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TL PhD Comprehensive Exam
  • Introduction
  • Tasklist
  • 1. Basics
    • 1.1 Basic Biology Review
    • 1.2 Basic Genetics Review
    • 1.3 Light & Photosynthesis
  • 2. Coral Biology
    • 2.1 Basic Coral Biology
      • 2.1a Food Webs
    • 2.2 Reef Structure
    • 2.3 Growth & Reproduction
    • 2.4 Morphology
    • 2.5 Physiology
    • 2.6 Mixotrophy & Energy
    • 2.7 Symbiosis
    • 2.8 Reef Mortality
      • 2.8a Conservation
  • 3. Ecology & Evolution
    • 3.1 Evolution & Plasticity
    • 3.2 General Ecology
    • 3.3 Species
    • 3.4 Cryptic Species
  • 4. Isotopes
    • 4.1 Isotope Basics
      • 4.1a Instrumentation & methodology
      • 4.1b Environmental O & H
      • 4.1c Environmental C and N
      • 4.1d Organismal Isotopes
    • 4.2 Fractionation in Corals
    • 4.3 Trophic Niche Analysis
    • 4.4 CSIA
      • 4.4a C: Essential vs. Nonessential
      • 4.4b N: Trophic vs. Source
  • 5. Other
    • 5.1 Science & Society
    • 5.2 Stats
  • 6. Summary & Resources
    • 6.1 Glossary
    • 6.2 Resources
    • 6.3 Questions From Exam
    • 6.4 Recommendations & Reflections
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  • Process of Reef Growth
  • Sexual Reproduction
  • References
  1. 2. Coral Biology

2.3 Growth & Reproduction

Last updated 1 year ago

Process of Reef Growth

  • Growth is affected by light intensity, water motion, depth, turbidity, day length, water temp, plankton concentration, predation, competition

Fragmentation

  • storms and waves can commonly break coral colonies, causing genetically identical copies of a colony

  • often contributes to single-species domination of an area

  • rapid recolonization after a disturbance

Skeletal growth

  • growth rate determined by skeleton density

  • Average growth 1mm upward and 8mm horizontally per year (marine life book)

  • depends on balance of deposition and removal of CaCO3

    • contributions form calcareous algae, colonial hydrozoans, skeletons of crustaceans, bryozoans, foraminifera, mollusks, echinoderms.

    • loss of CaCO3 can be caused by grazing/scraping urchins & fish, or etchers (bacteria, fungi, algae) that penetrate skeletons. Infaunal organisms (sponges, bivalves, worms) bore holes into skeletons.

Sexual Reproduction

  • strategy linked to taxonomy

  • Dioecious - only producing male or female gametes

  • hermaphroditic - possessing both male and female sex organs

Brooders

  • eggs remain in gastrovascular cavity where they are fertilized by motile sperm cells. developing zygotes are eventually released to settle nearby

  • commonly small-polyped species

Spawners

  • millions of gametes released into water column for external fertilization

  • commonly large-polyped species

Mass spawning events

  • induced by specific dark periods & the cycle of the moon

  • seasonality driven by temperatures

  • multi-speceis spawning may satiate predators by overwhelming them with food

Larvae & recruitment

  • planula larvae - at first they swim towards brighter light (stay at surface where currents can facilitate dispersal), then after some development they swim away from light to settle on sea floor

  • Single-polyp recruits metamorphose into a juveline byt developing a CaCO3 skeleton, mouth and tentacles

  • Develop to maturity in 7-10 years

References

Harriott 1983

Reproductive ecology of four scleractinian species. Describes patterns of coral reproduction. Histology.

See section for all growth papers

Asexual budding
Polyp Bailout
Morphology