IB Biology SL C4.2 Transfers of energy and matter Question Bank

There were widespread and intense wildfires in Southeast Australia during the summer season from November 2019 to January 2020. Estimates have been made of carbon dioxide emissions from these fires based on satellite monitoring data. The bar chart shows estimates made by five different research programmes: GFED, GFAS, QFED, FEER and FINN.

The table shows other statistics for comparison.

2019-2020 constrained by satellite. Nature (597), pp. 366-369. https://doi.org/10.1038/s41586-021-03712-y.]

Beavers are large rodents that live in waterways throughout the northern hemisphere. Dams made by beavers change the temperature of the streams and affect the mayfly, Baetis bicaudatus. In the summer of 2008, beaver ponds in West Brush Creek and Cement Creek, Colorado, were studied to evaluate their impacts on mayflies. The study sites included streams flowing into (upstream) and out of (downstream) each beaver pond.

Mayflies, including the species B. bicaudatus, are aquatic insects that hatch and spend their larval stages in water emerging from the water as adults. Larger females produce an increased number of better quality eggs.

When feed for animals is stored, moisture levels need to be kept low to prevent the growth of fungi. Feed was exposed to 15 % moisture and placed into a respirometer. $\mathrm{O}_{2}$ consumption was monitored using the respirometer over a period of six days.

Growth rates of marine algae can be investigated using experimental mesocosms such as those shown.

Data are shown for percentage growth rates of red algae, grown in their natural environment and using mesocosms. The conditions investigated included competition from green algae and from elevated $\mathrm{CO}_{2}$, as well as competition from green algae combined with elevated $\mathrm{CO}_{2}$.

Pictured below are Louis Pasteur's original drawings of swan-necked flasks.

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.

The diagrams show a virus and a bacterium.

An example of energy flow $\left(\mathrm{kJ} \mathrm{m}^{-2}\right.$ year $\left.{ }^{-1}\right)$ in the North Sea is shown.