The researchers studied the zooplankton in a creek in Nigeria to see how a nearby petroleum refinery affected the water. They collected samples in February and August and found that the types of zooplankton changed between the wet and dry months. In February, there were 72 organisms, with Protozoa being the most common. In August, there were 121 organisms, with Copepoda being the most common. The water's temperature, flow rate, depth, pH, salinity, dissolved oxygen, and biological oxygen demand also varied between the two months.