When was a control used in the investigation of the amphipods and sea butterflies?

A control was used in the investigation of amphipods and sea butterflies during experiments to assess the effects of ocean acidification. In these studies, researchers typically maintained a separate group of organisms in normal, unaltered seawater conditions to compare with those exposed to elevated CO2 levels. This control group allowed scientists to determine the specific impacts of acidification on the behavior, physiology, and survival of these marine species. By using controls, researchers could ensure that any observed changes were directly attributable to the experimental conditions.