Scheduled Special Issues

Data assimilation in carbon / biogeochemical cycles: consistent assimilation of multiple data streams (BG/ACP/GMD Inter-Journal SI)

  • Guest Editors: M. Scholze, M. Heimann, V. Brovkin, C. Sierra, and C. Gerbig
  • Timeline: 1 Jan 2015 – 1 May 2015

How changes in ice cover, permafrost and UV radiation impact on biodiversity and biogeochemical fluxes in the Arctic Ocean – The Malina project

  • Guest Editors: M. Babin, S. Belanger, P. Wassmann, E. Boss, A. Bracher, P. Matrai
  • Timeline: 1 Oct 2011 – 30 Nov 2014

We currently witness in the Arctic:

  1. a decrease in summer ice cover that exposes sea surface to solar radiation and physical forcings;
  2. permafrost thawing and increased river runoff, both leading to an increase in the export to the ocean of organic carbon previously sequestered in the Tundra;
  3. an increase in ultraviolet radiation.

These three phenomena favour a growing mineralization of organic carbon through photo-oxidation and bacterial activity, amplifying the increase in atmospheric CO2. At the same time, the exposure of a larger fraction of ocean surface to sun light and the increase in nutrients brought by rivers lead to larger autotrophic production and sequestration of organic carbon. To predict the balance of these processes, we conducted an extensive study in the Mackenzie River / Beaufort Sea system in July, August and September 2009 onboard the Canadian research ice-breaker CCGS Amundsen. The spatial distribution of organic carbon stocks (living and detrital) in the water column and sediments was determined on the shelf and beyond. The magnitude and variability of organic carbon mineralization through photo-oxidation and bacterial activity, and production through photosynthesis was measured. These targeted studies allows the monitoring of these processes using remote sensing in the coming years and decades. A detailed study of microbial biodiversity was conducted to describe the different biocenoses and biotopes and to anticipate their response to climate change. Diagnostic models of the studied processes (primary production, bacterial activity and light-driven mineralization of organic matter) are combined with a coupled physical-biological ecosystem model, and applied using outputs from global climate models to assess the fate of the associated carbon fluxes in the Arctic Ocean during the next decades under different climate change scenarios. Additionally, a retrospective approach was followed to partly answer the Malina questions, based on the analysis of geochemical proxies in the past 1000-y sediments.

Biogeochemical processes, tropospheric chemistry and interactions across the ocean–atmosphere interface in the coastal upwelling off Peru (BG/OS/ACP/AMT Inter-Journal SI)

  • Guest Editors: H. Bange, A. Chaigneau, A. Engel, C. Garbe, A. Kock, W. Naqvi, B. Thamdrup, B. Ward, C. Robinson, and A. Richter
  • Timeline: 1 Aug 2014 – 31 Jan 2015

The R/V Meteor cruise M91 (Callao-Callao) took place off Peru from 01 December to 26 December 2012. The overall goal of M91 was to conduct an integrated biogeochemical study on the upwelling region off Peru and its adjacent oxygen minimum zone in order to assess its importance for the emissions of various climate-relevant atmospheric trace gases and tropospheric chemistry. The various work packages of M91 included measurements of (1) atmospheric and dissolved trace gases, (2) aerosols, (3) nitrogen processes and isotopes in the water column, (4) dissolved organic matter in the surface microlayer, (5) upwelling velocity, and (6) exchange fluxes across the ocean−atmosphere interface. M91 was funded by the German BMBF project SOPRAN (Surface Ocean Processes in the Anthropocene; http://www.sopran.pangaea.de), which is a contribution to the International SOLAS (Surface Ocean – Lower Atmosphere Study; http://www.solas-int.org).

Low oxygen environments in marine, fresh and estuarine waters

  • Guest Editors: B. Currie, V. Garçon, M. Grégoire, L. Levin, C. Rabouille, and L. Stramma
  • Timeline: 15 Jul 2014 – 30 Dec 2014

General Scope: Hypoxic to anoxic and even sulfidic conditions have already been reported for various aquatic systems, from lakes, estuaries and coastal areas to off-shore regions of the ocean, where oxygen supply does not compensate for its consumption in various redox processes, including respiration of organic matter. In the coastal ocean, oxygen minimum zones (OMZs) have spread exponentially since the 1960s with potential catastrophic biological losses for the benthic communities living on the bottom. In the open ocean, eastern boundary upwelling systems (EBUSs) are characterized by high primary and export production that, in combination with weak ventilation, cause oxygen depletion and the development of OMZs in sub-surface waters.

The Liege Colloquium: The purpose of the 46th International Liege colloquium organized in May 2014 on "Low Oxygen Environments in marine, fresh and estuarine waters" was to generate an overview of the current knowledge on deoxygenation, its monitoring, modelling, impact on ecosystems and biogeochemical cycles as well as the potential evolution of low oxygen conditions in a changing climate (http://modb.oce.ulg.ac.be/?page=colloquium&year=2014). Thematic sessions have been organized on:

  1. Deoxygenation, marine resources, ecosystem functioning and structure of the foodweb.,
  2. Deoxygenation and biogeochemical cycles,
  3. Life and processes in redox gradients,
  4. Paleoproxies of hypoxia,
  5. Modelling hypoxia,
  6. Oxygen time series and instrumental developments,
  7. Eastern Boundary upwelling systems (EBUS) as natural SOLAS laboratories,
  8. Deoxygenation in a global change context.

Freshwater ecosystems in changing permafrost landscapes

  • Guest Editors: I. Laurion, J. E. Vonk, W. F. Vincent, and V. Brovkin
  • Timeline: 15 Apr 2014 – 31 Dec 2014

Considerable attention is now focused on permafrost systems given the accelerated warming of the Arctic and the potential mobilization of its vast stocks of soil organic carbon, and the wide-ranging importance of permafrost for geosystem and ecosystem processes throughout the polar regions. Although many terrestrial studies have provided new information about permafrost degradation and its associated carbon dynamics, few have considered the role of aquatic ecosystems in these processes. There has been little consideration given to the strikingly diverse and changing limnology of these lake and river systems, including their geomorphology, hydrology, hydrodynamics, other physical and ecosystem properties, biogeochemistry, biodiversity and food webs, microbiology, photochemistry and regional differences. More knowledge about each of these aspects is needed for a full understanding of the global importance of thaw aquatic ecosystems as biogeochemical reactors; as elemental sources, sinks and conduits; as ecological oases in the Arctic and Antarctica; and as systems that may respond rapidly to climate change. This special issue brings together specialists from different disciplines to share their knowledge about these dynamic systems on permafrost landscapes, and to identify priorities for future research.

KEOPS2: Kerguelen Ocean and Plateau Study 2

  • Guest Editors: S. Blain, I. Obernosterer, B. Queguiner, T. Trull, and G. Herndl
  • Timeline: 15 Dec 2013 – 30 Nov 2014

The project KEOPS studies the impact of natural iron fertilization of the Southern Ocean on the functioning of the ecosystem and on the biogeochemical cycles. In this context the region around Kerguelen is an exceptional natural laboratory where in situ observations and experimentations could be conducted both in iron fertilized and non-fertilized regions. The main objectives are (i) to identify and quantify the sources and the pathways for iron fertilization, (ii) to study and quantify the impact of iron fertilization on the biogeochemical processes occurring in the water column and at the interfaces with air and sediment, (iii) to study the impact of iron fertilization on the structure of the ecosystem, from viruses to zooplankton, and to investigate how changes in biology affect biogeochemical fluxes. This special issue will gather publications of the results of the second oceanographic campaign (KEOPS2) that took place in October-November 2011. It will include comparisons with the results of the first campaign (January-February 2005) and with other previous natural or artificial iron fertilization experiments in the Southern Ocean.

Geological and biological development of volcanic islands

  • Guest Editors: J.-A. Subke, B. D. Sigurdsson, P. Einarsson, B. Magnusson, K. Gunnarsson, H. Adsersen, S. Jewett, T. New, and N. M. Pérez
  • Timeline: 05 Sep 2013 – 01 Apr 2014

Protocols for biogeochemical and ecological measurements at ICOS greenhouse gas flux monitoring sites

  • Guest Editors: D. Papale, I. Janssens, D. Loustau, and G. Wohlfahrt
  • Timeline: 01 Sep 2013 – 31 Aug 2015

ICOS (www.icos-infrastructure.eu) is an ESFRI research infrastructure to monitor greenhouse gas fluxes and concentrations across Europe. One of the three ICOS compartments is the Ecosystem Network where CO2, CH4 and N2O fluxes with eddy covariance and chamber techniques, together with a wide suite of meteorological and biological variables, will be measured for 20 years. One of the main characteristics of ICOS is the high level of standardization in the data acquisition and processing and in this context it is crucial to have state-of-the-art protocols for the different measurements. To select the most suited protocols, the ICOS Ecosystem network organized a number of working groups (www.europe-fluxdata.eu/icos), open to the whole scientific community, that are currently discussing, testing and preparing these protocols.

The special issue will include papers covering one or more linked ecosystem variables following a similar structure and organized to answer the questions: why the variable is ecologically relevant, which are the important characteristics of the variable in terms of spatial and temporal variability that must be considered when it is measured, which are the methods available and which is the rational to choose the best/more appropriate method, which are the characteristics, limits and operational suggestions of the selected method. Papers not initiated in the context of the ICOS ecosystem network working groups should be first proposed to the guest editors to avoid overlaps in the special issue’s content as well as to narrow filter out protocols irrelevant to the monitoring network.

Air-sea flux climatology; progress and future prospects (BG/ACP/OS Inter-Journal SI)

  • Guest Editors: C. Robinson, J. Kaiser, C. McNeil, D. Woolf, J. Shutler, C. Garbe, and P. Challenor
  • Timeline: 01 Oct 2013 – 30 Jun 2014

Field investigation of ocean acidification effects in northwest European seas

  • Guest Editors: E. Achterberg, T. Tyrrell, and J.-P. Gattuso
  • Timeline: 01 Jun 2013 – 16 Feb 2014

The purpose of the cruise (June–July 2011) was to study the impact of ocean acidification on surface waters of the northwest European shelf, providing a glimpse into what may happen to the ocean as a whole as atmospheric CO2 concentrations continue to rise. The aim was to examine impacts on marine organisms and ecosystems, on the cycling of carbon and nutrients, and on the production of climatically important gases. These potential impacts were investigated in two main ways. Firstly, observational data was analysed to look at how organisms, ecosystems and processes vary between regions where the chemistry of seawater is naturally more acidic and those where it is more alkaline. This comparison of observational data gives insights into the effects of ocean acidification taking place over centuries, long enough for natural selection and adaptation to play out. The second approach was to conduct short-term CO2 bioassay perturbation experiments in bottles with natural communities collected in the surface layer and incubated in a controlled laboratory on deck. The natural communities were subjected to various levels of CO2 that may occur in the future and the responses were determined. This large experiment examined the effects of changing CO2 levels on real world samples whilst at sea, as opposed to monocultures in the laboratory.

9th International Carbon Dioxide Conference (ICDC9) (ESD/ACP/BG/AMT Inter-Journal SI)

  • Guest Editors: L. Bopp, V. Brovkin, J. Canadell, C. Gerbig, D. Griffith, M. Heimann, R. Keeling, Y. Luo, A. C. Manning, A. Michalak, Z. Xie, and N. Zeng
  • Timeline: 01 Jun 2013 – 31 May 2014

The International Carbon Dioxide Conference (ICDC) is the single largest conference organized by the global research community every four years to present the latest scientific findings on the science of the carbon cycle and its perturbation by human activities. The ICDC in 2013 is the 9th conference. The conference topics encompass the global carbon cycle, global and regional budgets, and processes with specialized sessions on the individual components of atmosphere, ocean and land, in the timeframes of past, present and future. It covers both fundamental science advancement and discovery, the generation of policy relevant information, and new technological observational platforms, datasets, and modeling approaches.

The three main themes of the conference are:

  • Theme 1: Past and present changes and variability
  • Theme 2: Carbon sources and sinks, their changes and trends
  • Theme 3: Future of the carbon cycle: drivers, vulnerabilities, feedbacks and management options

Conference website: http://icdc9.lasg.ac.cn

In-situ investigation of ocean acidification in northwest European seas

  • Guest Editors: E. Achterberg, T. Tyrrell, and J.-P. Gattuso
  • Timeline: 01 Jun 2013 – 01 Jan 2014

The purpose of the cruise (June–July 2011) was to study the impact of ocean acidification on surface waters of the northwest European shelf, providing a glimpse into what may happen to the ocean as a whole as atmospheric CO2 concentrations continue to rise. The aim was to examine impacts on marine organisms and ecosystems, on the cycling of carbon and nutrients, and on the production of climatically important gases. These potential impacts were investigated in two main ways. Firstly, observational data was analysed to look at how organisms, ecosystems and processes vary between regions where the chemistry of seawater is naturally more acidic and those where it is more alkaline. This comparison of observational data gives insights into the effects of ocean acidification taking place over centuries, long enough for natural selection and adaptation to play out. The second approach was to conduct short-term CO2 bioassay perturbation experiments in bottles with natural communities collected in the surface layer and incubated in a controlled laboratory on deck. The natural communities were subjected to various levels of CO2 that may occur in the future and the responses were determined. This large experiment examined the effects of changing CO2 levels on real world samples whilst at sea, as opposed to monocultures in the laboratory.

Geolog

  • Guest Editors: J.-A. Subke, B. D. Sigurdsson, P. Einarsson, B. Magnusson, K. Gunnarsson, H. Adsersen, S. Jewett, T. New, and N. M. Pérez
  • Timeline: 05 Sep 2013 – 01 Apr 2014

Carbon and greenhouse gases in managed peatlands

  • Guest Editors: A. Freibauer, B. Tiemeyer, and T. Laurila
  • Timeline: 01 May 2013 – 30 Jun 2014

Peatlands are ecosystems in which biological, chemical and physical processes are intimately interlinked drivers of greenhouse gas fluxes. Drained peatlands are hotspots of anthropogenic greenhouse gases. Recent national and international research projects have accumulated a wealth of new observational data, improved process understanding and new tools for empirical and process-based regionalization. The special issue aims to collect papers with a focus on understanding the human impact on the peatland carbon and greenhouse gas balance. Studies include experimental manipulations, gradient studies along land-use changes and management intensity, and studies of short-term and long-term dynamics of peatland restoration.

The special issue is solicited by the collaborative project "Organic soils" supported by the Thünen Institute and the European research project GHG-Europe – "Greenhouse gas management in European land use systems" supported by the European Commission in the 7th Framework Programme (grant agreement no. 244122). The special issue is open to for all submissions within the scope of the special issue.

Climate extremes and biogeochemical cycles in the terrestrial biosphere: impacts and feedbacks across scales

  • Guest Editors: M. Reichstein, Y. Luo, J. M. Moreno, K. Guan, C. Williams, and M. Bahn,  K. Guan, and P. van Bodegom
  • Timeline: 01 May 2013 – 30 Sep 2014

This special issue will address the relations between climate extremes and biogeochemical cycling in terrestrial ecosystem. It will emerge from a global conference on this topic (www.bgc-extremes2013.org). Contributions regarding the following topics are welcome: ecosystem responses to climate variability and weather extremes, recovery of ecosystems after extreme events and climate related disturbance (e.g. wind-throws, fire), feedback mechanisms from the biosphere to the climate system. We welcome conceptual, observational, experimental and modeling approaches, and studies from the local to the global scale.

The impact of anthropogenic perturbations on open ocean carbon transformation, export and sequestration

  • Guest Editors: C. Robinson, F. Azam, N. Jiao, H. Thomas, and G. Herndl
  • Timeline: 01 Feb 2013 – 31 Jan 2014

Anthropogenic impacts such as elevated pCO2 and eutrophication threaten the structure and functioning of marine ecosystems as well as the role of the ocean in the global carbon cycle. While sinking-particle-based carbon sequestration (the biological pump; BP) has been extensively studied, the biogeochemical behaviour of dissolved organic matter (DOM) and its role in carbon sequestration (the microbial carbon pump, MCP), is largely unexplored. The BP and the MCP operate simultaneously and interactively but their responses to environmental conditions may be regulated differently. These regulatory mechanisms have not been examined, and it is not known whether the BP and the MCP would interact to enhance or reduce their individual effects.

This special issue will bring together articles arising from discussions undertaken at IMBIZO III held in Goa in January 2013. Topics to be investigated include the organisms and microbial processes which produce and transform dissolved organic carbon in the ocean, organisms and processes which influence the interaction between the BP and the MCP, and the impact of anthropogenic perturbations such as nutrient addition and ocean acidification on oceanic carbon transformation, export and sequestration.

Current biogeochemical and ecosystem research in the Northern Indian Ocean

  • Guest Editors: G. Cowie, H. Kitazato, R. Hood, S.W.A. Naqvi, and A. Gooday
  • Timeline: 04 Jan 2013 – 15 Nov 2013

The Northern Indian Ocean is home to remarkable phenomena, including seasonally reversing monsoon winds and associated upwelling and productivity, as well as the planet’s largest expanses of oxygen-depleted waters. The upwelling, productivity and hypoxia (open-ocean and coastal) are associated with biogeochemical processes that are of exceptional importance to global bioelement cycles, ocean nutrient inventories, and future climate. Given the large human populations that inhabit the rim nations and depend on marine resources, processes affecting the region also have major societal relevance. However, the two main basins – the Bay of Bengal and the Arabian Sea - also represent striking contrasts, in terms of circulation, upwelling and degree of hypoxia, in riverine and terrestrial influence, and in the effects on associated biogeochemical processes. As a result, the Arabian Sea, and more recently the Bay of Bengal, have been sites of extensive biogeochemical and ecosystem research. With the advent of new methods and technology, and recognition of fundamental gaps in our understanding of both pelagic and benthic processes, a special issue focused on the Northern Indian Ocean region is timely.

The special issue will serve to highlight results of benthic and pelagic process studies in the Arabian Sea, and more recently the Bay of Bengal and Andaman Sea, including sediment trap deployments and moorings with biogeochemical sensors (etc). It will also be a venue for articles on coastal studies by scientists from Northern Indian Ocean rim nations, as well as diverse physical and biogeochemical modelling studies. Finally, the issue will serve to illustrate some of the key research areas that are relevant to the wider Indian Ocean, which have recently become the focus of the Sustained Indian Ocean Biogeochemistry and Ecosystem Research (SIBER) initiative.

EUROSPEC - spectral sampling tools for vegetation biophysical parameters and flux measurements

  • Guest Editors: G. Wohlfahrt, C. Nichol, M. Rossini, A. MacArthur, and E. Tomelleri
  • Timeline: 01 Feb 2014 – 31 Jan 2015

Improving our understanding of terrestrial carbon and water cycle is of the highest scientific and socio-economic importance. The key to understanding both the processes and spatial scaling of estimates requires a careful fusion of observations from ground, airborne and satellite systems. At present, a full integration of aircraft and space-sensed information and ecosystem level observations has not been achieved.

The main objective of the COST Action ES0903 "EUROSPEC" is to develop common protocols and new instruments within a larger European network for optical measurements, bringing together scientists and industries in order to increase the reliability, value and cost-efficiency of the existing spectral observations within the European flux network. In the last 3 years, the Action has focused on proximal sensing, which can be considered a fundamental tool in monitoring Biophysical Parameters and which acts as a "bridge" between the flux tower and the remote sensing community. In fact, the EUROSPEC activities actively involved researchers from the FLUXNET, SPECNET, ICOS, ABBA networks.

Four Working Groups have been active within EUROSPEC, organizing meetings, field campaigns, experiments and summer schools:

  • WG1 focused on the state of the art of the optical sampling network, database issues and building a common platform for storing, sharing, visualizing spectral data.
  • WG2 on instrument intercomparison, characterisation, standardisation, intercalibration and measurement protocol issues.
  • WG3 dealing with upgrading instruments for continuous measurements at the Eddy Covariance towers.
  • WG4 focused on scaling Biophysical Parameters and fluxes from the ecosystem at upper levels.

Towards a full GHG balance of the biosphere

  • Guest Editors: D. Zona, L. Merbold, K. Pilegaard, K. Butterbach-Bahl, P. Stoy, T. Del Sontro, and G. Wohlfahrt
  • Timeline: 01 Nov 2012 – 30 Apr 2014

How important are N2O and CH4 emissions in different ecosystems? How difficult is to measure and to model their emission? How do non-CO2 greenhouse gases contribute to the total global warming potential (GWP) of terrestrial and aquatic ecosystems?

The overall goal of this Special Issue is to gather contributions discussing the challenges and opportunities in measuring and modeling CH4 and N2O fluxes using the new available instrumentation. We encourage contributions that discuss the role of non-CO2 greenhouse gases to global biogeochemical cycles and planetary radiative forcing. This is a unique chance to cross compare the contribution of these non-CO2 gases to the carbon budget of the biosphere, and to quantify the full global warming potential (GWP) of terrestrial and aquatic ecosystems worldwide. This Special issue is linked to the goals of GHG-Europe and of the WP2 of the ABBA (COST Action ES0804), and to the Integrated Carbon Observation System (ICOS) aiming at harmonizing and integrating trace gas flux measurements around the globe.

The EU Project SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) (ACP/AMT/BG/OS Inter-Journal SI)

  • Guest Editors: W. T. Sturges, J. Williams, G. Roberts, C. Robinson, and R. Sander
  • Timeline: 01 Sep 2012 – 31 Dec 2014

Background

The EU project SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) was initiated by a larger international consortium, in order to study the contribution of mostly naturally emitted halogenated very short-lived substances (VSLS) to the stratospheric inventory of ozone destroying halogens. Today the SHIVA consortium comprises about 120 full or associated partners coming from 19 institutions in 9 countries.

SHIVA’s scientific objectives infer from past research that mostly brominated and less likely iodinated VSLS, predominately emitted from biologically active surface waters of the global oceans, are eventually significantly contributing to the halogen load of the global stratosphere. Moreover, theoretical studies revealed that only the combination of sufficiently strong VSLS sources together with efficient vertical atmospheric transport would support a relevant contribution of VSLS to the stratospheric halogen burden. Both conditions are likely to be met in the western Pacific during the wet season (November to March). Since details of the relevant processes and their relevance for stratospheric ozone are yet largely unexplored, four major objectives of EU-SHIVA were identified, namely investigations of:

  1. The oceanic emission strengths of a suite of halogenated VSLS
  2. The atmospheric transport and transformation of the halogenated VSLS
  3. The past, present and likely future trend of the total stratospheric halogen burden
  4. The impact of long and short-lived halogenated trace gases and their inorganic product gases for past, present and future ozone within the upper troposphere, TTL and global stratosphere

Synopsis

The special ACP-AMT-BG-OS SI is intended to cover the research performed within the EU project SHIVA and related undertakings. Contributing manuscripts may cover investigations of halogenated VSLS emissions from marine micro- and macro algae, to their atmospheric transport and transformation as well as impacts of VSLS for global ozone studied in the laboratory, field and by theoretical models.

Impacts of extreme climate events and disturbances on carbon dynamics

  • Guest Editors: J. Xiao, S. Liu, and P. Stoy
  • Timeline: 01 Aug 2012 – 30 Jun 2014

Extreme climate events (e.g., drought, heat and cold waves) and disturbances (e.g., fire, hurricane, and insect outbreaks) substantially affect carbon cycle processes. However, their impacts on terrestrial carbon dynamics over landscapes, regions, and continents are not well understood. We invite submissions that investigate and quantify the impacts of extreme climate events and disturbances on the terrestrial carbon dynamics over various spatial and temporal scales using observations (e.g., eddy covariance flux measurements, and national inventories), remote sensing, state-of-the-art modeling approaches (e.g., ecosystem models, upscaling methods), and model-data fusion techniques.

A special issue focusing on this topic will be timely and valuable to the research communities of carbon and global change. Collectively, we believe that this special issue will play a critical role in our understanding of how extreme climate events and disturbances influence the terrestrial carbon cycle and increase the visibility and influences of Biogeosciences in carbon cycle and climate change.

Impact of atmospheric inputs on an oligotrophic ecosystem - the DUNE experiment

  • Guest Editors: C. Guieu, F. Dulac, and E. Marañón
  • Timeline: 01 Aug 2012 – 16 Dec 2013

The main goal of DUNE (a DUst experiment in a low Nutrient, low chlorophyll Ecosystem) was to estimate by the mean of mesocosms experiments, the impact of atmospheric inputs on an oligotrophic ecosystem submitted to strong atmospheric inputs. Atmospheric deposition is currently recognized as a significant source of macro- and micro-nutrients for the surface ocean, but the quantification of its role on the biological carbon pump is still poorly determined. The main difficulty of such a quantification relies mainly on the diversity of the processes involved:

  1. within atmospheric cycling of particles (from emission processes to deposition onto surface ocean, including physical-chemical transformations occurring during transport) and;
  2. within the water column (uptake by bacteria and phytoplankton of particle-derived elements of biogeochemical interest, and carbon export resulting from fertilization induced by those inputs).
We proposed in DUNE to investigate the role of atmospheric inputs on the functioning of an oligotrophic system particularly well adapted to this kind of study: the Mediterranean Sea. The Mediterranean Sea – etymologically, sea surrounded by land, is submitted to atmospheric inputs that are very variable both in frequency and intensity. During the thermal stratification period, only atmospheric deposition is prone to fertilize surface waters which had become very oligotrophic due to the nutrient depletion (after the spring bloom). In order to quantify the impact of both natural and anthropogenic inputs on productivity and biogenic carbon sequestration, it is necessary to parameterize the processes affecting the ecosystem functioning.

During the DUNE project, large clean mesocosms (developed during the project) were successfully deployed twice (DUNE1 experiment in 2008 and DUNE2 experiment in 2010) in the oligotrophic waters of the preservation area of Scandola in Corsica. Dry, wet and successive wet depositions of Saharan dust were simulated. Chemical and biological changes, along with modification of the dynamic of particles following a dust event have been followed and the multidisciplinary results obtained are bringing new insights regarding the role of atmospheric deposition on oligotrophic ecosystem and carbon export. Those results are presented in this Special Issue.

Interactions between climate change and the Cryosphere: SVALI, DEFROST, CRAICC (2012-2016) (TC/ACP/BG Inter-Journal SI)

  • Guest Editors: J. Bäck, M. Bilde, M. Boy, T. R. Christensen, J. O. Hagen, M. Hansson, H. Järvinen, I. Jónsdóttir, M. Kulmala, T. Laurila, A. Stohl, H. Skov, A. Massling, M. Glasius, and S. M. Noe
  • Timeline: 19 Jun 2012 – 31 Dec 2016

Improving constraints on biospheric feedbacks in Earth system models (GREENCYCLESII)

  • Guest Editors: A. Friend, P. Cox, A. J. Dolman, M. Vogt, L. Bopp, and V. Brovkin
  • Timeline: 08 May 2012 – 30 Apr 2014

Increasing concentrations of anthropogenic greenhouse gases (GHGs) are known to be causing changes in global climate patterns, and will continue to do so for the foreseeable future. Our ability to predict future climatic states is still limited for a variety of reasons. Key among these reasons is our understanding of the coupled behaviour of the components of the Earth system. A research training programme GREENCYLCEII has scientific focus on the evaluation, improvement, and application of a range of different Earth System models (ESMs). This special issue brings together manuscripts from a range of GREENCYLCEII projects, broadly classed into data and model benchmarking, marine processes, terrestrial processes, high latitude feedbacks, and coupled modelling.

Boknis Eck Time Series Station (SW Baltic Sea)

  • Guest Editors: H. Bange, and T. Treude
  • Timeline: 01 Jan 2012 – 30 Apr 2014

Monthly sampling at the Boknis Eck (BE) Time Series Station started on 30 April 1957 and, thus, BE represents one of the oldest continuously sampled marine time series sites worldwide. The long high-quality time series observations at BE are invaluable to decipher long-term trends in a representative coastal environment, which is locally (via eutrophication) and globally (via climate change) influenced by human activities. The location of BE at the entrance of the Eckernförde Bay (SW Baltic Sea) makes it an ideal site (i) to study a coastal ecosystem under the influence of pronounced changes of salinity and (ii) to study biogeochemical processes sensitive to pronounced changes of dissolved oxygen (i.e. hypoxia/anoxia). This special issue of Biogeosciences (BG) aims to bring together papers which cover different topics (eutrophication, deoxygenation, trace gas production, nitrogen cycling, marine microbiology) and approaches (incl. measurements and model studies) in order to investigate the biogeochemical processes in the water column and in the sediments at BE and the SW Baltic Sea. You are welcome to submit manuscripts on related topics to this special issue of BG.

REgional Carbon Cycle Assessment and Processes (RECCAP)

  • Guest Editors: J. Canadell, P. Ciais, C. Sabine, and F. Joos
  • Timeline: 01 Nov 2011 – 31 May 2014

The REgional Carbon Cycle Assessment and Processes (RECCAP) is an international effort to establish the mean carbon balance and change over the period 1990–2009 for all subcontinents and ocean basins. It is based on comparing and reconciling multiple bottom-up estimates, which include observations and model outputs, with the results of regional top-down atmospheric CO2 inversions (and CH4 and N2O when possible).

This special issue presents the final synthesis papers for 14 RECCAP regional carbon budgets, 10 terrestrial regions (Africa, Arctic tundra, Australia, Europe, Russia, East Asia, South Asia, Southeast Asia, Central and South America, and North America) and 4 ocean regions (Atlantic and Arctic, Indian, Pacific, and Southern Ocean). In addition, 8 global synthesis support the regional budgets and their integration into the global picture.

RECCAP is an activity of the Global Carbon Project, with two major sponsors: E.U.-COCOS (Coordination Action on Carbon Observation Systems) and the U.S.-Carbon Cycle Science Program.

Integrated Land Ecosystem-Atmosphere Processes Study (iLEAPS) (ACP/BG Inter-Journal SI)

  • Guest Editors: A.-B. Guenther, P. Artaxo, L. Ganzeveld, H. P. Schmid, M. Kulmala, A. Neftel, A. Arneth, J. Pongratz, N. Saigusa, S. Seneviratne, and S. M. Noe
  • Timeline: 01 Jun 2011 – 31 Dec 2015

iLEAPS is the land-atmosphere core project of the International Geosphere-Biosphere Programme (IGBP). The scientific goal of iLEAPS is to provide understanding how interacting physical, chemical and biological processes transport and transform energy and matter through the land-atmosphere interface. Atmospheric Chemistry and Physics (ACP) and Biogeosciences (BG) have opened a joint special issue on iLEAPS-related science, and you are welcome to contribute by sending manuscripts on land-atmosphere interactions to this joint issue via either ACP or BG.

Human alteration of the nitrogen cycle represents a major driver of global environmental change. Since the invention, a century ago, of industrial methods to fix atmospheric di-nitrogen (N2), the production of reactive nitrogen (Nr) has roughly doubled at the global scale and tripled in Europe (Erisman et al., 2008; Galloway et al., 2008; Sutton et al. 2011a). The main use of this deliberate anthropogenic Nr production has been to produce fertilizers to increase crop production, allowing the world’s human population to increase, as well as for people to eat richer diets, with a larger fraction of animal products.

In parallel, increased rates of fuel combustion have caused an additional inadvertent rise in anthropogenic Nr production and release to the atmosphere. This has especially been the result of greater use of high temperature combustion processes in vehicles, electricity generation and other industries, which oxidize atmospheric N2 to nitrogen oxides (NOx). In addition, low temperature combustion processes, from domestic burning of coal, wood, dung and burning of forests and other land, have led to an increase in both NOx and ammonia (NH3) emissions. Together with the emissions of Nr from agricultural systems in the form of NH3, NOx, nitrous oxide (N2O), nitrates (NO3) and many organic nitrogen forms, this human alteration of the nitrogen cycle is causing multiple effects on global change. The consequences include pollution of air, soil and water, alteration of the climate balance and threats to biodiversity. While some policies have already been enacted in Europe and elsewhere, Nr pollution represents a still largely unsolved problem. Many details of the science remain uncertain, while levels of Nr pollution are causing major threats across Europe and other industrialized and agricultural areas of the world. The complexity is illustrated by the way in which Nr emissions alter climate balance. The recent European Nitrogen Assessment (ENA) estimates that Nr emissions may be having a net cooling effect on climate, as aerosol Nr effects and forest fertilization from atmospheric Nr deposition tend to outweigh the warming effects of N2O emissions and the Nr contribtion to O3 formation (Butterbach-Bahl et al., 2011). However, the cooling components of Nr have even bigger estimated societal costs than their climate benefits, as aerosols affect human health and Nr deposition threatens biodiversity. Overall, the ENA estimates a societal damage cost of between €70 billion to €320 billion per year across the European Union (Brink et al., 2011; Sutton et al., 2011c). Even from this limited set of interactions, it is clear that human alteration of the nitrogen cycle is a highly complex issue, with major economic consequences. Advances in the underlying science are needed using new measurement methods and models, as a basis to inform policies that maximize the intended benefits of Nr, while minimizing its environmental threats.

These issues have been addressed by concerted efforts in Europe over the last 5 years, as a number of projects have contributed to the global ambitions of the International Nitrogen Initiative (INI), a joint project under the International Geosphere Biosphere Programme (IGBP) and the Scientific Committee on Problems of the Environment (SCOPE). The European collaboration has linked closely to the efforts of the NitroEurope Integrated Project, a consortium of 62 institutes funded by the European Union 6th Framework Programme to examine the effect of nitrogen on the European greenhouse gas balance (Sutton et al., 2007, 2011b). Several of the outcomes have already been reported in earlier special issues (Reis et al., 2009; Beier et al. 2010, Ambus et al. 2011). In order to increase the scientific scope, NitroEurope has worked closely with the Nitrogen in Europe (NinE) framework networking programme of the European Science Foundation (Bleeker et al., 2008), allowing an increased focus on interactions with biodiversity, water quality, policy and economic issues. In parallel, the COST Action 729, “Assessing nitrogen fluxes in the atmosphere biosphere system”, has added to the critical mass through workshops to stimulate collaborative activities, including a major focus on the interaction between nitrogen deposition and the Natura 2000 network, protected under the EU Habitats Directive (Hicks et al. 2011; Bleeker and Erisman 2011).

These combined efforts have come to fruition in the presentations and discussions at the international science conference Nitrogen & Global Change (NEU, 2011), held in Edinburgh from 11-15 April, 2011. The conference launched the European Nitrogen Assessment, including the key messages (Sutton et al., 2011a,b), with an emphasis on improving public awareness of the nitrogen (see NinE, 2011, plus numerous press reports).

This special issue now reports the detail of the scientific findings discussed at the Nitrogen and Global Change conference. The papers discuss key aspects of Nr in the environment, including – but not limited to – the relevance of nitrogen for climate change and air quality, for food and energy security and for biodiversity and ecosystem health. While the focus is on Europe and terrestrial ecosystems, papers addressing issues from other parts of the world are represented, as well as contributions discussing the role of nitrogen in freshwater and marine environments. The submitted papers under discussion here in Biogeosciences thus reflect the full breadth of societal challenges related to human perturbation of the nitrogen cycle. As will be seen, the contributions are also broad in nature, covering the full suite of approaches, from measurement and modelling techniques, process understanding, temporal and spatial upscaling, to analysis of policy options and Nr biogeochemistry-economic interactions.

Finally, in addition to this special issue and the other products, the conference agreed ‘The Edinburgh Declaration on Reactive Nitrogen’ (Nitrogen and Global Change Conference, 2011). This short statement highlights the need for further scientific efforts to understand the ways in which nitrogen is both causing global change and being impacted by it. At the same time, it illustrates how continued integration between disciplines - a key theme of this special issue - will be essential to develop future solutions at local, European and global scales. We take this opportunity to thank the European Comission, the European Science Foundation and national and international organizations for supporting the the underlying work reported here, and thank the many policy, industry, agricultural and conservation stakeholders for their active involvement in the process.

One of the most important aspects to understand marine organic carbon fluxes is to resolve the molecular mechanisms which convert fresh, labile biomolecules into semi-labile and refractory dissolved and particulate organic compounds in the ocean. In this interdisciplinary project, we carried out a detailed molecular characterisation of dissolved organic matter (DOM) during a North-South transect in the Atlantic surface ocean to relate the data to different biological, climatic, oceanographic, and meteorological regimes. Our goal was to achieve a high resolution data set for the biogeochemical characterisation of the sources and reactivity of DOM. We applied various biogeochemical analyses for 220 samples from the upper water column (0-200m) and eight deep profiles. Spectroscopic techniques were applied continuously for phytoplankton characterization in a constant sample water flow supplied by a fish system and the moon pool. Radiocarbon dating enabled assessing DOC residence time. Bacterial abundance and production provided a me