Marine Ecology Coral reefs. Global distribution of coral reefs.
Coral Reefs
-
Upload
mackensie-marks -
Category
Documents
-
view
24 -
download
1
description
Transcript of Coral Reefs
Kingdom AnimaliaPhylum Cnideria
Class Hydrozoa- hydroidsClass Scyphozoa- jelliesClass Cubozoa- box jelliesClass Anthozoa- corals and anemones
Hermatypic corals:• possess zooxanthellae• are reef builders
Light: Clear water Warm temperature: 18-32oCLow nutrientsLow productivity in water
Ahermatypic corals:• no zooxanthellae• rely on tentacular feeding• can live in aphotic zone
Cauliflower coral(Pocillopora meandrina)
6 m
0 m
25 m
13 m
Lobe coral(Porites lobata)
Finger coral(Porites compressa)
Plate coral(Porites rus)
High light levelsModerate wave energy
Moderate light levelsOccasional storm wave energy
Low light levelsLow wave energy
Very low light, Primarily downwelling No wave energy
“True” Stony CoralsHermatypic- reef building, zooxanthellae
Common species:• Acroporidae- table• Acroporidea- rice • Agariciidae- flat lobe, corregated• Faviidae- crust, ocellated• Fungiidae- humpback, mushroom• Pocilloporidae- lace, antler, cauliflower• Poritidae- finger, lobe, plate
Family PocilloporidaeLace coral, antler coral, and cauliflower coral
Pocillopora damicornis
lace
Pocillopora eydouxi
antler
Pocillopora meaandrina
cauliflower
Family Acroporidae
Table coral, rice coral and spreading coral
Montipora flabellata Montipora patula
rice coral
Montipora capitata Acropora cytheria
table
Family Poritidae
Finger coral, lobe coral, Evermann’s coral, plate and pillar coral
Porites evermanni
Porites rus Porites compressa
Porites lobata
Family Agariciidae
flat lobe coral, corrugated coral
Pavona duerdeni
Pavona varians
Flat lobe
corrugated
Family Faviidaecrust coral, ocellated coral
Cyphastrae ocellina
Leptastrea bottae
Leptastrea purpurea
• Octocorals, wire corals, black corals, sea pens
• Both hard and soft forms exist• non reef-building• no photosynthesis
Ahermatypic Corals
Heterotrophic NutritionHeterotrophic Nutrition
General feeding modes:1. predaceous carnivores capturing live
prey2. detritus feeding3. absorption of dissolved organic
matter from surrounding water
Photosynthesis
6H2O + 6CO2 + light C6H12O6 + 6O26H2O + 6CO2 + light C6H12O6 + 6O2
Autotrophic NutritionAutotrophic Nutrition
Benefits to the Algal Symbiont
• Zooxanthellae gets a place to live
• Receive chemical wastes from animal metabolism (CO2 & NH3).
• Surrounding animal tissues can concentration substantial amounts of ultraviolet light absorbing compounds.
Benefits to the Coral Host• Higher rates of calcification (skeleton
deposition).• Receive DOM & O2 • Removal of chemical wastes from
animal metabolism (CO2 & NH3).• Receive chemicals that absorb
damaging ultraviolet light (Micosporine-like amino acids (MAAs)).
Asexual Reproduction
• budding and fissionbudding and fission• accidental fragmentationaccidental fragmentation• nonaccidental fragmentationnonaccidental fragmentation• partial colony mortalitypartial colony mortality• polyp bail-outpolyp bail-out
Nonaccidental Fragmentation
Radial Division in Radial Division in Cycloseris fragilisCycloseris fragilis
Nonaccidental Fragmentation
Transverse Division in Transverse Division in Fungia scutariaFungia scutaria
anthocaulusanthocaulus
anthocyathusanthocyathus
Nonaccidental Fragmentation
Transverse Division in Transverse Division in Fungia scutariaFungia scutaria
stalk regenerates new disk
Partial Colony MortalityThe Phoenix EffectThe Phoenix Effect
in in Porites compressaPorites compressa
P. JokielP. JokielP. JokielP. Jokiel Cut surface of a broken finger showing living tissue beneath the surface of the skeletonNormal colony next to
a colony exposed to freshwater
Sexuality
Acropora sp., a hermaphoditic coralAcropora sp., a hermaphoditic coral
Fungia scutaria, a gonochoric coralFungia scutaria, a gonochoric coral
eggseggs
sperm packetsperm packet
egg cloudegg cloud
Hermaphroditism: sexes in same individualGonochoric: separate sexes
Brooding Versus Broadcast Spawning
BroodingBroodingeggs develop to planula stage in gastrovascular eggs develop to planula stage in gastrovascular cavity of parent polypcavity of parent polyp
Broadcast SpawningBroadcast Spawningeggs and sperm are shed into the water column eggs and sperm are shed into the water column where fertilization and development occurswhere fertilization and development occurs
BroodingBroodingeggs develop to planula stage in gastrovascular eggs develop to planula stage in gastrovascular cavity of parent polypcavity of parent polyp
Broadcast SpawningBroadcast Spawningeggs and sperm are shed into the water column eggs and sperm are shed into the water column where fertilization and development occurswhere fertilization and development occurs
broadcast spawnerbroadcast spawnerPocillopora damicornis, a brooderPocillopora damicornis, a brooder
planula in polypplanula in polyp
released gametesreleased gametesD. GulkoD. Gulko
Environmental Factors Affecting Corals
Environmental Factors Affecting Corals
• Water Motion
• Depth: photic vs aphotic zone & water motion
• Sedimentation
• Salinity: 32-35o/oo
• Temperature: 18-32 oC
• Tidal fluctuations
• Nutrients: Eutrophic vs oligotrophic
• Water Motion
• Depth: photic vs aphotic zone & water motion
• Sedimentation
• Salinity: 32-35o/oo
• Temperature: 18-32 oC
• Tidal fluctuations
• Nutrients: Eutrophic vs oligotrophic
Coral reefs presently exist on every island and shallow bank in the Hawaiian chain
Fringing Reef- 100-1000 years to form youngest is on west coast of Hawaii
Barrier Reef- 2.5 ma to form Kaneohe & Moanalu Bay
Atoll- 10 ma to formfirst atoll French Frigate Shoals, dated 11.7 mya
Coral reef growth limited by:• wave exposure• sea level
Sheltered sites:Hanauma Bay and Kaneohe BayReef accretion ~ 2mm/yr
Wave exposed sites:Mamala Bay and Sunset BeachReef accretion ~ 0 mm/yr shallow (1m) and deep (12m)
Environmental Factors Affecting Corals
Environmental Factors Affecting Corals
• Water Motion
• Depth: photic vs aphotic zone & water motion
• Sedimentation
• Salinity: 32-35o/oo
• Temperature: 18-32 oC
• Tidal fluctuations
• Nutrients: Eutrophic vs oligotrophic
• Water Motion
• Depth: photic vs aphotic zone & water motion
• Sedimentation
• Salinity: 32-35o/oo
• Temperature: 18-32 oC
• Tidal fluctuations
• Nutrients: Eutrophic vs oligotrophic
Coral Reefs:Threats
Starfish: “crown of thorns” (why?)
Coral is a source of building materials
Pollution: particles in the water
Human impacts on coral includes:
• Aquarium/Souvenir Trade• Overfishing• Pollution• Dredging• Coastal Development• Tourism• Global Climate Change• Ozone Depletion
Coral Reefs: Human Impact
Worldwide disappearance
Fishing with explosives
Waste oil dumping
Sediments
Philippines: 75% of the reefs damaged
Acid Rain in Marine EnvironmentAcid Rain in Marine Environment
• reduces ability of marine organisms to utilize calcium carbonate
• Coral calcification rate reduced 15-20%
• Skeletal density decreased, branches thinner