014 Coral Reefs

Coral Reef Biology

Kingdom Animalia Phylum Cnideria Class Hydrozoa- hydroids Class Scyphozoa- jellies Class Cubozoa- box jellies Class Anthozoa- corals and anemones

The Cnidarian Life Cycle The Hydrozoan Life Cycle

Class Hydrozoa Hydrozoan Colony

Hydrozoan Colonies “Stinging Limu”

Fire Coral

By-the-Wind-Sailor A Floating Colony of Polyps

Man-of-War Phylum Cnidaria Coloniality Man-of-War Phylum Cnidaria

Close Up of a Portuguese Man-Of-War

Class Scyphozoa

Class Cubozoa Box Jellies & Sea Wasps

Corals: true stony corals and octocorals Class Anthozoa Sea Anemones & Corals: true stony corals and octocorals

Sea Anemones

Sea Anemone Anatomy

Hermatypic corals: possess zooxanthellae are reef builders Light: Clear water Warm temperature: 18-32oC Low nutrients Low productivity in water Ahermatypic corals: no zooxanthellae rely on tentacular feeding can live in aphotic zone

Distribution of Coral Reef Communities

Hawaiian Coral Zonation 0 m High light levels Moderate wave energy 6 m Cauliflower coral (Pocillopora meandrina) Moderate light levels Occasional storm wave energy Lobe coral (Porites lobata) 13 m Low light levels Low wave energy Finger coral (Porites compressa) 25 m Very low light, Primarily downwelling No wave energy Plate coral (Porites rus)

“True” Stony Corals

“True” Stony Corals Hermatypic- 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 Pocilloporidae Lace coral, antler coral, and cauliflower coral Pocillopora damicornis antler cauliflower Pocillopora eydouxi Pocillopora meaandrina

Table coral, rice coral and spreading coral Family Acroporidae Table coral, rice coral and spreading coral rice coral Montipora patula Montipora flabellata table Acropora cytheria Montipora capitata

Family Poritidae Finger coral, lobe coral, Evermann’s coral, plate and pillar coral Porites evermanni Porites lobata Porites rus Porites compressa

flat lobe coral, corrugated coral Family Agariciidae flat lobe coral, corrugated coral corrugated Flat lobe Pavona duerdeni Pavona varians

Humpback coral, mushroom coral Family Fungiidae Humpback coral, mushroom coral mushroom Fungia scutaria

Family Faviidae crust coral, ocellated coral Leptastrea bottae Cyphastrae ocellina Leptastrea purpurea

A Solitary Coral Polyp

Colonial Coral Polyps

Zooxanthellae in Gastrodermal Cells of Corals

Zooxanthellae: Symbiodinium microadriacticum

Ahermatypic Corals Octocorals, wire corals, black corals, sea pens Both hard and soft forms exist non reef-building no photosynthesis

Ahermatypic Corals

Heterotrophic Nutrition General feeding modes: predaceous carnivores capturing live prey detritus feeding absorption of dissolved organic matter from surrounding water

Nematocyst Discharge

Autotrophic Nutrition Photosynthesis 6H2O + 6CO2 + light  C6H12O6 + 6O2

Zooxanthellae in Coral Polyp

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 fission accidental fragmentation nonaccidental fragmentation partial colony mortality polyp bail-out

Budding Polyp within calyx

Fission Polyp within calyx

Accidental Fragmentation Wave Damage

Nonaccidental Fragmentation Radial Division in Cycloseris fragilis

Nonaccidental Fragmentation Transverse Division in Fungia scutaria anthocyathus anthocaulus

Nonaccidental Fragmentation Transverse Division in Fungia scutaria stalk regenerates new disk

Partial Colony Mortality The Phoenix Effect in Porites compressa Cut surface of a broken finger showing living tissue beneath the surface of the skeleton P. Jokiel Normal colony next to a colony exposed to freshwater

Polyp Bail-Out D. Gulko

zygote planula larvae egg sperm Sexual Reproduction

Planula Larvae

Sexual Reproduction Hermaphroditic vs gonochoric Broadcast spawning vs brooding

Sexuality Hermaphroditism: sexes in same individual Gonochoric: separate sexes Acropora sp., a hermaphoditic coral Fungia scutaria, a gonochoric coral eggs egg cloud sperm packet

Brooding Versus Broadcast Spawning eggs develop to planula stage in gastrovascular cavity of parent polyp Broadcast Spawning eggs and sperm are shed into the water column where fertilization and development occurs D. Gulko released gametes planula in polyp Pocillopora damicornis, a brooder broadcast spawner

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

Hanauma Bay Mamala Bay Kaneohe Sunset Beach

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 form first atoll French Frigate Shoals, dated 11.7 mya

Hawaiian Island Chain Coral reef growth limited by: wave exposure sea level Sheltered sites: Hanauma Bay and Kaneohe Bay Reef accretion ~ 2mm/yr Wave exposed sites: Mamala Bay and Sunset Beach Reef accretion ~ 0 mm/yr shallow (1m) and deep (12m)

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

Oligotrophic vs Eutrophic                                        

Reef Critters coralivore

Coral Reefs: Threats Starfish: “crown of thorns” (why?) Coral is a source of building materials Pollution: particles in the water

Aquarium/Souvenir Trade Overfishing Pollution Dredging 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

Dynamiting Reef

Destructive Resource Extraction Practices

Toxic Chemical Spills

Sediment Plume Entering the Ocean

Corals Smothered in Sediment

Dredging

Coastal Development

Anchor Damage

Diver Damage

Ecotourism Pennekamp Reef, Key Largo, FL

Net Damage

Net Entanglement                                                                                                                     

Overfishing and Bycatch

Ornamental Trade: Fan worm Threadfin Butterfly fish

Introduced Species Acanthophora, Eucheuma, & Gracillaria

Feeding Fish

Hanauma Bay

Kaneohe Bay and Bubble algae

Nutrients and Algae Growth Dictyosphaeria cavernosa

Bleaching

Global Bleaching (2002) none low moderate severe severity unknown

Acid Rain in Marine Environment reduces ability of marine organisms to utilize calcium carbonate Coral calcification rate reduced 15-20% Skeletal density decreased, branches thinner

Sea Level Rise