Scientific publications

We lead research into the changing marine carbonate system in the present-day ocean. We also contribute to studies on related topics including ocean acidification impacts, palaeoceanographic proxies, and sensor development.

Our key outputs

Dissolution of a submarine carbonate platform by a submerged lake of acidic seawater

Humphreys, M. P., Meesters, E. H., de Haas, H., Karancz, S., Delaigue, L., Bakker, K., Duineveld, G., de Goeyse, S., Haas, A., Mienis, F., Ossebaar, S., and van Duyl, F. C. (2022). Biogeosciences 19, 347-358.


PyCO2SYS v1.8: marine carbonate system calculations in Python

Humphreys, M. P., Lewis, E. R., Sharp, J. D. and Pierrot, D. (2022). Geoscientific Model Development 15, 15-43.


Air-sea CO2 exchange and ocean acidification in UK seas and adjacent waters

Humphreys, M. P., Artioli, Y., Bakker, D. C. E., Hartman, S. E., León, P., Wakelin, S., Walsham, P. and Williamson, P. (2020). MCCIP Science Review 2020, 54–75.


Mechanisms for a nutrient-conserving carbon pump in a seasonally stratified, temperate continental shelf sea

Humphreys, M. P., Achterberg, E. P., Hopkins, J. E., Chowdhury, M. Z. H., Griffiths, A. M., Hartman, S. E., Hull, T., Smilenova, A., Wihsgott, J., Woodward, E. M. S. and Moore, C. M. (2019). Progress in Oceanography 177, 101961.


Modelling seawater carbonate chemistry in shellfish aquaculture regions: Insights into CO2 release associated with shell formation and growth

Morris, J. P. and Humphreys, M. P. (2019). Aquaculture 501, 338–344.


On the influence of marine biogeochemical processes over CO2 exchange between the atmosphere and ocean

Humphreys, M. P., Daniels, C. J., Wolf-Gladrow, D. A., Tyrrell, T. and Achterberg, E. P. (2018). Marine Chemistry 199, 1–11.


Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design

Humphreys, M. P. (2017). ICES Journal of Marine Science 74(4), 934–940.


Stable carbon isotopes of dissolved inorganic carbon for a zonal transect across the subpolar North Atlantic Ocean in summer 2014

Humphreys, M. P., Greatrix, F. M., Tynan, E., Achterberg, E. P., Griffiths, A. M., Fry, C. H., Garley, R., McDonald, A. and Boyce, A. J. (2016). Earth System Science Data 8, 221–233.


Multidecadal accumulation of anthropogenic and remineralized dissolved inorganic carbon along the Extended Ellett Line in the northeast Atlantic Ocean

Humphreys, M. P., Griffiths, A. M., Achterberg, E. P., Holliday, N. P., Rérolle, V. M. C., Menzel Barraqueta, J.-L., Couldrey, M. P., Oliver, K. I. C., Hartman, S. E., Esposito, M. and Boyce, A. J. (2016). Global Biogeochemical Cycles 30(2), 293–310.


Collaborations and earlier work

Enhanced mercury reduction in the South Atlantic Ocean during carbon remineralization

Živković, I., Humphreys, M. P., Achterberg, E. P., Dumousseaud, C., Woodward, E. M. S., Bojanić, N., Šolić, M., Bratkič, A., Kotnik, J., Vahčič, M., Obu Vazner, K., Begu, E., Fajon, V., Shlyapnikov, Y. and Horvat, M. (2022). Marine Pollution Bulletin, 113644.


Chemical speciation models based upon the Pitzer activity coefficient equations, including the propagation of uncertainties. II. Tris buffers in artificial seawater at 25 °C, and an assessment of the seawater 'Total' pH scale

Clegg, S. L., Humphreys, M. P., Waters, J. F., Turner, D. R. and Dickson, A. G. (2022). Marine Chemistry, 104096.


Chemical speciation models based upon the Pitzer activity coefficient equations, including the propagation of uncertainties. I. Artificial seawater from 0 to 45 °C

Humphreys, M. P., Waters, J. F., Turner, D. R., Dickson, A. G. and Clegg, S. L. (2022). Marine Chemistry, 104095.


RADIv1: a non-steady-state early diagenetic model for ocean sediments in Julia and MATLAB/GNU Octave

Sulpis, O., Humphreys, M. P., Wilhelmus, M., Carroll, D., Berelson, W., Menemenlis, D., Middelburg, J. and Adkins, J. (2022). Geoscientific Model Development 15(5), 2105-2131.


Best Practice Data Standards for Discrete Chemical Oceanographic Observations

Jiang, L.-Q., Pierrot, D., Wanninkhof, R., Feely, R. A., Tilbrook, B., Alin, S., Barbero, L., Byrne, R. H., Carter, B. R., Dickson, A. G., Gattuso, J.-P., Greeley, D., Hoppema, M., Humphreys, M. P., Karstensen, J., Lange, N., Lauvset, S. K., Lewis, E. R., Olsen, A., Pérez, F. F., Sabine, C., Sharp, J. D., Tanhua, T., Trull, T. W., Velo, A., Allegra, A. J., Barker, P., Burger, E., Cai, W.-J., Chen, C.-T. A., Cross, J., Garcia, H., Hernandez-Ayon, J. M., Hu, X., Kozyr, A., Langdon, C., Lee, K., Salisbury, J., Wang, Z. A. and Xue, L (2022). Frontiers in Marine Science 8, 705638.


Equilibrium calculations of iron speciation and apparent iron solubility in the Celtic Sea at ambient seawater pH using the NICA-Donnan model

Zhu, K., Birchill, A. J., Milne, A., Ussher, S., Humphreys, M. P., Carr, N., Mahaffey, C., Lohan, M. C., Achterberg, E. P. and Gledhill, M. (2021). Marine Chemistry 237, 104038.


Air-Sea Gas Fluxes and Remineralization From a Novel Combination of pH and O2 Sensors on a Glider

Possenti, L., Humphreys, M. P., Bakker, D. C. E., Cobas-García, M., Fernand, L., Lee, G. A., Pallottino, F., Loucaides, S., Mowlem, M. C. and Kaiser, J. (2021). Frontiers in Marine Science 8, 696772.


Norwegian Sea net community production estimated from O2 and prototype CO2 optode measurements on a Seaglider

Possenti, L., Skjelvan, I., Atamanchuk, D., Tengberg, A., Humphreys, M. P., Loucaides, S., Fernand, L. and Kaiser, J. (2021). Ocean Science 17, 593–614.


Short-term responses to ocean acidification: effects on relative abundance of eukaryotic plankton from the tropical Timor Sea

Rahlff, J., Khodami, S., Voskuhl, L., Humphreys, M. P., Stolle, C., Martinez Arbizu, P., Wurl, O. and Ribas-Ribas, M. (2021). Marine Ecology Progress Series 658, 59–74.


The pH dependency of the boron isotopic composition of diatom opal (Thalassiosira weissflogii)

Donald, H. K., Foster, G. L., Fröhberg, N., Swann, G. E. A., Poulton, A., Moore, C. M. and Humphreys, M. P. (2020). Biogeosciences 17, 2825–2837.


Seasonality and spatial heterogeneity of the surface ocean carbonate system in the northwest European continental shelf

Hartman, S. E., Humphreys, M. P., Kivimäe, C., Woodward, E. M. S., Kitidis, V., McGrath, T., Hydes, D. J., Greenwood, N., Hull, T., Ostle, C., Pearce, D. J., Sivyer, D., Stewart, B. M., Walsham, P., Painter, S. C., McGovern, E., Harris, C., Griffiths, A., Smilenova, A., Clarke, J., Davis, C., Sanders, R. and Nightingale, P. (2019). Progress in Oceanography 177, 101909.


Winter weather controls net influx of atmospheric CO2 on the north-west European shelf

Kitidis, V., Shutler, J. D., Ashton, I., Warren, M., Brown, I., Findlay, H., Hartman, S. E., Sanders, R., Humphreys, M., Kivimäe, C., Greenwood, N., Hull, T., Pearce, D., McGrath, T., Stewart, B. M., Walsham, P., McGovern, E., Bozec, Y., Gac, J.-P., van Heuven, S. M. A. C., Hoppema, M., Schuster, U., Johannessen, T., Omar, A., Lauvset, S. K., Skjelvan, I., Olsen, A., Steinhoff, T., Körtzinger, A., Becker, M., Lefevre, N., Diverrès, D., Gkritzalis, T., Cattrijsse, A., Petersen, W., Voynova, Y.G., Chapron, B., Grouazel, A., Land, P. E., Sharples, J. and Nightingale, P. D. (2019). Scientific Reports 9, 20153.


Impact of Nonzero Intercept Gas Transfer Velocity Parameterizations on Global and Regional Ocean–Atmosphere CO2 Fluxes

Ribas-Ribas, M., Battaglia, G., Humphreys, M. P. and Wurl, O. (2019). Geosciences 9(5), 230.


Isotopic fractionation of carbon during uptake by phytoplankton across the South Atlantic subtropical convergence

Tuerena, R. E., Ganeshram, R. S., Humphreys, M. P., Browning, T. J., Bouman, H. and Piotrowski, A. P. (2019). Biogeosciences 16, 3621–3635.


What drives the latitudinal gradient in open ocean surface dissolved inorganic carbon concentration?

Wu, Y., Hain, M. P., Humphreys, M. P., Hartman, S. and Tyrrell, T. (2019). Biogeosciences 16, 2661–2681.


Controls on open-ocean North Atlantic ΔpCO2 at seasonal and interannual timescales are different

Henson, S. A., Humphreys, M. P., Land, P., Shutler, J., Goddijn-Murphy, L., Warren, M. and Schuster, U. (2018). Geophysical Research Letters 45.


Geographical CO2 sensitivity of phytoplankton correlates with ocean buffer capacity

Richier, S., Achterberg, E. P., Humphreys, M. P., Poulton, A. J., Suggett, D. J., Tyrrell, T. and Moore, C. M. (2018). Global Change Biology 24, 4438–4452.


The GEOTRACES Intermediate Data Product 2017

Schlitzer, R. et al. [286 authors incl. Humphreys, M. P.] (2018). Chemical Geology 493, 210–223.


Biological Pump

Giering, S. L. and Humphreys, M. P. (2017). Encylopedia of Geochemistry, ed. White, W. M., Springer, 1–6.


Characterization of a Time-Domain Dual Lifetime Referencing pCO2 Optode and Deployment as a High-Resolution Underway Sensor across the High Latitude North Atlantic Ocean

Clarke, J. S., Humphreys, M. P., Tynan, E., Kitidis, V., Brown, I., Mowlem, M. C. and Achterberg, E. P. (2017). Frontiers in Marine Science 4(396).


A multi-decade record of high-quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

Bakker, D. C. E. et al. [92 authors incl. Humphreys, M. P.] (2016). Earth System Science Data 8, 383–413.


An internally consistent dataset of δ13C-DIC in the North Atlantic Ocean – NAC13v1

Becker, M., Andersen, N., Erlenkeuser, H., Humphreys, M. P., Tanhua, T. and Körtzinger, A. (2016). Earth System Science Data 8, 559–570.


Species-specific calcite production reveals Coccolithus pelagicus as the key calcifier in the Arctic Ocean

Daniels, C. J., Poulton, A. J., Young, J. R., Esposito, M., Humphreys, M. P., Ribas Ribas, M., Tynan, E. and Tyrrell, T. (2016). Marine Ecology Progress Series 555, 29–47.


Carbon dioxide and ocean acidification observations in UK waters: Synthesis report with a focus on 2010–2015

Ostle, C., Williamson, P., Artoli, Y., Bakker, D. C. E., Birchenough, S., Davis, C. E., Dye, S., Edwards, M., Findlay, H. S., Greenwood, N., Hartman, S., Humphreys, M. P., Jickells, T., Johnson, M., Landschützer, P., Parker, R., Pearce, D., Pinnegar, J., Robinson, C., Schuster, U., Silburn, B., Thomas, R., Wakelin, S., Walsham, P. and Watson, A. J. (2016). Department for Environment, Food and Rural Affairs, pp. 44.


Production of dissolved organic carbon by Arctic plankton communities: Responses to elevated carbon dioxide and the availability of light and nutrients

Poulton, A. J., Daniels, C. J., Esposito, M., Humphreys, M. P., Mitchell, E., Ribas-Ribas, M., Russell, B. C., Stinchcombe, M. C., Tynan, E. and Richier, S. (2016). Deep-Sea Research Part II 127, 60–74.


Physical and biogeochemical controls on the variability in surface pH and calcium carbonate saturation states in the Atlantic sectors of the Arctic and Southern Oceans

Tynan, E., Clarke, J. S., Humphreys, M. P., Ribas-Ribas, M., Esposito, M., Rérolle, V. M. C., Schlosser, C., Thorpe, S. E., Tyrrell, T. and Achterberg, E. P. (2016). Deep-Sea Research Part II 127, 7–27.


Measurements of the stable carbon isotope composition of dissolved inorganic carbon in the northeastern Atlantic and Nordic Seas during summer 2012

Humphreys, M. P., Achterberg, E. P., Griffiths, A. M., McDonald, A. and Boyce, A. J. (2015). Earth System Science Data 7, 127–135.