77 2.9 NH4HCO3 NH4HCO3 77 146 70 Lay , 2005 Liu Shen, 2004 Morimoto , 2004 0-0.6 0.1-2 2-8 0.4 1 4 (Carbon to nitrogen ratio) 20 40-130 47 4.80 98 3.53 Lin Lay, 2004a Wang , 2009