The evolution of coral

The building blocks to every marine ecosystem

    

Fig 1: Coral Reef
Photographer: NOAA 2015

Corals are the backbone of marine ecosystems and provide food, shelter and habitat for marine organisms.  Due to climate change and human pressure, 15% of coral has been lost and a further 35% is at risk of bleaching (Wilkinson 2008).

Fig. 2: Craysfort Reef, a comparison of damage between 1975 and 2004
Photographer:Phillip Dunstan 2015

Thankfully, some corals have adapted to rising sea temperatures by developing heat shock resistant proteins (Guest et al 2012).

Given the corals quick ability to adapt, scientists such as Van Oppen and Mascerelli are talking about experimenting with ‘Assisted evolution’ whereby corals can be genetically altered to better prepare them for future global warming (Van Oppen et al 2015)(Mascerelli 2014).

Fig 3. Acropora hyacinthus: a heat resistant coral
Franco Banfi 2013

What is assisted evolution?

In this context, assisted evolution is when scientists genetically modify a species outside of its natural environment then place it back with a better chance of surviving global warming (Mascerelli 2014).

Although this sounds like a good idea, experimenting with keystone species could produce a whole range of ecological disasters (Oppen et al 2015). 

Fig 4: A Stanford researcher testing the heat tolerance of corals between normal water and +2 degrees
Photographer: Tom Oliver 2009

What could go wrong?

According to Van Oppen (Van Oppen et al 2015) some of the things that could go wrong include the altered coral becoming invasive, the introduction of a new pathogen from the altered species or an entire ecosystem collapse.

How is it done?

There are a range of different ways corals can be ‘adapted’ to rising temperature, these include:

Selective breeding

Fig 5: Researcher measuring coral for selective breeding 
Photgrapher: Ken Nedimyer 2015

Priming

 Growing corals in a heated environment to acclimatize them and possibly induce trans-generational plasticity (Van Oppen et al 2015).

  Fig 6: Stanford research on coral  heat tolerance and plasticity

Anonymous 2015

Changing algae

Fig 7: Symbiotic algae (Zooxanthellae) shown in yellow growing on coral 
Anonymous 2012

Another short term solution is to change the algae that live inside coral with a more heat resistant species ,this can increase a corals heat tolerance by 1- 1.5 degrees (Birkelmans and Van Oppen 2006).

Thank-you for reading J check back next week for more information on marine evolution.

References

Anonymous 2015, Stanford research on heat tolerance and plasticity, http://stanford.edu/~rbay/stanford/Research.html retrieved 22/3/15

Anonymous 2012, Symbiotic algae (Zooxanthellae) shown in yellow growing on coral http://deepbluehome.blogspot.com.au/2011/08/after-coral-bleaching-winner-is.html retrieved 22/3/15

Banfi F 2013, Acropora hyacinthus: a heat resistant coral, https://www.sciencenews.org/article/corals-beat-heat-being-prepared retrieved 22/3/15

Birkelmans R, M J H Van Oppen 2006, ‘The role of zooxanthellae in the thermal tolerance of corals: a ‘nugget of hope’ for coral reefs in an era of climate change’, Proc. R. Soc. B, vol 273, pp.2305-2312, doi: 10.1098/rspb.2006.3567

Dunstan P 2015, Craysfort Reef, a comparison of damage between 1975 and 2004, http://www.zoo.ox.ac.uk/group/oceans/research/shallowreef.html retrieved 22/3/15

Guest J R, Baird A H, Maynard J A, Muttaqin E, Edwards A J, Campbell S J, Yewdall K, Affendi Y A, Chou L M 2012, ‘Contrasting patterns of coral bleaching susceptibility in 2010 suggest an adaptive response to thermal stress’, PLOS ONE, vol 7, no 3, doi:10.1371/journal.pone.0033353

Mascarelli A 2014, ‘Climate-change adaptation: Designer reefs’ Nature, vol 508, no 7497 pp. 444–446, doi:10.1038/508444a

Nedimyer K 2015, Researcher measuring coral for selective breeding, http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/florida/interactive-media-staghorn-coral-17.xml retrieved 22/3/15

NOAA 2015, Coral Reef, http://www.noaa.gov/features/economic_0708/images/coralreef.jpg retrieved 22/3/15

Oliver T 2009, A stanford researcher testing the heat tolerance of coral between normal water and +2 degrees http://news.stanford.edu/news/2009/may20/corals-052009.html retrieved 22/3/15

Reusch T B H 2014, ‘Climate change in the oceans: evolutionary versus phenotypically plastic responses of marine animals and plants’, Evolutionary Applications, vol 7, no.1, pp.104 – 122, doi: 10.1111/eva.12109

Van Oppen M J H, Oliver J K, Putnam H M, Gates R D 2015, ‘Building coral reef resilience through assisted evolution’, PNAS, vol 112, no. 8, pp.2307-2313,  doi: 10.1073/pnas.1422301112

Wilkinson, C (ed.) 2008, Status of the coral reefs of the world: 2008, Global coral reef monitoring network and reef and rainforest research center, Townsville, Australia