Transcript FLORIDA COASTAL PRIMARY SUCCESSION

From sand and water to
Mangrove island formation
Rosa Whiting, MPH
FRESH WATER ECOSYSTEM:
Littoral zone - top zone, warmest, shallow and can absorb more of
the Sun’s heat. Many algae (like diatoms), rooted and floating plants,
snails, clams, insects, fishes, crustaceans, and amphibians, dragonflies,
midges, the egg and larvae stages are found here. Turtles, snakes, and
ducks find much food here!
MARINE ECOSYSTEM:
INTERTIDAL ZONE - submerged and exposed to waves and tides. Waves keep
mud and sand constantly moving, thus very few algae and plants can establish
themselves. The communities are constantly changing:
- upper area: algae and small animals, such as herbivorous snails, crabs, sea
stars, small fishes, worms, clams, crabs, shorebirds.
- bottom: exposed during the lowest tides, many invertebrates, fishes, and
seaweed; on sandier shores--not as stratified as in rocky areas.
Soil development in intertidal zones:
 Sand (particulates of shells and rocks) plus water
 Very little wave action
 Bacteria & protists that fill the water live, die, sink to bottom
of seabed
 Algae such as Grasselaria take root in the new “soil”
 Sea grasses can start living in areas when more nutrients are
available from organic material
 Eel/shoal grass (Syringonium)
 Manatee grass
 Turtle grass
 Mangroves begin to take root
 Red
 Black
 White
 Buttonbush
Primary marine coastal succession begins
with bare sand covered by shallow water.
Pioneer organisms begin to accumulate.
Microscopic
PIONEER ORGANISMS:
 Bacteria
 Protists – diatoms and dinoflagellates
Multicellular algae begins to take hold:
Phaeophyta
The brown algae are almost exclusively marine and are very
common in the coastal waters of Florida. Many are very large in size, as
the kelps of the Pacific coast. Brown algae have walls containing cellulose
and chloroplasts with chlorophylls a and c. They often store their sugars as
laminarin. The most common brown alga in South Florida is Sargasso
(Sargassum sp.), which is commonly left on our beaches after high tide.
Sargasso is very similar to the related Fucus, which is common to New
England coasts. Here is a diagram of Sargasso, showing the blades and
flotation bladders. The life cycle of Fucus is very similar to ours in that
the only haploid cells are the sexual gametes; it is almost identical to that
of Sargasso.
Sargasso
(Sargassum filipendula)
Here are some other brown algae, quite commonly seen on rock reefs and mangrove areas in south Florida.
Turbinaria
Stypopodium
Ectocarpus
Sea Grasses begin to grab a foothold:
Manatee grass (Syringodium filiforme)
Turtle grass (Thalassia testudinum)
Eel or Shoal grass (Halodule wrightii)
Widgeon grass (Ruppia
maritima) grows in both
fresh and salt water and is
widely distributed
throughout Florida's
estuaries in less saline
areas, particularly in inlets
along the Florida east
coast.
Mangroves arrive in succession:
 Red: has prop roots (drop roots)
 Black: has snorkel roots (pneumatospores); filter
salt
 White: has 2 salt glands at base of leaf
 Buttonbush – we do not have around here
Red mangrove seeds float, already
sprouted and ready to take root!
Red Mangrove - Rhizophora mangle
Black Mangroves have snorkel
roots or pneumatophores:
Black Mangrove –
Avicennia germinans
White mangrove: smallest seed,
last to inhabit a new area
Two salt glands at base
of leaf
White Mangrove –
Laguncularia racemosa
Propagule or seed
Buttonbush
Cephalanthus occidentalis