Marine Phosphorites Formation

• The movement of cold water from the ocean's depth to another depth level
• The sinking of warm, nutrient-poor water from the ocean's surface to the depth
• The movement of warm water from the surface to the ocean's depth
• The rise of cold, nutrient-rich water from the ocean's depth to the surface (correct)

• Direct precipitation of phosphate from sea water
• Combination of organic matter, phosphorous, skeletal debris, and phosphate (correct)
• Presence of high oxygen levels in the overlying sea floor
• The absence of phytoplanktons in the surface water

• Presence of oxygen-rich overlying sea floor
• High organic productivity and presence of phytoplanktons in the surface water (correct)
• Absence of fish mortality in the area of upwelling
• Low organic productivity and absence of phytoplanktons in the surface water