Why do seagrasses die when placed in fresh water?

Seagrasses are marine plants that have adapted to grow in saltwater environments, where they rely on saline conditions for physiological balance. When placed in fresh water, the osmotic pressure changes, causing their cells to take in excess water and potentially leading to cellular swelling and damage. This disruption in their internal balance affects their metabolism and can ultimately result in their death. Additionally, the lack of necessary nutrients and the altered microbial environment in fresh water can further stress and kill seagrasses.