Amassive toxic spill kills off half the population of photosynthetic plankton in the ocean. what do you predict may happen to the atmosphere as a result of this event?

The amount of oxygen in the atmosphere would decrease.

Explanation:

This is because phytoplankton have chlorophyll to capture sunlight, and they use photosynthesis to turn it into chemical energy. They consume carbon dioxide, and release oxygen. All phytoplankton photosynthesize, but some get additional energy by consuming other organisms.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme