Articles | Volume 21, issue 7
https://doi.org/10.5194/bg-21-1961-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-21-1961-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Vertical mixing alleviates autumnal oxygen deficiency in the central North Sea
Charlotte A. J. Williams
CORRESPONDING AUTHOR
National Oceanography Centre, Liverpool, L3 5DA, UK
Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, NR33 0HT, UK
Jan Kaiser
Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
Claire Mahaffey
Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3GP, UK
Naomi Greenwood
Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, NR33 0HT, UK
Matthew Toberman
Scottish Association for Marine Science, Oban, Scotland, PA37 1QA, UK
Matthew R. Palmer
Plymouth Marine Laboratory, Plymouth, PL1 3DH, UK
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Cited articles
Bittig, H. C., Fiedler, B., Scholz, R., Krahmann, G., and Körtzinger, A.: Time dependence on flow speed and temperature, Limnol. Oceanogr.-Method., 12, 617–636, https://doi.org/10.4319/lom.2014.12.617, 2014.
Brandt, P., Bange, H. W., Banyte, D., Dengler, M., Didwischus, S.-H., Fischer, T., Greatbatch, R. J., Hahn, J., Kanzow, T., Karstensen, J., Körtzinger, A., Krahmann, G., Schmidtko, S., Stramma, L., Tanhua, T., and Visbeck, M.: On the role of circulation and mixing in the ventilation of oxygen minimum zones with a focus on the eastern tropical North Atlantic, Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, 2015.
Burchard, H. and Rippeth, T. P.: Generation of bulk shear spikes in shallow stratified tidal seas, J. Phys. Oceanogr., 39, 969–985, https://doi.org/10.1175/2008JPO4074.1, 2009.
Butenschön, M., Clark, J., Aldridge, J. N., Allen, J. I., Artioli, Y., Blackford, J., Bruggeman, J., Cazenave, P., Ciavatta, S., Kay, S., Lessin, G., van Leeuwen, S., van der Molen, J., de Mora, L., Polimene, L., Sailley, S., Stephens, N., and Torres, R.: ERSEM 15.06: a generic model for marine biogeochemistry and the ecosystem dynamics of the lower trophic levels, Geosci. Model Dev., 9, 1293–1339, https://doi.org/10.5194/gmd-9-1293-2016, 2016.
Champenois, W. and Borges, A. V.: Seasonal and interannual variations of community metabolism rates of a Posidonia oceanica seagrass meadow, Limnol. Oceanogr., 57, 347–361, https://doi.org/10.4319/lo.2012.57.1.0347, 2012.
Daewel, U., Akhtar, N., Christiansen, N., and Schrum, C.: Offshore wind farms are projected to impact primary production and bottom water deoxygenation in the North Sea, Commun. Earth Environ., 3, 292, https://doi.org/10.1038/s43247-022-00625-0, 2022.
Davis, C. E., Mahaffey, C., Wolff, G. A., and Sharples, J.: A storm in a shelf sea: Variation in phosphorus distribution and organic matter stoichiometry, Geophys. Res. Let., 41, 8452–8459, https://doi.org/10.1002/2014GL061949, 2014.
Diaz, R. J. and Rosenberg, R.: Spreading dead zones and consequences for marine ecosystems, Science, 321, 926–929, https://doi.org/10.1126/science.1156401, 2008.
Efron, B. and Gong, G.: A leisurely look at the bootstrap, the jackknife, and cross-validation, Am. Stat., 37, 36–48, 1983.
Fischer, T., Banyte, D., Brandt, P., Dengler, M., Krahmann, G., Tanhua, T., and Visbeck, M.: Diapycnal oxygen supply to the tropical North Atlantic oxygen minimum zone, Biogeosciences, 10, 5079–5093, https://doi.org/10.5194/bg-10-5079-2013, 2013.
García-Martín, E. E., Daniels, C. J., Davidson, K., Davis, C. E., Mahaffey, C., Mayers, K. M., McNeill, S., Poulton, A. J., Purdie, D. A., Tarran, G. A., and Robinson, C.: Seasonal changes in plankton respiration and bacterial metabolism in a temperate shelf sea, Prog. Oceanogr., 177, 101884, https://doi.org/10.1016/j.pocean.2017.12.002, 2018.
Gilbert, D., Rabalais, N. N., Díaz, R. J., and Zhang, J.: Evidence for greater oxygen decline rates in the coastal ocean than in the open ocean, Biogeosciences, 7, 2283–2296, https://doi.org/10.5194/bg-7-2283-2010, 2010.
Grantham, B. A., Chan, F., Nielsen, K. J., Fox, D. S., Barth, J. A., Huyer, A., Lubchenco, J., and Menge, B. A.: Upwelling-driven nearshore hypoxia signals ecosystem and oceanographic changes in the northeast Pacific, Nature, 429, 749–754, https://doi.org/10.1038/nature02605, 2004.
Greenwood, N., Parker, E. R., Fernand, L., Sivyer, D. B., Weston, K., Painting, S. J., Kröger, S., Forster, R. M., Lees, H. E., Mills, D. K., and Laane, R. W. P. M.: Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health, Biogeosciences, 7, 1357–1373, https://doi.org/10.5194/bg-7-1357-2010, 2010.
Große, F., Greenwood, N., Kreus, M., Lenhart, H.-J., Machoczek, D., Pätsch, J., Salt, L., and Thomas, H.: Looking beyond stratification: a model-based analysis of the biological drivers of oxygen deficiency in the North Sea, Biogeosciences, 13, 2511–2535, https://doi.org/10.5194/bg-13-2511-2016, 2016.
Holt, J., Harle, J., Wakelin, S., Jardine, J., and Hopkins, J.: Why is seasonal density stratification in shelf seas expected to increase under future climate change?, Geophys. Res. Lett., 49, e2022GL100448, https://doi.org/10.1029/2022GL100448, 2022.
Inall, M. E., Rippeth, T. J., and Sherwin, T. J.: Impact of nonlinear waves on the dissipation of internal tidal energy at a shelf break, JGR Oceans, 105, 8687–8705, 2000.
Johnson, K. S., Riser S. C., and Karl D. M.: Nitrate supply from deep to near-surface waters of the North Pacific subtropical gyre, Nature, 465, 1062–1065, https://doi.org/10.1038/nature09170, 2010.
Körtzinger, A., Schimanski, J., Send, U., and Wallace, D.: The ocean takes a deep breath, Science, 306, 1337, https://doi.org/10.1126/science.1102557, 2004.
Lowe, J. A., Howard, T., Pardaens, A., Tinker, J., Holt, J., Wakelin, S., Milne, G., Leake, J., Wolf, J., Horsburgh, K., Reeder, T., Jenkins, G., Ridley, J., Dye, S., and Bradley, S.: UK Climate Projections science report: Marine and coastal projections, http://ukclimateprojections.defra.gov.uk/images/stories/marine_pdfs/UKP09_Marine_report.pdf (last access: 8 April 2024), 2009.
Mahaffey, C., Hull, T., Hunter, W., Greenwood, N., Palmer, M., Sharples, J., Wakelin, S., and Williams, C.: Climate change impacts on dissolved oxygen concentration in marine and coastal waters around the UK and Ireland, MCCIP Sci. Rev., 2002, 31 pp., https://doi.org/10.14465/2023.reu07.oxy, 2023.
Meire, L., Soetaert, K. E. R., and Meysman, F. J. R.: Impact of global change on coastal oxygen dynamics and risk of hypoxia, Biogeosciences, 10, 2633–2653, https://doi.org/10.5194/bg-10-2633-2013, 2013.
Moat, B. I., Smeed, D., Marcinko, C. L. J., and Turnock, S. R.: Flow distortion around underwater gliders and impacts on sensor measurements: a pilot study using large-eddy simulations, Research and Consultancy Report No. 58, National Oceanography Centre (NOC), UK, https://nora.nerc.ac.uk/id/eprint/514980 (last access: 8 April 2024), 2016.
Nicholson, D., Emerson, S., and Eriksen, C. C.: Net community production in the deep euphotic zone of the subtropical North Pacific gyre from glider surveys, Limnol. Oceanogr., 53, 2226–2236, https://doi.org/10.4319/lo.2008.53.5_part_2.2226, 2008.
Osborn, T. R.: Estimates of the local rate of vertical diffusion from dissipation measurements, J. Phys. Oceanogr., 10, 83–89, https://doi.org/10.1175/1520-0485(1980)010<0083:EOTLRO>2.0.CO;2, 1980.
Ostrovskii, A., Stepanov, D., Kaplunenko, D., Park, J.-H., Park, Y.-G., and Tishcenko, P.: Turbulent mixing and its contribution to the oxygen flux in the northwestern boundary current region of the Japan/East Sea, April–October 2015, J. Mar. Sys., 224, 103619, doi.org/10.1016/j.jmarsys.2021.103619, 2021.
Palmer, M. R., Stephenson, G. R., Inall, M. E., Balfour, C., Düsterhus, A., and Green, J. A. M.: Turbulence and mixing by internal waves in the Celtic Sea determined from ocean glider microstructure measurements, J. Mar. Syst., 144, 57–69, 2015.
Queste, B. Y., Fernand, L., Jickells, T. D., and Heywood, K. J.: Spatial extent and historical context of North Sea oxygen depletion in August 2010, Biogeochemistry, 113, 53–68, https://doi.org/10.1007/s10533-016-0258-9, 2013.
Queste, B. Y., Fernand, L., Jickells, T. D., Heywood, K. J., and Hind, A. J.: Drivers of summer oxygen depletion in the central North Sea, Biogeosciences, 13, 1209–1222, https://doi.org/10.5194/bg-13-1209-2016, 2016.
Rippeth, T. P.: Mixing in seasonally stratified shelf seas: a shifting paradigm, Philos. T. R. Soc. A, 363, 2837–2854, 2005.
Rippeth, T. P., Lincoln, B. J., Kennedy, H. A., Palmer, M. R., Sharples, J., and Williams, C. A. J.: Impact of vertical mixing on sea surface pCO2 in temperate seasonally stratified shelf seas, JGR Oceans, 119, 3868–3882, https://doi.org/10.1002/2014JC010089, 2014.
Rovelli, L., Dengler, M., Schmidt, M., Sommer, S., Linke, P., and McGinnis, D. F.: Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea, Biogeosciences, 13, 1609–1620, https://doi.org/10.5194/bg-13-1609-2016, 2016.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic oxygen content during the past five decades, Nature, 542, 335–339, https://doi.org/10.1038/nature21399, 2017.
Sharples, J., Moore, C. M., Rippeth, T. P., Holligan, P. M., Hydes, D. J., Fisher, N. R., and Simpson, J.: Phytoplankton distribution and survival in the thermocline, Limnol. Oceanogr., 46, 486–496, 2001.
Sharples, J., Tweddle, J. F., Green, J. A. M., Palmer, M. R., Kim, Y., Hickman, A. E., Holligan, P. M., Moore, C. M., Rippeth, T. P., Simpson, J. H., and Krivtsov, V.: Spring-neap modulation of internal tide mixing and vertical nitrate fluxes at a shelf edge in summer, Limnol. Oceanogr., 52, 1735–1747, https://doi.org/10.4319/lo.2007.52.5.1735, 2007.
Sharples, J., Holt, J., and Dye, S.: Impacts of climate change on shelf sea stratification, MCCIP Sci. Rev., 2013, 67–70, https://doi.org/10.14465/2013.arc08.067-070, 2013.
Tweddle, J. F., Sharples, J., Palmer, M. R., Davidson, K., and McNeill, S.: Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank, Prog. Oceanogr., 117, 37–47, https://doi.org/10.1016/j.pocean.2013.06.018, 2013.
Vanquer-Sunyer, R. and Duarte, C. M.: Thresholds of hypoxia for marine biodiversity, P. Natl. Acad. Sci. USA, 105, 15452–15457, https://doi.org/10.1073/pnas.0803833105, 2008.
Wakelin, S., Artioli, Y., Holt, J. T., Butenschön, M., and Blackford, J.: Controls on near-bed oxygen concentration on the Northwest European Continental Shelf under a potential future climate scenario, Prog. Oceanogr., 187, 102400, https://doi.org/10.1016/j.pocean.2020.102400, 2020.
Williams, C. A. J.: AlterEco 5 [data set], https://gliders.bodc.ac.uk/inventory/glider-inventory/, last access: 8 April 2024.
Williams, C. A. J., Sharples, J., Green, M., Mahaffey, C., and Rippeth, T.: The maintenance of the subsurface chlorophyll maximum in the stratified western Irish Sea, Limnol. Oceanogr. Fl. Env., 3, 61–73, 2013a.
Williams, C. A. J., Sharples, J., Mahaffey, C., and Rippeth, T.: Wind-driven nutrient pulses to the subsurface chlorophyll maximum in seasonally stratified shelf seas, Geophys. Res. Let., 40, 5467–5472, 2013b.
Williams, C. A. J., Davis, C. E., Palmer, M. R., Sharples, J., and Mahaffey, C.: The three Rs: Resolving Respiration Robotically in Shelf Seas, Geophys. Res. Let., 49, e2021GL096921, https://doi.org/10.1029/2021GL096921, 2022.
Short summary
Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive...
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