Historically, the earth’s ocean had a ph of 8.2. in recent years it dropped to 8.1. how might this affect the ocean environment

Well with the ph above 7 that means the water is more of a base due to the salt within the water.  the decrease in the ph is due to gloabal warming and the melting of ice which is somewhat diluting the water more.  the wildlife within the ocean has been there since you or i so some creatures have developed a very specific habbitat and less salt withing the water could have effects on them.  one such instace is if the organism needs a lot of salt.  a decrease in salt would mean that their cells would bloat with water until they explode. this would obviously hurt the species as a whole and in turn effect the whole food chain.

Ais the correct answer

The answer would be sand and gravel