seagrass and mangroves

introduction to mangroves and seagrasses

• mangroves → describes both the ecosystem type and the group of woody plants

taxonomy

• tru mangroves found in high salinity waters

• mangrove associates

• divided into red, white, and black mangroves

• convergent evolution → evolved many times over

scales, types and driver of mangrove forests

• fringe

• basin

• riverine

• overwash

• climate:   

  • temerpature, precipitation storms

• relative sea level changes

  • sea level rise

  • subsidence

• hydrodynamics

  • inundation → how long they are submerged in tides

  • ………

seagrasses

• the only angiosperms that are submerged in seawater

• interesting sturcuture analogous to grass on terrestrial grasses

• gone from the sea, to the land, and back to the sea

what is the difference between seagrass and macro algae?

• sediment type: seagrass are in soft sediment and algae are on hard substrate

• seagrass help with wave breaking and sediment

• reproduction:

  • seagrass → can have sexual reproduction; have make and female plants

  • macro algae → uses spores and fragmentation

• macroalgae are more diverse compared to seagrasses

• macroalgae takes in nutrients from above groundd structure

• seagrasses does both through roots and above ground

seagrass distribution

• adapted to many different environmental conditions

• not in antarctica

physical and biological drivers

• knee roots

• pneumatophores

why this mangrove root architecture?

• salinity → the salinity is lesser in teh upper part of the water column

• requirement for oxygen → more easily accessible above the water surface

• providing additional structure during storm surges

  • prevents erosion/ dislodging between 

adaptations to physical environemtn

• zonation of species and root strateggies

seagrass root structures

• lacunar systems to trasnport oxygen

• seagrasses are known to be able to release oxygen in the sediments through their roots to create a small oxic zone

salt adaptations in amngroves

• salt exclusion (red mangrove)

• salt extrection glands

• shedding of salt accumulated leaves

• water conservation by waxy cuticle

salt adaptations in seagrasses

• cell wall remodelling

  • stronger cell walls combating the hugh salninty

• accumulation of organic osmolytes

• active ion trasnport (na+ comes in but is packed away)

• increase in antioxidants to counter damage

reproduction

mangrove

• flowering plants (some wind and some pollinated)

• vivipary through propagules (fully developed seedlings) (the offspring growing in the individual itslef)

• the seedlings drop into the water after some time and settle, and then grow root strucutres to grow into a full plant

• species, size, and shape specific in the seedlings

seagrass

• strucutre growing from the meristem 

• sexual reproduction

  • affects only 10% of the shoots

  • includes female and male plants to avoid self fertilisation

…………………….

what are hte pros and cons of putting a price tag on mangrove and sea grass ecosystems

• conservation of it, making it difficult to people to access

• if they have monetary values, then it makes it difficult for people to abuse/destroy the area

• protects people from erosion and storms

• what if there is too much seagrass meadows