MARS2014 Lecture Notes - Lecture 9: Coralline Algae, Trophic Cascade, Red Algae
Friday, 9 March 2018
MARS2014- Week 3 Lecture 3
Costal Systems- Coral Reefs
-Australian kelp in decline- decrease in temperature, increased sea urchin grazing
through trophic cascade, over-harvesting, decrease in dissolved water nutrients, run-
off
-Shallow coral reefs- highly diverse, confined to tropical latitudes, exist in nutrient
deserts, highly productive
-Coral reefs- made of calcium carbonate, 3 zones (inner reef flat, reef crest, outer/fore
reef), reduce 90% of wave force onto the shore, cemented together by things such as
coralline algae and Rhodophyta, cemented through physical/chemical production of
CaCO3 cements, have symbiosis with Zooxanthellae
-Zooxanthellae- symbiotic dinoflagellates, have no cellulose/ornamentation, supply
carbon to host while receiving essential nutrients from host (e.g. ammonia,
phosphorus)
- Photosynthesis and calcification are linked processes in coral reefs- calcification
occurs in the calcification fluid
-Answer to Darwin's paradox is symbiosis
-Algal turfs- take over dead corals/coral skeletons, some of the most productive turfs,
fixing CO2
-Microphytobenthos are graziers- e.g. chitons, holothurians, snails, etc…
-Beggers Banquet- P to R ratio is at 1
-Coral bleaching- when corals loose their symbiotic dinoflagellates, response to
warmed water
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Document Summary
Australian kelp in decline- decrease in temperature, increased sea urchin grazing through trophic cascade, over-harvesting, decrease in dissolved water nutrients, run- off. Shallow coral reefs- highly diverse, con ned to tropical latitudes, exist in nutrient deserts, highly productive. Coral reefs- made of calcium carbonate, 3 zones (inner reef at, reef crest, outer/fore reef), reduce 90% of wave force onto the shore, cemented together by things such as coralline algae and rhodophyta, cemented through physical/chemical production of. Zooxanthellae- symbiotic dino agellates, have no cellulose/ornamentation, supply carbon to host while receiving essential nutrients from host (e. g. ammonia, phosphorus) Photosynthesis and calci cation are linked processes in coral reefs- calci cation occurs in the calci cation uid. Algal turfs- take over dead corals/coral skeletons, some of the most productive turfs, Microphytobenthos are graziers- e. g. chitons, holothurians, snails, etc . Beggers banquet- p to r ratio is at 1. Coral bleaching- when corals loose their symbiotic dino agellates, response to warmed water.
