The study looked at how much groundwater flows into the ocean in Punnakayal, India, and how it affects nutrient levels. By using different tracers, the researchers found that both fresh and salty groundwater enter the ocean. The amount of groundwater flowing into the ocean varied from 0.04 to 0.15 cubic meters per square meter per day. The levels of a specific tracer, 222Rn, were highest in the estuary. Nutrient levels were highest where there was a lot of rainwater mixing with the groundwater. Saltwater moving through rocks could also bring nutrients to the coast.