Biogeochemical controls on ammonium accumulation in the surface layer of the Southern Ocean

• Published in: Biogeosciences
• Main Authors: S. Smith, K. E. Altieri, M. Mdutyana, D. R. Walker, R. G. Parrott, S. Gallie, K. A. M. Spence, J. M. Burger, S. E. Fawcett
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2022
• Subjects: Ecology; QH540-549.5; Life; QH501-531; Geology; QE1-996.5; Southern Ocean
• Online Access: https://doi.org/10.5194/bg-19-715-2022; https://doaj.org/article/fdc2bd67175745dcb6b0ab433c913b96

The production and removal of ammonium ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="8aeb386a576ed6c8280ae774099f80e4"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-19-715-2022-ie00001.svg" width="24pt" height="15pt" src="bg-19-715-2022-ie00001.png"/></svg:svg> ) are essential upper-ocean nitrogen cycle pathways, yet in the Southern Ocean where <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="607f7ebf9a4fde3320a23a055c7bd38e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-19-715-2022-ie00002.svg" width="24pt" height="15pt" src="bg-19-715-2022-ie00002.png"/></svg:svg> has been observed to accumulate in surface waters, its mixed-layer cycling remains poorly understood. For surface seawater samples collected between Cape Town and the Marginal Ice Zone in winter 2017, we found that <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" ...