| Date | May 2016 | Marks available | 1 | Reference code | 16M.3.SL.TZ0.3 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | State | Question number | 3 | Adapted from | N/A |
Question
Increasing carbon dioxide concentration in the atmosphere leads to acidification of the ocean. This in turn reduces the amount of dissolved calcium carbonate. A study was undertaken to investigate the effect of increasing the concentration of atmospheric carbon dioxide on the calcification rate of marine organisms. Calcification is the uptake of calcium into the bodies and shells of marine organisms. The study was undertaken inside Biosphere-2, a large-scale closed mesocosm. The graph shows the results of the data collection.
State the relationship between atmospheric carbon dioxide and calcification rates.
Distinguish between the exchange of matter and energy with the surroundings in a closed mesocosm.
Markscheme
Negative correlation (Do not accept “negative” alone)
OR
inverse relationship
Decrease in calcification as atmospheric CO2/pCO2 rises
Matter does not exchange/enter/leave but energy exchanges/enters/leaves
Examiners report
N/A
Generally well answered though many referred to exchange within the mesocosm rather than with the surroundings.
