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5. Bioavailability of Macro and Micronutrients Across Global Topsoils: Main Drivers and Global Change Impacts

Author

Ochoa-Hueso, Raúl, Delgado-Baquerizo, Manuel, Risch, Anita C., Ashton, Louise, Augustine, David, Bélanger, Nicolas, Bridgham, Scott, Britton, A.J., Bruckman, Viktor J., Camarero, Jesús Julio, Cornelissen, Gerard, Crawford John A., Dijkstra, Feike A., Diochon, Amanda, Earl, Stevan, Edgerley, James, Epstein, Howard, Felton, Andrew, Fortier, Julien, Gagnon, Daniel, Greer, Ken, Griffiths, Hannah M, Halde, Caroline, Hanslin, Hans M., Harris, Lorna I., Hartsock, Jeremy, Hendrickson, Paul, Hovstad, Knut Anders, Hu, Jia, Jani. Arun D., Kent, Kelcy, Kerdraon-Byrne, Deirdre, Khalsa, Sat Darshan S., Lai, Derrick Y. F., Lambert, France, LaMontagne, Jalene M., Lavergne, Stéphanie, Lawrence. Beth A., Littke, Kim, Leeper, Abigail C., Licht, Mark A., Liebig, Mark A., Lynn, Joshua S., Maclean, Janet E., Martinsen, Vegard, McDaniel, Marshall D., McIntosh, Anne C. S., Miesel, Jessica R., Miller, Jim, Mulvaney, Michael J., Moreno, Gerardo, Newstead, Laura, Pakeman, Robin J., Pergl, Jan, Piñeiro, Juan, Quigley, Kathleen, Radtke, Troy M., Reed, Paul, Rolo, Víctor, Rudgers, Jennifer, Rutherford, P. Michael, Sayer, Emma J., Serrano-Grijalva, Lilia, Strack, Maria, Sukdeo, Nicole, Taylor, Andy F. S., Truax, Benoit, Tsuji, Leonard J. S., Van Gestel, Natasja, Vaness, Brenda M., Van Sundert, Kevin, Vitkova, Michaela, Weigel, R., Wilton, Meaghan, Yano, Yuriko, Teen, Ewing, Bremer, Eric, Ministerio de Ciencia e Innovación (España), Agencia Estatal de Investigación (España), Ministerio de Universidades (España), European Commission, Junta de Andalucía, Fundación Biodiversidad, National Science Foundation Macrosystems Biology, Belgian American Educational Foundation, Fulbright Program and the Fund for Scientific Research-Flanders, European Agricultural Fund for Rural Development, Czech Science Foundation, Czech Academy of Sciences, National Science Foundation (US), National Institute of Food and Agriculture (US), DePaul University, Huron Mountain Wildlife Foundation, Ochoa-Hueso, Raúl, Delgado-Baquerizo, Manuel, Britton, A.J., Camarero, Jesús Julio, Earl, Stevan, Epstein, Howard, Felton, Andrew, Halde, Caroline, Hanslin, Hans M., Harris, Lorna I., Hartsock, Jeremy, Hovstad, Knut Anders, Khalsa, Sat Darshan S., LaMontagne, Jalene M., Lavergne, Stéphanie, Littke, Kim, Licht, Mark A., McDaniel, Marshall D., McIntosh, Anne C. S., Miesel, Jessica R., Moreno, Gerardo, Pakeman, Robin J., Pinno, Bradley D., Piñeiro, Juan, Rolo, Víctor, Rutherford, P. Michael, Sayer, Emma J., Van Sundert, Kevin, Vitkova, Michaela, Weigel, R., and Wilton, Meaghan

Abstract

14 páginas.- 6 figuras.- 53 referencias, Understanding the chemical composition of our planet's crust was one of the biggest questions of the 20th century. More than 100 years later, we are still far from understanding the global patterns in the bioavailability and spatial coupling of elements in topsoils worldwide, despite their importance for the productivity and functioning of terrestrial ecosystems. Here, we measured the bioavailability and coupling of thirteen macro- and micronutrients and phytotoxic elements in topsoils (3–8 cm) from a range of terrestrial ecosystems across all continents (∼10,000 observations) and in response to global change manipulations (∼5,000 observations). For this, we incubated between 1 and 4 pairs of anionic and cationic exchange membranes per site for a mean period of 53 days. The most bioavailable elements (Ca, Mg, and K) were also amongst the most abundant in the crust. Patterns of bioavailability were biome-dependent and controlled by soil properties such as pH, organic matter content and texture, plant cover, and climate. However, global change simulations resulted in important alterations in the bioavailability of elements. Elements were highly coupled, and coupling was predictable by the atomic properties of elements, particularly mass, mass to charge ratio, and second ionization energy. Deviations from the predictable coupling-atomic mass relationship were attributed to global change and agriculture. Our work illustrates the tight links between the bioavailability and coupling of topsoil elements and environmental context, human activities, and atomic properties of elements, thus deeply enhancing our integrated understanding of the biogeochemical connections that underlie the productivity and functioning of terrestrial ecosystems in a changing world., We acknowledge the following people as additional data contributors: Drs. G. Blume-Werry, V. Bruckman, J. Buss, S. Collins, E. Dorrepaal, K.N. Egger, J. Fridley, Gibson-Roy, R. Harrison, J. Heberling, K. Helsen, E. Hinman, A. K olstad, N. Lemoine, M. Lesser, E. Li, S. E. Macdonald, E. Mallory, E. Massicotte, H.B. Massicotte, T. Moore, C. Morris, L. Nijs, M. Smith, Suojala-Ahlfors, E. Thiffault, K. Trepanier, R. Uusitalo, L. Van Langenhove, S. Vicca, F. Wang, M. Werner, K. White and S. Wilson. R.O.H. was funded by the Ramón y Cajal program of the MICINN (RYC-2017 22032), by the R&D Project of the Ministry of Science and Innovation PID2019-106004RA-I00 funded by MCIN/AEI/10.13039/501100011033, by the program José Castillejo” of the “Ministry of Universities” (CAS21/00125), by a project of the European Regional Development Fund (FEDER) and the Ministry of Economic Transformation, Industry, Knowledge and Universities of the Junta de Andalucía (ERDF Andalucía 2014–2020 Thematic objective “01—Reinforcement of research, technological development and innovation”): P20_00323 (FUTURE-VINES), by the European Agricultural Fund for Rural Development (EAFRD) through the “Aid to operational groups of the European Association of Innovation (AEI) in terms of agricultural productivity and sustainability,” Reference: GOPC-CA-20-0001, and from Fundación Biodiversidad (SOILBIO). M.D-B. was supported by a Ramón y Cajal Grant (RYC2018-025483-I), a project from the Spanish Ministry of Science and Innovation (PID2020-115813RA-I00), and a project PAIDI 2020 from the Junta de Andalucía (P20_00879). JP acknowl-edges funding from MICINN (RYC–2021–033454). S. Bridgham and P. Reed were supported from National Science Foundation Macrosystems Biology Grant 1340847. KVS acknowledges support from the Belgian American Educational Foundation (Paul Vernel Fellow), the Fulbright Program and the Fund for Scientific Research-Flanders. J. Pergl and M. Vítková were partly supported by 17-19025S, EXPRO Grant 19-28807X (Czech Science Foundation), BiodivClim Call 2019 (Grant TACR SS70010001) and long-term research development project RVO 67985939 (Czech Academy of Sciences). Natasja van Gestel was funded by the National Science Foundation Grant 1643871. Stevan Earl was partially supported by the National Science Foundation under Grant DEB-2224662, Central Arizona-Phoenix Long-Term Ecological Research Program (CAP LTER). Lilia Serrano-Grijalva has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 890874. Kevin van Sundert acknowledges support from the Fund for Scientific Research-Flanders. Yuriko Yano acknowledges USDA, National Institute of Food and Agriculture Grant, Award number 2015-67020-23454. A. Leeper, B. Lawrence, and J. LaMontagne acknowledge support from National Science Foundation Grant DEB-1745496, the University Research Council Collaborative Grant from DePaul University, and the Huron Mountain Wildlife Foundation.

Published
2023

7. A holistic and comprehensive data approach validates the distribution of the critically endangered flapper skate (Dipturus intermedius)

Author

Garbett, Amy, primary, Loca, Sophie L., additional, Barreau, Thomas, additional, Biscoito, Manuel, additional, Bradley, Caroline, additional, Breen, Joe, additional, Clarke, Maurice, additional, Ellis, Jim R., additional, Griffiths, Andrew M., additional, Hannon, Gary, additional, Jakobsdóttir, Klara, additional, Junge, Claudia, additional, Lynghammar, Arve, additional, McCloskey, Matthew, additional, Minos, George, additional, Phillips, Natasha D., additional, Prodöhl, Paulo A., additional, Roche, William, additional, Iglésias, Samuel P., additional, Thorburn, James, additional, and Collins, Patrick C., additional

Published
2023
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8. Super-killer CTLs are generated by single gene deletion of Bach2

Author

Barton, Philippa R, Davenport, Alexander J, Hukelmann, Jens, Cantrell, Doreen A, Stinchcombe, Jane C, Richard, Arianne C, Griffiths, Gillian M, Griffiths, Gillian M [0000-0003-0434-5842], and Apollo - University of Cambridge Repository

Subjects
Cytotoxicity, Immunologic, Proteomics, Mice, Basic-Leucine Zipper Transcription Factors, Perforin, CTL, cytotoxicity, Animals, BACH2, CD8-Positive T-Lymphocytes, Gene Deletion, Granzymes, T-Lymphocytes, Cytotoxic
Abstract

Bach2 codes for a transcriptional regulator exerting major influences on T cell-mediated immune regulation. Effector CTLs derived from in vitro activation of murine CD8+ T cells showed increased proliferative and cytolytic capacity in the absence of BACH2. Before activation, BACH2-deficient splenic CD8+ T cells had a higher abundance of memory and reduced abundance of naïve cells compared to wild-type. CTLs derived from central memory T cells were more potently cytotoxic than those derived from naïve T cells, but even within separated subsets, BACH2-deficiency conferred a cytotoxic advantage. Immunofluorescence and electron microscopy revealed larger granules in BACH2-deficient compared to wild-type CTLs, and proteomic analysis showed an increase in granule content, including perforin and granzymes. Thus, the enhanced cytotoxicity observed in effector CTLs lacking BACH2 arises not only from differences in their initial differentiation state but also inherent production of enlarged cytolytic granules. These results demonstrate how a single gene deletion can produce a CTL super-killer.

Published
2022

15. Early Change in Fecal Calprotectin Predicts One‐Year Outcome in Children Newly Diagnosed With Ulcerative Colitis

Author

Krishnakumar, Chenthan, primary, Ananthakrishnan, Ashwin N., additional, Boyle, Brendan M., additional, Griffiths, Anne M., additional, LeLeiko, Neal S., additional, Mack, David R., additional, Markowitz, James F., additional, Rosh, Joel R., additional, Sauer, Cary G., additional, Walters, Thomas D., additional, Bonkowski, Erin, additional, Denson, Lee A., additional, Hyams, Jeffrey S., additional, and Kugathasan, Subra, additional

Published
2021
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20. Identifying causes of low persistence of perennial ryegrass (Lolium perenne) dairy pasture using the Basic Grassland model (BASGRA)

Author

Woodward, Simon J.R., Van Oijen, Marcel, Griffiths, Wendy M., Beukes, Pierre C., Chapman, David F., Woodward, Simon J.R., Van Oijen, Marcel, Griffiths, Wendy M., Beukes, Pierre C., and Chapman, David F.

Abstract

Recent years have seen a decline in herbage production and tiller populations in New Zealand's perennial ryegrass (Lolium perenne) dairy pastures. One hypothesis is that modern genotypes are less suited to the warmer, drier weather experienced under changing climate patterns. In this study, a combination of long‐term trial data (2011–2017) and a process‐based pasture model (BASGRA) was used to explore the causes and possible mitigation of the observed production and population loss at three sites (dryland sites in Northland and Waikato and an irrigated site in Canterbury). Bayesian calibration was used to identify the model parameter sets that were consistent with the trial data and to identify differences in plant morphology and responses between sites. The model successfully simulated the observed differences in tiller numbers between the dryland sites, where populations and production declined rapidly after the second year and the irrigated site where populations and production were maintained. Analysis of the model calibrations along with preliminary scenario simulations suggests that increased tiller mortality associated with drought was the main cause of persistence failure at the dryland sites and that decreasing grazing pressure or breeding for tolerance to higher temperatures may not be successful in preventing this.

Published
2020

21. Complex associations between cross-kingdom microbial endophytes and host genotype in ash dieback disease dynamics

Author

Griffiths, Sarah M, Galambao, Marciana, Rowntree, Jennifer, Goodhead, Ian, Hall, Jeanette, O'Brien, David, Atkinson, Nick, Antwis, Rachael E, Griffiths, Sarah M, Galambao, Marciana, Rowntree, Jennifer, Goodhead, Ian, Hall, Jeanette, O'Brien, David, Atkinson, Nick, and Antwis, Rachael E

Abstract

Tree pathogens are a major threat to forest ecosystems. Conservation management strategies can exploit natural mechanisms of resistance, such as tree genotype and host‐associated microbial communities. However, fungal and bacterial communities are rarely looked at in the same framework, particularly in conjunction with host genotype. Here, we explore these relationships and their influence on ash dieback disease, caused by the pathogen Hymenoscyphus fraxineus, in European common ash trees. We collected leaves from UK ash trees and used microsatellite markers to genotype trees, quantitative PCR to quantify H. fraxineus infection load and ITS and 16S rRNA amplicon sequencing to identify fungal and bacterial communities, respectively. There was a significant association between H. fraxineus infection intensity and ash leaf fungal and bacterial community composition. Higher infection levels were positively correlated with fungal community alpha‐diversity, and a number of fungal and bacterial genera were significantly associated with infection presence and intensity. Under higher infection loads, leaf microbial networks were characterized by stronger associations between fewer members than those associated with lower infection levels. Together these results suggest that H. fraxineus disrupts stable endophyte communities after a particular infection threshold is reached, and may enable proliferation of opportunistic microbes. We identified three microbial genera associated with an absence of infection, potentially indicating an antagonistic relationship with H. fraxineus that could be utilized in the development of anti‐pathogen treatments. Host genotype did not directly affect infection, but did significantly affect leaf fungal community composition. Thus, host genotype could have the potential to indirectly affect disease susceptibility through genotype × microbiome interactions, and should be considered when selectively breeding trees. Synthesis. We show that the diver

Published
2020

25. A new direction for Traffic

Author

Marks, Michael S., primary, Parton, Robert G., additional, Schroer, Trina A., additional, Tooze, Sharon A., additional, Brodsky, Frances M., additional, Marsh, Mark, additional, Schmid, Sandra L., additional, Griffiths, Gillian M., additional, Stevens, Tom H., additional, and van Meer, Gerrit, additional

Published
2020
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34. Complex associations between cross-kingdom microbial endophytes and host genotype in ash dieback disease dynamics

Author

Griffiths, Sarah M, Galambao, Marciana, Rowntree, Jennifer, Goodhead, Ian, Hall, Jeanette, O'Brien, David, Atkinson, Nick, Antwis, Rachael E, Griffiths, Sarah M, Galambao, Marciana, Rowntree, Jennifer, Goodhead, Ian, Hall, Jeanette, O'Brien, David, Atkinson, Nick, and Antwis, Rachael E

Abstract

Tree pathogens are a major threat to forest ecosystems. Conservation management strategies can exploit natural mechanisms of resistance, such as tree genotype and host‐associated microbial communities. However, fungal and bacterial communities are rarely looked at in the same framework, particularly in conjunction with host genotype. Here, we explore these relationships and their influence on ash dieback disease, caused by the pathogen Hymenoscyphus fraxineus, in European common ash trees. We collected leaves from UK ash trees and used microsatellite markers to genotype trees, quantitative PCR to quantify H. fraxineus infection load and ITS and 16S rRNA amplicon sequencing to identify fungal and bacterial communities, respectively. There was a significant association between H. fraxineus infection intensity and ash leaf fungal and bacterial community composition. Higher infection levels were positively correlated with fungal community alpha‐diversity, and a number of fungal and bacterial genera were significantly associated with infection presence and intensity. Under higher infection loads, leaf microbial networks were characterized by stronger associations between fewer members than those associated with lower infection levels. Together these results suggest that H. fraxineus disrupts stable endophyte communities after a particular infection threshold is reached, and may enable proliferation of opportunistic microbes. We identified three microbial genera associated with an absence of infection, potentially indicating an antagonistic relationship with H. fraxineus that could be utilized in the development of anti‐pathogen treatments. Host genotype did not directly affect infection, but did significantly affect leaf fungal community composition. Thus, host genotype could have the potential to indirectly affect disease susceptibility through genotype × microbiome interactions, and should be considered when selectively breeding trees. Synthesis. We show that the diver

Published
2019

35. Fas Ligand localizes to intraluminal vesicles within NK cell cytolytic granules and is enriched at the immune synapse

Author

Lee, Jeansun, Dieckmann, Nele MG, Edgar, James R, Griffiths, Gillian M, Siegel, Richard M, Siegel, Richard M [0000-0001-5953-9893], and Apollo - University of Cambridge Repository

Subjects
intra-luminal vesicles (ILVs), B-Lymphocytes, Fas Ligand Protein, Immunological Synapses, Perforin, Tetraspanin 30, immune synapse, Cell Culture Techniques, hemic and immune systems, chemical and pharmacologic phenomena, Cytoplasmic Granules, Cytolytic granules, Granzymes, Cell Line, fas ligand (CD178), Killer Cells, Natural, Microscopy, Electron, HLA Antigens, Humans, biological phenomena, cell phenomena, and immunity
Abstract

INTRODUCTION: T cell and NK cell cytotoxicity can be mediated via the perforin/granzyme system and Fas Ligand (FasL, CD178). FasL is synthesized as a type II transmembrane protein that binds its cognate receptor Fas (CD95). Membrane-bound FasL is expressed on the plasma membrane of activated lymphocytes and is the main form of FasL with cytotoxic activity, but whether FasL is delivered to the immune synapse along with granzyme and perforin-containing granules is unclear. METHODS: We stably expressed FasL-fluorescent fusion proteins into human NK cells and examined the localization of FasL relative to other intracellular markers by confocal and immunoelectron microscopy, and examined the trafficking of FasL during formation of immune synapses with HLA-deficient B cells. RESULTS: FasL co-localized with CD63 more strongly than perforin or Lamp1+ in cytolytic granules. Electron microscopy revealed that FasL is enriched on intraluminal vesicles (ILVs) adjacent to the dense-core within cytolytic granules. In NK cells forming immune synapses with HLA-deficient B cells, a portion of FasL-containing granules re-localize toward the immune synapse, while a distinct pool of FasL remains at the distal pole of the cell. CONCLUSIONS: Localization of FasL to intra-luminal vesicles within cytolytic granules facilitates FasL trafficking to immune synapses and cytotoxic function in NK cells.

Published
2018

39. Management of Paediatric Ulcerative Colitis, Part 1

Author

Turner, Dan, primary, Ruemmele, Frank M., additional, Orlanski‐Meyer, Esther, additional, Griffiths, Anne M., additional, de Carpi, Javier Martin, additional, Bronsky, Jiri, additional, Veres, Gabor, additional, Aloi, Marina, additional, Strisciuglio, Caterina, additional, Braegger, Christian P., additional, Assa, Amit, additional, Romano, Claudio, additional, Hussey, Séamus, additional, Stanton, Michael, additional, Pakarinen, Mikko, additional, de Ridder, Lissy, additional, Katsanos, Konstantinos, additional, Croft, Nick, additional, Navas‐López, Victor, additional, Wilson, David C., additional, Lawrence, Sally, additional, and Russell, Richard K., additional

Published
2018
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41. Understanding and managing fish populations: keeping the toolbox fit for purpose

Author

Paris, J. R., primary, Sherman, K. D., additional, Bell, E., additional, Boulenger, C., additional, Delord, C., additional, El‐Mahdi, M. B. M., additional, Fairfield, E. A., additional, Griffiths, A. M., additional, Gutmann Roberts, C., additional, Hedger, R. D., additional, Holman, L. E., additional, Hooper, L. H., additional, Humphries, N. E., additional, Katsiadaki, I., additional, King, R. A., additional, Lemopoulos, A., additional, Payne, C. J., additional, Peirson, G., additional, Richter, K. K., additional, Taylor, M. I., additional, Trueman, C. N., additional, Hayden, B., additional, and Stevens, J. R., additional

Published
2018
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42. Munc18-2 is required for Syntaxin 11 Localization on the Plasma Membrane in Cytotoxic T-Lymphocytes

Author

Dieckmann, Nele MG, Hackmann, Yvonne, Aricò, Maurizio, Griffiths, Gillian M, Griffiths, Gillian [0000-0003-0434-5842], and Apollo - University of Cambridge Repository

Subjects
FHL4, Qa-SNARE Proteins, FHL5, Cell Membrane, Infant, Lymphohistiocytosis, Hemophagocytic, Syntaxin 11, Protein Transport, Munc18 Proteins, Microscopy, Fluorescence, CTL, Munc18-2, Mutation, Humans, Cells, Cultured, T-Lymphocytes, Cytotoxic
Abstract

Cytotoxic T-lymphocytes (CTL) kill their targets by cytolytic granule secretion at the immunological synapse. The Sec/Munc protein, Munc18-2, and its binding partner Syntaxin 11 (STX11) are both required for granule secretion, with mutations in either leading to the primary immunodeficiency, Familial Haemophagocytic Lymphohistiocytosis (FHL4 and 5). Understanding how Munc18-2 and STX11 function in CTL has been hampered by not knowing the endogenous localization of these proteins. Using a novel FHL5 Munc18-2 mutation that results in loss of protein, cytotoxicity and degranulation together with CTL from an FHL4 patient lacking STX11, enabled us to localize endogenous STX11 and Munc18-2 in CTL. Munc18-2 localized predominantly to cytolytic granules with low levels associated with the plasma membrane where STX11 localized. Importantly, while Munc18-2 localization is unaffected by the absence of STX11 in FHL4 CTL, STX11 is lost from the plasma membrane in FHL5 CTL lacking Munc18-2. These findings support a role for Munc18-2 in chaperoning STX11 to the plasma membrane where the final fusion events involved in secretion occur.

Published
2015

45. Isolation by oceanic distance and spatial genetic structure in an overharvested international fishery

Author

Truelove, Nathan K., primary, Box, Stephen J., additional, Aiken, Karl A., additional, Blythe-Mallett, Azra, additional, Boman, Erik M., additional, Booker, Catherine J., additional, Byfield, Tamsen T., additional, Cox, Courtney E., additional, Davis, Martha H., additional, Delgado, Gabriel A., additional, Glazer, Bob A., additional, Griffiths, Sarah M., additional, Kitson-Walters, Kimani, additional, Kough, Andy S., additional, Pérez Enríquez, Ricardo, additional, Preziosi, Richard F., additional, Roy, Marcia E., additional, Segura-García, Iris, additional, Webber, Mona K., additional, and Stoner, Allan W., additional

Published
2017
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49. Molecular diversity and distribution of eastern Atlantic and Mediterranean dogfishesSqualushighlight taxonomic issues in the genus

Author

Veríssimo, Ana, primary, Zaera-Perez, Diana, additional, Leslie, Rob, additional, Iglésias, Samuel P., additional, Séret, Bernard, additional, Grigoriou, Panagiotis, additional, Sterioti, Aspasia, additional, Gubili, Chrysoula, additional, Barría, Claudio, additional, Duffy, Clinton, additional, Hernández, Sebastián, additional, Batjakas, Ioannis E., additional, and Griffiths, Andrew M., additional

Published
2016
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50. Multidecadal accumulation of anthropogenic and remineralized dissolved inorganic carbon along the Extended Ellett Line in the northeast Atlantic Ocean

Author

Humphreys, Matthew P., Griffiths, Alex M., Achterberg, Eric P., Holliday, N. Penny, Rérolle, Victoire M. C., Menzel Barraqueta, Jan-Lukas, Couldrey, Matthew P., Oliver, Kevin I. C., Hartman, Susan E., Esposito, Mario, Boyce, Adrian J., Humphreys, Matthew P., Griffiths, Alex M., Achterberg, Eric P., Holliday, N. Penny, Rérolle, Victoire M. C., Menzel Barraqueta, Jan-Lukas, Couldrey, Matthew P., Oliver, Kevin I. C., Hartman, Susan E., Esposito, Mario, and Boyce, Adrian J.

Abstract

Marine carbonate chemistry measurements have been carried out annually since 2009 during UK research cruises along the Extended Ellett Line (EEL), a hydrographic transect in the northeast Atlantic Ocean. The EEL intersects several water masses that are key to the global thermohaline circulation, and therefore the cruises sample a region in which it is critical to monitor secular physical and biogeochemical changes. We have combined results from these EEL cruises with existing quality-controlled observational data syntheses to produce a hydrographic time series for the EEL from 1981 to 2013. This reveals multidecadal increases in dissolved inorganic carbon (DIC) throughout the water column, with a near-surface maximum rate of 1.800.45 mu molkg(-1)yr(-1). Anthropogenic CO2 accumulation was assessed, using simultaneous changes in apparent oxygen utilization (AOU) and total alkalinity (TA) as proxies for the biogeochemical processes that influence DIC. The stable carbon isotope composition of DIC (C-13(DIC)) was also determined and used as an independent test of our method. We calculated a volume-integrated anthropogenic CO2 accumulation rate of 2.80.4mgCm(-3)yr(-1) along the EEL, which is about double the global mean. The anthropogenic CO2 component accounts for only 316% of the total DIC increase. The remainder is derived from increased organic matter remineralization, which we attribute to the lateral redistribution of water masses that accompanies subpolar gyre contraction. Output from a general circulation ecosystem model demonstrates that spatiotemporal heterogeneity in the observations has not significantly biased our multidecadal rate of change calculations and indicates that the EEL observations have been tracking distal changes in the surrounding North Atlantic and Nordic Seas.

Published
2016
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