Here's a breakdown of how it works:
* Saltwater Environment: The ocean has a higher salt concentration than the fish's body fluids.
* Osmotic Pressure: This difference in salt concentration creates a pressure difference, driving water from areas of high concentration (inside the fish) to areas of low concentration (the ocean).
* Water Movement: Water moves across the fish's cell membranes, following the concentration gradient to try and equalize the salt levels. This results in a net loss of water from the fish's body.
To counteract this water loss, saltwater fish have adapted:
* Drinking Seawater: They constantly drink seawater to replenish lost fluids.
* Specialized Gills: Their gills are equipped to actively remove excess salt from their bodies.
* Concentrated Urine: They produce a highly concentrated urine to minimize water loss.
These adaptations allow saltwater fish to maintain a stable internal environment despite living in a hypertonic (higher salt concentration) environment.
