Remote Western Arctic Nutrients Fuel Remineralization in Deep Baffin Bay

The oceanic nitrogen cycle is critically important for the partitioning of greenhouse gases between ocean and atmosphere. Baffin Bay connects ocean regions that are major sources (North Atlantic) and sinks (North Pacific and western Arctic) of biologically available nitrogen and further harbors supersaturation of nitrous oxide and a coincident deficit in nitrate in the deep basin. Isotopic tracer profiles of both nitrogen species presented here provide novel insights into the origin and cycling of reactive nitrogen in Baffin Bay, highlighting the connectivity between different Arctic systems and horizontal components of basin‐scale nutrient transport. Baffin Bay bottom water properties are derived from export production in northern Baffin Bay, which is largely fueled by Pacific‐derived nutrients. In situ remineralization at depth gives rise to benthic denitrification, evidenced by a pronounced accumulation of nitrous oxide with a distinctively high site preference (<44‰) in the deep basin. Nutrients supplied to Baffin Bay are hence stripped from surface waters and trapped at depth over long timescales, where sedimentary denitrification further adds to the N removal capacity of the Arctic Ocean.

[1]  J. Zorab.  Nitrous oxide , 2019, Reactions Weekly.

[2]  H. Synal,et al.  Tracing water masses with 129I and 236U in the subpolar North Atlantic along the GEOTRACES GA01 section , 2018, Biogeosciences.

[3]  D. Sigman,et al.  On the Properties of the Arctic Halocline and Deep Water Masses of the Canada Basin from Nitrate Isotope Ratios , 2018, Journal of Geophysical Research: Oceans.

[4]  C. Humborg,et al.  Influence of the bordering shelves on nutrient distribution in the Arctic halocline inferred from water column nitrate isotopes , 2018, Limnology and Oceanography.

[5]  D. Bianchi,et al.  Global niche of marine anaerobic metabolisms expanded by particle microenvironments , 2018, Nature Geoscience.

[6]  P. Tréguer,et al.  Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic , 2017 .

[7]  Craig M. Lee,et al.  Cascading off the West Greenland Shelf: A numerical perspective , 2017 .

[8]  P. Myers,et al.  Evolution of Baffin Bay Water Masses and Transports in a Numerical Sensitivity Experiment under Enhanced Greenland Melt , 2017 .

[9]  M. Altabet,et al.  N2O production and consumption from stable isotopic and concentration data in the Peruvian coastal upwelling system , 2017 .

[10]  F. D’Ortenzio,et al.  Changes in phytoplankton bloom phenology over the North Water (NOW) polynya: a response to changing environmental conditions , 2017, Polar Biology.

[11]  J. Klymak,et al.  Water mass modification and mixing rates in a 1/12° simulation of the Canadian Arctic Archipelago , 2017 .

[12]  R. Gerdes,et al.  Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments , 2016, Journal of geophysical research. Oceans.

[13]  D. Sigman,et al.  Nitrate isotope distributions on the US GEOTRACES North Atlantic cross-basin section: Signals of polar nitrate sources and low latitude nitrogen cycling , 2015 .

[14]  Yuhong Li,et al.  Coexistence of nitrous oxide undersaturation and oversaturation in the surface and subsurface of the western Arctic Ocean , 2015 .

[15]  L. Anderson,et al.  Global and regional drivers of nutrient supply, primary production and CO2 drawdown in the changing Arctic Ocean , 2015 .

[16]  K. Arrigo,et al.  Aspects of the marine nitrogen cycle of the Chukchi Sea shelf and Canada Basin , 2015 .

[17]  B. Thamdrup,et al.  Size-fraction partitioning of community gene transcription and nitrogen metabolism in a marine oxygen minimum zone , 2015, The ISME Journal.

[18]  H. Melling,et al.  Baffin Island and West Greenland Current Systems in northern Baffin Bay , 2015 .

[19]  Yuhong Li,et al.  A vertical gradient of nitrous oxide below the subsurface of the Canada Basin and its formation mechanisms , 2015 .

[20]  C. Mordy,et al.  Nitrous oxide cycling in the Eastern Tropical South Pacific as inferred from isotopic and isotopomeric data , 2014, Deep Sea Research Part II: Topical Studies in Oceanography.

[21]  N. Brüggemann,et al.  Interlaboratory assessment of nitrous oxide isotopomer analysis by isotope ratio mass spectrometry and laser spectroscopy: current status and perspectives. , 2014, Rapid communications in mass spectrometry : RCM.

[22]  J. Tremblay,et al.  Shifts in biological productivity inferred from nutrient drawdown in the southern Beaufort Sea (2003–2011) and northern Baffin Bay (1997–2011), Canadian Arctic , 2014 .

[23]  T. Machida,et al.  Decadal time series of tropospheric abundance of N2O isotopomers and isotopologues in the Northern Hemisphere obtained by the long‐term observation at Hateruma Island, Japan , 2013 .

[24]  S. Bacon,et al.  Export of nutrients from the Arctic Ocean , 2013 .

[25]  Craig M. Lee,et al.  Composition and fluxes of freshwater through Davis Strait using multiple chemical tracers , 2012 .

[26]  S. Juniper,et al.  Upper Water Column Nitrous Oxide Distributions in the Northeast Subarctic Pacific Ocean , 2012 .

[27]  C. Hannah,et al.  The circulation of eastern Canadian seas , 2012 .

[28]  Marcel Babin,et al.  Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding , 2012 .

[29]  M. Gosselin,et al.  First measurements of nitrous oxide in Arctic sea ice , 2012 .

[30]  M. McIlvin,et al.  Oxygen isotopic composition of nitrate and nitrite produced by nitrifying cocultures and natural marine assemblages , 2012 .

[31]  M. Gosselin,et al.  Environmental forcing of phytoplankton community structure and function in the Canadian High Arctic: contrasting oligotrophic and eutrophic regions , 2011 .

[32]  L. V. Morales,et al.  Coupled nitrification‐denitrification in sediment of the eastern Bering Sea shelf leads to 15N enrichment of fixed N in shelf waters , 2011 .

[33]  M. McIlvin,et al.  Isotopic Signature of N2O Produced by Marine Ammonia-Oxidizing Archaea , 2011, Science.

[34]  K. Arrigo,et al.  Secular trends in Arctic Ocean net primary production , 2011 .

[35]  R. Kwok,et al.  Arctic ice-ocean simulation with optimized model parameters: Approach and assessment , 2011 .

[36]  Craig M. Lee,et al.  Volume, Freshwater, and Heat Fluxes through Davis Strait, 2004–05* , 2011 .

[37]  K. Casciotti,et al.  Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium , 2010 .

[38]  V. Kitidis,et al.  Methane and nitrous oxide in surface water along the North-West Passage, Arctic Ocean , 2010 .

[39]  C. Buchwald,et al.  Oxygen isotopic fractionation and exchange during bacterial nitrite oxidation , 2010 .

[40]  D. Sigman,et al.  Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method. , 2009, Rapid communications in mass spectrometry : RCM.

[41]  U. Tsunogai,et al.  Enrichment of nitrous oxide in the water columns in the area of the Bering and Chukchi Seas , 2009 .

[42]  A. Ravishankara,et al.  Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century , 2009, Science.

[43]  D. Barber,et al.  Variability in the annual cycle of vertical particulate organic carbon export on Arctic shelves: Contrasting the Laptev Sea, Northern Baffin Bay and the Beaufort Sea , 2009 .

[44]  D. Sigman,et al.  The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen , 2009 .

[45]  N. Yoshida,et al.  Denitrification and nitrous oxide cycling within the upper oxycline of the eastern tropical South Pacific oxygen minimum zone , 2009 .

[46]  B. Ward.  Nitrification in Marine Systems , 2008 .

[47]  D. Sigman,et al.  Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria , 2008 .

[48]  Kevin R. Arrigo,et al.  Impact of a shrinking Arctic ice cover on marine primary production , 2008 .

[49]  David M. Glover,et al.  Constraints on nitrogen cycling at the subtropical North Pacific Station ALOHA from isotopic measurements of nitrate and particulate nitrogen , 2008 .

[50]  H. Melling,et al.  Spatial continuity of measured seawater and tracer fluxes through Nares Strait, a dynamically wide channel bordering the Canadian Archipelago , 2007 .

[51]  G. Robertson,et al.  Isotopologue effects during N2O reduction in soils and in pure cultures of denitrifiers , 2007 .

[52]  I. Yashayaev.  Hydrographic changes in the Labrador Sea, 1960–2005 , 2007 .

[53]  B. Popp,et al.  The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry. , 2007, Rapid communications in mass spectrometry : RCM.

[54]  J. Böhlke,et al.  Oxygen isotopes in nitrite: analysis, calibration, and equilibration. , 2007, Analytical chemistry.

[55]  E. Carmack,et al.  Nitrogen balance and Arctic throughflow , 2006, Nature.

[56]  M. Zweng,et al.  Warming and freshening of Baffin Bay, 1916-2003 , 2006 .

[57]  K. Hobson,et al.  � 2006, by the American Society of Limnology and Oceanography, Inc. Bloom dynamics in early opening waters of the Arctic Ocean , 2022 .

[58]  J. Breznak,et al.  Distinguishing Nitrous Oxide Production from Nitrification and Denitrification on the Basis of Isotopomer Abundances , 2006, Applied and Environmental Microbiology.

[59]  D. Sigman,et al.  Origin of the deep Bering Sea nitrate deficit: Constraints from the nitrogen and oxygen isotopic composition of water column nitrate and benthic nitrate fluxes , 2005 .

[60]  D. Sigman,et al.  Coupled nitrogen and oxygen isotope measurements of nitrate along the eastern North Pacific margin , 2005 .

[61]  S. Watanabe,et al.  Contributions of denitrification and mixing on the distribution of nitrous oxide in the North Pacific , 2005 .

[62]  P. Eriksson,et al.  Atlantic sources of the Arctic Ocean surface and halocline waters , 2004 .

[63]  B. Petrie,et al.  The circulation, water masses and sea-ice of Baffin Bay , 2004 .

[64]  N. Yoshida,et al.  Is the isotopic composition of nitrous oxide an indicator for its origin from nitrification or denitrification? A theoretical approach from referred data and microbiological and enzyme kinetic aspects. , 2004, Rapid communications in mass spectrometry : RCM.

[65]  D. Sigman,et al.  Coupled nitrogen and oxygen isotope fractionation of nitrate during assimilation by cultures of marine phytoplankton , 2004 .

[66]  J. Butler,et al.  Global distribution of N2O and the ΔN2O‐AOU yield in the subsurface ocean , 2003 .

[67]  Y. Tanji,et al.  Fractionation of N2O isotopomers during production by denitrifiers , 2003 .

[68]  J. Böhlke,et al.  Oxygen isotopes in nitrate: new reference materials for 18O:17O:16O measurements and observations on nitrate-water equilibration. , 2003, Rapid communications in mass spectrometry : RCM.

[69]  D. Sigman,et al.  Distinguishing between water column and sedimentary denitrification in the Santa Barbara Basin using the stable isotopes of nitrate , 2003 .

[70]  M. Lipizer,et al.  Tracing Pacific water in the North Atlantic Ocean , 2003 .

[71]  D. Sigman,et al.  Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. , 2002, Analytical chemistry.

[72]  E. Carmack,et al.  Impact of the large‐scale Arctic circulation and the North Water Polynya on nutrient inventories in Baffin Bay , 2002 .

[73]  M. Gosselin,et al.  Preferential sinking export of biogenic silica during the spring and summer in the North Water Polynya (northern Baffin Bay): Temperature or biological control? , 2002 .

[74]  U. Tsunogai,et al.  Production mechanism and global budget of N2O inferred from its isotopomers in the western North Pacific , 2002 .

[75]  L. Legendre,et al.  Phytoplankton biomass, production and potential export in the North Water , 2002, Deep Sea Research Part II: Topical Studies in Oceanography.

[76]  H. Melling,et al.  Ocean circulation within the North Water polynya of Baffin Bay , 2001 .

[77]  C. Barford,et al.  A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. , 2001, Analytical chemistry.

[78]  D. Karl,et al.  Mechanisms of nitrous oxide production in the subtropical North Pacific based on determinations of the isotopic abundances of nitrous oxide and di-oxygen , 2000 .

[79]  N. Yoshida,et al.  Constraining the atmospheric N2O budget from intramolecular site preference in N2O isotopomers , 2000, Nature.

[80]  Roger Kerouel,et al.  A simple and precise method for measuring ammonium in marine and freshwater ecosystems , 1999 .

[81]  N. Yoshida,et al.  Determination of Nitrogen Isotopomers of Nitrous Oxide on a Modified Isotope Ratio Mass Spectrometer , 1999 .

[82]  Stauffer,et al.  Variations in atmospheric N2O concentration during abrupt climatic changes , 1999, Science.

[83]  Nicolas Gruber,et al.  Global patterns of marine nitrogen fixation and denitrification , 1997 .

[84]  A. Devol,et al.  Isotopic fractionation of oxygen and nitrogen in coastal marine sediments , 1997 .

[85]  Jorge L. Sarmiento,et al.  Redfield ratios of remineralization determined by nutrient data analysis , 1994 .

[86]  Louis I. Gordon,et al.  Oxygen solubility in seawater : better fitting equations , 1992 .

[87]  S. Prinsenberg,et al.  Mixing and transports in Barrow Strait, the central part of the Northwest passage , 1987 .

[88]  B. Rudels.  The outflow of polar water through the Arctic Archipelago and the oceanographic conditions in Baffin Bay , 1986 .

[89]  R. Gonfiantini.  Stable Isotope Reference Samples for Geochemical and Hydrological Investigations , 1984 .

[90]  W. A. Kaplan,et al.  Production of NO2- and N2O by Nitrifying Bacteria at Reduced Concentrations of Oxygen , 1980, Applied and environmental microbiology.

[91]  F. C. Tan,et al.  The distribution of sea ice meltwater in the eastern Canadian Arctic , 1980 .

[92]  R. Weiss,et al.  Nitrous oxide solubility in water and seawater , 1980 .

[93]  L. Gordon,et al.  Nitrous oxide in the oxygen minimum of the eastern tropical North Pacific: evidence for its consumption during denitrification and possible mechanisms for its production , 1978 .

[94]  J. H. Carpenter.  THE CHESAPEAKE BAY INSTITUTE TECHNIQUE FOR THE WINKLER DISSOLVED OXYGEN METHOD , 1965 .

[95]  Charles D. Keeling,et al.  The concentration and isotopic abundances of carbon dioxide in rural and marine air , 1961 .

[96]  W. B. Bailey.  On the Origin of Deep Baffin Bay Water , 1956 .

[97]  S. Vagle,et al.  Methane and nitrous oxide distributions across the North American Arctic Ocean during summer, 2015 , 2017 .

[98]  S. Wankel,et al.  A dual nitrite isotopic investigation of chemodenitrification by mineral-associated Fe(II) and its production of nitrous oxide , 2017 .

[99]  R. T. Newman,et al.  Applied Radiation and Isotopes , 2008 .

[100]  R. Bourke,et al.  Formation of Baffin Bay Bottom and Deep Waters , 1991 .

[101]  H. Melling,et al.  Oceanic thermal structure in the western Canadian Arctic , 1984 .

[102]  D. Dyrssen,et al.  Nutrient Regeneration in Deep Baffin Bay with Consequences for Measurements of the Conservative Tracer NO and Fossil Fuel CO2 in the Oceans , 1984 .

[103]  R. Muench.  THE PHYSICAL OCEANOGRAPHY OF THE NORTHERN BAFFIN BAY REGION , 1971 .