The second chapter similarly investigates the changes in bacteria dominating benthic cyanobacterial mats (BCMs) in response to nitrogen and phosphorus enrichment. This chapter aims to better understand the ecology of change in reefs that have seen increasing cover of BCMs over the last decades. It asks whether we can understand the extent to which nutrient enrichment drives ecological dynamics that may favour the proliferation of BCMs over reefs. The third chapter asks whether the steady decline in coral cover observed on permanent quadrats in Curacao and Bonaire can be well explained by climate change in the form of sea surface temperature rises and heat waves, and by population trends as a proxy for local stress on the islands. In the coral reef management literature there is a strong view that we must decrease local stressors to increase reef resilience so that corals can cope better with climate change. This chapter uses the longest coral time-series in the world to characterize how local and global stressors have changed over time and how changes to the reef composition associate to them. The fourth chapter also investigates these stressors at a narrower temporal scale but with higher spatial resolution, at the 115 sites monitored on Bonaire.