genes to ecosystems Flashcards
(292 cards)
where are shallow water and coral ecosystems distributed
around the tropics
what is the estimation of the total number of marine species and what proportion of these are coral species
1.5 million - 50% of which are coral species
why do Scottish corals cope better than tropical corals
they are not as sensitive to water temperature fluctuation
ecosystems are in a constant state of …………….
flux
what are the steps of reef radiations in the cenzoic
- mass extinction
- post extinction time of anoxia and changes in sea water chemistry – coral and reef gap
- stony corals present in shallow water carbonates but not as reef builders - reef recovery
- adaptive radiation
- reef extinction
what is adaptive radiation
when organisms diversify rapidly from and ancestral species
what do major coral extinction events correspond to
rapid cataclysmic environmental changes
where do corals live
in shallow warm water usually between late 20-late 30 C
what is the temperature of corals usually when they are bleaching
late 30s
describe the nutritional content of waters that are undergoing coral bleaching
nutrient poor with poor oxygen content
what are corals and what do they feed on
cnidarians and they feed on zoo plankton
what organism have coral formed a facultative endosymbiotic relationship with and what do they provide them with
zooxanthellae dinoflagellate - they provide coral with vital additional nutrients
90% of all algal nutrients are used by coral including 2 essential amino acids
what is facultative endosymbiosis
endosymbiotic - when an organisms lives inside another
facultative - can survive without the relationship for short periods of time
how do algae and coral benefit from the endosymbiotic relationship
algae get a nutrient rich stable refuge
coral get food
are zooxanthellae and coral showing specificity in their relationship
yes - zooxanthellae clades are specific to particular coral families
is the zooxanthellae and coral relationship always mutualistic
no it can turn parasitic - coral bleaching
what is important to note about coral polyps
each polyp is an individual organ
where are the algal dinoflagellates found in the coral
they are found in the gastrodermis of the tentacles of coral polyps
what happens when coral bleaching occurs
- when the dinoflagellates living inside the coral get hot (due to climate change) their photosystems start working too fast and produce ROS which cause damage
- in response, the corals exocytose the symbiont (dinoflagellates) and the coral bleaches as a result
what kind of damage do the ROS produced by dinoflagellates cause
oxidative damage
DNA damage
cell death
give some examples of environmental stresses that can contribute to causing coral bleaching
- CO2 emissions and climate change - sea surface temperatures increase
- ozone depletion - increased solar irradiance
- deforestation
- silt deposition (granule between sand and clay) - can cause anoxia by blanketing corals and preventing them from photosynthesising
- fertilizer run off - can cause algal blooms to grow which use oxygen and cause coral anoxia - overfishing
- prey overabundance - the prey use up a lot of oxygen which causes coral anoxia
what is anoxia
lack of oxygen
mutualistic relationship of coral and algae maintains the ……….
ecosystem
the relationship between coral and algae can become tempestuous, what does this mean
it s no longer mutualistic - it turns parasitic