Final answer:
The dissolved CO2 in the deep ocean would steadily increase after fossil fuels are exhausted until a new steady state is reached. The oceans absorb this excess CO2, eventually leading to a balance, but increased levels have negative effects such as ocean acidification.
Step-by-step explanation:
After the fossil fuels are exhausted, the amount of dissolved CO2 in the deep ocean would increase steadily until a new equilibrium is reached. This increase is due to the continued absorption of excess atmospheric CO2 by the ocean over time. Eventually, the system will balance the levels of dissolved CO2 throughout the ocean layers, leading to a steady state in which the dissolved carbon dioxide no longer changes. The cycle of carbon in the environment is slow, and when fossil fuels are burned, the balance is disrupted, increasing atmospheric and oceanic CO2 levels. The oceans act as a carbon sink, with the upper layers absorbing CO2 from the atmosphere and transporting it to the deeper regions. Over time, these processes reach a balance, and the levels in the deep ocean normalize.
Factors such as ocean acidification are a direct result of increased CO2 levels and have severe impacts on marine life, especially those relying on calcium carbonate for their exoskeletons. As the ocean absorbs more CO2, it becomes more acidic, and the ability of marine organisms to produce hard exoskeletons is compromised. Reducing atmospheric levels of CO2 is critical to mitigate these effects and to protect marine biodiversity and ecosystems.