How do bioclastic Corals affect environmental coastline issues and vice versa?

How do bioclastic Corals affect environmental coastline issues and vice versa? Coral reefs are calcium carbonate bioclastic material covered by living organisms.  How do coral reefs help the environment? How do coral reefs form, die (life cycle) Dredging?
Resources
https://www.epa.gov/coral-reefs/threats-coral-reefs
https://oceanservice.noaa.gov/facts/coral_protect.html
https://www.usgs.gov/news/sea-floor-erosion-coral-reef-ecosystems-leaves-coastalcommunities-risk?qt-news_science_products=3#qt-news_science_products
https://www.wri.org/blog/2011/08/how-reduce-your-coral-reef-footprint

https://www.forbes.com/sites/allenelizabeth/2019/06/16/how-dredging-adds-stress-to-alreadystruggling-coral-reefs/#2fdbc7f16850
https://e360.yale.edu/digest/miami-dredging-project-killed-more-than-half-a-million-corals?
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