Title:
Nitrogen stable isotope dynamics in the central Baltic Sea: influence of deep-water renewal on the N-cycle
Nitrogen stable isotope dynamics in the central Baltic Sea: influence of deep-water renewal on the N-cycle
| dc.contributor.author | Voss, Maren | en_US |
| dc.contributor.author | Nausch, Günter | en_US |
| dc.contributor.author | Montoya, Joseph P. | en_US |
| dc.contributor.corporatename | Universität Rostock. Institut für Ostseeforschung Warnemünde | en_US |
| dc.contributor.corporatename | Harvard University. Biological Laboratories | en_US |
| dc.date.accessioned | 2012-03-26T20:26:33Z | |
| dc.date.available | 2012-03-26T20:26:33Z | |
| dc.date.issued | 1997-11-17 | |
| dc.description | © 1997 Inter-Research | en_US |
| dc.description | DOI:10.3354/meps158011 | en_US |
| dc.description.abstract | The vertical profiles of NO₃-, NH₄+, O₂, and H₂S as well as the isotopic composition of particulate nitrogen and NH4+ were sampled yearly over a 5 yr period in the Gotland Basin to follow biochemical changes in N-cycling resulting from an inflow of saltwater. The water column has a pronounced interface at 80 to 120 m depth which separates warm (13°C) brackish surface waters (salinity 7 psu) and the underlying cold winter water layer from more saline (9 to 11 psu) bottom waters originating from irregularly occurring inflow events of oxygenated, nitrate-rich North Sea water masses. Anoxic conditions usually exist in the deep stagnant waters, where nutrients only occur as ammonia, which reaches concentrations of up to 30 µmol l-1. In spring 1993 large amounts of nitrate- and oxygen-rich water were transported into the deep waters of the Gotland Basin, thus displacing the stagnant deep water body. With the inflow, oxygen and nitrate concentrations rose by 3 ml l-1 and more than 10 µmol l-1 respectively. During the following years the concentrations of oxygen in the near bottom layer decreased again. The isotope signature of the suspended particles in the layer below 120 m reflects these changes: in 1993 the mean stable nitrogen isotope value in the anoxic water was at 1.1o/oo. We assume bacterial incorporation of ammonia to be the mechanism producing isotopically light particles. A fractionation factor calculated for ammonia uptake of 11 ‰ supports this hypothesis. During the following years the particles in the oxygenated water column were around 8o/oo which is characteristic for microbially degraded material. The surface sediment of the central Gotland Sea has a low isotope signal of 3 to 4o/oo. These findings might have consequences for the interpretation of sediment δ15N data where low isotope contents are usually taken as an indicator of high nutrient concentrations in surface waters. | en_US |
| dc.identifier.citation | Voss, M, Nausch, G., and J.P. Montoya. 1997. Nitrogen stable isotope dynamics in the central Baltic Sea: influence of deep-water renewal on the N-cycle. Mar. Ecol. Prog. Ser. 158: 11-21. | en_US |
| dc.identifier.doi | 10.3354/meps158011 | |
| dc.identifier.issn | 0171-8630 | |
| dc.identifier.uri | http://hdl.handle.net/1853/43097 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Georgia Institute of Technology | en_US |
| dc.publisher.original | Inter-Research | en_US |
| dc.subject | δ¹⁵N | en_US |
| dc.subject | Nitrogen cycling | en_US |
| dc.subject | Baltic Sea | en_US |
| dc.title | Nitrogen stable isotope dynamics in the central Baltic Sea: influence of deep-water renewal on the N-cycle | en_US |
| dc.type | Text | |
| dc.type.genre | Article | |
| dspace.entity.type | Publication | |
| local.contributor.author | Montoya, Joseph P. | |
| local.contributor.corporatename | College of Sciences | |
| local.contributor.corporatename | School of Biological Sciences | |
| relation.isAuthorOfPublication | 0000b67d-bef5-4edf-b2d6-3577c297f4c3 | |
| relation.isOrgUnitOfPublication | 85042be6-2d68-4e07-b384-e1f908fae48a | |
| relation.isOrgUnitOfPublication | c8b3bd08-9989-40d3-afe3-e0ad8d5c72b5 |
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