Title

Abundance and Chemical Speciation of Phosphorus in Sediments of the Mackenzie River Delta, the Chukchi Sea and the Bering Sea: Importance of Detrital Apatite

Document Type

Article

Publication Date

6-1-2010

Department

Marine Science

Abstract

Utilizing a sequential extraction technique this study provides the first quantitative analysis on the abundance of sedimentary phosphorus and its partitioning between chemically distinguishable phases in sediments of the Bering Sea, the Chukchi Sea and the Mackenzie River Delta in the western Arctic Ocean. Total sedimentary phosphorus (TSP) was fractionated into five operationally defined phases: (1) adsorbed inorganic and exchangeable organic phosphorus, (2) Fe-bound inorganic phosphorus, (3) authigenic carbonate fluorapatite, biogenic apatite and calcium carbonate-bound inorganic and organic phosphorus, (4) detrital apatite, and (5) refractory organic phosphorus. TSP concentrations in surface sediments increased from the Chukchi Sea (18 mu mol g(-1) of dried sediments) to the Bering Sea (22 mu mol g(-1)) and to the Mackenzie River Delta (29 mu mol g(-1)). Among the five pools, detrital apatite phosphorus of igneous or metamorphic origin represents the largest fraction (similar to 43%) of TSP. The second largest pool is the authigenic carbonate fluorapatite, biogenic apatite as well as CaCO(3) associated phosphorus (similar to 24% of TSP), followed by the Fe-bound inorganic phosphorus, representing similar to 20% of TSP. The refractory organic P accounts for similar to 10% of TSP and the readily exchangeable adsorbed P accounts for only 3.5% of TSP. Inorganic phosphorus dominates all of phosphorus pools, accounting for an average of 87% of the TSP. Relatively high sedimentary organic carbon and total nitrogen contents and low delta(13)C values in the Mackenzie River Delta together with the dominance of detrital apatite in the TSP demonstrate the importance of riverine inputs in governing the abundance and speciation of sedimentary phosphorus in the Arctic coastal sediments.

Publication Title

Aquatic Geochemistry

Volume

16

Issue

3

First Page

353

Last Page

371