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You can make a habitat suitability map without presence or absence

• Species Distribution map needs those

Coral Bleaching

• healthy coral → algae and coral depend on each other

• stressed coral → algae leaves coral when stressed

• bleached coral → coral is left vulnerable

Seagrass Beds

3 major seagrass species (in Florida)

• Turtle grass, shoal grass, manatee grass

• Porifera (sponges)

• Cnidaria

  • crabs, shrimp, lobster

• Mollusca

  • Gastropods, cephalopods, bivalves, chitons

• Echindodermata

  • Sea stars, sea cucumbers, urchins

• Fishes

  • rays, snappers, groupers, grunts

What is seagrass

• seagrass have a root system, hidden beneath the sediment just like most terrestrial plants

  • produce flowers

  • most are fertilized by undersea pollen, linked by water movement

• asexual growth - shoot (leaf) extends towards sunlight

  • growth can be relatively rapid

  • beds can extend for miles

• evolved from land plants back to oceans 75-100 mya

seagrass - distribution

• not just tropical, highest diversity and biomass is in tropical latitudes

  • with excepts - north sea

• 20-40 ppt salinity

• generally occur on seascape with low (or no) slope

• mostly 1-3 m depth

  • deepest 58 m (a euryhaline, mesophotic species)

• distributions of organisms can’t ignore tectonic history

To survive in a marine environment, a plant must deal with":

• sargassum (algae) blooms

• light attenuation and variability

• high wave energy

• anoxia in sediment, and slow diffusion of O2 in water column

• accumulation of toxic levels of sulfides, other compounds in sediment due to anaerobic activity in sediment

any other plant would die in these conditions

Adaptations

• root system

  • belowground roots and rhizomes up to 60% of seagrass biomass

  • stabilize sediment and lets shoot go with the flow

• diffusion

  • no stomata, but porous cuticle to draw in O2 from water and send to roots thru lacunae

• mutualism between fungal rhizome, bacteria, and the plant

  • highly efficient nutrient sequestration and O2 transport; protection against sulfides

• efficient photosynthesis

  • high rates during peak sunlight; aerenchyma acts like straws to deliver O2 to roots

blue carbon (marine environments that sequester carbon)

• seagrasses (both tropical and temperate) globally sequester carbon up to 35x faster than tropical rainforests

  • account for up to 10% of oceans blue carbon

• a massive and critical carbon sink in the 21st century

Further importance of seagrass

• sentinel species for degradation

  • environmental indicators of pollution and stressors

• filtration

  • filter pollutants (to a degree)

  • trap sediment, absorb nutrients and pathogens

• harbor endangered species

  • queen conch

  • larvae of Caribbean spiny lobster

  • very important fisheries

Entire worlds nested within the meadow

• lucinid bivalves enjoy full life cycles tied to seagrass meadows

  • live in the sediment-root-rhizome matrix

  • living in likely mutualism with seagrass

    • bivalve remove sulfides from pore water

    • seagrass provides habitat and O2

Mangroves

• 3 major species

  • red mangrove (pioneer species) early succession in barren habitat

  • black mangrove

  • white mangrove

• mostly the same phyla found in seagrasses

• upside down jellyfish

• special flowering plants

  • some of the only ones in the world to produce live young

  • seeds germinate on the parent plant, then drop off and disperse

• obligate halophytes

  • require saltwater, but can tolerate freshwater

• have clear zonation (white → black → red (inland→ocean))

Function

• Nurseries for a range of fishes

  • snappers, grunts grow here and find plentiful food during the vulnerable early life stages

• massive storm surge reduction thru root systems