Impact of deep-water renewal events on fixed nitrogen loss from seasonally-anoxic Saanich Inlet

Simple item page
dc.contributor.authorManning, Cara C.
dc.contributor.authorHamme, Roberta C.
dc.contributor.authorBourbonnais, Annie
dc.date.accessioned2021-04-20T18:09:17Z
dc.date.available2021-04-20T18:09:17Z
dc.date.copyright2010en_US
dc.date.issued2010
dc.description.abstractWe interpreted profiles of N2/Ar ratios, , and O2 concentration collected in Saanich Inlet, British Columbia, Canada over an annual cycle. Our measurements and data from a regional cabled observatory indicated that four deep- or bottom-water renewal events occurred over our study period. Each event was correlated with a period of weak tidal currents, such that very low tidal mixing allowed inflowing water to retain its high density as it moved across the sill and into the deeper basin. By quantifying the concentration of excess N2 in each month and the vertical diffusion rate, we determined that the N2 production rate ranged from 1.7 ± 0.3 mmol N2 m − 2 d − 1 in summer to 8.1 ± 2.8 mmol N2 m − 2 d − 1 in winter. This depth-integrated estimate accounts for all pathways resulting in fixed (bioavailable) nitrogen loss as N2 gas, including denitrification and anammox, and incorporates any benthic production of N2 that diffuses into the overlying water column. In spring and summer, the maximum N2 excess corresponded to the maximum , indicating that denitrification approached completion. In these months, the average isotopic composition of the fixed N consumed was 7.5 ± 1.2‰. Following bottom-water renewal in fall, which brought in nutrient-rich, low-N2 water, the N2 concentration increased and became progressively more enriched in 15N. The high rates of N2 production in Saanich Inlet likely exist in other anoxic basins that undergo periodic deep-water renewal by nitrate-rich waters.en_US
dc.description.reviewstatusRevieweden_US
dc.description.scholarlevelFacultyen_US
dc.description.sponsorshipWe thank Ian Beveridge, Paul Covert, Courtney Dean, Karina Giesbrecht, and Victoria Gray for assistance with field work and sample processing. Alice Chang, Jay Cullen, Vera Pospelova, and Sarah Thornton shared lab space and equipment. Jody Klymak helped with our diffusivity and renewal analysis, and Richard Dewey assisted with processing and interpreting the VENUS and tidal data. Mark Altabet and two anonymous reviewers helped to improve the manuscript. We used data from the following sources in our figures and calculations: CTD data from VENUS (http://venus.uvic.ca), upwelling index data from NOAA (http://pfeg.noaa.gov), and Fraser River outflow measurements from the Water Survey of Canada (http://scitech.pyr.ec.gc.ca/waterweb). This work was supported by NSERC under 328290-2006 to Hamme, 356654-08 and 134794-2006 to Kim Juniper, and research awards to Manning and Bourbonnais. Lab equipment was funded by grants from the CFI and BCKDF to Hamme. Additionally, Manning was supported by the Bob Wright Scholarship and the Meteorological Service of Canada.en_US
dc.identifier.citationManning, C. C., Hamme, R. C., & Bourbonnais, A. (2010). Impact of deep-water renewal events on fixed nitrogen loss from seasonally-anoxic Saanich Inlet. Marine Chemistry, 122(1-4), 1-10. https://doi.org/10.1016/j.marchem.2010.08.002.en_US
dc.identifier.urihttps://doi.org/10.1016/j.marchem.2010.08.002
dc.identifier.urihttp://hdl.handle.net/1828/12858
dc.language.isoenen_US
dc.publisherMarine Chemistryen_US
dc.subjectAnoxic basinen_US
dc.subjectnitrogen cycleen_US
dc.subjectnitrogen isotopesen_US
dc.subjectdenitrificationen_US
dc.subjectanammoxen_US
dc.subjectdissolved oxygenen_US
dc.subjectrenewalen_US
dc.subjectmonitoring systemsen_US
dc.subjectCanadaen_US
dc.subjectBritish Columbiaen_US
dc.subjectSaanich Inleten_US
dc.titleImpact of deep-water renewal events on fixed nitrogen loss from seasonally-anoxic Saanich Inleten_US
dc.typePostprinten_US

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Manning_Cara_MarChem_2010.pdf
Size:
1.49 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
2 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

Faculty Publications (BioMed Central & Faculty of Science)
 
University of Victoria Libraries

We acknowledge and respect the Lək̓ʷəŋən (Songhees and Esquimalt) Peoples on whose territory the university stands, and the Lək̓ʷəŋən and W̱SÁNEĆ Peoples whose historical relationships with the land continue to this day.