Question 19N.3.SL.TZ0.14b
| Date | November 2019 | Marks available | [Maximum mark: 3] | Reference code | 19N.3.SL.TZ0.14b |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe | Question number | b | Adapted from | N/A |
Blue fin tuna (Thunnus orientalis) are top carnivores in the marine ecosystem. Some radioisotopes of elements are produced by nuclear reactors. Following a nuclear accident at Fukushima in Japan in March 2011, the levels of certain radioisotopes were measured in the bodies of blue fin tuna caught off California in August 2011, the other side of the Pacific Ocean from Japan. The becquerel (Bq) is a measure of radioactivity.
[Source: reproduced from Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California
Daniel J. Madigan, Zofi a Baumann, and Nicholas S. Fisher PNAS June 12, 2012 109 (24) 9483–9486]
Describe the use of indicator species in monitoring environmental change.
[3]
a. presence/absence indicate environmental conditions ✔
b. changes in the environment affect these species ✔ Number or type of species
c. «relative» numbers of individuals/indicator species can be used to calculate a biotic index ✔
d. changes monitored over time ✔ Example of time frame
e. changes can lead to measures to protect the environment ✔
f. example of an indicator species AND what it indicates «e.g. Tubifex for sediment pollution» ✔ Award marks for a species, not a group
Award mp for species not group.
