Download presentation
Presentation is loading. Please wait.
Published byDorcas Wilcox Modified over 9 years ago
1
DescriptionDescription Coral ecology and symbiosisCoral ecology and symbiosis ThreatsThreats Class 38 CORAL REEF COMMUNITIES
2
Diverse and productiveDiverse and productive Thousands of invertebrate and vertebrate speciesThousands of invertebrate and vertebrate species “Rainforests” of the marine world“Rainforests” of the marine world
9
Coral Reef
10
Related to Jellyfish and Sea AnenomesRelated to Jellyfish and Sea Anenomes Colonies; individual polyps with tentaclesColonies; individual polyps with tentacles -predators and filter feeders. Coral animal -- dominant reef-builder
12
Individuals secrete supporting "cup" of CaCO 3 (grow up to 10 cm per year!) Variety of growth forms --Variety of growth forms -- massive, columnar, branching, etc. Coral animal -- dominant reef-builder
15
T: >18˚C…..23-25˚ is best --> mostly low latitude, mostly low latitude, < 30˚ N or S Environmental requirements of growing coral reefs: growing coral reefs:
16
T: >18˚C…..23-25˚ is best --> mostly low latitude, mostly low latitude, < 30˚ N or S Salinitycannot be low (e.g., near rivers) Depth: Photic zone only, cannot grow deeper than 50-150 m Clear water (little suspended sediment, phytoplankton) Environmental requirements of growing coral reefs: growing coral reefs:
17
Symbiotic algae provide much food Tentacles capture additional food Coral Nutrition
18
Zooxanthellae are dinoflagellates (photosynthesis)... give corals color (pink, purple, green)... corals grow only in photic zone Symbiosis: Zooxanthellae get from corals: constant, protected environmentconstant, protected environment source of CO 2 and nutrients (P, N)source of CO 2 and nutrients (P, N) Zooxanthellae give to corals: Food (sugars; they are not eaten)Food (sugars; they are not eaten) O 2O 2 Symbiotic zooxanthellae in corals
21
Types of coral reefs: Fringing reef -- borders shoreline Barrier reef -- further offshore, lagoon in between Atolls -- ring-shaped
27
1.Natural predators (e.g., crown of thorns star fish) Coral reefs in trouble
28
2. Human activities (nutrients, fishing, recreation) Coral reefs in trouble Cyanide Fishing
29
Coral ecosystems well suited for low nutrient levels (P and N) Nutrients can come from sewage and fertilizer Coral reefs and nutrients
30
Coral ecosystems well suited for low nutrient levels (P and N) Nutrients can come from sewage and fertilizer Increased nutrient levels allow other species to dominate (e.g., phytoplankton) Ecosystem changes, slow-growing corals can’t compete, or are attacked by disease Coral reefs and nutrients
31
3. Coral bleaching: zooxanthellae expelled Most common in unusually warm waters: >32˚C 2 degrees above normal maximum causes it Result of global warming? Coral reefs in trouble
32
Blue=low threat, yellow= med., red= high
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.