The term ocean acidification describes a direction of chemical change. It does not mean that every part of the ocean has crossed below a pH of seven or that all locations share one fixed value.
Start with the process
NOAA describes ocean acidification as a longer-term reduction in ocean pH, driven primarily by uptake of atmospheric carbon dioxide. The resulting chemical changes reduce the availability of carbonate ions used by many organisms to build calcium carbonate structures.
NOAA’s education overview also explains that average seawater can remain alkaline while becoming more acidic. Change and present classification are different ideas.
Read a measurement with its context
For a local dataset, look for the sampling location, depth, date, method and uncertainty. One reading cannot establish a long-term trend on its own.
A chart should make its time span and scale clear. Avoid transferring a global summary directly to one estuary without local evidence.
Keep related questions distinct
Water colour, clarity and pH describe different properties. A clear-looking shoreline photograph cannot establish the chemical condition of the water.
Read this alongside changing estuary salinity. Coastal understanding improves when each measurement keeps its definition, location and timescale rather than becoming a general label for good or bad water.