Answer Happy

2. Consider two hypothetical regions of the surface ocean: Region-A and -B. The two regions are virtually identical, except for the fact that in Region-A, coccolithophores are the sole primary producers, whereas in Region-B, diatoms are the sole primary producers. Coccolithophores and diatoms are both phytoplankton, but coccolithophores have hard parts made of CaCO3(s), whereas diatoms have hard parts made of opal (or biogenic silica; SiO2.nH2O(s)). a. For every 106 moles of organic carbon (OC) produced, by how much do DIC and At change, and in which direction? Please answer this for each of the two regions by completing the table below. Assume that: coccolithophores produce 1 mole of CaCO3(s) for every 8 moles of OC; and that photosynthesis occurs according to the following reaction: 106 CO2 + 16 NO3 + H3PO4 + 80 H2O + 16H → C106H179038N16P + 153 02 Note that C106H179038N16P represents organic matter containing 106 moles of OC. You may ignore changes in At due to DIP uptake. [10 pts] + Region-A (Coccolithophore-dominated) Clearly indicate direction of change using + or - sign 1. Change due to 2. Change due to production of Net change (sum of 1 and 2) production of OC (mol) CaCO3(s) (mol) (mol) ADIC -106 AAT Region-B (Diatom-dominated) Clearly indicate direction of change using + or - sign 1. Change due to 2. Change due to Net change (sum of 1 and 2) production of OC (mol) production of opal (mol) (mol) ADIC -106 AAT b. Suppose the two regions export carbon out of the surface mixed layer at the same rate. Please state which of the two regions is expected to have lower Pco2, and hence greater capacity to absorb atmospheric CO2(g). Please defend your selection. [1+3 pts] Region is expected to have lower Pco2. Scientific support for above selection: