Coral reefs • One of the most biological diverse and productive ecosystem • Found in warm, clear and shallow tropical oceans • On CaCO3 substrate deposited by reef building corals (50% of all Ca deposit in the sea) and other calcified organisms. • Provide shelters and food to fish
Higher coral generic richness in Indo-Pacific (and accompanying fish diversity)
Figure 4. Analysis of factors influencing biodiversity of coral reefs, illustrated by the percent variation in taxonomic composition of fish and coral assemblages explained by habitat area, longitude, and latitude. (Bellwood & Hugh 2001, Science 292: 1532-1535)
Types of reefs: fringe, barrier, atolls Atolls “final stage of tropical island development” (Charles Darwin 1942, Structure and Development of Coral Reefs”)
Sandy flats dominated by Parchment worms (Chaetopterus spp.)
Brain corals With extended polyps
Coral Anatomy: mutualism between corals and Zooxanthellae algae
Mutualism between clown fish and sea anemone • Clown fish is coated with the same mucous as anemone. • Fish brings food. • Anemone protect fish.
Why is diversity so high in coral reefs and rain forest? • On nutrient poor water • High level of mutualism and symbiosis • High productivity and high rates of nutrient cycling • Finely divided niches • Control by herbivores and competitions?
Limestone outcrops in S. Florida: >10,000 yr old land rich in endemic Ca-loving herbaceous plants • Miami rock ridge & upper keys: Oolitic limestone, precipitated in sallow sea supersaturated with CaCO3 • Lower keys: coral origin
Florida geology: 140 yr old lime stone, 14,000-9,000 yr old corals to make the Keys
Florida marsh distribution • North: sink hole origin and untable. • Kissimmee river basin: where the land sagged slightly from dissolution of underlying limestone. • Lake Okeechobee: water dammed by the sedimentation in the southern rim. • Northern Everglades: river of grass, following the gradual elevational gradient to SW. • Southern Everglades: freshwater lens pushed up by the saltwater underneath.
Tropical estuary: • Sea grass beds • Mangroves, mudflat, marshes • Higher species diversity of mangroves and seagrass species in Asia-Australia (eastern group) than in America (western group).
Seagrasses of W. Australia Posidonia seagrass meadow in W. Australia
Seagrasses: flowering plants that returned to the sea • Origin: 100 m.y. BP., in Tethys Sea • 2 families: Potamogetonaceae & Hydrocharitaceae (NOT in grass family) • 58 species, 12 genera, mostly in tropical Asia-Australia. • Found mostly in shallow coastal water, salt marshes, and estuary.
Dinosaurs dominant, mammals evolving as subdominant.Angiosperm is rapidly increasing dominance, replacing ferns and gymnosperms. But, no tropical rain forest dominated by tall angiosperm trees yet.
Mangroves • 75% of tropical coast lines (water temp above 24 C) • 40 spp. in Eastern group, 8 spp in Western group. Convergent evolution in different families. • 3 spp. in Florida (red, black, and white) • Highly productive • Important habitat for costal animals
Mangrove biogeography ocean current and continental movement (Osborn Fig. 10.2)
Mangrove species in Indonesia (FAO World Atlas of Mangroves) Acanthus ebracteatus Acanthus ilicifolius Acrostichumaureum Acrostichumspeciosum Aegialitisannulata Aegicerascorniculatum Aegicerasfloridum Avicennia alba Avicennia marina Avicenniaofficinalis Avicenniarumphiana Bruguieracylindrica Bruguieraexaristata Bruguieragymnorrhiza Bruguierahainesii Bruguieraparviflora Bruguierasexangula Camptostemonphilippinensis Camptostemonschultzii Ceriopsdecandra Ceriopstagal Excoecariaagallocha Excoecariaindica Heritieraglobosa Heritieralittoralis Kandeliacandel Lumnitzeralittorea Lumnitzeraracemosa Nypafruticans Osborniaoctodonta Pemphisacidula Rhizophoraapiculata Rhizophoramucronata Rhizophorastylosa Rhizophoraxlamarckii Scyphiphorahyrophyllacea Sonneratia alba Sonneratiacaseolaris Sonneratiaovata Sonneratiaxgulngai Sonneratiaxurama Xylocarpusgranatum Xylocarpusmekongensis
Taller & species rich mangroves in Australia Rhizophora & Soneratia in Darwin Harbor, AU
Faunal zonation in mangrove and salt flat zones: Australia (Osborn Fig. 10.5)
New World mangroves Red = Rhizophora mangle (Rhizophoraceae) Black = Avicinia germinans (Rhizophoraceae) White = Laguncularia racemosa (Combretaceae) (http://www.floridaoceanographic.org/environ/mangrove1.htm) Often accompanied by: Conocarpus electus (Combretaceae) Pelliciera rhizophorae (Pellicieraceae) Acrostricum spp. (ferns)
Mangroves in Florida Red mangrove (Rhizophora mangle) Black mangrove (Avicenia germinans)
Mangroves in Florida White mangrove (Laguncularia racemosa) Acrostichum spp. (mangrove ferns)
Mangrove zonation: Florida Salt excluder Salt excreters
Physiological adaptation of mangroves • Salt management: • exclude (Rhisophora) • excrete (from salt glands in leaves, Avicinnia, Laguncularia) • tolerate (accumulate in vacuoles – not in FL) • Thick cuticles on leaves to tolerate desiccation • High tannin to prevent herbivory • Pneumatophores and lenticels to send oxygen to roots
Not all mangroves have (true) vivipary. Black mangrove (cryptovivipary) Red mangroves
Zonation mechanisms • Salt tolerance (frequency and duration of inundation, maximum salt concentration) • Ocean current’s force (especially during storms) • Competition • Seedling establishment
Mangroves in Mexico Destruction of mangroves for shrimp farming