Ocean acidification
Ocean surface pH is estimated to have decreased from about 8.25 to 8.14 since the beginning of the industrial era, and a further drop of 0.3–0.4 units is expected. This drop has made it so the amount of hydrogen ions have increased by 30%. Before the industrial age the conditions for calcium carbonate production were typically stable in surface waters since the carbonate ion is at supersaturated concentrations. However, as the ionic concentration falls, carbonate becomes under-saturated, making calcium carbonate structures vulnerable to dissolution. Corals experience reduced calcification or enhanced dissolution when exposed to elevated . This causes the skeletons of the corals to weaken, or even not be made at all. Ocean acidification may also have an effect of 'gender discrimination' as spawning female corals are significantly more susceptible to the negative effects of ocean acidification than spawning male coral