UQ MB II Flashcards
What are reefs mainly composed of?
carbonate sand
Define primary production
taking atm/oceanic CO2 turning it into organic material
What are the primary producers of the ocean?
phytoplankton
Describe BMAs
Benthic MicroAlgae
-dinos, diatoms, cyanobact. that well in the sand
Which meiofauna dominate the sand?
copepods and nematodes
Describe the significance of holothurians
- benthic detritus feeders
- eating of BMA regulates bioturbidity and nutrients in water
- they enhance productivity
Describe the significance of meiofauna
- small benthic invertebrates
- important in foodchains and eat plankton
- high turnover: abundance of food
What is a haloe?
a geo. structure that is hard rock/coral substrate in the middle and soft sediment surrounding it
Describe DVM
Diurnal Vertical Movement
-movement of benthic community into the water column (at night) when predatory pressures are off
What is the key to survival of corals against one another?
Growth rate
What are the two types of corals?
branching: pioneer type
massive
What is the DAM for corals?
attacking with
-mesentaerial filaments, sweeper tentacles/polyps, overgrowth
Are branching or massive coral better fighters?
Massive
Describe sweeper tentacles
longer projections full of nematocysts and sparocysts for stinging and snaring (attack and feeding)
T/F: DAMs are constantly happening between corals
FALSE - only happen when threatened to conserve energy
Which coral species is one of the “best at fighting”
Montipera
-large “disposable” army of polyps
What are IAMS of corals?
indirect attach mechs
- overgrowth : block light
- allelopathy : secrete chemical to keep others from growing around them
Name some outcomes of coral competition
standoffs, fusion, changing shape, reorienting growth (avoidance), overgrowth
What is darwins paradox?
Much diversity in nutrient poor waters
Two types of herbivory?
grazing - “lawn mow” feeding
browsing - selective feeding (damselfish)
Why is grazing important in reefs?
- trophic linkages between producers and consumers
- promote production and nutrient cycling
- keep algal population at bay
What is the keystone group of reefs?
Grazers (herbivores)
What happens if there are no sea cucumbers or grazers
nutrients build up and less light passes through and respiration makes things anoxic which increases the acidity of waters (h. sulfide)
What happens if the water gets disturbed (storm) when there is high nutrient buildup?
Nutrients get thrown in the air and the bacteria go crazy and grow and respire making things anoxic (taking all the oxygen) and also secreting toxins (blooms)
5 main fish grazers
Rabbit, damsel, blennie, parrot, surgeon
Cons to being an herbivore
plant cellulose hard to digest
carbon/nitrogen balance hard to maintain with energy
Plant defenses to grazers
- spikes, skeletons, boring, encrusting, rip stops, inaccessiblity
- toxins, digestion inhibitors, un-edible parts
What is grazer importance to coral?
keeps algal population at bay so it doesnt overgrow coral
Which is more of a concern: the existence of grazers or the nutrient level/being added to systems
Nutrient level is the overall concern
T/F: marine grazers perform the most grazing out of any habitat
True!
Describe the EAM
Epithilial Algal Matrix
-a network of algae that grows together (diatoms, dinos, cyanobact., algal turf)
-traps sediment and detritus
the “salad”