The Ocean’s Changing Chemistry
Nitrogen, oxygen and carbon all have major effects on ocean life—and vice-versa. For example, the availability of nitrogen-containing nutrients can limit the growth of the phytoplankton that are the foundation of food chains in the sea. The different chemical forms of nitrogen also determine the type of plankton that grows. Lack of oxygen can restrict the habitats of fish and/or microbes, and the CO2 content of seawater controls its acidity and the growth of corals and other organisms.
The distribution of chemicals and their forms are themselves affected by the growth and decay of organisms, the circulation of ocean waters, exchanges with the atmosphere, and sediments and inputs from land. And their variations contain valuable clues to the complex biological and physical processes occurring in our oceans.
As Canada Research Chair in Ocean Science and Technology, Dr. Doug Wallace and his team are developing new analytical and robotic technologies to measure natural and human-caused variations of these chemical elements in our oceans. Their work helps quantify how much CO2 is taken up from the atmosphere, how the ocean ecosystem responds to inputs of nitrogen, and how oxygen, CO2 and other gases are exchanged between the atmosphere and the ocean interior.
We already know that human activity is overprinting the natural variability of these elements. For example, the oceans have sequestered 40 per cent of the CO2 emitted by fossil fuels. But Wallace’s research will improve our understanding of the ocean’s uptake of anthropogenic CO2 and the impact of human activity on ocean ecosystems.