Problem 1
"Red tides" are spectacular dinoflagellate blooms that occur in the sea and often lead to mass mortality of marine fishes and invertebrates. Human deaths from eating shellfish poisoned with red tide algae is a worldwide problem. Review the evidence available about the origin of red tides, and discuss the implications for general ideas about what controls primary production in the sea. Landsberg (2002) Kubanek et al. \((2005),\) and Wong et al. (2007) discuss this problem.
Problem 3
In the Great Plains grasslands of the United States, Epstein et al. (1997) showed that primary production of \(\mathrm{C}_{3}\) grasses could be predicted from mean annual temperature, with minimal contribution from mean annual precipitation. Discuss why precipitation and soil nutrients do not appear to be relevant variables for \(\mathrm{C}_{3}\) grass production in this ecosystem.
Problem 5
Even though the concentration of inorganic phosphate in the water of the North Atlantic Ocean is only about \(50 \%\) of that found in the other oceans, the North Atlantic is more productive than most of the other oceans. How can one reconcile these observations if nutrients limit primary productivity in the oceans?
Problem 8
Tilman et al. \((1982, \mathrm{p} .367)\) state: We suggest that the spatial and temporal heterogeneity of pelagic environments will prevent us from meaningfully addressing questions on short time scales or small spatial scales. Discuss the general issue of whether there are some questions in community ecology that we cannot answer because of scale.
Problem 9
North American grasslands are similar in structure to South African grasslands but the grass species differ because of their divergent evolutionary history. Both areas have dominant \(\mathrm{C}_{4}\) grasses with less abundant \(\mathrm{C}_{3}\) forbs and woody plants. But South Africa has greater climatic variability and poorer soils than North America. Would you expect the two areas to show the same relationships between rainfall and net primary production? Knapp et al. (2006) present an analysis of these questions.
Problem 11
Photosynthetic organisms produce about \(300 \times\) \(10^{15} \mathrm{g}\) of oxygen per year (Holland 1995 ). If this oxygen accumulated, the oxygen content of the atmosphere would double every 2000 years. Why does this not happen? Is the global system regulated? If so, how is this regulation accomplished?
