1. Calculate the residence time for each of the following ions found in seawater using the input from river water. (12 pts.) Identify the possible outputs (sinks) for the following ions: Cl, Na, Mg, K, Ca, Si, P, and Mn. (8 pts.)

Ion	Seawater composition (mol/m3)	Atlantic M.O.R. a (mol/m3)	East Pacific M.O.R. a (mol/m3)	River water composition (mol/m3)
Cl	559520000	678111000	870534000	230000
Na	480670000	524790000	679140000	315000
Mg	54000000	0	0	160000
K	10500000	17493000	43012200	34500
Ca	10600000	26754000	36220800	364000
Si	84000	22638000	20580000	193000
P	2000			1300
Ti	0.02			200
Mn	0.2	1029000	878766	150
Al	1000	545.4	0	1900
Fe	0.7	1687560	3457440	700
Cu	1.9			160

^a Data from Von Damm, 1995; and Kadko et al., 1994.

Please use the following variables in your calculations:

Volume of Ocean = 1.29x10¹⁸ m³,

Global River Discharge (including direct groundwater discharge) to the oceans = 3.7 x10¹⁴ m³/year