BG Biogeosciences BG Biogeosciences 1726-4189 Copernicus Publications Göttingen, Germany 10.5194/bg-10-3767-2013 NW European shelf under climate warming: implications for open ocean – shelf exchange, primary production, and carbon absorption Gröger M. https://orcid.org/0000-0002-9927-5164 1 Maier-Reimer E. 1 Mikolajewicz U. 1 Moll A. 2 Sein D. 1 Max Planck Institute for Meteorology, Bundesstrasse 53, 20146 Hamburg, Germany Institut für Meereskunde, Universität Hamburg (CEN), Bundesstrasse 53, 20146 Hamburg, Germany 12 06 2013 10 6 3767 3792 Copyright: © 2013 M. Gröger et al. 2013 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://bg.copernicus.org/articles/10/3767/2013/bg-10-3767-2013.html The full text article is available as a PDF file from https://bg.copernicus.org/articles/10/3767/2013/bg-10-3767-2013.pdf

Shelves have been estimated to account for more than one-fifth of the global marine primary production. It has been also conjectured that shelves strongly influence the oceanic absorption of anthropogenic CO<sub>2</sub> (carbon shelf pump). Owing to their coarse resolution, currently applied global climate models are inappropriate to investigate the impact of climate change on shelves and regional models do not account for the complex interaction with the adjacent open ocean. In this study, a global ocean general circulation model and biogeochemistry model were set up with a distorted grid providing a maximal resolution for the NW European shelf and the adjacent northeast Atlantic. <br><br> Using model climate projections we found that already a~moderate warming of about 2.0 K of the sea surface is linked with a reduction by ~ 30% of the biological production on the NW European shelf. If we consider the decline of anthropogenic riverine eutrophication since the 1990s, the reduction of biological production amounts is even larger. The relative decline of NW European shelf productivity is twice as strong as the decline in the open ocean (~ 15%). The underlying mechanism is a spatially well confined stratification feedback along the continental shelf break. This feedback reduces the nutrient supply from the deep Atlantic to about 50%. In turn, the reduced productivity draws down CO<sub>2</sub> absorption in the North Sea by ~ 34% at the end of the 21st century compared to the end of the 20th century implying a strong weakening of shelf carbon pumping. Sensitivity experiments with diagnostic tracers indicate that not more than 20% of the carbon absorbed in the North Sea contributes to the long-term carbon uptake of the world ocean. The rest remains within the ocean's mixed layer where it is exposed to the atmosphere. <br><br> The predicted decline in biological productivity, and decrease of phytoplankton concentration (in the North Sea by averaged 25%) due to reduced nutrient imports from the deeper Atlantic will probably affect the local fish stock negatively and therefore fisheries in the North Sea.

 References Adlandsvik,&nbsp;B.: Marine downscaling of a future climate scenario for the North Sea, Tellus, 60, 451–458, 2008. Allen,&nbsp;M. R. and Ingram,&nbsp;W.J.: Constraints on future changes in climate and the hydrologic cycle, Nature, 419, 224, 2002. Artioli,&nbsp;Y., Blackford,&nbsp;J. C., Butenschön,&nbsp;M., Holt,&nbsp;J. T., Wakelin,&nbsp;S. L., Thomas,&nbsp;H., Borges,&nbsp;A. V., and Allen,&nbsp;J. I.: The carbonate system in the North Sea: Sensitivity and model validation, J. Mar. Syst., 102–104, 1–13, 2012. Beaugrand,&nbsp;G.: the North Sea regime shift: evidence, causes, mechanisms and consequences, Prog. Oceanogr., 60, 245–262, 2004. Bergeron,&nbsp;J.-P. and Koueta,&nbsp;N.: Biological productivity enhancement over a&nbsp;continental shelf break (bay of biscay, NE Atlantic) evidenced by mesozooplankton aspartate transcarbamylase activity, J. Oceanogr., 67, 249–252, 2011. Borges,&nbsp;A. V., Schiettecatte,&nbsp;L.-S., Abril,&nbsp;G., Delille,&nbsp;B., and Gazeau,&nbsp;F.: Carbon dioxide in european coastal waters, Estuarine Coastal Shelf Science, 70, 375–387, 2006. Bozec,&nbsp;Y., Thomas,&nbsp;H., Elkalay,&nbsp;K., and de Baar,&nbsp;H.&nbsp;J.&nbsp;W.: The continental shelfpump for \chem{CO-2} in the North Sea – evidence from summer observation, Mar. Chem., 93, 131–147, 2005. Broecker,&nbsp;W. S., and Peng,&nbsp;T.-H.: Tracers in the sea, eldigio press, palisades, New York, 690 pp, 1982. Broecker,&nbsp;W. S.: The great ocean conveyor, Oceanography 4, 79–89, 1991. Chassot,&nbsp;E., Bonhommeau,&nbsp;S., Dulvy,&nbsp;N.&nbsp;K., Melin,&nbsp;F., Watson,&nbsp;R., Gascuel,&nbsp;D., and le Pape,&nbsp;O.: Global marine primary production constrains fisheries catches, Ecol. Lett., 13, 495–505, <a href="http://dx.doi.org/10.1111/j.1461-0248.2010.01443.x">https://doi.org/10.1111/j.1461-0248.2010.01443.x</a>, 2010. Chen,&nbsp;C.-T.&nbsp;A. and Borges,&nbsp;A.&nbsp;V.: Reconciling opposing views on carbon cycling in the coastal ocean: continental shelves as sinks and near-shore ecosystems as sources of atmospheric \chem{CO-2}, Deep-Sea Res. Pt.&nbsp;II, 56, 578–590, 2009. Dobrynin,&nbsp;M.: Investigating the dynamics of suspended particulate matter in the North Sea using a&nbsp;hydrodynamic transport model and satellite data assimilation, reports of the gkss research center, GKSS-Forschungszentrum Geesthacht GmbH, 12/2009, 93 pp., ISSN 0344-9629, 2009. Durack,&nbsp;P. J., Wijffels,&nbsp;S. E., and Matear,&nbsp;R. J.: Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000, Science, 336, 455–458, <a href="http://dx.doi.org/10.1126/science.1212222">https://doi.org/10.1126/science.1212222</a>, 2012. Eppley,&nbsp;R. W.: Temperature and phytoplankton growth in sea, Fish. Bull., 70, 1063–1085, 1972. Food and Agriculture organization of the united nations: the state of world fisheries and aquaculture, Rome, ISSN 1020-5489, available at: <a href="http://www.fao.org/docrep/013/i1820e/i1820e.pdf">http://www.fao.org/docrep/013/i1820e/i1820e.pdf</a>, 2010. Frankignoulle,&nbsp;M. and Borges,&nbsp;A.: European continental shelf a&nbsp;significant sink for atmospheric carbon dioxide, Global Biogeochem. Cy., 15, 560–576, 2001. Friedland,&nbsp;K.&nbsp;D., Stock,&nbsp;C., Drinkwater,&nbsp;K.&nbsp;F., Link,&nbsp;J.&nbsp;S., Leaf,&nbsp;R.&nbsp;T., Shank,&nbsp;B.&nbsp;V., Rose,&nbsp;J.&nbsp;M., Pilskaln,&nbsp;C.&nbsp;H., Michael&nbsp;J.,&nbsp;and Fogarty,&nbsp;M.&nbsp;J.: Pathways between primary production and fisheries yields of large marine ecosystems, Plos One 7, e28945, <a href="http://dx.doi.org/10.1371/journal.pone.0028945">https://doi.org/10.1371/journal.pone.0028945</a>, 2012. Garcia,&nbsp;H.&nbsp;E., Locarnini,&nbsp;R.&nbsp;A., Boyer,&nbsp;T.&nbsp;P., Antonov,&nbsp;J.&nbsp;I., Zweng,&nbsp;M.&nbsp;M., Baranova,&nbsp;O.&nbsp;K., and Johnson,&nbsp;D.&nbsp;D.: World ocean atlas 2009, Vol.&nbsp;4, nutrients (phosphate, nitrate, silicate), edited by: Levitus,&nbsp;S., NOAA Atlas nesdis 71,&nbsp;us government printing office, Washington,&nbsp;DC, 398 pp., 2010. Giorgetta, M. A., Jungclaus, J. H., Reick, C. H., Legutke, S., Brovkin, V., Crueger, T., Esch, M., Fieg, K., Glushak, K., Gayler, V., Haak, H., Hollweg, H.-D., Ilyina, T., Kinne, S., Kornblueh, L., Matei, D., Mauritsen, T., Mikolajewicz, U., Mueller, W. A., Notz, D., Raddatz, T., Rast, S., Redler, R., Roeckner, E., Schmidt, H., Schnur, R., Segschneider, J., Six, K., Stockhause, M., Wegner, J., Widmann, H., Wieners, K.-H., Claussen, M., Marotzke, J., and Stevens, B: Climate change from 1850 to 2100 in MPI-ESM simulations for the Coupled Model Intercomparison Project 5, submitted, 2013. Green,&nbsp;J. A. M., Simpson,&nbsp;J. H., Legg,&nbsp;S., and Palmer,&nbsp;M. R.: Internal waves, baroclinic energy fluxes and mixing at the European shelf edge, Cont. Shelf Res., 28, 937–950, <a href="http://dx.doi.org/10.1016/j.csr.2008.01.014">https://doi.org/10.1016/j.csr.2008.01.014</a>, 2008. Gröger,&nbsp;M. and Mikolajewicz, U.: Note on the CO<sub>2</sub> air-sea gas exchange at high temperatures, Ocean Model., 39, 284–290, <a href="http://dx.doi.org/10.1016/j.ocemod.2011.05.003">https://doi.org/10.1016/j.ocemod.2011.05.003</a>, 2011. Groß{}e,&nbsp;F. and Moll,&nbsp;A.: Validation tool for analyzing vertical profile data of one state variable (valpro1var) by comparison of merged observational data sets and their preparation (obs_prep) – description and user guide, Technical Reports 01-2011, Institute of Oceanography, Hamburg, Germany, 83 pages, 2011. Gypens, N., Lancelot, C., and Borges, A. V.: Carbon dynamics and CO<sub>2</sub> air-sea exchanges in the eutrophied coastal waters of the Southern Bight of the North Sea: a modelling study, Biogeosciences, 1, 147–157, <a href="http://dx.doi.org/10.5194/bg-1-147-2004">https://doi.org/10.5194/bg-1-147-2004</a>, 2004. Heath,&nbsp;M.&nbsp;R., Edwards,&nbsp;A.&nbsp;C., Paetsch,&nbsp;J., and Turell,&nbsp;W.&nbsp;R.: Modelling the behaviour of nutrients in the coastal waters of Scotland, fisheries research services marine laboratory aberdeen, Scottish executive central research unit contract, 106&nbsp;pp., 2002. Heinze,&nbsp;C., Maier-Reimer,&nbsp;E., Winguth,&nbsp;A. M. E., and Archer,&nbsp;D.: A global oceanic sediment model for long term climate studies, Global Biogeochem. Cycles, 13, 221–250, 1999. Heldt,&nbsp;I. M., and Soden,&nbsp;B. J.: Robust responses of the hydrological cycle to global warming, J. Clim. 19, 5686–5696, 2006. Hibler,&nbsp;W. D.: A Dynamic Thermodynamic Sea Ice Model, J. Phys. Oceanogr., 9, 815–846, <a href="http://dx.doi.org/10.1175/1520-0485(1979)009<0815:ADTSIM>2.0.CO;2">https://doi.org/10.1175/1520-0485(1979)009<0815:ADTSIM>2.0.CO;2</a>, 1979. Holt,&nbsp;J., Wakelin,&nbsp;S., and Huthnance, J.: Down-welling circulation of the northwest european continental shelf: a driving mechanism for the continental shelf carbon pump, Geophys. Res. Lett., 36, l14602, <a href="http://dx.doi.org/10.1029/2009gl038997">https://doi.org/10.1029/2009gl038997</a>, 2009. Holt,&nbsp;J., Wakelin,&nbsp;S, Lowe,&nbsp;J., and Tinker,&nbsp;J.: The potential impacts of climate change on the hydrography of the northwest european continental shelf, Prog. Oceanogr., 86, 361–379, 2010. Huthnance, J. M., Holt, J. T., and Wakelin, S. L.: Deep ocean exchange with west-European shelf seas, Ocean Sci., 5, 621–634, <a href="http://dx.doi.org/10.5194/os-5-621-2009">https://doi.org/10.5194/os-5-621-2009</a>, 2009. Ilyina,&nbsp;T., Six,&nbsp;K., Segschneider,&nbsp;J., Maier-Reimer,&nbsp;E., Li,&nbsp;H., and Nunez-Riboni,&nbsp;I.: The global ocean biogeochemistry model HAMOCC: model architecture and performance as component of the mpi-earth system model in different cmip5 experimental realizations, J. Adv. Model. Earth Syst., <a href="http://dx.doi.org/10.1002/jame.20017">https://doi.org/10.1002/jame.20017</a>, accepted, 2013. Joint, I., Wollast, R., Chou, L., Batten, S., Elskens, M., Edwards, E., Hirst, A., Burkill, P., Groom, S., Gibb, S., Miller,&nbsp;A., Hydes, D., Dehairs, F., Antia, A., Barlow, R., Rees, A., Pomroy, A., Brockmann, U., Cummings, D., Lampitt, R., Loijens, M., Mantoura, F., Miller, P., Raabe, T., Alvarez-Salgado, X., Stelfox, C., and Woolfenden, J.: Pelagic production at the Celtic Sea shelf break (1995), Deep-Sea Res. Pt.&nbsp;I, 48, 3049–3081, 2001. Jungclaus, J., Keenlyside,&nbsp;N., Botzet,&nbsp;M., Haak,&nbsp;H, Luo,&nbsp;J.-J., Latif,&nbsp;M. Marotzke,&nbsp;J., Mikolajewicz,&nbsp;U., and Roeckner,&nbsp;E.: Ocean circulation and tropical variability in the coupled model ECHAM5/mpi-om, J. Climate, 19, 3952–972, https://doi.org/ http://dx.doi.org/10.1175/jcli3827.1, 2006. Jungclaus,&nbsp;J. H., Fischer,&nbsp;N., Haak,&nbsp;H., Lohmann,&nbsp;K., Marotzke,&nbsp;J., Matei,&nbsp;D., Mikolajewicz,&nbsp;U., Notz,&nbsp;D., and von Storch,&nbsp;J.-S: Characteristics of the ocean simulations in mpiom, the ocean component of the MPI Earth System Model, J. Adv. Model. Earth Syst., <a href="http://dx.doi.org/10.1002/jame.20023">https://doi.org/10.1002/jame.20023</a>, 2013. Kühn,&nbsp;W., Paetsch,&nbsp;J., Thomas,&nbsp;H., Borges,&nbsp;A.&nbsp;V., Schiettecatte,&nbsp;L.&nbsp;S., Bozec,&nbsp;Y., and Prowe,&nbsp;A.&nbsp;E.&nbsp;F.: Nitrogen and carbon cycling in the North Sea and exchange with the north Atlantic – a&nbsp;model case study, part ii: carbon budget and fluxes, Cont. Shelf Res., 16, 1701–1716, 2010. Kanzow, T., Cunningham,&nbsp; S. A., Johns,&nbsp; W. E., Hirschi,&nbsp;J. J.-M., Marotzke,&nbsp;J., Baringer,&nbsp;M. O., Meinen,&nbsp;C. S., Chidichimo,&nbsp;M. P., Atkinson,&nbsp; C., Beal,&nbsp;L. M., Bryden,&nbsp;H. L., and Collins,&nbsp;J.: Seasonal variability of the Atlantic meridional overturning circulation at 26.5° N, J. Clim., 23, 5678–5698, <a href="http://dx.doi.org/10.1175/2010JCLI3389.1">https://doi.org/10.1175/2010JCLI3389.1</a>, 2010. Lorkowski, I., Paetsch, J., Moll, A., and Kühn, W.: Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – comparing effects of abiotic and biotic drivers of the gas-exchange of co<sub>2</sub>, Esutar. Coast. Shelf S., 100, 38–57, 2012. Marsland,&nbsp;S.&nbsp;J., Haak,&nbsp;H., Jungclaus,&nbsp;J.&nbsp;H., Latif,&nbsp;M., and Röske,&nbsp;F.: The max planck institute global ocean/sea-ice model with orthogonal curvilinear coordinates, pelagic production at the celtic sea shelf break (1995), Ocean Model., 5, 91–127, 2003. Maier-Reimer,&nbsp;e.: geochemical cycles in an ocean general circulation model. preindustrial tracer distributions, Blobal Biogeochemical Cycles, 7, 645–677, 1993. Maier-Reimer,&nbsp;E., Kriest,&nbsp;I., Segschneider,&nbsp;J., and Wetzel,&nbsp;P.: The hamburg ocean carbon cycle model hamocc 5.1 – technical description release 1.1, reports on earth system science, 14, 50&nbsp;pp., available at: <a href="http://www.mpimet.mpg.de/fileadmin/publikationen/erdsystem_14.pdf">http://www.mpimet.mpg.de/fileadmin/publikationen/erdsystem_14.pdf</a>, 2005. Meier,&nbsp;H.E.M, Hordoir,&nbsp;R., Andersson,&nbsp;H.C., Dieterich,&nbsp;C., Eilola,&nbsp;K., Gustafsson,&nbsp;B.G., Höglund,&nbsp;A., and Schimanke,&nbsp;S.: Modeling the combined impact of changing climate and changing nutrient loads on the Baltic sea environment in an ensemble of transient simuilation for 1961-2099, Climate Dynamics, 39, 2421–2441, https://doi.org/<a href="http://dx.doi.org/10.1007/s00382-012-1339-7">10.1007/s00382-012-1339-7</a> Meybeck, M. and Ragu, A.: River discharges to the oceans: an assessment of suspended solids, major ions and nutrients, unpublished report of the United Nations Environmental Programme, 1995. Moll,&nbsp;A.: Regional distribution of primary production in the North Sea simulated by a&nbsp;three-dimensional model, J. Marine Syst., 16, 151–170, 1998. Moll,&nbsp;A. and Radach,&nbsp;G.: Review of three-dimensional ecological modelling related to the North Sea shelf system, part 1: models and their results, Prog. Oceanogr., 57, 175–217, https://doi.org/<a href="http://dx.doi.org/10.1016/s0079-6611(03)00067-3">10.1016/s0079-6611(03)00067-3</a>, 2003. Mikolajewicz, U., Gröger, M., Maier-Reimer, E., Schurgers, G. Vizcaino, M.: Long-term effects of anthropogenic CO<sub>2</sub> emissions simulated with a complex earth system model, Clim. Dyn., 28, 599–633, <a href="http://dx.doi.org/10.1007/s00382-006-0204-y">https://doi.org/10.1007/s00382-006-0204-y</a>, 2007. New,&nbsp;A.&nbsp;L. and Pingree,&nbsp;R.&nbsp;D.: Evidence for internal tidal mixing near the shelf break in the bay of biscay, Deep-Sea Res., 37, 1783–1803, 1990. Olbert,&nbsp;A., Hartnett,&nbsp;M., Dabrowski,&nbsp;T., and Mikolajewicz,&nbsp;U.: Long-term inter-annual variability of a cyclonic gyre in the western Irish Sea, Cont. Shelf Res., 31, 1343–1356, <a href="http://dx.doi.org/10.1016/j.csr.2011.05.010">https://doi.org/10.1016/j.csr.2011.05.010</a>, 2011. Orr,&nbsp;J., Maier-Reimer,&nbsp;E., Mikolajewicz,&nbsp;U., Monfray,&nbsp;P., Sarmiento,&nbsp;J.&nbsp;L., Toggweiler,&nbsp;J.&nbsp;R., Taylor,&nbsp;N.&nbsp;K., Palmer,&nbsp;J., Gruber,&nbsp;N., Sabine,&nbsp;C.-L., le Quere,&nbsp;C., Key,&nbsp;R.&nbsp;M., and Boutin,&nbsp;J.: Estimates of anthropogenic carbon uptake from four 3-d global ocean models, Global Biogeochem. cy., 15, 43–60, 2001. Pacanowski,&nbsp;R. C. and Philander,&nbsp;S. G. H.: Parameterization of vertical mixing in numerical models of tropical oceans, J. Phys. Oceanogr, 11, 1981. Paetsch,&nbsp;J. and Kühn, W.: Nitrogen and carbon cycling in the North Sea and exchange with the north Atlantic&nbsp;–&nbsp;a&nbsp;model study. part&nbsp;i. nitrogen budget and fluxes, Cont. Shelf Res., 28, 767–787, 2008. Paetsch,&nbsp;J. and Lenhart, H.-J.: Daily loads of nutrients, total alkalinity, dissolved inorganic carbon and dissolved organic carbon of the european continental rivers for the years 1977–2002, reports center for marine und climate research – Series b: Oceanography 2004, University of Hamburg, 2004. Pauly,&nbsp;D., Christensen,&nbsp;V., Guenette,&nbsp;S., Pitcher,&nbsp;T.&nbsp;J., Rashid,&nbsp;T.&nbsp;U., Walters,&nbsp;C.&nbsp;J., Watson,&nbsp;R., and Zeller,&nbsp;D.: Towards sustainability in world fisheries, Nature, 418, 689–695, 2002. Persechino,&nbsp;A., Mignot,&nbsp;J., Swingedouw,&nbsp;D., Labetoulle,&nbsp;S., and Guilyardi,&nbsp;E.: Decadal predictability of the Atlantic meridional overturning circulation and climate in the IPSL-CM5A-LR model, Clim. Dyn., <a href="http://dx.doi.org/10.1007/s00382-012-1466-1">https://doi.org/10.1007/s00382-012-1466-1</a>, 2012. Pingree,&nbsp;R.&nbsp;D. and Mardell,&nbsp;G.&nbsp;T.: Slope turbulence, internal waves, and phytoplankton growth at the celtic sea shelf break, Philos. T.&nbsp;R. Soc. Lond.&nbsp;a, 302, 663–682, 1981. Prowe,&nbsp;A.&nbsp;E.&nbsp;F., Thomas,&nbsp;H., Paetsch,&nbsp;J., Kühn,&nbsp;W., Bozec,&nbsp;Y., Schiettecatte,&nbsp;L.-S., Borges,&nbsp;A.&nbsp;V., and de Baar,&nbsp;H.&nbsp;J.&nbsp;W.: Mechanisms controlling the air-sea CO<sub>2</sub> flux in the North Sea, Cont. Shelf Res., 29, 1801–1808, 2009. Radach,&nbsp;G., and Moll,&nbsp;A.: Review of three-dimensional ecological modelling related to the North Sea shelf system. Part II: Model validation and data needs, Oceanogr. Mar. Biol.: an Anual Review, 44, 1–60, 2006. Raven,&nbsp;J.&nbsp;A. and Falkowski,&nbsp;P.&nbsp;G.: Oceanic sinks for atmospheric CO<sub>2</sub>, Plant Cell Environ., 2, 741–755, <a href="http://dx.doi.org/10.1046/j.1365-3040.1999.00419.x">https://doi.org/10.1046/j.1365-3040.1999.00419.x</a>, 1999. Roeckner,&nbsp;E., Lautenschlager,&nbsp;M., and Esch,&nbsp;M.: IPCC-ar4 mpi-ECHAM5_t63l31 mpi-om_gr1.5l40, (pre-industrial control experiment): atmosphere 6 hour values mpimet/mad germany, World Data Center for Climate,&nbsp;Deutsches Klimarechenzentrum DKRZ GmbH, Hamburg, <a href="http://dx.doi.org/10.1594/wdcc/eh5-t63l31_om-gr1.5l40_ctl_6h">https://doi.org/10.1594/wdcc/eh5-t63l31_om-gr1.5l40_ctl_6h</a>, 2006. Sein, D. V., Mikolajewicz, U., Gröger, M., Maier-Reimer, E., Fast, I., Jacob, D., and Hagemann, S.: Regionally coupled atmosphere –ocean –sea ice –marine biogeochemistry model REMO/MPIOM/HAMOCC. Downscaling of future climate change A1B scenario for the North Atlantic and North European shelves, in preparation, 2013. Skogen,&nbsp;M.D., Drinkwater,&nbsp;K., Hjollo,&nbsp;S.S., and Schrumm, C.: North Sea sensitivity to atmospheric forcing, J. Mar. Syst., 78, 180–192, <a href="http://dx.doi.org/10.1016/j.jmarsys.2009.06.001">https://doi.org/10.1016/j.jmarsys.2009.06.001</a>, 2011. Steinacher,&nbsp;M., Joos,&nbsp;F., Frölicher,&nbsp;T.&nbsp;L., Bopp,&nbsp;L., Cadule,&nbsp;P., Cocco,&nbsp;V., Doney,&nbsp;S.&nbsp;C., Gehlen,&nbsp;M., Lindsay,&nbsp;K., Moore,&nbsp;J.&nbsp;K., Schneider,&nbsp;B., and Segschneider,&nbsp;J.: Projected 21st century decrease in marine productivity: a multi-model analysis, Biogeosciences, 7, 979–1005, <a href="http://dx.doi.org/10.5194/bg-7-979-2010">https://doi.org/10.5194/bg-7-979-2010</a>, 2010. Sweby,&nbsp;P.&nbsp;K.: High resolution schemes using flux limiters for hyperbolic conservation laws, Siam&nbsp;J. Numer. Anal., 21, 995–1011, 1984. Taucher, J., and Oschlies,&nbsp;A.: Can we predict the direction of marine primary production change under global warming?, Geophys. Res. Lett., 38, l02603, <a href="http://dx.doi.org/10.1029/2010gl045934">https://doi.org/10.1029/2010gl045934</a>, 2011. Taylor,&nbsp;K.&nbsp;E.: Summerizing multiple aspects of model performance in a&nbsp;single diagram, J. Geophys. Res., 106, 7183–7192, 2001. Thomas,&nbsp;H., Bozec,&nbsp;Y., Eelkalay,&nbsp;K., and de Baar,&nbsp;H.&nbsp;J.&nbsp;W.: Enhanced open ocean storage of \chem{CO-2} from shelf sea pumping, Science, 304, 1005–1008, 2004. Thomas,&nbsp;H., Bozec,&nbsp;Y., de&nbsp;Baar,&nbsp;H.&nbsp;J.&nbsp;W., Elkalay,&nbsp;K., Frankignoulle,&nbsp;M., Schiettecatte,&nbsp;L.-S., Kattner,&nbsp;G., and Borges,&nbsp;A.&nbsp;V.: The carbon budget of the North Sea, Biogeosciences, 2, 87–96, <a href="http://dx.doi.org/10.5194/bg-2-87-2005">https://doi.org/10.5194/bg-2-87-2005</a>, 2005. Thomas, H.: The continental shelf pump hypothesis: a pilot study in the North Sea (canoba), shipboard report of the rv pelagia cruises 64pe184, 64pe187, 64pe190 and 64pe195, 63 pp., R. Neth. Inst. of Sea Res., Texel, Netherlands, 2002. Thomas,&nbsp;M., Sündermann,&nbsp;J., and Maier-Reimer,&nbsp;E.: Consideration of ocean tides in an oGCM and impacts on subseasonal to decadal polar motion excitation, Geophys. Res. Lett., 28, 2457–2460, 2001. Tsunogai,&nbsp;S., Watanabe,&nbsp;S., and Sato,&nbsp;T.: Is there a&nbsp;continental shelf pump for the absorption of atmospheric \chem{CO-2}?, Tellus&nbsp;B, 51, 701–712, 1999. Wakelin,&nbsp;S.&nbsp;L., Holt,&nbsp;J. T., Blackford,&nbsp;J. C., Allen,&nbsp;J. I., Butenschön,&nbsp;M., and Artioli,&nbsp;Y.: Modeling the carbon fluxes of the northwest european continental shelf: validation and budgets, J. Geophys. Res., 117, C05020, <a href="http://dx.doi.org/10.1029/2011jc007402">https://doi.org/10.1029/2011jc007402</a>, 2012. Wanninkhof,&nbsp;R.: Relationship between wind speed and gas exchange over the ocean, J. Geophys. Res., 97, 7373–7382, 1992. Wentz,&nbsp;F. J., Ricciardulli,&nbsp;L., Hilburn,&nbsp;K., and Mears,&nbsp;C.: How Much More Rain Will Global Warming Bring?, Science, 317, 233–235, <a href="http://dx.doi.org/10.1126/science.1140746">https://doi.org/10.1126/science.1140746</a>, 2007. Wetzel, P.: Interannual and decadal variability in the air-sea exchange of CO<sub>2</sub> – a model study, reports on earth system science, 7, availble at: <a href="www.mpimet.mpg.de/fileadmin/publikationen/erdsystem_07.pdf">www.mpimet.mpg.de/fileadmin/publikationen/erdsystem_07.pdf</a>, 2004. Wetzel,&nbsp;P., Winguth,&nbsp;A., and Maier-Reimer,&nbsp;E.: Sea to air \chem{CO-2} flux from 1948 to 2003, a&nbsp;model study, Global Biogeochem. Cy., 19, gb2005, <a href="http://dx.doi.org/10.1029/2004gb002339">https://doi.org/10.1029/2004gb002339</a>, 2005. Winther,&nbsp;N.&nbsp;G. and Johannessen,&nbsp;J. A.: North Sea circulation: Atlantic inflow and its destination, J. Geophys. Res., 111, c12018, <a href="http://dx.doi.org/10.1029/2005jc003310">https://doi.org/10.1029/2005jc003310</a>, 2006. Wollast,&nbsp;R.: Continental margin – review of geoachemical settings, in: ocean margin systems, edited by: Wefer,&nbsp;G., Billet,&nbsp;D., Hebbeln,&nbsp;D., Joergenson,&nbsp;B.&nbsp;B., Schlueter,&nbsp;M.,&nbsp;and van Weering,&nbsp;T.&nbsp;C.&nbsp;E., Springer Verlag, Berlin Heidelberg New York, 15–31, 1998. Yool,&nbsp;A. and Fasham,&nbsp;J. R.: An examination of the "continental shelf pump" in an open ocean general circulation model, Global Biogeochem. Cy., 15, 831–844, 2001.