Export flux of particulate organic carbon from the central equatorial Pacific determined using a combined drifting trap-234Th approach

Murray, James; Young, Jennifer A.; Newton, Jan; Dunne, John; Chapin, Thomas P.; Paul, Barbara; McCarthy, James J.

doi:10.1016/0967-0645(96)00036-7

Cited by 221 publications

(125 citation statements)

References 59 publications

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“…Beginning with the earliest applications, differences in C / 234 Th were found between samples and between studies depending on the different particle collection devices used, such as sediment traps, filtration from ocean sample bottles, or in situ filtration using pumps and size fractionated particle sampling (Buesseler et al, 1995;Murray et al, 1996). Regional differences and changes with depth and season were also evident.…”

Section: Introductionmentioning

confidence: 93%

“…We have shown that regional and size variations in C / 234 Th are most apparent when C / 234 Th data are compared using a single sampling device, since differences between collection techniques have been documented (e.g., Buesseler et al, 1995;Murray et al, 1996). Which sampling system best represents truly sinking material is a more difficult question to answer.…”

Section: Methodological Issues-traditional Particle Sampling Methodsmentioning

confidence: 99%

“…In all cases, POC fluxes were significantly lower than the earlier North Atlantic Bloom study. Looking at only the boreal spring cruises and equatorial stations along 1408W, and using either z 53 Am C/ 234 Th from in situ pumps (Bacon et al, 1996;Buesseler et al, 1995) sediment traps (Murray et al, 1996), POC fluxes were estimated to be 3-6 mmol C m À 2 d À 1 at 100 m with the higher values calculated when C / 234 Th in trap samples was used. New production determined using 15 N bottle incubations ranged from b6 to 19 mmol C m À 2 d À 1 .…”

Section: Split Flow Thin Cell Fractionationmentioning

confidence: 99%

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An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

et al. 2006

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Thorium-234 is increasingly used as a tracer of ocean particle flux, primarily as a means to estimate particulate organic carbon export from the surface ocean. This requires determination of both the 234 Th activity distribution (in order to calculate 234 Th fluxes) and an estimate of the C / 234 Th ratio on sinking particles, to empirically derive C fluxes. In reviewing C / 234 Th variability, results obtained using a single sampling method show the most predictable behavior. For example, in most studies that employ in situ pumps to collect size fractionated particles, C / 234 Th either increases or is relatively invariant with increasing particle size (size classes N 1 to 100s Am). Observations also suggest that C / 234 Th decreases with depth and can vary significantly between regions (highest in blooms of large diatoms and highly productive coastal settings). Comparisons of C fluxes derived from 234 Th show good agreement with independent estimates of C flux, including mass balances of C and nutrients over appropriate space and time scales (within factors of 2-3). We recommend sampling for C / 234 Th from a standard depth of 100 m, or at least one depth below www.elsevier.com/locate/marchem the mixed layer using either large volume size fractionated filtration to capture the rarer large particles, or a sediment trap or other device to collect sinking particles. We also recommend collection of multiple 234 Th profiles and C / 234 Th samples during the course of longer observation periods to better sample temporal variations in both 234 Th flux and the characteristic of sinking particles. We are encouraged by new technologies which are optimized to more reliably sample truly settling particles, and expect the utility of this tracer to increase, not just for upper ocean C fluxes but for other elements and processes deeper in the water column. D

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Section: Introductionmentioning

confidence: 93%

Section: Methodological Issues-traditional Particle Sampling Methodsmentioning

confidence: 99%

Section: Split Flow Thin Cell Fractionationmentioning

confidence: 99%

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An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

et al. 2006

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“…OC : 234 Th ratios in marine suspended matter, which are used to determine new production rates, decrease with increasing depth, decrease with decreasing particle size, and are generally lower for sediment trap material than for large sinking particle aggregates (Buesseler et al 1992(Buesseler et al , 1995Moran and Buesseler 1993;Bacon et al 1996;Murray et al 1996). Our results, which demonstrate stronger sorption with higher polysaccharide content, would predict a polysaccharide enrichment with depth, with size, and in sinking particulate matter caught in sediment traps.…”

Section: D Page Experimental Evidence Formentioning

confidence: 99%

Importance of acid polysaccharides for ²³⁴Th complexation to marine organic matter

Quigley

Santschi

Hung

et al. 2002

Limnology & Oceanography

176

119

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“…Nearly all (> 90%) of the nitrate removed was convened to particulate nitrogen during austral spring, but this percentage steadily decreased as the bloom progressed (Fig. 3) [Smith and Dunbar, 1998]. It is likely that by using means for the entire transect and completing the analysis over seasonal time scales that these species effects became quantitatively less important.…”

Section: Resultsmentioning

confidence: 99%

A balanced nitrogen budget of the surface layer of the southern Ross Sea, Antarctica

Smith

Asper

2000

Geophysical Research Letters

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Export flux of particulate organic carbon from the central equatorial Pacific determined using a combined drifting trap-234Th approach

Cited by 221 publications

References 59 publications

An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

Importance of acid polysaccharides for ²³⁴Th complexation to marine organic matter

A balanced nitrogen budget of the surface layer of the southern Ross Sea, Antarctica

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Export flux of particulate organic carbon from the central equatorial Pacific determined using a combined drifting trap-234Th approach

Cited by 221 publications

References 59 publications

An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

Importance of acid polysaccharides for 234Th complexation to marine organic matter

A balanced nitrogen budget of the surface layer of the southern Ross Sea, Antarctica

Contact Info

Product

Resources

About

Importance of acid polysaccharides for ²³⁴Th complexation to marine organic matter