Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores

Area of Science:

• Environmental Science
• Paleoclimatology
• Analytical Chemistry

Background:

• Phosphorus is a vital macronutrient for all life.
• Phosphate ions (PO4(3-)) in ice cores can serve as indicators of past biological activity.
• Understanding past phosphorus levels is crucial for reconstructing environmental conditions.

Purpose of the Study:

• To develop a sensitive method for detecting dissolved reactive phosphorus (DRP) in ice cores.
• To analyze DRP concentrations in Greenland ice cores to understand past environmental conditions.
• To identify the sources of phosphorus deposition in Northeast Greenland.

Main Methods:

• A continuous, highly sensitive absorption method was developed using a molybdate reagent.
• A 2-meter liquid waveguide capillary cell (LWCC) was employed for detection.
• The method was optimized for low DRP concentrations in ice, achieving a depth resolution of ~2 cm and analytical uncertainty of 1.1 nM PO4(3-).

Main Results:

• The developed method was applied to a firn core from Northeast Greenland.
• Mean DRP concentration from 1930-2005 was 2.74 nM PO4(3-), with values up to 10.52 nM PO4(3-).
• Similar DRP levels were observed for the period 1771-1823, suggesting dust and biogenic particles as primary sources.

Conclusions:

• The new method provides a sensitive tool for analyzing past phosphorus levels in ice cores.
• DRP concentrations in Greenland ice cores offer insights into historical biological activity and deposition sources.
• Dust and biogenic particles are identified as significant contributors to phosphorus deposition in the region.