Week 1 Flashcards
What is a usual percentage of “High live coral cover”?
Around 40-50 % is considered high.
Much lower than a 100 %
What is turf algae?
Cropped algae only a few centimeters high, typically growing on rock, rubble or sand.
It is a complex matrix of algae, detritus, small invertebrates, bacteria etc.
How do soft corals stand upright?
By use of sclerites and hydrostatic pressure
What is crustose coralline algae and why are they important?
Algae with hard calcareous deposits within their cell walls, often pink.
They help cement the reef together thereby minimising erosion, and they promote settlement of larvae of other invertebrates (including hard corals)
What is a foundation species?
“A species that by virtue of its structural or functional attributes creates and defines an entire ecological community or ecosystem”
What is a keystone species?
A species that have a larger effect on the structure of a community than their abundance would suggest
What is an Ecosystem Engineer?
A species that creates, modifies or maintains an ecosystem
What are the 4 roles of a foundation species?
- Create and define ecosystem
- Usually low trophic level
- Create condition required by many other species
- Stabilise fundamental ecosystem processes (Productivity, nutrient balance)
How do corals create and define the reef ecosystem?
- Corals settle and grow on hard substratum
- Over time; Gaps beteween corals are filled with carbonate sediments, which are consolidated by crustose coralline algae (CCA)
- New corals settle on the consolidated carbonate framework
Corals are low in the trophic web. How?
- 128 species of fish eat live coral tissue
- Bioeroders eat dead coral tissue
- Corals produce mucus that is either dissolved (56-80%) and eaten by planktonic bacteria or floats of, gets “enriched” and settles in lagoons wher it is eaten by benthic fauna + bacteria (20-44 %)
- Coral gametes/eggs are eaten by 36 species of fish
How do corals create conditions required by other species?
They provide fish with
- Food
- Shelter
- Recruitment habitat
How is species richness and total abundance coupled with structural complexity on coral reefs?
When structural complexity declines, richness and abundance declines too.
Turf algae are more productive than corals. Why are they not considered foundation species?
Because they can be seasonal and because they are constantly being consumed, and therefore has a low standing biomass/low standing stock.
Corals provide high and STABLE productivity.
How do corals import resources from the open ocean?
By ingestion of suspended particulate matter (SPM)
What is unspecialised detrital feeding?
Corals expulse mesenterial filaments to clean nearby substratum. They do this either to eat it (source of carbon and nitrogen) or to clear space for growth.
