

Turtle Grass (Thalassia species)

Manatee GrassSyringodium filiformeFig. 7-16

Paddle GrassHalophila sp.Fig. 7-16

Leaves in pairs

Leaves cylindrical

I. Flowering Plants (Anthophyta)

A. Seagrasses• Leaves – periods of growth & senescence

• Small blades/rapid senescence few epiphytes• Large blades/slow senescence more epiphytes

• Relatively weak attachment of leaves• Protects rhizome from breakage• Facilitates recovery following damage from storms, grazing

• Important in sediment deposition, stabilization• Enhance deposition of fine particles• Reduce flow, resuspension of sediment

• Support diverse ecosystem• Many species inhabit seagrass beds• Below sediment-water interface: rhizosphere• Symbiotic associations with lucinid clams (Zostera)

• Roots oxygenate sediments• Clams oxidize sulfide (van der Heide et al. 2012)

I. Flowering Plants (Anthophyta)

B. Salt Marsh Plants• Facultative halophytes• Shallow roots and rhizomes

• Stabilize soils and sediments (esp. grasses & rushes)• Cycle nutrients (esp. phosphorus)• Food for terrestrial animals

1. Cordgrass (Spartina)• Salt-tolerant true grass• Salt glands in leaves excrete excess salts• Inhabit temperate soft-bottom coastal areas• Important sources of

• Detritus for estuarine food webs • Habitat for birds, fishes, etc.

• Primarily propagate vegetatively

backbaybirds.com

Fig. 7-21

Fig. 7-19

Cordgrass (Spartina alterniflora)

I. Flowering Plants (Anthophyta)

B. Salt Marsh Plants2. Needlerushes

3. Saltworts

4. Glassworts• Succulent leaves, cuticle help to retain water• Pickleweed (Salicornia)

• Occurs at higher levels in marsh with less inundation by salt water

• Edible (sea beans)

Fig. 7-20

Needlerush (Juncus) Saltwort (Batis)

Pickleweed (Salicornia) Glasswort (Sarcocornia)

I. Flowering Plants (Anthophyta)

C. Mangroves• Salt tolerant shrubs, trees, palms, ferns (54+ species)• Tropical terrestrial plants living in protected areas with

soft sediments, often organic-rich, anoxic• Poor competitors

• All share certain characteristics• Shallow, broad root system and aerial roots with

pneumatophores (pores for gas exchange)• Salt tolerance (halophytes)

• Salt exclusion at roots• Tough, succulent leaves: thick cuticle, reduced stomata,

storage of water & salt, senesce• Salt glands: excrete excess salt

• Viviparity (mainly seaward spp.)• Embryo grows on parent plant propagule• Hypocotyl develops, buoyant after separation from

parent (red mangroves)

Avicennia germinanseolspecies.lifedesks.org

RedMangrove

Fig. 7-24

Red mangrove- Propagules w/hypocotyl

Black mangrove- Propagules

White mangrove- Floating seeds

Buttonwood- Floating seeds

I. Flowering Plants (Anthophyta)

C. Mangroves• Root systems designed for immersion in soft,

anoxic sediments• Mostly horizontal, shallow• Pores for gas exchange

Fig. 7-22

Red mangrove

Black mangrove

Fig. 7-23

Red mangrove- Prop root

Black mangrove- Cable root

I. Flowering Plants (Anthophyta)

C. Mangroves• Mangrove forests = mangals

• Broad distribution in tropics• Co-occur with coral reefs but more tolerant of

temperature extremes than hermatypic corals and occur over a wider geographic range

• Maximum diversity in Indo-West Pacific• Some mangals may contain up to 30 species• Ten species in New World, three in Florida

Fig. 14-19

I. Flowering Plants (Anthophyta)

C. Mangroves• Mangrove forests (mangals)

• Extremely productive systems• High levels of solar radiation, efficient nutrient

recycling• Provide important habitat for many spp., including

larval and juvenile life stages• Protect shorelines against erosion and wave action• Create new land

• Ex: Marco Polo visited port city of Palembang (Sumatra) in 1292 when city was directly on coast- As of 1967, Palembang was 50 km inland, a land accumulation rate of 73 m y-1 over 675 y

• Ex: Java - Accumulation rates of ca. 200 m y-1 have been reported from Bodri Delta of east Java

I. Flowering Plants (Anthophyta)

C. Mangroves• Mangrove forests (mangals)

• Horizontal zonation: Transition from terrestrial to marine conditions• Onshore-offshore zonation of mangroves also

may represent stages in succession from offshore “pioneer zone” with early successional stages to later successional stages onshore

I. Flowering Plants (Anthophyta)

C. Mangroves• Mangrove forests (mangals)

• Vertical zonation: Transition from canopy to subtidal• Above-water forest

- Arboreal habitat (birds, reptiles, insects,

crustaceans)

- Senescing leaves fuel detrital food web• Intertidal swamp

- Includes mud flats, community shifts with tides

- Mobile and sessile epibionts on/in stilt roots• Subtidal zone

- Burrowing fauna (worms, snails, shrimp, crabs)

- Important nursery grounds

Caroline Rogers

Fig. 14-24

Fig. 14-22

Mangrove Food Web