If the temperature of our oceans continues to rise, what possible long-term effect will this have on marine organisms?
the geographic range of phytoplankton will decrease thus increasing the base of the marine food chain.
the distribution of marine life will increase.
the diversity of marine life will increase.
the available oxygen of ocean waters will decrease, thus reducing marine life diversity.

The increase in temperature of the oceans is brought about by the general increase in the temperature of the Earth especially due to global warming and others.

If the temperature of the water, in this case ocean, increases, the solubility of the oxygen is decreased. This is because oxygen molecules have higher kinetic energy allowing them to move out of the soution or water body. Generally, this means that the oxygen level would deplete and thus reducing marine life diversity.

The answer to this item is letter D.