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RESEARCH ARTICLE
Contents Vol 61(3)

Rayleigh distillation equations applied to isotopic evolution of organic nitrogen across a continental shelf

Robert Van Hale A B and Russell D. Frew A
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A Department of Chemistry, University of Otago, Dunedin, New Zealand.

B Corresponding author. Email: robertv@chemistry.otago.ac.nz

Marine and Freshwater Research 61(3) 369-378 https://doi.org/10.1071/MF09041
Submitted: 27 February 2009  Accepted: 1 October 2009   Published: 29 March 2010

Abstract

The isotope enrichment of nitrate due to uptake by phytoplankton has previously been measured in a variety of ways, both in the field over time or space, and in vitro. This study provided an unusual opportunity to measure the isotopic fractionation of nitrate over an extended spatial scale. Results are presented from the Otago Continental shelf, New Zealand. δ15N-PON and [NO3–] was correlated using Rayleigh distillation equations to obtain isotope enrichment factors for the uptake of nitrate. The decrease in nitrate concentration during advection landward across the shelf was consistent with removal by phytoplankton, with an average enrichment factor (ϵ) of 8.2 per mil, as calculated using the Rayleigh accumulated product equation. The spatial evolution of δ15N-PON and [NO3–] across the Otago continental shelf led to the conclusion that cross-shelf advection is the predominant process bringing nutrients to the shelf. No Rayleigh distillation-type process is observable from monthly observations. However, in subantarctic surface water (SASW), a seasonal variation in δ15N-PON was seen that was in the opposite phase to that expected for isotopic enrichment of the nutrient pool. In SASW, δ15N-PON peaked at 4‰ in winter months and fell to –2‰ in the spring and summer.

Additional keywords: field measurements, nitrogen isotopes, particulate organic nitrogen, subantarctic zone (SA), subtropical water (STW).


References

Altabet, M. A. (1988). Variations in nitrogen isotope composition between sinking and suspended particles: implications for nitrogen cycling and particle transformation in the open ocean. Deep-Sea Research. Part A, Oceanographic Research Papers 35, 535–554.
| Crossref | GoogleScholarGoogle Scholar | CAS | Altabet M., and Francois R. (1993). The use of nitrogen isotopic ratios for reconstruction of past changes in surface ocean nutrient utilization. In ‘Carbon Cycling in the Glacial Ocean: Constraints on the Ocean’s Role in Global Change. Vol. I 17’. (Eds R. Zahn, T. F. Pedersen, M. Kaminski and L. D. Labeyrie.) pp. 281–306. (Springer-Verlag: New York.)

Altabet, M. A. , and Francois, R. (1994). Sedimentary nitrogen isotopic ratio as a recorder for surface ocean nitrate utilization. Global Biogeochemical Cycles 8, 103–116.
| Crossref | GoogleScholarGoogle Scholar | CAS | Criss R. E. (1999). ‘Principles of Stable Isotope Distribution.’ (Oxford University Press: New York.)

Croot P. L. (1994). The marine biogeochemistry of iron. PhD Thesis, University of Otago, Dunedin, Otago.

DiFiore, P. J. , Sigman, D. M. , Trull, T. W. , Lourey, M. J. , Karsh, K. , Cane, G. , and Ho, R. (2006). Nitrogen isotope constraints on subantarctic biogeochemistry. Journal of Geophysical Research-Oceans 111, C08016.
| Crossref | GoogleScholarGoogle Scholar | Hoefs J. (1997). ‘Stable Isotope Geochemistry.’ (Springer-Verlag: Berlin.)

Holmes, M. E. , Muller, P. J. , Schneider, R. R. , Segl, M. , Patzold, J. , and Wefer, G. (1996). Stable nitrogen isotopes in Angola Basin surface sediments. Marine Geology 134, 1–12.
| Crossref | GoogleScholarGoogle Scholar | CAS | Kirchlechner T. M. (1999). Biogeochemical aspects of the New Zealand sector of the Southern Ocean. PhD Thesis, University of Otago, Dunedin.

Landry, M. , Barber, R. T. , Bidigare, R. R. , Chai, F. , and Coale, K. H. , et al. (1997). Iron and grazing constraints on primary production in the central equatorial Pacific: an EqPac synthesis. Limnology and Oceanography 42, 405–418.
|  CAS | Liss P. S. (1976). Conservative and non-conservative behaviour of dissolved constituents during estuarine mixing. In ‘Estuarine Chemistry’. (Eds J. D. Burton and P. S. Liss.) pp. 93–130. (Academic Press: London.)

Lourey, M. J. , Trull, T. W. , and Sigman, D. M. (2003). Sensitivity of δ15N of nitrate, surface suspended and deep sinking particulate nitrogen to seasonal nitrate depletion in the Southern Ocean. Global Biogeochemical Cycles 17, 1081.
| Crossref | GoogleScholarGoogle Scholar | McCarthy J. J. (1980). Nitrogen. In ‘The Physiological Ecology of Phytoplankton’. (Ed. I. Morris.) pp. 191–234. (Blackwell Scientific Publications.)

Montoya J. P. (1994). Nitrogen isotope fractionation in the modern ocean: implications for the sedimentary record. In ‘Carbon Cycling in the Glacial Ocean: Constraints on the Ocean’s Role in Global Change. Vol I 17’. (Eds R. Zahn, T. F. Pedersen, M. Kaminski and L. D. Labeyrie.) pp. 259–279. (Springer-Verlag: New York.)

Murdoch, R. C. , Proctor, R. , Jillett, J. B. , and Zeldis, J. B. (1990). Evidence for an eddy in the downstream lee of the Otago Peninsula, New Zealand. Estuarine, Coastal and Shelf Science 30, 489–507.
| Crossref | GoogleScholarGoogle Scholar | Summerhays C. P., Emeis K.-C., Angel M. V., Smith R. L., and Zeitzschel B. (1994). ‘Upwelling in the Ocean: Modern Processes and Ancient Records. Dahlem Workshop on Upwelling in the Ocean.’ (John Wiley: Berlin.)

Timmermans, K. R. , Stolte, W. , and De Baar, H. J. W. (1994). Iron mediated effects on nitrate reductase in marine phytoplankton. Marine Biology 121, 389–396.
| Crossref | GoogleScholarGoogle Scholar | CAS | Van Hale R. J. (2003). Stable isotope biogeochemistry of the Otago continental shelf. PhD Thesis, University of Otago, Dunedin.

Verardo, D. J. , Froelich, P. N. , and McIntyre, A. (1990). Determination of organic carbon and nitrogen in marine sediments using the Carlo Erber NA1500 analyser. Deep-Sea Research 37, 157–165.
| Crossref | GoogleScholarGoogle Scholar | CAS |

Villareal, T. A. , and Lipschultz, F. (1995). Internal nitrate concentrations in single cells of large phytoplankton from the Sargasso Sea. Journal of Phycology 31, 689–696.
| Crossref | GoogleScholarGoogle Scholar | CAS |

Wang, H. , Huang, B. , and Hong, H. (1997). Size-fractionated productivity and nutrient dynamics of phytoplankton in subtropical coastal environments. Hydrobiologia 352, 97–106.
| Crossref | GoogleScholarGoogle Scholar | CAS |

Woods, S. , and Villareal, T. A. (2008). Intracellular ion concentrations and cell sap density in positively buoyant oceanic phytoplankton. Nova Hedwigia 133, 131–145.


Wu, J. , Calvert, S. E. , and Wong, C. S. (1997). Nitrogen isotope variations in the subarctic northeast Pacific: relationships to nitrate utilization and trophic structure. Deep-Sea Research 44, 287–314.
| Crossref | GoogleScholarGoogle Scholar | CAS |

Yin, K. , Harrison, P. J. , and Dortch, Q. (1998). Lack of ammonium inhibition of nitrate uptake for a diatom grown under low light conditions. Journal of Experimental Marine Biology and Ecology 228, 151–165.
| Crossref | GoogleScholarGoogle Scholar | CAS |

Yoshinari, T. , Altabet, M. A. , Naqvi, S. W. A. , Codispoti, L. , Jayakumar, A. , Kuhland, M. , and Devol, A. (1997). Nitrogen and oxygen isotopic composition of N2O from suboxic waters of the eastern tropical North Pacific and the Arabian Sea – measurement by continuous-flow isotope-ratio monitoring. Marine Chemistry 56, 253–264.
| Crossref | GoogleScholarGoogle Scholar | CAS |