The researchers studied the zooplankton in Al-Habbaniya Lake to learn about the different types of tiny aquatic animals living there. They found 67 different species, with rotifers being the most common, followed by copepods and cladocerans. The water temperature, oxygen levels, and pH of the lake affected the abundance of zooplankton. The diversity of species was highest among rotifers, showing that the lake's ecosystem is stable and balanced.