Hanna Marine pH Pocket Checker Colorimeter - HI-780Over the years however, acidification tendency is to decrease 0. 1 to 0. 2 pH units century. Acidification is a consequence of carbon dioxide (CO2) absorption in seawaters and oceans. Carbon dioxide reacts with seawater to produce carbonic acid (H2CO2). pH modifications affect marine life growth, reproduction, and communication. Hydrogen ions have a tendency to bond with carbonate to form bicarbonate. The greater attraction to carbonate over calcium