To measure primary production of algae in a stream, you place two sealed chambers in the stream, each enclosing the sediments as well as the water above them. One chamber is covered with black tape (blocking all light) while the other is transparent to light. You measure dissolved oxygen (DO) before and after a 24-hour incubation. DO in the light chamber increased by 1.5 g/m^2 while DO in the dark chamber decreased by 2.0 g/m^2. Required:
a. What is the estimated ecosystem respiration (Re) for the stream?
b. What is the stream’s estimated NEP (net ecosystem production)?
c. Based on these data, what is the stream’s estimated gross primary production (GPP)?
d. With the current configuration of Earth’s continents, global atmospheric CO2 peaks in late April. Imagine that all of Earth’s land mass was instead bunched tightly together around the South Pole. Assume that seasonal patterns of growth and respiration are otherwise the same, with summer occurring June-August in the Northern Hemisphere and December-February in the Southern Hemisphere. How will this new configuration affect seasonal swings in average global CO2?