Robinson Laura F.

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Robinson

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Laura F.

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Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - modern calibration and evaluation of palaeo-applications

(Elsevier, 2017-01-27) Struve, Torben ; van de Flierdt, Tina ; Burke, Andrea ; Robinson, Laura F. ; Hammond, Samantha J. ; Crocket, Kirsty C. ; Bradtmiller, Louisa I. ; Auro, Maureen E. ; Mohamed, Kais J. ; White, Nicholas J.

Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs.
Primary U distribution in scleractinian corals and its implications for U series dating

(American Geophysical Union, 2006-05-24) Robinson, Laura F. ; Adkins, Jess F. ; Fernandez, Diego P. ; Burnett, Donald S. ; Wang, S.-L. ; Gagnon, Alexander C. ; Krakauer, Nir

In this study we use microsampling techniques to explore diagenetic processes in carbonates. These processes are important as they can affect the accuracy of U series chronometry. Fission track maps of deep-sea scleractinian corals show a threefold difference between the minimum and maximum [U] in modern corals, which is reduced to a factor of 2 in fossil corals. We use micromilling and MC-ICP-MS to make detailed analyses of the [U] and δ234Uinitial distributions in corals from 218 ka to modern. Within each fossil coral we observe a large range of δ234Uinitial values, with high δ234Uinitial values typically associated with low [U]. A simple model shows that this observation is best explained by preferential movement of alpha-decay produced 234U atoms (alpha-recoil diffusion). Open-system addition of 234U may occur when alpha-recoil diffusion is coupled with a high [U] surface layer, such as organic material. This process can result in large, whole-coral δ234Uinitial elevations with little effect on the final age. The diagenetic pathways that we model are relevant to both shallow-water and deep-sea scleractinian corals since both exhibit primary [U] heterogeneity and may be subject to U addition.
Deep-sea scleractinian coral age and depth distributions in the northwest Atlantic for the last 225,000 years

(University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2007-11-01) Robinson, Laura F. ; Adkins, Jess F. ; Scheirer, Daniel S. ; Fernandez, Diego P. ; Gagnon, Alexander C. ; Waller, Rhian G.

Deep-sea corals have grown for over 200,000 yrs on the New England Seamounts in the northwest Atlantic, and this paper describes their distribution both with respect to depth and time. Many thousands of fossil scleractinian corals were collected on a series of cruises from 2003-2005; by contrast, live ones were scarce. On these seamounts, the depth distribution of fossil Desmophyllum dianthus (Esper, 1794) is markedly different to that of the colonial scleractinian corals, extending 750 m deeper in the water column to a distinct cut-off at 2500 m. This cut-off is likely to be controlled by the maximum depth of a notch-shaped feature in the seamount morphology. The ages of D. dianthus corals as determined by U-series measurements range from modern to older than 200,000 yrs. The age distribution is not constant over time, and most corals have ages from the last glacial period. Within the glacial period, increases in coral population density at Muir and Manning Sea-mounts coincided with times at which large-scale ocean circulation changes have been documented in the deep North Atlantic. Ocean circulation changes have an effect on coral distributions, but the cause of the link is not known.
Neodymium isotope analyses after combined extraction of actinide and lanthanide elements from seawater and deep-sea coral aragonite

(John Wiley & Sons, 2016-01-09) Struve, Torben ; van de Flierdt, Tina ; Robinson, Laura F. ; Bradtmiller, Louisa I. ; Hines, Sophia K. ; Adkins, Jess F. ; Lambelet, Myriam ; Crocket, Kirsty C. ; Kreissig, Katharina ; Coles, Barry ; Auro, Maureen E.

Isotopes of the actinide elements protactinium (Pa), thorium (Th), and uranium (U), and the lanthanide element neodymium (Nd) are often used as complementary tracers of modern and past oceanic processes. The extraction of such elements from low abundance matrices, such as seawater and carbonate, is however labor-intensive and requires significant amounts of sample material. We here present a combined method for the extraction of Pa, Th, and Nd from 5 to 10 L seawater samples, and of U, Th, and Nd from <1 g carbonate samples. Neodymium is collected in the respective wash fractions of Pa-Th and U-Th anion exchange chromatographies. Regardless of the original sample matrix, Nd is extracted during a two-stage ion chromatography, followed by thermal ionization mass spectrometry (TIMS) analysis as NdO+. Using this combined procedure, we obtained results for Nd isotopic compositions on two GEOTRACES consensus samples from Bermuda Atlantic Time Series (BATS), which are within error identical to results for separately sampled and processed dedicated Nd samples (εNd = −9.20 ± 0.21 and −13.11 ± 0.21 for 15 and 2000 m water depths, respectively; intercalibration results from 14 laboratories: εNd = −9.19 ± 0.57 and −13.14 ± 0.57). Furthermore, Nd isotope results for an in-house coral reference material are identical within analytical uncertainty for dedicated Nd chemistry and after collection of Nd from U-Th anion exchange chromatography. Our procedure does not require major adaptations to independently used ion exchange chromatographies for U-Pa-Th and Nd, and can hence be readily implemented for a wide range of applications.
Low reservoir ages for the surface ocean from mid-Holocene Florida corals

(American Geophysical Union, 2008-05-13) Druffel, Ellen R. M. ; Robinson, Laura F. ; Griffin, Sheila ; Halley, Robert B. ; Southon, John R. ; Adkins, Jess F.

The 14C reservoir age of the surface ocean was determined for two Holocene periods (4908–4955 and 3008–3066 calendar (cal) B.P.) using U/Th-dated corals from Biscayne National Park, Florida, United States. We found that the average reservoir ages for these two time periods (294 ± 33 and 291 ± 27 years, respectively) were lower than the average value between A.D. 1600 and 1900 (390 ± 60 years) from corals. It appears that the surface ocean was closer to isotopic equilibrium with CO2 in the atmosphere during these two time periods than it was during recent times. Seasonal δ 18O measurements from the younger coral are similar to modern values, suggesting that mixing with open ocean waters was indeed occurring during this coral's lifetime. Likely explanations for the lower reservoir age include increased stratification of the surface ocean or increased Δ14C values of subsurface waters that mix into the surface. Our results imply that a more correct reservoir age correction for radiocarbon measurements of marine samples in this location from the time periods ∼3040 and ∼4930 cal years B.P. is ∼292 ± 30 years, less than the canonical value of 404 ± 20 years.
Interlaboratory study for coral Sr/Ca and other element/Ca ratio measurements

(John Wiley & Sons, 2013-09-23) Hathorne, Ed C. ; Gagnon, Alexander C. ; Felis, Thomas ; Adkins, Jess F. ; Asami, Ryuji ; Boer, Wim ; Caillon, Nicolas ; Case, David H. ; Cobb, Kim M. ; Douville, Eric ; deMenocal, Peter B. ; Eisenhauer, Anton ; Garbe-Schonberg, Dieter ; Geibert, Walter ; Goldstein, Steven L. ; Hughen, Konrad A. ; Inoue, Mayuri ; Kawahata, Hodaka ; Kolling, Martin ; Cornec, Florence L. ; Linsley, Braddock K. ; McGregor, Helen V. ; Montagna, Paolo ; Nurhati, Intan S. ; Quinn, Terrence M. ; Raddatz, Jacek ; Rebaubier, Helene ; Robinson, Laura F. ; Sadekov, Aleksey ; Sherrell, Robert M. ; Sinclair, Dan ; Tudhope, Alexander W. ; Wei, Gangjian ; Wong, Henri ; Wu, Henry C. ; You, Chen-Feng

The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twenty-one laboratories took part in an interlaboratory study of coral Sr/Ca measurements. Results show interlaboratory bias can be significant, and in the extreme case could result in a range in SST estimates of 7°C. However, most of the data fall within a narrower range and the Porites coral reference material JCp-1 is now characterized well enough to have a certified Sr/Ca value of 8.838 mmol/mol with an expanded uncertainty of 0.089 mmol/mol following International Association of Geoanalysts (IAG) guidelines. This uncertainty, at the 95% confidence level, equates to 1.5°C for SST estimates using Porites, so is approaching fitness for purpose. The comparable median within laboratory error is <0.5°C. This difference in uncertainties illustrates the interlaboratory bias component that should be reduced through the use of reference materials like the JCp-1. There are many potential sources contributing to biases in comparative methods but traces of Sr in Ca standards and uncertainties in reference solution composition can account for half of the combined uncertainty. Consensus values that fulfil the requirements to be certified values were also obtained for Mg/Ca in JCp-1 and for Sr/Ca and Mg/Ca ratios in the JCt-1 giant clam reference material. Reference values with variable fitness for purpose have also been obtained for Li/Ca, B/Ca, Ba/Ca, and U/Ca in both reference materials. In future, studies reporting coral element/Ca data should also report the average value obtained for a reference material such as the JCp-1.
GEOTRACES intercalibration of 230Th, 232Th, 231Pa, and prospects for 10Be

(Association for the Sciences of Limnology and Oceanography, 2012-04) Anderson, Robert F. ; Fleisher, Martin Q. ; Robinson, Laura F. ; Edwards, R. Lawrence ; Hoff, John A. ; Moran, S. Bradley ; Rutgers van der Loeff, Michiel M. ; Thomas, Alexander L. ; Roy-Barman, Matthieu ; Francois, Roger

Nineteen labs representing nine nations participated in the GEOTRACES intercalibration initiative that determined concentrations of 232Th, 230Th, 231Pa, or 10Be in seawater, suspended particles or sediments. Results generally demonstrated good agreement among labs that analyzed marine sediments. Two sets of seawater samples, aliquots of particulate material filtered in situ, and/or aliquots of biogenic sediments were distributed to participating labs. Internal consistency among participating labs improved substantially between the first and second set of seawater samples. Contamination was a serious problem for 232Th. Standard Niskin bottles introduced no detectable contamination, whereas sample containers, reagents, and labware were implicated as sources of contamination. No detectable differences in concentrations of dissolved 232Th, 230Th, or 231Pa were observed among samples of seawater filtered through Nuclepore, Supor, or QMA (quartz) filters with pore diameters ranging between 0.4 and 1.0 μm. Isotope yield monitors equilibrate with dissolved Th in seawater on a time scale of much less than 1 day. Samples of filtered seawater acidified to a pH between 1.7 and 1.8 experienced no detectable loss of dissolved Th or Pa during storage for up to 3 years. The Bermuda Atlantic Time Series station will serve as a GEOTRACES baseline station for future intercalibration of 232Th and 230Th concentrations in seawater. Efforts to improve blanks and standard calibration are ongoing, as is the development of methods to determine concentrations of particulate nuclides, tests of different filtration methods, and an increasing awareness of the need to define protocols for reporting uncertainties.
Ancient DNA techniques : applications for deep-water corals

(University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2007-11-01) Waller, Rhian G. ; Adkins, Jess F. ; Robinson, Laura F. ; Shank, Timothy M.

The potential applications of ancient DNA (aDNA) techniques have been realized relatively recently, and have been revolutionized by the advent of pCR techniques in the mid 1980s. Although these techniques have been proven valuable in ancient specimens of up to 100,000 yrs old, their use in the marine realm has been largely limited to mammals and fish. Using modifications of techniques developed for skeletons of whales and mammals, we have produced a method for extracting and amplifying aDNA from sub-fossil (not embedded in rock) deep-water corals that has been successful in yielding 351 base pairs of the ITS2 region in sub-fossil Desmophyllum dianthus (Esper, 1794) and Lophelia pertusa (Linnaeus, 1758). The comparison of DNA sequences from fossil and live specimens resulted in clustering by species, demonstrating the validity of this new aDNA method. Sub-fossil scler-actinian corals are readily dated using U-series techniques, and so the abundance of directly-dateable skeletons in the world's oceans, provides an extremely useful archive for investigating the interactions of environmental pressures (in particular ocean circulation, climate change) on the past distribution, and the evolution of deep-water corals across the globe.
Exploring B/Ca as a pH proxy in bivalves : relationships between Mytilus californianus B/Ca and environmental data from the northeast Pacific

(Copernicus Publications on behalf of the European Geosciences Union, 2011-09-13) McCoy, S. J. ; Robinson, Laura F. ; Pfister, Catherine A. ; Wootton, J. T. ; Shimizu, Nobumichi

A distinct gap in our ability to understand changes in coastal biology that may be associated with recent ocean acidification is the paucity of directly measured ocean environmental parameters at coastal sites in recent decades. Thus, many researchers have turned to sclerochronological reconstructions of water chemistry to document the historical seawater environment. In this study, we explore the relationships between B/Ca and pH to test the feasibility of B/Ca measured on the ion probe as a pH proxy in the California mussel, Mytilus californianus. Heterogeneity in a range of ion microprobe standards is assessed, leading to reproducible B/Ca ratios at the 5% level. The B/Ca data exhibit large excursions during winter months, which are particularly pronounced during the severe winters of 2004–2005 and 2005–2006. Furthermore, B/Ca ratios are offset in different parts of the skeleton that calcified at the same time. We compare the M. californianus B/Ca record to directly measured environmental data during mussel growth from the period of 1999–2009 to examine whether seawater chemistry or temperature plays a role in controlling shell B/Ca. A suite of growth rate models based on measured temperature are compared to the B/Ca data to optimise the potential fit of B/Ca to pH. Despite sampling conditions that were well-suited to testing a pH control on B/Ca, including a close proximity to an environmental record, a distinct change in pH at the sampling locale, and a growth model designed to optimise the correlations between seawater pH and shell B/Ca, we do not see a strong correlations between pH and shell B/Ca (maximum coefficient of determination, r2, of 0.207). Instead, our data indicate a strong biological control on B/Ca as observed in some other carbonate-forming organisms.
Temporal stability of the neodymium isotope signature of the Holocene to glacial North Atlantic

(American Geophysical Union, 2006-11-25) van de Flierdt, Tina ; Robinson, Laura F. ; Adkins, Jess F. ; Hemming, Sidney R. ; Goldstein, Steven L.

The neodymium isotopic composition of marine precipitates is increasingly recognized as a powerful tool for identifying changes in ocean circulation and mixing on million year to millennial time-scales. Unlike nutrient proxies such as δ13C or Cd/Ca, Nd isotopes are not thought to be altered in any significant way by biological processes, and thus can serve as a quasi-conservative water mass tracer. However, the application of Nd isotopes in understanding the role of thermohaline circulation in rapid climate change is currently hindered by the lack of direct constraints on the signature of the North Atlantic end-member through time. Here we present the first results of Nd isotopes measured in U-Th dated deep-sea corals from the New England seamounts in the northwest Atlantic Ocean. Our data are consistent with the conclusion that the Nd isotopic composition of North Atlantic deep and intermediate water has remained nearly constant through the last glacial cycle. The results address longstanding concerns that there may have been significant changes in the Nd isotopic composition of the North Atlantic end member during this interval, and substantiate the applicability of this novel tracer on millennial time-scales for palaeoceanography research.
Improvements to 232-thorium, 230-thorium, and 231- protactinium analysis in seawater arising from GEOTRACES intercalibration

(Association for the Sciences of Limnology and Oceanography, 2012-07) Auro, Maureen E. ; Robinson, Laura F. ; Burke, Andrea ; Bradtmiller, Louisa I. ; Fleisher, Martin Q. ; Anderson, Robert F.

The GEOTRACES program requires the analysis of large numbers of seawater samples for 232Th, 230Th, and 231Pa. During the GEOTRACES international intercalibration exercise, we encountered unexpected difficulties with recovery and contamination of these isotopes, 232Th in particular. Experiments were carried out to identify the source of these issues, leading to a more streamlined and efficient procedure. The two particular problems that we identified and corrected were (1) frits in columns supplied by Bio-Rad Laboratories caused loss of Th during column chemistry and (2) new batches of AG1-X8 resin supplied by Bio-Rad Laboratories released more than 100 pg of 232Th during elution of sample. To improve yields and blanks, we implemented a series of changes including switching to Eichrom anion exchange resin (100-200 μm mesh) and Environmental Express columns. All Th and Pa samples were analyzed on a Neptune multi-collector inductively-coupled-plasma mass spectrometer (MC-ICP-MS) using peak hopping of 230Th and 229Th on the central SEM, with either 232Th, 236U (or both) used to monitor for beam intensity. We used in-house laboratory standards to check for machine reproducibility, and the GEOTRACES intercalibration standard to check for accuracy. Over a 1-y period, the 2 s.d. reproducibility on the GEOTRACES SW STD 2010-1 was 2.5% for 230Th, 1.8% for 232Th, and 4% for 231Pa. The lessons learned during this intercalibration process will be of value to those analyzing U-Th-Pa and rare earth elements as part of the GEOTRACES program as well as those using U-series elements in other applications that require high yields and low blanks, such as geochronology.
Global ocean sediment composition and burial flux in the deep sea

(American Geophysical Union, 2021-03-21) Hayes, Christopher T. ; Costa, Kassandra M. ; Anderson, Robert F. ; Calvo, Eva ; Chase, Zanna ; Demina, Ludmila L. ; Dutay, Jean-Claude ; German, Christopher R. ; Heimbürger, Lars-Eric ; Jaccard, Samuel L. ; Jacobel, Allison W. ; Kohfeld, Karen E. ; Kravchishina, Marina ; Lippold, Jörg ; Mekik, Figen ; Missiaen, Lise ; Pavia, Frank ; Paytan, Adina ; Pedrosa-Pamies, Rut ; Petrova, Mariia V. ; Rahman, Shaily ; Robinson, Laura F. ; Roy-Barman, Matthieu ; Sanchez-Vidal, Anna ; Shiller, Alan M. ; Tagliabue, Alessandro ; Tessin, Allyson C. ; van Hulten, Marco ; Zhang, Jing

Quantitative knowledge about the burial of sedimentary components at the seafloor has wide-ranging implications in ocean science, from global climate to continental weathering. The use of 230Th-normalized fluxes reduces uncertainties that many prior studies faced by accounting for the effects of sediment redistribution by bottom currents and minimizing the impact of age model uncertainty. Here we employ a recently compiled global data set of 230Th-normalized fluxes with an updated database of seafloor surface sediment composition to derive atlases of the deep-sea burial flux of calcium carbonate, biogenic opal, total organic carbon (TOC), nonbiogenic material, iron, mercury, and excess barium (Baxs). The spatial patterns of major component burial are mainly consistent with prior work, but the new quantitative estimates allow evaluations of deep-sea budgets. Our integrated deep-sea burial fluxes are 136 Tg C/yr CaCO3, 153 Tg Si/yr opal, 20Tg C/yr TOC, 220 Mg Hg/yr, and 2.6 Tg Baxs/yr. This opal flux is roughly a factor of 2 increase over previous estimates, with important implications for the global Si cycle. Sedimentary Fe fluxes reflect a mixture of sources including lithogenic material, hydrothermal inputs and authigenic phases. The fluxes of some commonly used paleo-productivity proxies (TOC, biogenic opal, and Baxs) are not well-correlated geographically with satellite-based productivity estimates. Our new compilation of sedimentary fluxes provides detailed regional and global information, which will help refine the understanding of sediment preservation.
Rapid radiocarbon (14C) analysis of coral and carbonate samples using a continuous-flow accelerator mass spectrometry (CFAMS) system

(American Geophysical Union, 2011-11-05) McIntyre, Cameron P. ; Roberts, Mark L. ; Burton, Joshua R. ; McNichol, Ann P. ; Burke, Andrea ; Robinson, Laura F. ; von Reden, Karl F. ; Jenkins, William J.

Radiocarbon analyses of carbonate materials provide critical information for understanding the last glacial cycle, recent climate history and paleoceanography. Methods that reduce the time and cost of radiocarbon (14C) analysis are highly desirable for large sample sets and reconnaissance type studies. We have developed a method for rapid radiocarbon analysis of carbonates using a novel continuous-flow accelerator mass spectrometry (CFAMS) system. We analyzed a suite of deep-sea coral samples and compared the results with those obtained using a conventional AMS system. Measurement uncertainty is <0.02 Fm or 160 Ryr for a modern sample and the mean background was 37,800 Ryr. Radiocarbon values were repeatable and in good agreement with those from the conventional AMS system. Sample handling and preparation is relatively simple and the method offered a significant increase in speed and cost effectiveness. We applied the method to coral samples from the Eastern Pacific Ocean to obtain an age distribution and identify samples for further analysis. This paper is intended to update the paleoceanographic community on the status of this new method and demonstrate its feasibility as a choice for rapid and affordable radiocarbon analysis.
Cold-water coral distributions in the Drake Passage area from towed camera observations – initial interpretations

(Public Library of Science, 2011-01-25) Waller, Rhian G. ; Scanlon, Kathryn M. ; Robinson, Laura F.

Seamounts are unique deep-sea features that create habitats thought to have high levels of endemic fauna, productive fisheries and benthic communities vulnerable to anthropogenic impacts. Many seamounts are isolated features, occurring in the high seas, where access is limited and thus biological data scarce. There are numerous seamounts within the Drake Passage (Southern Ocean), yet high winds, frequent storms and strong currents make seafloor sampling particularly difficult. As a result, few attempts to collect biological data have been made, leading to a paucity of information on benthic habitats or fauna in this area, particularly those on primarily hard-bottom seamounts and ridges. During a research cruise in 2008 six locations were examined (two on the Antarctic margin, one on the Shackleton Fracture Zone, and three on seamounts within the Drake Passage), using a towed camera with onboard instruments to measure conductivity, temperature, depth and turbidity. Dominant fauna and bottom type were categorized from 200 randomized photos from each location. Cold-water corals were present in high numbers in habitats both on the Antarctic margin and on the current swept seamounts of the Drake Passage, though the diversity of orders varied. Though the Scleractinia (hard corals) were abundant on the sedimented margin, they were poorly represented in the primarily hard-bottom areas of the central Drake Passage. The two seamount sites and the Shackleton Fracture Zone showed high numbers of stylasterid (lace) and alcyonacean (soft) corals, as well as large numbers of sponges. Though data are preliminary, the geological and environmental variability (particularly in temperature) between sample sites may be influencing cold-water coral biogeography in this region. Each area observed also showed little similarity in faunal diversity with other sites examined for this study within all phyla counted. This manuscript highlights how little is understood of these isolated features, particularly in Polar regions.
The GEOTRACES Intermediate Data Product 2014

(Elsevier, 2015-04-16) Mawji, Edward ; Schlitzer, Reiner ; Dodas, Elena Masferrer ; Abadie, Cyril ; Abouchami, Wafa ; Anderson, Robert F. ; Baars, Oliver ; Bakker, Karel ; Baskaran, Mark ; Bates, Nicholas R. ; Bluhm, Katrin ; Bowie, Andrew R. ; Bown, Johann ; Boye, Marie ; Marie, Edward A. ; Branellec, Pierre ; Bruland, Kenneth W. ; Brzezinski, Mark A. ; Bucciarelli, Eva ; Buesseler, Ken O. ; Butler, Edward ; Cai, Pinghe ; Cardinal, Damien ; Casciotti, Karen L. ; Chaves, Joaquin E. ; Cheng, Hai ; Chever, Fanny ; Church, Thomas M. ; Colman, Albert S. ; Conway, Tim M. ; Croot, Peter L. ; Cutter, Gregory A. ; Baar, Hein J. W. de ; de Souza, Gregory F. ; Dehairs, Frank ; Deng, Feifei ; Dieu, Huong Thi ; Dulaquais, Gabriel ; Echegoyen-Sanz, Yolanda ; Edwards, R. Lawrence ; Fahrbach, Eberhard ; Fitzsimmons, Jessica N. ; Fleisher, Martin Q. ; Frank, Martin ; Friedrich, Jana ; Fripiat, Francois ; Galer, Stephen J. G. ; Gamo, Toshitaka ; Garcia Solsona, Ester ; Gerringa, Loes J. A. ; Godoy, Jose Marcus ; Gonzalez, Santiago ; Grossteffan, Emilie ; Hatta, Mariko ; Hayes, Christopher T. ; Heller, Maija Iris ; Henderson, Gideon M. ; Huang, Kuo-Fang ; Jeandel, Catherine ; Jenkins, William J. ; John, Seth G. ; Kenna, Timothy C. ; Klunder, Maarten ; Kretschmer, Sven ; Kumamoto, Yuichiro ; Laan, Patrick ; Labatut, Marie ; Lacan, Francois ; Lam, Phoebe J. ; Lannuzel, Delphine ; le Moigne, Frederique ; Lechtenfeld, Oliver J. ; Lohan, Maeve C. ; Lu, Yanbin ; Masqué, Pere ; McClain, Charles R. ; Measures, Christopher I. ; Middag, Rob ; Moffett, James W. ; Navidad, Alicia ; Nishioka, Jun ; Noble, Abigail E. ; Obata, Hajime ; Ohnemus, Daniel C. ; Owens, Stephanie A. ; Planchon, Frederic ; Pradoux, Catherine ; Puigcorbe, Viena ; Quay, Paul D. ; Radic, Amandine ; Rehkamper, Mark ; Remenyi, Tomas A. ; Rijkenberg, Micha J. A. ; Rintoul, Stephen R. ; Robinson, Laura F. ; Roeske, Tobias ; Rosenberg, Mark ; Rutgers van der Loeff, Michiel M. ; Ryabenko, Evgenia ; Saito, Mak A. ; Roshan, Saeed ; Salt, Lesley ; Sarthou, Geraldine ; Schauer, Ursula ; Scott, Peter M. ; Sedwick, Peter N. ; Sha, Lijuan ; Shiller, Alan M. ; Sigman, Daniel M. ; Smethie, William M. ; Smith, Geoffrey J. ; Sohrin, Yoshiki ; Speich, Sabrina ; Stichel, Torben ; Stutsman, Johnny ; Swift, James H. ; Tagliabue, Alessandro ; Thomas, Alexander L. ; Tsunogai, Urumu ; Twining, Benjamin S. ; van Aken, Hendrik M. ; van Heuven, Steven ; van Ooijen, Jan ; van Weerlee, Evaline ; Venchiarutti, Celia ; Voelker, Antje H. L. ; Wake, Bronwyn ; Warner, Mark J. ; Woodward, E. Malcolm S. ; Wu, Jingfeng ; Wyatt, Neil ; Yoshikawa, Hisayuki ; Zheng, Xin-Yuan ; Xue, Zichen ; Zieringer, Moritz ; Zimmer, Louise A.

The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes.
230 Th normalization: new insights on an essential tool for quantifying sedimentary fluxes in the modern and quaternary ocean

(John Wiley & Sons, 2020-01-27) Costa, Kassandra M. ; Hayes, Christopher T. ; Anderson, Robert F. ; Pavia, Frank ; Bausch, Alexandra ; Deng, Feifei ; Dutay, Jean-Claude ; Geibert, Walter ; Heinze, Christoph ; Henderson, Gideon M. ; Hillaire‐Marcel, Claude ; Hoffmann, Sharon S. ; Jaccard, Samuel L. ; Jacobel, Allison W. ; Kienast, Stephanie S. ; Kipp, Lauren ; Lerner, Paul ; Lippold, Jörg ; Lund, David C. ; Marcantonio, Franco ; McGee, David ; McManus, Jerry F. ; Mekik, Figen ; Middleton, Jennifer L. ; Missiaen, Lise ; Not, Christelle ; Pichat, Sylvain ; Robinson, Laura F. ; Rowland, George H. ; Roy-Barman, Matthieu ; Tagliabue, Alessandro ; Torfstein, Adi ; Winckler, Gisela ; Zhou, Yuxin

230Th normalization is a valuable paleoceanographic tool for reconstructing high‐resolution sediment fluxes during the late Pleistocene (last ~500,000 years). As its application has expanded to ever more diverse marine environments, the nuances of 230Th systematics, with regard to particle type, particle size, lateral advective/diffusive redistribution, and other processes, have emerged. We synthesized over 1000 sedimentary records of 230Th from across the global ocean at two time slices, the late Holocene (0–5,000 years ago, or 0–5 ka) and the Last Glacial Maximum (18.5–23.5 ka), and investigated the spatial structure of 230Th‐normalized mass fluxes. On a global scale, sedimentary mass fluxes were significantly higher during the Last Glacial Maximum (1.79–2.17 g/cm2kyr, 95% confidence) relative to the Holocene (1.48–1.68 g/cm2kyr, 95% confidence). We then examined the potential confounding influences of boundary scavenging, nepheloid layers, hydrothermal scavenging, size‐dependent sediment fractionation, and carbonate dissolution on the efficacy of 230Th as a constant flux proxy. Anomalous 230Th behavior is sometimes observed proximal to hydrothermal ridges and in continental margins where high particle fluxes and steep continental slopes can lead to the combined effects of boundary scavenging and nepheloid interference. Notwithstanding these limitations, we found that 230Th normalization is a robust tool for determining sediment mass accumulation rates in the majority of pelagic marine settings (>1,000 m water depth).
Clumped isotope composition of cold-water corals : a role for vital effects?

(Elsevier, 2016-02-02) Spooner, Peter T. ; Guo, Weifu ; Robinson, Laura F. ; Thiagarajan, Nivedita ; Hendry, Katharine R. ; Rosenheim, Brad E. ; Leng, Melanie J.

The carbonate clumped isotope thermometer is a promising tool for determining past ocean temperatures. It is based on the temperature dependence of rare isotopes ‘clumping’ into the same carbonate ion group in the carbonate mineral lattice. The extent of this clumping effect is independent of the isotope composition of the water from which carbonate precipitates, providing unique advantages over many other paleotemperature proxies. Existing calibrations of this thermometer in cold-water and warm-water corals suggest clumped isotope ‘vital effects’ are negligible in cold-water corals but may be significant in warm-water corals. Here, we test the calibration of the carbonate clumped isotope thermometer in cold-water corals with a recently collected and well characterised sample set spanning a range of coral genera (Balanophyllia, Caryophyllia, Dasmosmilia, Desmophyllum, Enallopsammia and Javania). The clumped isotope compositions (Δ47) of these corals exhibit systematic dependences on their growth temperatures, confirming the basis of the carbonate clumped isotope thermometer. However, some cold-water coral genera show Δ47 values that are higher than the expected equilibrium values by up to 0.05‰ (equivalent to underestimating temperature by ∼9 °C) similar to previous findings for some warm-water corals. This finding suggests that the vital effects affecting corals Δ47 are common to both warm- and cold-water corals. By comparison with models of the coral calcification process we suggest that the clumped isotope offsets in these genera are related to the kinetic isotope effects associated with CO2 hydration/hydroxylation reactions in the corals’ calcifying fluid. Our findings complicate the use of the carbonate clumped isotope thermometer in corals, but suggest that species- or genus-specific calibrations could be useful for the future application of this paleotemperature proxy.
Dynamic intermediate ocean circulation in the North Atlantic during Heinrich Stadial 1 : a radiocarbon and neodymium isotope perspective

(John Wiley & Sons, 2014-11-20) Wilson, David J. ; Crocket, Kirsty C. ; van de Flierdt, Tina ; Robinson, Laura F. ; Adkins, Jess F.

The last deglaciation was characterized by a series of millennial-scale climate events that have been linked to deep ocean variability. While often implied in interpretations, few direct constraints exist on circulation changes at mid-depths. Here we provide new constraints on the variability of deglacial mid-depth circulation using combined radiocarbon and neodymium isotopes in 24 North Atlantic deep-sea corals. Their aragonite skeletons have been dated by uranium-series, providing absolute ages and the resolution to record centennial-scale changes, while transects spanning the lifetime of a single coral allow subcentennial tracer reconstruction. Our results reveal that rapid fluctuations of water mass sourcing and radiocarbon affected the mid-depth water column (1.7–2.5 km) on timescales of less than 100 years during the latter half of Heinrich Stadial 1. The neodymium isotopic variability (−14.5 to −11.0) ranges from the composition of the modern northern-sourced waters towards more radiogenic compositions, suggesting the presence of a greater southern-sourced component at some times. However, in detail, simple two-component mixing between well-ventilated northern-sourced and radiocarbon-depleted southern-sourced water masses cannot explain all our data. Instead, corals from ~15.0 ka and ~15.8 ka may record variability between southern-sourced intermediate waters and radiocarbon-depleted northern-sourced waters, unless there was a major shift in the neodymium isotopic composition of the northern end-member. In order to explain the rapid shift towards the most depleted radiocarbon values at ~15.4 ka, we suggest a different mixing scenario involving either radiocarbon-depleted deep water from the Greenland-Iceland-Norwegian Seas or a southern-sourced deep water mass. Since these mid-depth changes preceded the Bolling-Allerod warming and were apparently unaccompanied by changes in the deep Atlantic, they may indicate an important role for the intermediate ocean in the early deglacial climate evolution.
The GEOTRACES Intermediate Data Product 2017

(Elsevier, 2018-06-01) Schlitzer, Reiner ; Anderson, Robert F. ; Dodas, Elena Masferrer ; Lohan, Maeve C. ; Geibert, Walter ; Tagliabue, Alessandro ; Bowie, Andrew R. ; Jeandel, Catherine ; Maldonado, Maria T. ; Landing, William M. ; Cockwell, Donna ; Abadie, Cyril ; Abouchami, Wafa ; Achterberg, Eric P. ; Agather, Alison ; Aguliar-Islas, Ana ; van Aken, Hendrik M. ; Andersen, Morten ; Archer, Corey ; Auro, Maureen E. ; Baar, Hein J. W. de ; Baars, Oliver ; Baker, Alex R. ; Bakker, Karel ; Basak, Chandranath ; Baskaran, Mark ; Bates, Nicholas R. ; Bauch, Dorothea ; van Beek, Pieter ; Behrens, Melanie K. ; Black, Erin E. ; Bluhm, Katrin ; Bopp, Laurent ; Bouman, Heather ; Bowman, Katlin ; Bown, Johann ; Boyd, Philip ; Boye, Marie ; Boyle, Edward A. ; Branellec, Pierre ; Bridgestock, Luke ; Brissebrat, Guillaume ; Browning, Thomas ; Bruland, Kenneth W. ; Brumsack, Hans-Jürgen ; Brzezinski, Mark A. ; Buck, Clifton S. ; Buck, Kristen N. ; Buesseler, Ken O. ; Bull, Abby ; Butler, Edward ; Cai, Pinghe ; Cámara Mor, Patricia ; Cardinal, Damien ; Carlson, Craig ; Carrasco, Gonzalo ; Casacuberta, Nuria ; Casciotti, Karen L. ; Castrillejo, Maxi ; Chamizo, Elena ; Chance, Rosie ; Charette, Matthew A. ; Chaves, Joaquin E. ; Cheng, Hai ; Chever, Fanny ; Christl, Marcus ; Church, Thomas M. ; Closset, Ivia ; Colman, Albert S. ; Conway, Tim M. ; Cossa, Daniel ; Croot, Peter L. ; Cullen, Jay T. ; Cutter, Gregory A. ; Daniels, Chris ; Dehairs, Frank ; Deng, Feifei ; Dieu, Huong Thi ; Duggan, Brian ; Dulaquais, Gabriel ; Dumousseaud, Cynthia ; Echegoyen-Sanz, Yolanda ; Edwards, R. Lawrence ; Ellwood, Michael J. ; Fahrbach, Eberhard ; Fitzsimmons, Jessica N. ; Flegal, A. Russell ; Fleisher, Martin Q. ; van de Flierdt, Tina ; Frank, Martin ; Friedrich, Jana ; Fripiat, Francois ; Fröllje, Henning ; Galer, Stephen J. G. ; Gamo, Toshitaka ; Ganeshram, Raja S. ; Garcia-Orellana, Jordi ; Garcia Solsona, Ester ; Gault-Ringold, Melanie ; George, Ejin ; Gerringa, Loes J. A. ; Gilbert, Melissa ; Godoy, Jose Marcus ; Goldstein, Steven L. ; Gonzalez, Santiago ; Grissom, Karen ; Hammerschmidt, Chad R. ; Hartman, Alison ; Hassler, Christel ; Hathorne, Ed C. ; Hatta, Mariko ; Hawco, Nicholas J. ; Hayes, Christopher T. ; Heimbürger, Lars-Eric ; Helgoe, Josh ; Heller, Maija Iris ; Henderson, Gideon M. ; Henderson, Paul B. ; van Heuven, Steven ; Ho, Peng ; Horner, Tristan J. ; Hsieh, Yu-Te ; Huang, Kuo-Fang ; Humphreys, Matthew P. ; Isshiki, Kenji ; Jacquot, Jeremy E. ; Janssen, David J. ; Jenkins, William J. ; John, Seth ; Jones, Elizabeth M. ; Jones, Janice L. ; Kadko, David ; Kayser, Rick ; Kenna, Timothy C. ; Khondoker, Roulin ; Kim, Taejin ; Kipp, Lauren ; Klar, Jessica K. ; Klunder, Maarten ; Kretschmer, Sven ; Kumamoto, Yuichiro ; Laan, Patrick ; Labatut, Marie ; Lacan, Francois ; Lam, Phoebe J. ; Lambelet, Myriam ; Lamborg, Carl H. ; le Moigne, Frederique ; Le Roy, Emilie ; Lechtenfeld, Oliver J. ; Lee, Jong-Mi ; Lherminier, Pascale ; Little, Susan ; López-Lora, Mercedes ; Lu, Yanbin ; Masque, Pere ; Mawji, Edward ; McClain, Charles R. ; Measures, Christopher I. ; Mehic, Sanjin ; Menzel Barraqueta, Jan-Lukas ; Merwe, Pier van der ; Middag, Rob ; Mieruch, Sebastian ; Milne, Angela ; Minami, Tomoharu ; Moffett, James W. ; Moncoiffe, Gwenaelle ; Moore, Willard S. ; Morris, Paul J. ; Morton, Peter L. ; Nakaguchi, Yuzuru ; Nakayama, Noriko ; Niedermiller, John ; Nishioka, Jun ; Nishiuchi, Akira ; Noble, Abigail E. ; Obata, Hajime ; Ober, Sven ; Ohnemus, Daniel C. ; van Ooijen, Jan ; O'Sullivan, Jeanette ; Owens, Stephanie A. ; Pahnke, Katharina ; Paul, Maxence ; Pavia, Frank ; Pena, Leopoldo D. ; Peters, Brian ; Planchon, Frederic ; Planquette, Helene ; Pradoux, Catherine ; Puigcorbé, Viena ; Quay, Paul D. ; Queroue, Fabien ; Radic, Amandine ; Rauschenberg, Sara ; Rehkämper, Mark ; Rember, Robert ; Remenyi, Tomas A. ; Resing, Joseph A. ; Rickli, Joerg ; Rigaud, Sylvain ; Rijkenberg, Micha J. A. ; Rintoul, Stephen R. ; Robinson, Laura F. ; Roca-Martí, Montserrat ; Rodellas, Valenti ; Roeske, Tobias ; Rolison, John M. ; Rosenberg, Mark ; Roshan, Saeed ; Rutgers van der Loeff, Michiel M. ; Ryabenko, Evgenia ; Saito, Mak A. ; Salt, Lesley ; Sanial, Virginie ; Sarthou, Geraldine ; Schallenberg, Christina ; Schauer, Ursula ; Scher, Howie ; Schlosser, Christian ; Schnetger, Bernhard ; Scott, Peter M. ; Sedwick, Peter N. ; Semiletov, Igor P. ; Shelley, Rachel U. ; Sherrell, Robert M. ; Shiller, Alan M. ; Sigman, Daniel M. ; Singh, Sunil Kumar ; Slagter, Hans ; Slater, Emma ; Smethie, William M. ; Snaith, Helen ; Sohrin, Yoshiki ; Sohst, Bettina M. ; Sonke, Jeroen E. ; Speich, Sabrina ; Steinfeldt, Reiner ; Stewart, Gillian ; Stichel, Torben ; Stirling, Claudine H. ; Stutsman, Johnny ; Swarr, Gretchen J. ; Swift, James H. ; Thomas, Alexander ; Thorne, Kay ; Till, Claire P. ; Till, Ralph ; Townsend, Ashley T. ; Townsend, Emily ; Tuerena, Robyn ; Twining, Benjamin S. ; Vance, Derek ; Velazquez, Sue ; Venchiarutti, Celia ; Villa-Alfageme, Maria ; Vivancos, Sebastian M. ; Voelker, Antje H. L. ; Wake, Bronwyn ; Warner, Mark J. ; Watson, Ros ; van Weerlee, Evaline ; Weigand, M. Alexandra ; Weinstein, Yishai ; Weiss, Dominik ; Wisotzki, Andreas ; Woodward, E. Malcolm S. ; Wu, Jingfeng ; Wu, Yingzhe ; Wuttig, Kathrin ; Wyatt, Neil ; Xiang, Yang ; Xie, Ruifang C. ; Xue, Zichen ; Yoshikawa, Hisayuki ; Zhang, Jing ; Zhang, Pu ; Zhao, Ye ; Zheng, Linjie ; Zheng, Xin-Yuan ; Zieringer, Moritz ; Zimmer, Louise A. ; Ziveri, Patrizia ; Zunino, Patricia ; Zurbrick, Cheryl

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.

Robinson Laura F.

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