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2. Iodide, iodate & dissolved organic iodine in the temperate coastal ocean

Author

Matthew R. Jones, Rosie Chance, Thomas Bell, Oban Jones, David C. Loades, Rebecca May, Liselotte Tinel, Katherine Weddell, Claire Widdicombe, and Lucy J. Carpenter

Subjects
iodine speciation, biogeochemistry, marine systems, seasonal time series, iodide, iodate, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

The surface ocean is the main source of iodine to the atmosphere, where it plays a crucial role including in the catalytic removal of tropospheric ozone. The availability of surface oceanic iodine is governed by its biogeochemical cycling, the controls of which are poorly constrained. Here we show a near two-year time series of the primary iodine species, iodide, iodate and dissolved organic iodine (DOI) in inner shelf marine surface waters of the Western English Channel (UK). The median ± standard deviation concentrations between November 2019 and September 2021 (n=76) were: iodide 88 ± 17 nM (range 61-149 nM), iodate 293 ± 28 nM (198-382 nM), DOI 16 ± 16 nM (

Published
2024
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3. Surface Inorganic Iodine Speciation in the Indian and Southern Oceans From 12°N to 70°S

Author

Rosie Chance, Liselotte Tinel, Amit Sarkar, Alok K. Sinha, Anoop S. Mahajan, Racheal Chacko, P. Sabu, Rajdeep Roy, Tim D. Jickells, David P. Stevens, Martin Wadley, and Lucy J. Carpenter

Subjects
iodine, iodide, iodate, seawater, Indian Ocean, Southern Ocean, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Marine iodine speciation has emerged as a potential tracer of primary productivity, sedimentary inputs, and ocean oxygenation. The reaction of iodide with ozone at the sea surface has also been identified as the largest deposition sink for tropospheric ozone and the dominant source of iodine to the atmosphere. Accurate incorporation of these processes into atmospheric models requires improved understanding of iodide concentrations at the air-sea interface. Observations of sea surface iodide are relatively sparse and are particularly lacking in the Indian Ocean basin. Here we examine 127 new sea surface (≤10 m depth) iodide and iodate observations made during three cruises in the Indian Ocean and the Indian sector of the Southern Ocean. The observations span latitudes from ∼12°N to ∼70°S, and include three distinct hydrographic regimes: the South Indian subtropical gyre, the Southern Ocean and the northern Indian Ocean including the southern Bay of Bengal. Concentrations and spatial distribution of sea surface iodide follow the same general trends as in other ocean basins, with iodide concentrations tending to decrease with increasing latitude (and decreasing sea surface temperature). However, the gradient of this relationship was steeper in subtropical waters of the Indian Ocean than in the Atlantic or Pacific, suggesting that it might not be accurately represented by widely used parameterizations based on sea surface temperature. This difference in gradients between basins may arise from differences in phytoplankton community composition and/or iodide production rates. Iodide concentrations in the tropical northern Indian Ocean were higher and more variable than elsewhere. Two extremely high iodide concentrations (1241 and 949 nM) were encountered in the Bay of Bengal and are thought to be associated with sedimentary inputs under low oxygen conditions. Excluding these outliers, sea surface iodide concentrations ranged from 20 to 250 nM, with a median of 61 nM. Controls on sea surface iodide concentrations in the Indian Ocean were investigated using a state-of-the-art iodine cycling model. Multiple interacting factors were found to drive the iodide distribution. Dilution via vertical mixing and mixed layer depth shoaling are key controls, and both also modulate the impact of biogeochemical iodide formation and loss processes.

Published
2020
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4. Return of naturally sourced Pb to Atlantic surface waters

Author

Luke Bridgestock, Tina van de Flierdt, Mark Rehkämper, Maxence Paul, Rob Middag, Angela Milne, Maeve C. Lohan, Alex R. Baker, Rosie Chance, Roulin Khondoker, Stanislav Strekopytov, Emma Humphreys-Williams, Eric P. Achterberg, Micha J. A. Rijkenberg, Loes J. A. Gerringa, and Hein J. W. de Baar

Subjects
Science
Abstract

Anthropogenic lead (Pb) has overwhelmed natural Pb sources for over a century, yet the phasing out of leaded petrol in the early 2000s has renewed hope. Here, Bridgestock et al. use Pd isotopes to reassess the origins of Pd deposited in the tropical North Atlantic and reveal a significant natural source.

Published
2016
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5. Extensive field evidence for the release of HONO from the photolysis of nitrate aerosols

Author

Simone T. Andersen, Lucy J. Carpenter, Chris Reed, James D. Lee, Rosie Chance, Tomás Sherwen, Adam R. Vaughan, Jordan Stewart, Pete M. Edwards, William J. Bloss, Roberto Sommariva, Leigh R. Crilley, Graeme J. Nott, Luis Neves, Katie Read, Dwayne E. Heard, Paul W. Seakins, Lisa K. Whalley, Graham A. Boustead, Lauren T. Fleming, Daniel Stone, and Khanneh Wadinga Fomba

Subjects
Multidisciplinary
Abstract

Particulate nitrate ( pNO 3 − ) has long been considered a permanent sink for NO x (NO and NO 2 ), removing a gaseous pollutant that is central to air quality and that influences the global self-cleansing capacity of the atmosphere. Evidence is emerging that photolysis of pNO 3 − can recycle HONO and NO x back to the gas phase with potentially important implications for tropospheric ozone and OH budgets; however, there are substantial discrepancies in “renoxification” photolysis rate constants. Using aircraft and ground-based HONO observations in the remote Atlantic troposphere, we show evidence for renoxification occurring on mixed marine aerosols with an efficiency that increases with relative humidity and decreases with the concentration of pNO 3 − , thus largely reconciling the very large discrepancies in renoxification photolysis rate constants found across multiple laboratory and field studies. Active release of HONO from aerosol has important implications for atmospheric oxidants such as OH and O 3 in both polluted and clean environments.

Published
2023

6. Influence of the Sea Surface Microlayer on Oceanic Iodine Emissions

Author

Alice J. M. Bridger, Lucy J. Carpenter, Rosie Chance, Lloyd D. J. Hollis, Martyn W. Ward, Thomas J. Adams, Liselotte Tinel, and Stephen M. Ball

Subjects
chemistry.chemical_element, Artificial seawater, General Chemistry, 010501 environmental sciences, Iodides, Iodine, 01 natural sciences, Sea surface microlayer, Article, Hypoiodous acid, chemistry.chemical_compound, Flux (metallurgy), chemistry, 13. Climate action, Environmental chemistry, Environmental Chemistry, Seawater, Solubility, Spectroscopy, 0105 earth and related environmental sciences
Abstract

The influence of organic compounds on iodine (I2) emissions from the O3 + I- reaction at the sea surface was investigated in laboratory and modeling studies using artificial solutions, natural subsurface seawater (SSW), and, for the first time, samples of the surface microlayer (SML). Gas-phase I2 was measured directly above the surface of liquid samples using broadband cavity enhanced absorption spectroscopy. I2 emissions were consistently lower for artificial seawater (AS) than buffered potassium iodide (KI) solutions. Natural seawater samples showed the strongest reduction of I2 emissions compared to artificial solutions with equivalent [I-], and the reduction was more pronounced over SML than SSW. Emissions of volatile organic iodine (VOI) were highest from SML samples but remained a negligible fraction (

Published
2020

7. The Milan Campaign: Studying the Sea Surface Microlayer

Author

Blaženka Gašparović, Matthew Salter, Rosie Chance, Jonathan Barnes, Liisa Kallajoki, Luisa Galgani, Lars Riis Damgaard, Ana María Durán Quesada, Franziska Radach, Michaela Gerriets, Philippa Rickard, Oliver Wurl, Adam Saint, Paul Zieger, Anja Engel, Maren Striebel, Sanja Frka, Thomas H. Badewien, Lucy J. Carpenter, Mariana Ribas-Ribas, Ryan Pereira, Niels Peter Revsbech, Nur Ili Hamizah Mustaffa, Christian Stolle, Robert C. Upstill-Goddard, Guenther Uher, Nadja Triesch, Birthe Zäncker, Manuela van Pinxteren, and Hartmut Herrmann

Subjects
Atmospheric Science, Oceanography, Environmental science, Sea surface microlayer
Published
2020

9. Oxidation of iodide to iodate by cultures of marine ammonia-oxidising bacteria

Author

Karen Hogg, Helmke Hepach, Tim Jickells, Martin R. Wadley, Matthew D. Pickering, Andreas Pommerening-Röser, Rosie Chance, Claire Hughes, Eleanor Barton, and David P. Stevens

Subjects
0106 biological sciences, Ozone, 010504 meteorology & atmospheric sciences, Iodide, chemistry.chemical_element, Oceanography, Iodine, 01 natural sciences, chemistry.chemical_compound, Ammonia, Environmental Chemistry, 14. Life underwater, Iodate, Nitrosomonas, 0105 earth and related environmental sciences, Water Science and Technology, chemistry.chemical_classification, biology, Chemistry, 010604 marine biology & hydrobiology, General Chemistry, biology.organism_classification, 13. Climate action, Nitrifying bacteria, Environmental chemistry, Nitrification
Abstract

Reaction with iodide (I-) at the sea surface is an important sink for atmospheric ozone, and causes sea-air emission of reactive iodine which in turn drives further ozone destruction. To incorporate this process into chemical transport models, improved understanding of the factors controlling marine iodine speciation, and especially sea-surface iodide concentrations, is needed. The oxidation of I- to iodate (IO3-) is the main sink for oceanic I-, but the mechanism for this remains unknown. We demonstrate for the first time that marine nitrifying bacteria mediate I- oxidation to IO3-. A significant increase in IO3- concentrations compared to media-only controls was observed in cultures of the ammonia-oxidising bacteria Nitrosomonas sp. (Nm51) and Nitrosoccocus oceani (Nc10) supplied with 9-10 mM I-, indicating I- oxidation to IO3-. Cell-normalised production rates were 15.69 (+/- 4.71) fmol IO3- cell(-1) d(-1) for Nitrosomonas sp., and 11.96 (+/- 6.96) fmol IO3- cell(-1) d(-1) for Nitrosococcus oceani, and molar ratios of iodate-to-nitrite production were 9.2 +/- 4.1 and 1.88 +/- 0.91 respectively. Preliminary experiments on nitrite-oxidising bacteria showed no evidence of I- to IO3- oxidation. If the link between ammonia and I oxidation observed here is representative, our ocean iodine cycling model predicts that future changes in marine nitrification could alter global sea surface I fields with potential implications for atmospheric chemistry and air quality.

Published
2021

10. An overview of iodine chemistry over the Indian and Southern Ocean waters using ship-based observations and modelling

Author

Alba Badia, Qinyi Li, Kirpa Ram, Swaleha Inamdar, Lucy J. Carpenter, Anoop S. Mahajan, Rosie Chance, Alfonso Saiz-Lopez, Lisolotte Tinel, Indian Institute of Tropical Meteorology (IITM), Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Instituto de Quimica Fisica Rocasolano, CSIC, Universitat Autònoma de Barcelona (UAB), Banaras Hindu University [Varanasi] (BHU), University of York [York, UK], Earth and Climate Science Department [IISER Pune], and Indian Institute of Science Education and Research Pune (IISER Pune)

Subjects
Oceanography, chemistry, 13. Climate action, chemistry.chemical_element, [INFO]Computer Science [cs], 14. Life underwater, Iodine, ComputingMilieux_MISCELLANEOUS
Abstract

This study presents an overview of observations and modelling of reactive iodine chemistry in the marine boundary layer (MBL) of the Indian and Southern Ocean. Ship observations of iodine oxide (IO) from 2015 to 2017 show its ubiquitous presence with values up to 1 pptv (parts per trillion) in this region. To identify the source of iodine in this region, we computed inorganic fluxes of iodine using tropospheric ozone (O3), sea surface iodide concentration, and wind speed. The estimated fluxes of hypoiodous acid (HOI) and elemental iodine (I2) did not adequately explain the observed IO levels in the Indian and Southern Ocean region. However, a significant correlation of IO with chlorophyll-a indicates a possible biogenic control on iodine chemistry in the Indian Ocean MBL. To understand the role of organic and inorganic precursors in MBL iodine chemistry, we used the Weather Research and Forecast model coupled with Chemistry (WRF-Chem version 3.7.1) incorporating halogen (Br, Cl, and I) chemistry. The modelling study shows that including only organic sources of iodine underestimate the detected IO in the northern Indian Ocean MBL. This highlights the importance of inorganic emissions as a source of iodine over the ocean. However, the inorganic flux emissions in the model had to be reduced by 40% to match the detected IO levels in this region. The reduced emission produces an overall good match between the observed and modelled IO levels. This discrepancy with flux emissions and IO levels in both the modelled IO simulation and observation highlights that there may be uncertainties in estimating the fluxes or that the flux parameterisation does not perform well for the Indian and Southern Ocean region. The model results show that inclusion of iodine chemistry causes significant regional changes to O3 (up to 25%), nitrogen oxides (up to 50%), and hydroxyl radicals (up to 15%) affecting the chemical composition of open ocean MBL and coastal regions of the Indian sub-continent. Accurate estimation of iodine precursors in the MBL calls for an urgent need to improve the existing parameterisation of inorganic fluxes. Direct measurements of the HOI and I2 may prove useful in the accurate quantification of iodine precursors in the marine atmosphere.

Published
2021

11. Marine iodine emissions in a changing world

Author

Tim Jickells, Martin R. Wadley, Mat J. Evans, David P. Stevens, Thomas J. Adams, Stephen M. Ball, Helmke Hepach, Lloyd D. J. Hollis, Anoop S. Mahajan, Tomás Sherwen, Rosie Chance, Claire Hughes, Liselotte Tinel, and Lucy J. Carpenter

Subjects
chemistry.chemical_classification, Ozone, 010504 meteorology & atmospheric sciences, General Mathematics, Iodide, General Engineering, Trace element, General Physics and Astronomy, chemistry.chemical_element, 010501 environmental sciences, Iodine, 01 natural sciences, Earth system science, chemistry.chemical_compound, Human health, chemistry, 13. Climate action, Environmental chemistry, Halogen, Environmental science, 14. Life underwater, 0105 earth and related environmental sciences
Abstract

Iodine is a critical trace element involved in many diverse and important processes in the Earth system. The importance of iodine for human health has been known for over a century, with low iodine in the diet being linked to goitre, cretinism and neonatal death. Research over the last few decades has shown that iodine has significant impacts on tropospheric photochemistry, ultimately impacting climate by reducing the radiative forcing of ozone (O 3 ) and air quality by reducing extreme O 3 concentrations in polluted regions. Iodine is naturally present in the ocean, predominantly as aqueous iodide and iodate. The rapid reaction of sea-surface iodide with O 3 is believed to be the largest single source of gaseous iodine to the atmosphere. Due to increased anthropogenic O 3 , this release of iodine is believed to have increased dramatically over the twentieth century, by as much as a factor of 3. Uncertainties in the marine iodine distribution and global cycle are, however, major constraints in the effective prediction of how the emissions of iodine and its biogeochemical cycle may change in the future or have changed in the past. Here, we present a synthesis of recent results by our team and others which bring a fresh perspective to understanding the global iodine biogeochemical cycle. In particular, we suggest that future climate-induced oceanographic changes could result in a significant change in aqueous iodide concentrations in the surface ocean, with implications for atmospheric air quality and climate.

Published
2021

12. A Global Model for Iodine Speciation in the Upper Ocean

Author

Martin R. Wadley, David P. Stevens, Helmke Hepach, Liselotte Tinel, Tim Jickells, Lucy J. Carpenter, Rosie Chance, and Claire Hughes

Subjects
0106 biological sciences, chemistry.chemical_classification, Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Advection, Mixed layer, 010604 marine biology & hydrobiology, Iodide, chemistry.chemical_element, Flux, Iodine, Atmospheric sciences, 01 natural sciences, Sea surface temperature, chemistry.chemical_compound, chemistry, 13. Climate action, Environmental Chemistry, Environmental science, 14. Life underwater, Carbon, Iodate, 0105 earth and related environmental sciences, General Environmental Science
Abstract

An ocean iodine cycling model is presented, which predicts upper ocean iodine speciation. The model comprises a three-layer advective and diffusive ocean circulation model of the upper ocean, and an iodine cycling model embedded within this circulation. The two primary reservoirs of iodine are represented, iodide and iodate. Iodate is reduced to iodide in the mixed layer in association with primary production, linked by an iodine to carbon (I:C) ratio. A satisfactory model fit with observations cannot be obtained with a globally constant I:C ratio, and the best fit is obtained when the I:C ratio is dependent on sea surface temperature, increasing at low temperatures. Comparisons with observed iodide distributions show that the best model fit is obtained when oxidation of iodide back to iodate is associated with mixed layer nitrification. Sensitivity tests, where model parameters and processes are perturbed, reveal that primary productivity, mixed layer depth, oxidation, advection, surface fresh water flux and the I:C ratio all have a role in determining surface iodide concentrations, and the timescale of iodide in the mixed layer is sufficiently long for non-local processes to be important. Comparisons of the modelled iodide surface field with parameterisations by other authors shows good agreement in regions where observations exist, but significant differences in regions without observations. This raises the question of whether the existing parameterisations are capturing the full range of processes involved in determining surface iodide, and shows the urgent need for observations in regions where there are currently none.

Published
2020

13. Surface Inorganic Iodine Speciation in the Indian and Southern Oceans From 12°N to 70°S

Author

Alok Kumar Sinha, Anoop S. Mahajan, P. Sabu, Rosie Chance, Rajdeep Roy, Liselotte Tinel, Racheal Chacko, Martin R. Wadley, Amit Sarkar, Lucy J. Carpenter, Tim Jickells, and David P. Stevens

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:QH1-199.5, Iodide, chemistry.chemical_element, Ocean Engineering, Aquatic Science, lcsh:General. Including nature conservation, geographical distribution, Oceanography, Iodine, 01 natural sciences, chemistry.chemical_compound, iodate, Ocean gyre, Phytoplankton, Tropospheric ozone, Southern Ocean, lcsh:Science, Indian Ocean, 0105 earth and related environmental sciences, Water Science and Technology, seawater, chemistry.chemical_classification, Global and Planetary Change, geography, geography.geographical_feature_category, iodine, 010604 marine biology & hydrobiology, fungi, Sea surface temperature, chemistry, Environmental science, Seawater, lcsh:Q, iodide, Oceanic basin
Abstract

Marine iodine speciation has emerged as a potential tracer of primary productivity, sedimentary inputs, and ocean oxygenation. The reaction of iodide with ozone at the sea surface has also been identified as the largest deposition sink for tropospheric ozone and the dominant source of iodine to the atmosphere. Accurate incorporation of these processes into atmospheric models requires improved understanding of iodide concentrations at the air-sea interface. Observations of sea surface iodide are relatively sparse and are particularly lacking in the Indian Ocean basin. Here we examine 127 new sea surface (≤10 m depth) iodide and iodate observations made during three cruises in the Indian Ocean and the Indian sector of the Southern Ocean. The observations span latitudes from ∼12°N to ∼70°S, and include three distinct hydrographic regimes: the South Indian subtropical gyre, the Southern Ocean and the northern Indian Ocean including the southern Bay of Bengal. Concentrations and spatial distribution of sea surface iodide follow the same general trends as in other ocean basins, with iodide concentrations tending to decrease with increasing latitude (and decreasing sea surface temperature). However, the gradient of this relationship was steeper in subtropical waters of the Indian Ocean than in the Atlantic or Pacific, suggesting that it might not be accurately represented by widely used parameterizations based on sea surface temperature. This difference in gradients between basins may arise from differences in phytoplankton community composition and/or iodide production rates. Iodide concentrations in the tropical northern Indian Ocean were higher and more variable than elsewhere. Two extremely high iodide concentrations (1241 and 949 nM) were encountered in the Bay of Bengal and are thought to be associated with sedimentary inputs under low oxygen conditions. Excluding these outliers, sea surface iodide concentrations ranged from 20 to 250 nM, with a median of 61 nM. Controls on sea surface iodide concentrations in the Indian Ocean were investigated using a state-of-the-art iodine cycling model. Multiple interacting factors were found to drive the iodide distribution. Dilution via vertical mixing and mixed layer depth shoaling are key controls, and both also modulate the impact of biogeochemical iodide formation and loss processes.

Published
2020

14. Iodate production in cultures of marine ammonia-oxidising bacteria: implications for future inorganic iodine distributions in the oceans

Author

Karen Hogg, Martin R. Wadley, Andreas Pommerening-Röser, Rosie Chance, David P. Stevens, Claire Hughes, Matthew D. Pickering, Eleanor Barton, Tim Jickells, and Helmke Hepach

Subjects
chemistry.chemical_classification, geography, geography.geographical_feature_category, Ozone, biology, Iodide, chemistry.chemical_element, biology.organism_classification, Iodine, Sink (geography), chemistry.chemical_compound, Ammonia, Inorganic iodine, chemistry, Environmental chemistry, Bacteria, Iodate
Abstract

Reaction with iodide (I) at the sea surface is an important sink for atmospheric ozone, and causes sea-air emission of reactive iodine which in turn drives further ozone destruction. To incorporate...

Published
2020

15. Trace Metal Fractional Solubility in Size‐Segregated Aerosols From the Tropical Eastern Atlantic Ocean

Author

Alex R. Baker, Mingpei Li, and Rosie Chance

Subjects
0106 biological sciences, Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, chemistry.chemical_element, Thorium, Manganese, Mineral dust, 01 natural sciences, Aerosol, chemistry, Environmental chemistry, Environmental Chemistry, Trace metal, Seawater, Solubility, Cobalt, 0105 earth and related environmental sciences, General Environmental Science
Abstract

Soluble and total trace metals were measured in four size fractionated aerosol samples collected over the tropical eastern Atlantic Ocean. In samples that were dominated by Saharan dust, the size distributions of total iron, aluminum, titanium, manganese, cobalt, and thorium were very similar to one another and to the size distributions of soluble manganese, cobalt, and thorium. Finer particle sizes (< ~3 μm) showed enhanced soluble concentrations of iron, aluminum, and titanium, possibly as a result of interactions with acidic sulfate aerosol during atmospheric transport. The difference in fine particle solubility between these two groups of elements might be related to the hyperbolic increase in the fractional solubility of iron, and a number of other elements, during the atmospheric transport of Saharan dust, which is not observed for manganese and its associated elements. In comparison to elements whose solubility varies during atmospheric transport, the stability of thorium fractional solubility should reduce uncertainties in the use of dissolved concentrations of this element in seawater as a proxy for dust deposition, although this topic requires further work.

Published
2020

16. Senescence as the main driver of iodide release from a diverse range of marine phytoplankton

Author

Susannah Collings, Karen Hogg, Rosie Chance, Claire Hughes, and Helmke Hepach

Subjects
0106 biological sciences, Biogeochemical cycle, Ozone, 010504 meteorology & atmospheric sciences, Iodide, lcsh:Life, chemistry.chemical_element, Iodine, 01 natural sciences, Atmosphere, chemistry.chemical_compound, lcsh:QH540-549.5, Phytoplankton, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Iodate, 0105 earth and related environmental sciences, Earth-Surface Processes, chemistry.chemical_classification, Chemistry, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, lcsh:Geology, lcsh:QH501-531, Deposition (aerosol physics), Environmental chemistry, lcsh:Ecology
Abstract

The reaction between ozone and iodide at the sea surface is now known to be an important part of atmospheric ozone cycling, causing ozone deposition and the release of ozone-depleting reactive iodine to the atmosphere. The importance of this reaction is reflected by its inclusion in chemical transport models (CTMs). Such models depend on accurate sea surface iodide fields, but measurements are spatially and temporally limited. Hence, the ability to predict current and future sea surface iodide fields, i.e. sea surface iodide concentration on a narrow global grid, requires the development of process-based models. These models require a thorough understanding of the key processes that control sea surface iodide. The aim of this study was to explore if there are common features of iodate-to-iodide reduction amongst diverse marine phytoplankton in order to develop models that focus on sea surface iodine and iodine release to the troposphere. In order to achieve this, rates and patterns of changes in inorganic iodine speciation were determined in 10 phytoplankton cultures grown at ambient iodate concentrations. Where possible these data were analysed alongside results from previous studies. Iodate loss and some iodide production were observed in all cultures studied, confirming that this is a widespread feature amongst marine phytoplankton. We found no significant difference in log-phase, cell-normalised iodide production rates between key phytoplankton groups (diatoms, prymnesiophytes including coccolithophores and phaeocystales), suggesting that a phytoplankton functional type (PFT) approach would not be appropriate for building an ocean iodine cycling model. Iodate loss was greater than iodide formation in the majority of the cultures studied, indicating the presence of an as-yet-unidentified “missing iodine” fraction. Iodide yield at the end of the experiment was significantly greater in cultures that had reached a later senescence stage. This suggests that models should incorporate a lag between peak phytoplankton biomass and maximum iodide production and that cell mortality terms in biogeochemical models could be used to parameterise iodide production.

Published
2020

18. Iodine chemistry in the tropical and remote open ocean marine boundary layer

Author

Swaleha Inamdar, Liselotte Tinel, Rosie Chance, Lucy Jane Carpenter, Sabu Prabhakaran, Racheal Chacko, Sarat Chandra Tripathy, Anvita Ulhas Kerkar, Alok Kumar Sinha, Bhaskar Parli Venkateswaran, Amit Sarkar, Rajdeep Roy, Tomas Sherwen, Carlos Alberto Cuevas, Alfonso Saiz-Lopez, Kirpa Ram, and Anoop Sharad Mahajan

Abstract

Iodine chemistry plays an essential role in controlling the radiation budget by changing various atmospheric parameters. Iodine in the atmosphere is known to cause depletion of ozone via catalytic reaction cycles. It alters the atmospheric oxidation capacity, and lead to ultrafine particle formation that acts as potential cloud condensation nuclei. The ocean is the primary source of iodine; it enters the atmosphere through fluxes of gaseous reactive iodine species. At the ocean surface, seawater iodide reacts with tropospheric ozone (gas) to form inorganic iodine species in gaseous form. These species namely, hypoiodous acid (HOI) and molecular iodine (I2) quickly photolyse to release reactive iodine (I) in the atmosphere. This process acts as a significant sink for tropospheric ozone contributing to ~16% ozone loss throughout the troposphere. Reactive iodine released in the atmosphere undergoes the formation of iodine monoxide (IO) or higher oxides of iodine (IxOx) via self-recombination reactions. It is known that inorganic iodine fluxes (HOI and I2) contribute to 75% of the detected IO over the Atlantic Ocean. However, we did not observe this from ship-based MAX-DOAS studies between 2014-2017. At present, there are no direct observations of inorganic iodine (HOI; few for I2) and are estimated via empirical methods derived from the interfacial kinetic model by Carpenter et al. in 2013. Based on the kinetic model, estimation of HOI and I2 fluxes depends on three parameters, namely, ozone concentration, surface iodide concentration, and the wind speed. This parameterisation for inorganic fluxes assumes a sea surface temperature (SST) of 293 K and has limiting wind speed conditions. Since the parameterisation conditions assumed SST of 293 K higher uncertainties due to errors in activation energy creeps in the estimation of HOI flux compared to I2 as the flux of HOI is ~20 times greater than that of I2. For three consecutive expeditions in the Indian and Southern Ocean, we detected ~1 pptv of IO in the marine boundary layer. These levels are not explained by the calculated inorganic fluxes by using observed and predicted sea surface iodide concentrations. This method of iodine flux estimation is currently used in all global models, along with the MacDonald et al. 2014 iodide estimation method. Model output using these parameterisations have not been able to match the observed IO levels in the Indian and Southern Ocean region. This discrepancy suggests that the process of efflux of iodine to the atmosphere may not be fully understood, and the current parametrisation does not do justice to the observations. It also highlights that the flux of organic iodine may also play a role in observed IO levels, especially in the Indian Ocean region. A correlation of 0.7 was achieved above the 99% confidence limit for chlorophyll-a with observed IO concentration in this region. There is a need to carry more observations to improve the estimation technique of iodine sea-air flux thus improving model predictions of IO in the atmosphere.

Published
2020

20. Modelling iodine in the ocean

Author

Martin Robert Wadley, David P. Stevens, Tim Jickells, Claire Hughes, Rosie Chance, Helmke Hepach, and Lucy J. Carpenter

Published
2020

21. The MILAN campaign: Studying diel light effects on the air-sea interface

Author

Mariana Ribas-Ribas, Manuela van Pinxteren, Luisa Galgani, Lars Riis Damgaard, Niels Peter Revsbech, Maren Striebel, Oliver Wurl, Michaela Gerriets, Christian Stolle, Philippa Rickard, Franziska Radach, Matthew Salter, Adam Saint, Nur Ili Hamizah Mustaffa, Hartmut Herrmann, Blaženka Gašparović, Paul Zieger, Rosie Chance, Jonathan Barnes, Liisa Kallajoki, Sanja Frka, Anja Engel, Birthe Zäncker, Thomas H. Badewien, Ana María Durán Quesada, Guenther Uher, Nadja Triesch, Robert C. Upstill-Goddard, Lucy J. Carpenter, and Ryan Pereira

Subjects
Wind-driven, Atmospheric Science, 010504 meteorology & atmospheric sciences, Sea-surface, Interface (Java), 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Sea surface microlayer, Light effect, Turbulence, Atmosphere, Wind driven, Chemistry, 13. Climate action, Environmental Science, Solar radiation, Marine Science, 14. Life underwater, sea surface miscrolayers, diel light effect, aerosol, North Sea, chemistry, microbiology, Diel vertical migration, 0105 earth and related environmental sciences
Abstract

MILAN was a multidisciplinary, international study examining how the diel variability of sea-surface microlayer biogeochemical properties potentially impacts ocean-atmosphere interaction, in order to improve our understanding of this globally important process. The sea-surface microlayer (SML) at the air-sea interface is < 1 mm deep but it is physically, chemically and biologically distinct from the underlying water and the atmosphere above. Wind-driven turbulence and solar radiation are important drivers of SML physical and biogeochemical properties. Given that the SML is involved in all ocean-atmosphere exchanges of mass and energy, its response to solar radiation, especially in relation to how it regulates the air-sea exchange of climate-relevant gases and aerosols, is surprisingly poorly characterised. MILAN (sea-surface MIcroLAyer at Night) was an international, multidisciplinary campaign designed to specifically address this issue. In spring 2017, we deployed diverse sampling platforms (research vessels, radio-controlled catamaran, free-drifting buoy) to study full diel cycles in the coastal North Sea SML and in underlying water, and installed a land-based aerosol sampler. We also carried out concurrent ex situ experiments using several microsensors, a laboratory gas exchange tank, a solar simulator, and a sea spray simulation chamber. In this paper we outline the diversity of approaches employed and some initial results obtained during MILAN. Our observations of diel SML variability, e.g. the influence of changing solar radiation on the quantity and quality of organic material, and diel changes in wind intensity primarily forcing air-sea CO2 exchange, underline the value and the need of multidisciplinary campaigns for integrating SML complexity into the context of air-sea interaction.

Published
2020

23. Global sea-surface iodide observations, 1967-2018

Author

Tim Jickells, Ieuan J. Roberts, Peter Croot, Rajdeep Roy, Mingxi Yang, Anoop S. Mahajan, Alex R. Baker, Gill Malin, He Peng, Kathrin Wuttig, Zhou Peng, Liselotte Tinel, Thomas G. Bell, Hugh W. Ducklow, Alok Kumar Sinha, Tomás Sherwen, Lucy J. Carpenter, Amit Sarkar, Maria Lúcia Arruda de Moura Campos, Babette A A Hoogakker, Rosie Chance, Frances E. Hopkins, Claire Hughes, John Brindle, Dharma Andrea Reyes Macaya, Daniel Phillips, Xiuxian Song, David Loades, and Helge Arne Winkelbauer

Subjects
Statistics and Probability, Data Descriptor, Atmospheric chemistry, Ozone, 010504 meteorology & atmospheric sciences, Iodide, chemistry.chemical_element, 010501 environmental sciences, Library and Information Sciences, Iodine, Atmospheric sciences, 01 natural sciences, Sink (geography), Latitude, Education, chemistry.chemical_compound, Element cycles, 14. Life underwater, Tropospheric ozone, lcsh:Science, Air quality index, 0105 earth and related environmental sciences, chemistry.chemical_classification, geography, geography.geographical_feature_category, Computer Science Applications, Marine chemistry, chemistry, 13. Climate action, Environmental science, lcsh:Q, Statistics, Probability and Uncertainty, Information Systems
Abstract

The marine iodine cycle has significant impacts on air quality and atmospheric chemistry. Specifically, the reaction of iodide with ozone in the top few micrometres of the surface ocean is an important sink for tropospheric ozone (a pollutant gas) and the dominant source of reactive iodine to the atmosphere. Sea surface iodide parameterisations are now being implemented in air quality models, but these are currently a major source of uncertainty. Relatively little observational data is available to estimate the global surface iodide concentrations, and this data has not hitherto been openly available in a collated, digital form. Here we present all available sea surface (, Measurement(s)iodideTechnology Type(s)digital curationFactor Type(s)sampling time and placeSample Characteristic - Environmentsea water • oceanSample Characteristic - LocationEarth (planet) Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.10130129

Published
2019

24. Common features of iodate to iodide reduction amongst a diverse range of marine phytoplankton

Author

Helmke Hepach, Rosie Chance, Claire Hughes, Karen Hogg, and Susannah Collings

Subjects
chemistry.chemical_classification, Biogeochemical cycle, Ozone, 010504 meteorology & atmospheric sciences, Chemistry, media_common.quotation_subject, fungi, Iodide, chemistry.chemical_element, Iodine, 01 natural sciences, Speciation, chemistry.chemical_compound, Deposition (aerosol physics), Environmental chemistry, Phytoplankton, Iodate, 0105 earth and related environmental sciences, media_common
Abstract

The reaction between ozone and iodide at the sea surface is now known to be an important part of atmospheric ozone cycling, causing ozone deposition and the release of ozone-depleting reactive iodine to the atmosphere. The importance of this reaction is reflected by its inclusion in chemical transport models (CTMs). Such models depend on accurate sea surface iodide fields but measurements are spatially and temporally limited. The ability to predict current and future sea surface iodide fields requires the development of process-based models which in turn require a thorough understanding of the key processes controlling inorganic iodine cycling. The aim of this study was to inform the development of ocean iodine cycling models by exploring if there are common features of iodate to iodide reduction amongst diverse marine phytoplankton. In order to achieve this, rates and patterns of changes in inorganic iodine speciation were determined in 10 phytoplankton cultures grown at ambient iodate concentrations. Where possible these data were analysed alongside results from previous studies. Iodate loss and some iodide production was observed in all cultures studied, confirming that this is a widespread feature amongst marine phytoplankton. We found no significant difference in log-phase, cell-normalised iodide production rates between key phytoplankton groups (diatoms, prymesiophytes including coccolithophores and phaeocystales) suggesting that a Phytoplankton Functional Type (PFT) approach would not be appropriate for building an ocean iodine cycling model. Iodate loss was greater than iodide formation in the majority of the cultures studied, indicating the presence of an as yet unidentified missing iodine fraction. Iodide yield at the end of the experiment was significantly greater in cultures that had reached a later senescence stage. This suggests that models should incorporate a lag between peak phytoplankton biomass and maximum iodide production, and that cell mortality terms in biogeochemical models could be used to parameterize iodide production.

Published
2019

25. Atmospheric trace metal concentrations, solubility and deposition fluxes in remote marine air over the south-east Atlantic

Author

Alex R. Baker, Tim Jickells, and Rosie Chance

Subjects
Chemistry(all), 010504 meteorology & atmospheric sciences, Geotraces, Fraction (chemistry), General Chemistry, 010501 environmental sciences, Oceanography, 01 natural sciences, Aerosol, chemistry.chemical_compound, Deposition (aerosol physics), Volume (thermodynamics), chemistry, 13. Climate action, Environmental chemistry, Environmental Chemistry, Trace metal, 14. Life underwater, Solubility, Ammonium acetate, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

Total and soluble trace metal concentrations were determined in atmospheric aerosol and rainwater samples collected during seven cruises in the south-east Atlantic. Back trajectories indicated that the samples all represented remote marine air masses, consistent with climatological expectations. Aerosol trace metal loadings were similar to previous measurements in clean, marine air masses. Median total Fe, Al, Mn, V, Co and Zn concentrations were 206, 346, 5, 3, 0.7 and 11 pmol m− 3 respectively. Solubility was operationally defined as the fraction extractable using a pH 4.7 ammonium acetate leach. Median soluble Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb concentrations were 6, 55, 1, 0.7, 0.06, 24, 2, 1, 0.05 and 0.3 pmol m− 3 respectively. Large ranges in fractional solubility were observed for all elements except Co; median solubility values for Fe, Al and Mn were below 20% while the median for Zn was 74%. Volume weighted mean rainwater concentrations were 704, 792, 32, 10, 3, 686, 25, 0.02, 0.3 and 10 nmol L− 1 for Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb respectively (n = 6). Wet deposition fluxes calculated from these values suggest that rain makes a significant contribution to total deposition in the study area for all elements except perhaps Ni.

Published
2015

26. The GEOTRACES Intermediate Data Product 2017

Author

Thomas J. Browning, Hans-Jürgen Brumsack, Katharina Pahnke, Saeed Roshan, Stephanie Owens, Rosie Chance, Peter Croot, Steven van Heuven, Alison E. Hartman, Mercedes López-Lora, Pu Zhang, Heather A. Bouman, Géraldine Sarthou, François Lacan, Robyn E. Tuerena, José Marcus Godoy, Ester Garcia-Solsona, Steven L. Goldstein, Hans A. Slagter, Celia Venchiarutti, A. Russell Flegal, Emily Townsend, Ralph Till, Christopher T. Hayes, Melanie Gault-Ringold, Ros Watson, Peter N. Sedwick, Chandranath Basak, Bronwyn Wake, Loes J. A. Gerringa, Noriko Nakayama, Lars-Eric Heimbürger, Paul J. Morris, François Fripiat, Paul B. Henderson, Chris J. Daniels, Catherine Jeandel, Helen M. Snaith, Patrizia Ziveri, Toshitaka Gamo, Yanbin Lu, Oliver J. Lechtenfeld, Yingzhe Wu, Andreas Wisotzki, Hajime Obata, Cynthia Dumousseaud, Ashley T. Townsend, Sebastian Mieruch, Donna Cockwell, Laurent Bopp, Elena Masferrer Dodas, Bernhard Schnetger, J. K. Klar, Sunil K. Singh, Joaquin E. Chaves, Kuo-Fang Huang, Louise A. Zimmer, Laura F. Robinson, Michiel M Rutgers van der Loeff, Corey Archer, Feifei Deng, Karen Grissom, Robert Rember, Nicholas J. Hawco, Jingfeng Wu, Robert M. Sherrell, Rachel U. Shelley, Jan-Lukas Menzel Barraqueta, E. Malcolm S. Woodward, Fanny Chever, Yuichiro Kumamoto, Hélène Planquette, Dorothea Bauch, Frank Dehairs, Daniel C. Ohnemus, Akira Nishiuchi, Paul D. Quay, Sanjin Mehic, Zichen Xue, Maxi Castrillejo, Brian Peters, Michael J. Ellwood, Stephen R. Rintoul, Tobias Roeske, Jing Zhang, Gretchen J. Swarr, Peng Ho, Ken O. Buesseler, Gwenaelle Moncoiffe, Martin Frank, Maureen E. Auro, Abby Bull, David Kadko, Montserrat Roca-Martí, Maeve C. Lohan, Roulin Khondoker, Patricia Cámara Mor, Melissa Gilbert, Sebastian M. Vivancos, Erin E. Black, Santiago R. Gonzalez, Gideon M. Henderson, David J. Janssen, Sylvain Rigaud, Amandine Radic, Maxence Paul, Cyril Abadie, Ana Aguliar-Islas, Seth G. John, Marie Boye, Evgenia Ryabenko, Abigail E. Noble, Luke Bridgestock, Brian Duggan, Hisayuki Yoshikawa, Jun Nishioka, Kathrin Wuttig, Pieter van Beek, Jana Friedrich, Thomas M. Church, Maija Heller, Stephen J.G. Galer, Pier van der Merwe, Claire P. Till, Xin Yuan Zheng, Henning Fröllje, John Niedermiller, Howie D. Scher, Johnny Stutsman, Patricia Zunino, Christel S. Hassler, Ye Zhao, Tim M. Conway, William M. Landing, Yang Xiang, Katrin Bluhm, Maria T. Maldonado, Elena Chamizo, Sabrina Speich, Claudine H. Stirling, Guillaume Brissebrat, Matthew A. Charette, Jeremy E. Jacquot, Yu-Te Hsieh, Pinghe Cai, Ivia Closset, Yoshiki Sohrin, Ejin George, Jong-Mi Lee, Leopoldo D. Pena, Edward Mawji, Damien Cardinal, Catherine Pradoux, Martin Q. Fleisher, Virginie Sanial, Derek Vance, Craig A. Carlson, Pere Masqué, Katlin L. Bowman, Evaline M. van Weerlee, Oliver Baars, Ruifang C. Xie, María Villa-Alfageme, Hein J W de Baar, M. Alexandra Weigand, Tina van de Flierdt, J. Bown, Timothy C. Kenna, Kenneth W. Bruland, Jeroen E. Sonke, Hai Cheng, Mark J. Warner, Sven Ober, Rob Middag, Jessica N. Fitzsimmons, Emilie Le Roy, Yishai Weinstein, Nicholas R. Bates, Joerg Rickli, Daniel M. Sigman, Hendrik M. van Aken, Angela Milne, Cheryl M. Zurbrick, Gregory A. Cutter, Igor Semiletov, Marie Labatut, Torben Stichel, Pascale Lherminier, Gabriel Dulaquais, Jay T. Cullen, Christopher I. Measures, Mark Rosenberg, Tomoharu Minami, Mariko Hatta, Alexander L. Thomas, Gonzalo Carrasco, Karel Bakker, Clifton S. Buck, Maarten B Klunder, Willard S. Moore, Reiner Schlitzer, Tomas A. Remenyi, Susan H. Little, Eberhard Fahrbach, Charles R. McClain, Edward A. Boyle, Ursula Schauer, Linjie Zheng, Alex R. Baker, Emma Slater, Kay Thorne, Patrick Laan, Christina Schallenberg, Reiner Steinfeldt, Benjamin S. Twining, Yolanda Echegoyen-Sanz, Neil J. Wyatt, Alison M. Agather, Viena Puigcorbé, Peter Scott, Gillian Stewart, Matthew P. Humphreys, Frédéric A. C. Le Moigne, Phoebe J. Lam, Núria Casacuberta, Josh Helgoe, Edward C.V. Butler, Mark Rehkämper, Elizabeth M. Jones, Karen L. Casciotti, James W. Moffett, Tristan J. Horner, Sue Velazquez, Yuzuru Nakaguchi, Micha J.A. Rijkenberg, Antje H L Voelker, Joseph A. Resing, Lesley Salt, Eric P. Achterberg, Sven Kretschmer, Jan van Ooijen, Dominik J. Weiss, Moritz Zieringer, Carl H. Lamborg, Rick Kayser, Pierre Branellec, John M. Rolison, Sara Rauschenberg, Walter Geibert, Raja S. Ganeshram, Myriam Lambelet, Janice L. Jones, Chad R. Hammerschmidt, William J. Jenkins, Jordi Garcia-Orellana, Alessandro Tagliabue, Philip W. Boyd, Alan M. Shiller, Marcus Christl, Mark Baskaran, Mak A. Saito, Huong Thi Dieu, Morten B. Andersen, Kenji Isshiki, Taejin Kim, Christian Schlosser, Melanie K. Behrens, Albert S. Colman, Frédéric Planchon, Bettina Sohst, Andrew R. Bowie, Mark A. Brzezinski, R. Lawrence Edwards, Kristen N. Buck, Jeanette O'Sullivan, William M. Smethie, Wafa Abouchami, Valentí Rodellas, Ed C Hathorne, Robert F. Anderson, James H. Swift, Frank J. Pavia, Daniel Cossa, Lauren Kipp, Peter L. Morton, Fabien Quéroué, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Centre for Automotive Safety Research, University of Adelaide, University of California, National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS), Department of Oceanography [Cape Town], University of Cape Town, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, University of Toyama, Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Royal Netherlands Institute for Sea Research (NIOZ), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Department of Geology, Wayne State University [Detroit], The Bartlett, University College of London [London] (UCL), Institute for Environmental Research, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Department of Earth Sciences [Oxford], University of Oxford [Oxford], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute for Research on Learning, Services communs OMP - UMS 831 (UMS 831), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UCSB), University of California-University of California, National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut Français de Recherche pour l'Exploitation de la Mer - Nantes (IFREMER Nantes), Université de Nantes (UN), University of Victoria [Canada] (UVIC), Massachusetts Institute of Technology (MIT), Universidad de Dakota del Sur, Analytical, Environmental and Geo- Chemistry, Vrije Universiteit [Brussels] (VUB), Wright State University, School of Geography, Earth and Environmental Sciences [Plymouth] (SoGEES), Plymouth University, Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Alfred Wegener Institute [Potsdam], Institute of Global Environmental Change [China] (IGEC), Xi'an Jiaotong University (Xjtu), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Department of Mathematics and Science, National Taiwan Normal University (NTNU), School of Information Technology [Kharagpur], Indian Institute of Technology Kharagpur (IIT Kharagpur), GEOMAR - Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), University of California [Davis] (UC Davis), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona [Barcelona] (UAB), Institute of Low Temperature Science, Hokkaido University, The University of Tokyo, Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania (UTAS), Joint Institute for the Study of the Atmosphere and Ocean (JISAO), University of Washington [Seattle], Institute of Geochemistry and Petrology, Détection, évaluation, gestion des risques CHROniques et éMErgents (CHROME) / Université de Nîmes (CHROME), Université de Nîmes (UNIMES), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), School of Earth and Ocean Sciences, University of Victoria, Knowledge Media Institute (KMI), The Open University [Milton Keynes] (OU), Bermuda Biological Station for Research (BBSR), Bermuda Biological Station for Research, Department of Geosciences [Princeton], Princeton University, Kyoto University [Kyoto], Géochimie des Isotopes Stables (GIS), Géosciences Environnement Toulouse (GET), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), School of Earth and Environmental Sciences [Queens New York], Queens College [New York], City University of New York [New York] (CUNY)-City University of New York [New York] (CUNY), SOEST, University of Hawai‘i [Mānoa] (UHM), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Bigelow Laboratory for Ocean Sciences, Department of Earth Science and Technology [Imperial College London], Imperial College London, Plymouth Marine Laboratory, Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Tsinghua National Laboratory for Information Science and Technology (TNList), RITE, Research Institute of Innovative Technology for the Earth, Agricultural Information Institute (AII), Chinese Academy of Agricultural Sciences (CAAS), Department of Mathematics [Shanghai], Shanghai Jiao Tong University [Shanghai], University of California [Irvine] (UCI), Institute of Environmental Science and Technology [Barcelona] (ICTA), University of California (UC), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Southern California (USC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Vrije Universiteit Brussel (VUB), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Florida International University [Miami] (FIU), Department of Earth Science and Engineering [Imperial College London], Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Universitat Autònoma de Barcelona (UAB), British Oceanographic Data Centre (BODC), Institute of Low Temperature Science [Sapporo], Hokkaido University [Sapporo, Japan], The University of Tokyo (UTokyo), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), College of Earth, Ocean, and Environment [Newark] (CEOE), University of Delaware [Newark], Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Knowledge Media Institute (KMi), Kyoto University, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Academia Sinica, University of California [Irvine] (UC Irvine), Danish Technological Institute (DTI), Scientific Committee on Oceanic Research (SCOR) from the U.S. National Science Foundation [OCE-0608600, OCE-0938349, OCE-1243377, OCE-1546580], UK Natural Environment Research Council (NERC), Ministry of Earth Science of India, Centre National de Recherche Scientifique, l'Universite Paul Sabatier de Toulouse, Observatoire Midi-Pyrenees Toulouse, Universitat Autonoma de Barcelona, Kiel Excellence Cluster The Future Ocean, Swedish Museum of Natural History, University of Tokyo, University of British Columbia, Royal Netherlands Institute for Sea Research, GEOMAR-Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Scientific Committee on Oceanic Research, National Science Foundation (US), Natural Environment Research Council (UK), Ministry of Earth Sciences (India), Centre National de la Recherche Scientifique (France), Université Toulouse III Paul Sabatier, Observatoire Midi-Pyrénées (France), Universidad Autónoma de Barcelona, Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (Germany), Schlitzer, Reiner [0000-0002-3740-6499], Masferrer Dodas, Elena [0000-0003-0879-1954], Chamizo, Elena [0000-0001-8266-6129], Christl, M. [0000-0002-3131-6652], Masqué, Pere [0000-0002-1789-320X], Villa-Alfageme, María [0000-0001-7157-8588], Universitat de Barcelona, Natural Environment Research Council (NERC), Leverhulme Trust, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Carrasco Rebaza, Gonzalo, Echegoyen Sanz, Yolanda, Kayser, Richard A, Isotope Research, Ocean Ecosystems, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Hassler, Christel, Schlitzer, Reiner, Masferrer Dodas, Elena, Chamizo, Elena, Christl, M., Masqué, Pere, and Villa-Alfageme, María

Subjects
Geochemistry & Geophysics, 010504 meteorology & atmospheric sciences, Isòtops, sub-01, Geotraces, MODELS, Digital data, Context (language use), 010502 geochemistry & geophysics, 01 natural sciences, IDP2017, Isotopes, Geochemistry and Petrology, Oceans, Electronic atlas, ddc:550, 0402 Geochemistry, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, NetCDF, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Trace elements, Science & Technology, Information retrieval, ACL, Geology, computer.file_format, Ocean Data View, Metadata, Data processing, GEOTRACES, 0403 Geology, Data extraction, 13. Climate action, Data quality, Physical Sciences, [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0406 Physical Geography and Environmental Geoscience, computer, Processament de dades, Trace elements Isotopes
Abstract

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González., National Science Foundation (U.S.) (Grant OCE-0608600), National Science Foundation (U.S.) (Grant OCE0938349), National Science Foundation (U.S.) (Grant OCE-1243377), National Science Foundation (U.S.) (Grant OCE-1546580)

Published
2018

27. Spring–summer net community production, new production, particle export and related water column biogeochemical processes in the marginal sea ice zone of the Western Antarctic Peninsula 2012–2014

Author

Alex R. Baker, Oscar Schofield, Hugh W. Ducklow, Michael R. Stukel, Nicholas Cassar, Tim Jickells, Scott C. Doney, Rachel Eveleth, Rosie Chance, and John Brindle

Subjects
0106 biological sciences, geography, Biogeochemical cycle, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Continental shelf, 010604 marine biology & hydrobiology, General Mathematics, General Engineering, General Physics and Astronomy, Primary production, Growing season, Articles, New production, 01 natural sciences, Water column, Oceanography, Peninsula, Sea ice, Environmental science, 0105 earth and related environmental sciences
Abstract

New production (New P, the rate of net primary production (NPP) supported by exogenously supplied limiting nutrients) and net community production (NCP, gross primary production not consumed by community respiration) are closely related but mechanistically distinct processes. They set the carbon balance in the upper ocean and define an upper limit for export from the system. The relationships, relative magnitudes and variability of New P (from 15 NO 3 – uptake), O 2 : argon-based NCP and sinking particle export (based on the 238 U : 234 Th disequilibrium) are increasingly well documented but still not clearly understood. This is especially true in remote regions such as polar marginal ice zones. Here we present a 3-year dataset of simultaneous measurements made at approximately 50 stations along the Western Antarctic Peninsula (WAP) continental shelf in midsummer (January) 2012–2014. Net seasonal-scale changes in water column inventories (0–150 m) of nitrate and iodide were also estimated at the same stations. The average daily rates based on inventory changes exceeded the shorter-term rate measurements. A major uncertainty in the relative magnitude of the inventory estimates is specifying the start of the growing season following sea-ice retreat. New P and NCP(O 2 ) did not differ significantly. New P and NCP(O 2 ) were significantly greater than sinking particle export from thorium-234. We suggest this is a persistent and systematic imbalance and that other processes such as vertical mixing and advection of suspended particles are important export pathways. This article is part of the theme issue ‘The marine system of the west Antarctic Peninsula: status and strategy for progress in a region of rapid change’.

Published
2018

28. Particulate phases are key in controlling dissolved iron concentrations in the (sub)-tropical North Atlantic

Author

Alex R. Baker, Angela Milne, Alex Forryan, Rosie Chance, Christian Schlosser, Maeve C. Lohan, Eric P. Achterberg, and Bronwyn Wake

Subjects
0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Geotraces, Flux, Particulates, Oxygen minimum zone, 01 natural sciences, Carbon cycle, Geophysics, Oceanography, Deposition (aerosol physics), 13. Climate action, Environmental chemistry, General Earth and Planetary Sciences, Environmental science, 14. Life underwater, Cycling, 0105 earth and related environmental sciences
Abstract

The supply and bioavailability of iron (Fe) controls primary productivity and N2 fixation in large parts of the global ocean. An important, yet poorly quantified, source to the ocean is particulate Fe (pFe). Here we present the first combined dataset of particulate, labile-particulate (L-pFe), and dissolved Fe (dFe) from the (sub)tropical North Atlantic. We show a strong relationship between L-pFe and dFe, indicating a dynamic equilibrium between these two phases whereby particles “buffer” dFe and maintain the elevated concentrations observed. Moreover, L-pFe can increase the overall “available” (L-pFe + dFe) Fe pool by up to 55%. The lateral shelf flux of this available Fe was similar in magnitude to observed soluble aerosol-Fe deposition, a comparison that has not been previously considered. These findings demonstrate that L-pFe is integral to Fe cycling and hence plays a role in regulating carbon cycling, warranting its inclusion in Fe budgets and biogeochemical models.

Published
2017

29. Atmospheric transport of trace elements and nutrients to the oceans

Author

Alex R. Baker, Rosie Chance, and Tim Jickells

Subjects
010504 meteorology & atmospheric sciences, General Mathematics, Geotraces, Earth science, General Engineering, Trace element, General Physics and Astronomy, Biogeochemistry, Context (language use), Articles, Mineral dust, 010502 geochemistry & geophysics, 01 natural sciences, Trace (semiology), Deposition (aerosol physics), Nutrient, Oceanography, 0105 earth and related environmental sciences
Abstract

This paper reviews atmospheric inputs of trace elements and nutrients to the oceans in the context of the GEOTRACES programme and provides new data from two Atlantic GEOTRACES cruises. We consider the deposition of nitrogen to the oceans, which is now dominated by anthropogenic emissions, the deposition of mineral dust and related trace elements, and the deposition of other trace elements which have a mixture of anthropogenic and dust sources. We then consider the solubility (as a surrogate for bioavailability) of the various elements. We consider briefly the sources, atmospheric transport and transformations of these elements and how this results in strong spatial deposition gradients. Solubility of the trace elements also varies systematically between elements, reflecting their sources and cycling, and for some trace elements there are also systematic gradients in solubility related to dust loading. Together, these effects create strong spatial gradients in the inputs of bioavailable trace elements to the oceans, and we are only just beginning to understand how these affect ocean biogeochemistry. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

Published
2016

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