In my HW, it asked to explain how the salinity of water changes in an estuarine environment....
this is a totally new question for me, please help...
http://en.wikipedia.org/wiki/Estuary
What happens when it rains? When it floods due to rain upstream? When the tide goes out, or in? In the summer when evaporation is high?
Sure, I can help you with that! The salinity of water in an estuarine environment can change due to a combination of factors. Estuaries are partially enclosed bodies of water where freshwater from rivers and streams meets and mixes with saltwater from the ocean. Here's how you can explain the changes in salinity in an estuarine environment:
1. Start by understanding the sources of freshwater and saltwater in an estuary:
- Freshwater input: Rivers and streams that flow into the estuary bring freshwater from the land.
- Saltwater input: The estuary is connected to the ocean, which provides a source of saltwater.
2. Explain how the mixing of freshwater and saltwater occurs:
- As freshwater from rivers enters the estuary, it carries dissolved salts and lowers the salinity of the surrounding water.
- The saltwater from the ocean, on the other hand, has a higher salinity.
- When these two types of water meet, they mix together, creating a transition zone called the "thalweg" or "salt wedge."
3. Describe the factors influencing salinity changes:
- Tides: The movement of tides affects the mixing of freshwater and saltwater. During high tide, the saltwater flows further upstream, increasing the salinity in that area. During low tide, more freshwater flows downstream, reducing the salinity.
- Precipitation: Rainfall can significantly impact salinity. Heavy rainfall can increase the freshwater input, diluting the saltwater and lowering the salinity levels.
- Evaporation: When water evaporates from the estuary's surface, it leaves behind the dissolved salts, increasing the salinity of the remaining water.
4. Explain the importance of the estuarine environment:
- The ever-changing salinity levels in estuaries create unique habitats for various organisms, as they adapt to different ranges of salinity.
- Estuaries serve as important nurseries and feeding grounds for diverse species, including fish, crustaceans, and birds.
- The mixing of freshwater and saltwater in estuaries also plays a crucial role in nutrient cycling and sediment transport.
In conclusion, the salinity of water in an estuarine environment changes due to the interaction between freshwater from rivers and saltwater from the ocean, influenced by tides, precipitation, and evaporation. Estuaries are dynamic environments that support a rich diversity of life and contribute to important ecological processes.