The researchers studied phosphorus in a tropical lake's sediment to see if it could be released into the water. They found that most of the phosphorus in the sediment is not easily released, but a type bound to iron and manganese can be. When they tested the water and sediment, they saw that phosphorus levels in the water initially decreased, then increased later on. This suggests that phosphorus can be released from the sediment, especially in organic forms, when oxygen levels drop. Overall, the balance of phosphorus between water and sediment is influenced by organisms and temperature.