A series of experiments was designed to test the effects of ultraviolet (UV) radiation on the productivity of polar phytoplankton. Samples of these single-celled organisms were placed in four tanks, which were exposed to ambient natural solar radiation and to three modifications of ambient radiation. The design of the experiments is shown in the table below, along with measurements of photosynthesis in each tank.
Tank 1 had no added treatment for 22mg/m^2/hr in CO2 uptake
Tank 2 had all UV removed for 720mg/m^2/hr in CO2 uptake
Tank 3 had filters to remove 33% of UV for 31mg/m^2/hr in CO2 uptake
Tank 4 had UV amplified by 16% for 12mg/m^2/hr in CO2 uptake
Which of the following inferences is supported by the results of this series of experiments?
A
The atmosphere over Antarctica still contains some ozone.
B
Doubling of UV radiation will suppress photosynthesis completely.
C
The ozone hole over Antarctica is being destroyed by chlorofluorocarbons (CFCs).
D
Increased UV penetration through the Antarctic ozone hole would further depress productivity of phytoplankton.
E
Higher levels of UV radiation will eventually occur over Antarctica.
A laboratory experiment was done to show the effects of organic waste on the dissolved oxygen (DO) content in water. Five tanks were set up, each containing fresh water and a small amount of single-celled green algae. Specified amounts of organic waste were added to the tanks. The results below show the amount of DO in each tank after a period of one week.
Chart: Tanks 1-5 started with 10ppm of DO. Then, organic waste was added. Then, the effect on DO after one week is shown.
Tank 1: +0g = 10ppm
Tank 2: +10g = 10ppm
Tank 3: +20g = 8ppm
Tank 4: +30g = 5ppm
Tank 5 +40g = 0ppm
What is the main purpose for the experiment?
A
To determine how much O2 the algae can produce
B
To show how much CO2 is consumed by decomposition
C
To collect data to determine how waste in water can be useful
D
To demonstrate that initial DO is not important
E
To observe the effect of organic waste on DO
In 1950 the pH of the pond water was 8.2, but by 2000 the pH had decreased to 5.2.
Which of the following changes would also be expected in the pond over the same time period?
Increased levels of dissolved oxygen
Increased levels of heavy metals
Increased number of fish species
A
I only
B
II only
C
III only
D
II and III
E
I, II, and III
Two questions
Of these, which is a source that is not renewable?
Which produces hazardous wastes?
A
Biomass
B
Wind
C
Tidal energy
D
Nuclear fission
E
Sunlight