What concerns you about the effects of increasing levels of carbon dioxide in the marine environment? Do you think that coral reefs will still be in existence by the end of the century? Why, or why not?

Only 46% by the end of this century.

Explanation:

The oceans are the storehouse of world global carbon dioxide gas as these water bodies tend to absorb this greenhouse gas and thus thus reacts with the seawater making it saltier and hence more saline in nature. Apart from this human often dump waste and toxic chemicals that directly release harmful gases and runoff content from the agricultural lands that increase the concentration of phosphorus and nitrogen in the oceanic water and raise their temperatures. Increasing acidity makes it difficult for t corals exoskeletons to grow and for the selfish to build shells this, as a matter of fact, coral bleaching has taken place in oceans and is growing at an alarming rate though some corals have regenerative properties they can adjust to the rising in temperature but the majority of them die on spot.