Question

1. why are fish eggs particularly sensitive to ph changes?
2. how does low ph affect metals in water? why is this dangerous for aquatic organisms?

part 3: natural ph variations

1. daily ph changes:

• ph is highest during:
• ph is lowest during:
• this happens because:

1. look at figure 3. in a well - buffered pond, ph fluctuates between and
2. what is \buffering capacity\?
3. seasonal ph changes:

• ph is lower during seasons with:
• ph is higher during:
• why does this happen?

part 4: human impacts on ph

1. list four ways human activities can affect water ph:

a)
b)
c)

Explanation:

1. Fish eggs are sensitive to pH changes because their protective membranes can be damaged and the development - related chemical reactions can be disrupted.
2. Low pH in water can dissolve metals, making them more bio - available. This is dangerous for aquatic organisms as metals can be toxic, causing damage to organs, disrupting physiological processes, and even leading to death.
3. pH is highest during the early morning as plants consume carbon dioxide through photosynthesis during the day, reducing the amount of carbonic acid in water. pH is lowest during the late afternoon/evening as plants respire at night, releasing carbon dioxide which forms carbonic acid and lowers the pH.
4. In a well - buffered pond, pH typically fluctuates between 6.5 and 8.5.
5. Buffering capacity is the ability of a solution to resist changes in pH when small amounts of an acid or a base are added.
6. pH is lower during seasons with high plant decay (such as autumn) as the decomposition process releases carbon dioxide and other acidic substances. pH is higher during spring when there is more plant growth and carbon dioxide is being consumed for photosynthesis.
7. a) Industrial waste discharge can introduce acids or bases into water bodies. b) Agricultural runoff, especially from fertilizers and pesticides, can change water pH. c) Acid rain, formed from sulfur and nitrogen oxides reacting with water in the atmosphere, can lower the pH of surface waters. d) Deforestation can lead to increased soil erosion, and the eroded soil may contain substances that affect water pH.

Answer:

1. Their membranes are vulnerable and chemical reactions for development can be affected.
2. Low pH dissolves metals making them bio - available; metals are toxic to aquatic organisms.
3. Highest during early morning; lowest during late afternoon/evening; due to plant photosynthesis and respiration.
4. 6.5; 8.5
5. Ability to resist pH changes when acid or base is added.
6. Lower during seasons with high plant decay; higher during spring; due to plant decay and growth.
7. a) Industrial waste discharge

b) Agricultural runoff
c) Acid rain
d) Deforestation