genomes to ecosystems lecture 1- coral bleaching

Question 1

what is the progression in the health of coral?

Answer 1

in December 2014 a coral was healthy, by feb the coral was dying and by august 2015 it was dead

Question 2

what is the reef distribution like?

Answer 2

• shallow water coral ecosystem distributed around the tropics
• its exceptionally biodiverse
• the total number of all marine species estimates at 1.5 million and over 50% is coral

Question 3

explain the positive symbiosis relationship between corals and zooxanthellae dinoflagellate algae

Answer 3

• corals live in shallow, warm water in nutrient poor waters. corals are colonial cnidarians and feed on zooplankton
• corals have evolved facultative endosymbiosis with zooxanthellae dinoflagellate algae ro provide vital nutrients.
  -90% of algal nutrients are used by coral, including 2 essential amino acids
  -algae get a nutrient rich stable refuge, coral gets food
  -Evidence of genomic co-evolution & co-adaptation
  -Zooxanthellae clades are specific to particular coral families

Question 4

what are reef radiations in the cenozoic like?

Answer 4

Cycles of radiation and extinctions of current coral families (Scleractinians)

Major extinction events correspond to rapid and cataclysmic environmental changes

Radiations – favorable habitats, ocean physicochemistry.

Question 5

how could this relationship turn sour?

Answer 5

-under stressful conditions, algae produces clouds of reactive oxygen species, ROS cause oxidative damage, dna mutations and cell death
- the coral then boots them out

Question 6

what are the conditions that turn the relationship sour?

Answer 6

most are manmade such as
-overfishing –> prey overabundance (anoxia)
-deforestation–> slit deposition (anoxia)
-ozone depletion –> increased solar irradiance
-CO2 emissions and climate change –> sea surface temperature increases

Question 7

what services are the human population provided in a coral ecosystem?

Answer 7

-biodiversity
-carbon sinks
-medicine/drug discovery
-coastal protection
-tourism
-habitats for fisheries

Monetising ecosystem services is an important means for ecologists and conservation biologists to engage with gov’t and industry

Question 8

what is done to protect and conserve coral bleaching?

Answer 8

Marine Protected Areas can provide conservation status and prevent physical damage to reef and associated animal and plant communities (fishing etc)

Only 0.5% ocean ‘no-take’, 4% protected

However, it is likely that the main driver of coral bleaching is more intangible and much harder to address – ie climate change

Double edged sword of increased oceanic CO2 is acidification which makes carbonate deposition all the harder

Evolution - is time running out ? Is change of environment outpacing potential for adaption and resilience ??