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doi:10.2204/iodp.proc.336.205.2015

Data report: characteristics of sedimentary phosphorus
at North Pond, IODP Expedition 336¹

Delphine Defforey² and Adina Paytan^2,3

Abstract

Phosphorus (P) plays an important role in fueling life, including microbial life in the deep subseafloor environment, which is estimated to contain up to 1% of Earth’s total biomass. These microorganisms play a significant role in controlling the chemical composition of the deep ocean and atmosphere on geological timescales by selectively degrading organic matter through metabolic respiration. Consequently, understanding P geochemistry in subseafloor sediments is important, as P bioavailability can impact microbial activity. This study focuses on characterizing and quantifying the main reservoirs of solid-phase P in open-ocean sediments. The sediment samples used in this study were collected during Integrated Ocean Drilling Program (IODP) Expedition 336 to North Pond, a sediment pond located on the western flank of the Mid-Atlantic Ridge. We characterized solid-phase P reservoirs in sediments from four holes (U1384A, U1382B, U1383D, and U1383E) using the sedimentary extraction (SEDEX) sequential extraction scheme. This method quantitatively separates five distinct sedimentary P reservoirs: (1) loosely sorbed P, (2) ferric iron-bound P, (3) authigenic carbonate fluorapatite + biogenic apatite + CaCO₃-associated P, (4) detrital apatite, and (5) refractory organic P. The separation of these P-bearing phases is based on the reactivity of each targeted phase to a particular extractant solution.

¹ Defforey, D., and Paytan, A., 2015. Data report: characteristics of sedimentary phosphorus at North Pond, IODP Expedition 336. In Edwards, K.J., Bach, W., Klaus, A., and the Expedition 336 Scientists, Proc. IODP, 336: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.336.205.2015

² Department of Earth and Planetary Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz CA 95064, USA. Correspondence author: ddeffore@ucsc.edu

³ Also at: Institute of Marine Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz CA 95064, USA.

Initial receipt: 15 October 2014
Acceptance: 4 June 2015
Publication: 2 September 2015
MS 336-205

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