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Storage and Hydrolysis of Seawater Samples for Inorganic Carbon Isotope Analysis
- Charlotte L Bryant, Sian F Henley, Callum Murray, Raja S Ganeshram, Richard Shanks
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- Journal:
- Radiocarbon / Volume 55 / Issue 2 / 2013
- Published online by Cambridge University Press:
- 09 February 2016, pp. 401-409
- Print publication:
- 2013
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Preservation of seawater samples was tested for total inorganic carbon (∑CO2), stable carbon isotope (δ13C), and radiocarbon (14C) applications using foil bags and storage by refrigeration and freezing. The aim was to preserve representative samples with minimal storage effects but without using toxic methods such as mercuric chloride poisoning. Hydrolysis of samples to CO2 was based on existing methods. Results of IAEA-C2 standard used with deionized water stored in the foil bags showed complete reaction yields, 14C results within 2σ of the consensus value, and δ13C that were internally consistent, indicating that there were no procedural effects associated with the foil bags. 14C results were statistically indistinguishable across the storage times, for frozen and refrigerated seawater samples from a coastal site, Elie Ness, Fife, UK. The scatter of ∑CO2 concentrations and δ13C was within scatter observed in other studies for lake- and seawater samples preserved by acidification or using mercuric chloride. However, both ∑CO2 and δ13C were less variable for frozen samples compared with refrigerated samples. The foil bags are lighter, safer to transport, and similar in cost to glass bottles and allow sample collection in the field and transfer to the hydrolysis vessel without exposure of the sample to atmosphere. Storage of seawater samples in the foil bags was considered a reliable, alternative method to poisoning for ∑CO2, δ13C, and 14C, and freezing the samples is recommended for storage time beyond a week.
Use of radium isotopes to estimate mixing rates and trace sediment inputs to surface waters in northern Marguerite Bay, Antarctic Peninsula
- Part of
- Amber L. Annett, Sian F. Henley, Pieter Van Beek, Marc Souhaut, Raja Ganeshram, Hugh J. Venables, Michael P. Meredith, Walter Geibert
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- Journal:
- Antarctic Science / Volume 25 / Issue 3 / June 2013
- Published online by Cambridge University Press:
- 29 October 2012, pp. 445-456
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In the western Antarctic Peninsula region, micronutrient injection facilitates strong plankton blooms that support productive food webs, unlike large areas of the low-productivity Southern Ocean. We use naturally occurring radioisotopes of radium to constrain rates of chemical fluxes into Ryder Bay (a small coastal embayment in northern Marguerite Bay), and hence to evaluate possible sources of sediment-derived micronutrients and estimate sediment-ocean mixing rates. We present the first coupled, short-lived radium isotope (223Ra and 224Ra) measurements from Antarctic waters, both present at very low activities (mean 0.155 and 3.21 dpm m-3, respectively), indicating much lower radium inputs than in other coastal environments. Longer-lived 228Ra activity was also lower than existing nearshore values, but higher than open ocean waters, indicating some degree of coastal radium input on timescales exceeding the week-to-month range reflected by 223Ra and 224Ra. Using a simple diffusion model along a shore to mid-bay transect, effective horizontal eddy diffusivity estimates ranged from 0.22–0.83 m2 s-1 from 223Ra and 224Ra, respectively, much lower than already-low mixing estimates for the Southern Ocean. Significant radium enrichment and much faster mixing (18 m2 s-1) was found near a marine-terminating glacier and consequently any sediment-derived micronutrient inputs in this location are more probably dominated by glacial processes than groundwater, land runoff, or marine sediment sources.
13 - Nitrogen flows from European regional watersheds to coastal marine waters
- from Part III - Nitrogen flows and fate at multiple spatial scales
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- By Gilles Billen, University Pierre & Marie Curie, Marie Silvestre, CNRS – FR3020 FIRE, Bruna Grizzetti, European Commission Joint Research Centre, Adrian Leip, European Commission Joint Research Centre, Josette Garnier, UMR Sisyphe UPMC & CNRS, Maren Voss, Leibniz-Institute of Baltic Sea Research Warnemuende, Robert Howarth, Cornell University, Fayçal Bouraoui, European Commission Joint Research Centre, Ahti Lepistö, Finnish Environment Institute, Pirkko Kortelainen, Finnish Environment Institute, Penny Johnes, University of Reading, Chris Curtis, University College London Environmental Change Research Centre, Christoph Humborg, Stockholm University, Erik Smedberg, Stockholm University, Øyvind Kaste, Norwegian Institute for Water Research, Raja Ganeshram, University of Edinburgh, Arthur Beusen, Netherlands Environmental Assessment Agency, Christiane Lancelot, Université Libre de Bruxelles
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 271-297
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Summary
Executive summary
Nature of the problem
Most regional watersheds in Europe constitute managed human territories importing large amounts of new reactive nitrogen.
As a consequence, groundwater, surface freshwater and coastal seawater are undergoing severe nitrogen contamination and/or eutrophication problems.
Approaches
A comprehensive evaluation of net anthropogenic inputs of reactive nitrogen (NANI) through atmospheric deposition, crop N fixation, fertiliser use and import of food and feed has been carried out for all European watersheds. A database on N, P and Si fluxes delivered at the basin outlets has been assembled.
A number of modelling approaches based on either statistical regression analysis or mechanistic description of the processes involved in nitrogen transfer and transformations have been developed for relating N inputs to watersheds to outputs into coastal marine ecosystems.
Key findings/state of knowledge
Throughout Europe, NANI represents 3700 kgN/km²/yr (range, 0–8400 depending on the watershed), i.e. five times the background rate of natural N2 fixation.
A mean of approximately 78% of NANI does not reach the basin outlet, but instead is stored (in soils, sediments or ground water) or eliminated to the atmosphere as reactive N forms or as N2.
N delivery to the European marine coastal zone totals 810 kgN/km²/yr (range, 200–4000 depending on the watershed), about four times the natural background. In areas of limited availability of silica, these inputs cause harmful algal blooms.
8 - Nitrogen processes in coastal and marine ecosystems
- from Part II - Nitrogen processing in the biosphere
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- By Maren Voss, Leibniz-Institute of Baltic Sea Research Warnemuende, Alex Baker, University of East Anglia, Hermann W. Bange, Leibniz-Institut für Meereswissenschaften, Daniel Conley, Lund University, Sarah Cornell, University of Bristol, Barbara Deutsch, Stockholm University, Anja Engel, Alfred Wegener Institute for Polar and Marine Research, Raja Ganeshram, University of Edinburgh, Josette Garnier, UMR Sisyphe UPMC & CNRS, Ana-Stiina Heiskanen, Finnish Environment Institute, Tim Jickells, University of East Anglia, Christiane Lancelot, Université Libre de Bruxelles, Abigail McQuatters-Gollop, Sir Alister Hardy Foundation for Ocean Science, Jack Middelburg, Utrecht University, Doris Schiedek, National Environmental Research Institute, Caroline P. Slomp, Utrecht University, Daniel P. Conley, Lund University
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 147-176
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Summary
Executive summary
Nature of the problem
Nitrogen (N) inputs from human activities have led to ecological deteriorations in large parts of the coastal oceans along European coastlines, including harmful algae blooms and anoxia.
Riverine N-loads are the most pronounced nitrogen sources to coasts and estuaries. Other significant sources are nitrogen in atmospheric deposition and fixation.
Approaches
This chapter describes all major N-turnover processes which are important for the understanding of the complexity of marine nitrogen cycling, including information on biodiversity.
Linkages to other major elemental cycles like carbon, oxygen, phosphorus and silica are briefly described in this chapter.
A tentative budget of all major sources and sinks of nitrogen integrated for global coasts is presented, indicating uncertainties where present, especially the N-loss capacity of ocean shelf sediments.
Finally, specific nitrogen problems in the European Regional Seas, including the Baltic Sea, Black Sea, North Sea, and Mediterranean Sea are described.
Key findings/state of knowledge
Today, human activity delivers several times more nitrogen to the coasts compared to the natural background of nitrogen delivery. The source of this is the land drained by the rivers. Therefore, the major European estuaries (e.g. Rhine, Scheldt, Danube and the coastlines receiving the outflow), North Sea, Baltic Sea, and Black Sea as well as some parts of the Mediterranean coastlines are affected by excess nutrient inputs.
Biodiversity is reduced under high nutrient loadings and oxygen deficiency. This process has led to changes in the nutrient recycling in sediments, because mature communities of benthic animals are lacking in disturbed coastal sediments. The recovery of communities may not be possible if high productivity and anoxia persist for longer time periods.