YOUR QUESTION VERY GENERAL.  Kindly pin point the situation to which comments are required?

Resilience to the synergistic impacts of climate change and anthropogenic pressure. Not specific to any geographical location, but in general around the world.

Coral cover is but one measure of coral reef health and resilience. These papers should give you some direction:

http://www.ucipfg.com/Repositorio/MLGA/MLGA-01/BLOQUE-INICIAL/Bibliografia/Climate-Change_Human_Impacts_Coral_Reefs.pdf

https://www.researchgate.net/profile/Jeremy_Jackson5/publication/46034636_Rising_to_the_challenge_of_sustaining_coral_reef_resilience/links/0c96051fe9f2ab8c2f000000.pdf

https://www.researchgate.net/profile/Fredrik_Moberg/publication/222554059_Coral_reef_disturbance_and_resilience_in_a_human-dominated_environment/links/53fc36540cf2dca8fffef100.pdf

Hope this helps,

Tomas

Article Rising to the challenge of sustaining coral reef resilience

Article Coral reef disturbance and resilience in a human-dominated environment

From a longer-term perspective, carbonate budgets are useful for evaluating

resilience of reefs. This takes into account if the structure of a reef will be maintained to continue providing ecosystem services. It all depends on what you mean by "resilience", what spatial and temporal scales you are speaking of, and if you are speaking from a strictly biological standpoint or a reef framework standpoint. See some of the attached papers (but there are many more) for help and let me know if you have any questions.

Dear David K Weinstein

Thanks for your inputs as I already started working on this perspective. But still some clarifications required. The work by Dr C Perry consider only the biological erosion process mediated by parrot fish and seaurchins while calculating the carbonate erosion. However, erosion of carbonate structures also occurs due to physical forces such as wave action and chemical forces such as low pH. I'm trying integrate all these processes to derive the net erosion rate. Your comments and suggestions are welcomed.

Thanks

B Manikandan

B Manikandan, you are absolutely correct. One of the biggest flaws with Perry's work is what you just explained (I am not judging though, they did a great job tackling this topic where there is no full solution). Another issue with the bioerosion part of their work is that the method assumes somewhat controversial rates for sponge bioerosion from other studies can be applied to percent benthic cover of sponges (hard when considering most of these sponges are cryptic organisms that hide within the substrate). They also do not account of other macroborers such as mollusks and worms (which usually are not huge contributors but it varies by orders of magnitude depending on the location). The way they handle microboring is also difficult at best. To deal with these issues, I and others used experimental substrate blocks of known weight. However, this method also has inherent flaws (see attached paper that discusses some of these issues).

Very few people have been able to directly consider physical erosion and it is usually assumed to be minimal. I work in deeper water so this usually is not a problem for me. Researchers often assume most physical erosion is facilitated by bioerosion (organisms loosing up material) but its hard to account for how sediment abrasion may remove carbonate or other physical processes.

Chemical processes are also assumed to be relatively negligible (but this is hard to test). It is unknown how much carbonate cementation processes actually add per weight and volume to the framework. Dissolution in most areas of standard pH can be assumed to be minimal though.

Ultimately, we are trying to quantify a "simple" mass-balance equation with almost an infinite amount of variables. We do the best we can to account for major factors modifying carbonate structure but it is impossible to account for everything unfortunately. Still, I hope I have provided some help to you. Please let me know if you have any more questions.