[问答题]
1. A student had a s
6mr h6vs ( -a4lhnx(r0xy/yvlng: 33)ilyal zmall pond in the backyard and wanted to add some fish. The fish would be predators of the pond and feed on the
l3zgna ):iyl3 zooplankton (prey) growing in the pond. Zooplankton are small floating or weakly swimming organisms that are dependent on the phytoplankton or algae for their supply of nutrition.
She wanted to first determine whether Fish A or Fish B would be more suitable, or if both fish could be added to the pond. As a trial, she set up four mesocosms using water from the pond. She monitored the mesocosms and then added the fish to three of the mesocosms as shown. She took samples of water from the different mesocosms and tested it for chlorophyll content at a research lab nearby.
1.Outline why the mesocosms used would be considered a ‘closed system’.
2.Describe why adding mud or soil to the mesocosms would be advantageous.
3.Outline the reason for including ‘Mesocosm A’ with the experiment.
4.Explain the reason for monitoring chlorophyll content to analyze the effects of the fish as a predator.
5.State another variable that could be monitored to see the effect of adding fish to the mesocosms.
The following table shows the results obtained for chlorophyll (μg dm$^{-3}$) with the different additions of fish.
6.From the results obtained, suggest why the student decided to add both fish A and fish B to the pond.
