In the summer, in the daytime, lakes and oceans can absorb a lot of heat from the sun, keeping the surrounding air much cooler. That's why costal areas tend to have more mild seasonal changes. If ice sank, in winter as water froze, it would sink to the bottom of ponds and lakes, thus they would freeze from the bottom up. Thus, it would be impossible for any organisms to live in water. A neutral solution has a pH of 7.
Different buffers work best at different pH ranges.
The concept of pH is important in our bodies and in other branches of in biology. For example, an enzyme called pepsin digests protein in our stomachs, but must have an acid environment to function. Not all of the food we eat is acidic, and might destroy the normal stomach pH, thus making the pepsin ineffective. Because of the buffers in our stomach, the pH is kept fairly constant. Calcium, by the way, is absorbed better into one s body if the stomach contents are acidic, thus antacids also interfere with our bodies ability to properly absorb calcium.