The following special issues are scheduled for publication in BG:
GEOVIDE, an international GEOTRACES study along the OVIDE section in the North Atlantic and in the Labrador Sea (GA01)
18 Apr 2017–18 Sep 2017 | Guest editors: G. Henderson, M. Lohan, L. Bopp, C. Jeandel, and G. Reverdin | Information
GEOTRACES is an international scientific collaboration that aims to improve the understanding of biogeochemical cycles and large-scale distribution of trace elements and isotopes (TEIs) in the marine environment. The central focus of this programme is a series of cruises – GEOTRACES sections – that cover the global ocean. In the North Atlantic, a first zonal transect was carried out by the US in 2010–2011 (GEOTRACES Section GA03; Boyle et al., 2015, and articles in the Deep Sea 2 special issue). The GEOVIDE cruise is the GEOTRACES Section GA01 led by the French community and carried out in 2014. The cruise track (North Atlantic and Labrador Sea) is located in a crucial area for the Earth climate and the thermohaline circulation as it represents a major overturning area of the so-called Meridional Overturning Circulation (MOC). Moreover, TEI distribution is poorly constrained in this area. The main scientific objectives of GEOVIDE are to (i) better know and quantify the MOC and the carbon cycle in a decadal variability context, adding new key tracers; (ii) map the TEI distribution with their physical and chemical speciation along a full-depth, high-resolution ocean section; (iii) investigate the link between the TEIs and the production, export, and remineralisation of particulate organic matter; (iv) characterise the TEI sources and sinks and quantify their fluxes at the ocean boundaries; and (v) better understand and quantify the palaeoproxies 231Pa/230Th, εNd, and δ30Si.
This special issue will present the first outputs of this interdisciplinarity (physical oceanography, geochemistry, and biogeochemistry) and international collaborative project, based on a 47-day oceanographic cruise on the R/V Pourquoi Pas? (May–June 2014).
Biological soil crusts and their role in biogeochemical processes and cycling
01 Apr 2017–01 Sep 2017 | Guest editors: A. Antoninka, E. Rodriguez-Caballero, B. Weber, and K. J. van Groenigen | Information
Biological soil crusts (biocrusts) are complex communities of photoautotrophic cyanobacteria, algae, lichens, and bryophytes growing together with heterotrophic fungi, bacteria, and archaea within the uppermost millimeters of the soil. They cover about 40 % of the open ground surface in hot, cool, and cold arid and semiarid regions around the world. When active, biocrusts provide significant contributions to ecosystem primary productivity, taking up atmospheric CO2 and fixing N2. As result of their physiological activity they secrete some organic compounds that contribute to soil formation rates, modifying key soil surface properties with direct implications for soil fertility, runoff generation, evaporation, and water availability for vascular plants and microorganisms. Moreover, they increase soil cohesion and stability, reducing water and wind erosion and providing stable environments for vascular plants and higher trophic levels. Recent studies also show that they have influenced Earth's ambient conditions for more than 2 billion years by modifying soil surface albedo and solar radiation budgets, and emitting reactive nitrogen species that affect ozone production and self-cleaning capacity of the atmosphere. However, biocrusts are also recognized as being particularly sensitive to climate change and anthropogenic disturbance, with biocrust destruction causing detrimental effects for habitats and the environment. Natural recovery after disturbance has been shown to depend on a variety of environmental factors and tends to be slow. Thus, there have been several attempts to accelerate biocrust recovery after disturbance by means of artificial inoculation, which presents a promising biotechnological tool for dryland restoration after disturbance events.
In this special issue, we seek to understand the functional roles of biocrusts in biogeochemical cycling processes in a changing environment. We present papers investigating biocrust effects on C and N fluxes, soil formation and stabilization, and restoration methods and success within different areas around the world.
Interactions between planktonic organisms and biogeochemical cycles across trophic and N2 fixation gradients in the western tropical South Pacific Ocean: a multidisciplinary approach (OUTPACE experiment)
15 Feb 2017–31 Jul 2017 | Guest editors: T. M. Moutin, S. Bonnet, K. Richards, D. G. Capone, and E. Marañón | Information
The goal of this special issue is to present the knowledge obtained concerning the functioning of the western tropical South Pacific (WTSP) ecosystems and associated biogeochemical cycles based on the datasets acquired during the OUTPACE experiment. The physical variability and the hydrodynamic context of biogeochemical sampling are described, as well as the impacts of mesoscale circulation and forcing on biogeographic gradients, along with the longitudinal contrast in small-scale turbulence along ~20° S. An optimum multi-parameter analysis of the water mass structure is also provided.
The focus on diazotrophs and dinitrogen fixation concerns the distribution and drivers of symbiotic and free-living diazotrophic cyanobacteria, the contribution of particulate and dissolved (N release) fractions to the hotspot of N2 fixation found during the cruise, zonal gradient in N2 fixation rates, the partition of N2 fixation rates between the particulate and dissolved fractions, the diazotroph-derived N transfer to the planktonic food web, the N2 fixation contribution to export production, and finally the N budget at the long-duration stations studied using a Lagrangian adaptative strategy. Aphotic N2 fixation, heterotrophic diazotrophs and their relationship with labile organic matter, as well as programmed cell death in diazotrophs, are also investigated.
The dynamics of phytoplankton, heterotrophic bacterioplankton, and zooplankton along the gradient of diazotroph diversity and activity are described together with the composition and distribution of dissolved organic carbon and the changes in inorganic carbon content along the longitudinal transect. Net community production, the assimilation of organic carbon and nutrient substrates by unicellular cyanobacteria, and microbial response to the N and P compounds excreted by copepods are quantified. A specific focus on siliceous plankton and Si biogeochemical cycling is also presented.
Optical properties of the WTSP waters are presented, with a focus on the cyanobacterial (diazotroph) impact on bio-optical properties, UV–visible light attenuation and Chl a algorithms for WTSP oligotrophic waters. Finally, the main processes controlling the biological carbon pump in the WTSP are investigated using a 1DV biogeochemical–physical coupled model, and the new knowledge gained on the interactions between planktonic organisms and the cycle of biogenic elements is used to propose a new scheme for this functioning and role, at the present time and in the near future, in the oligotrophic Pacific Ocean.
This special issue will be a collection of original research highlighting progress in the field of ocean acidification and presented at the 4th International Symposium on the Ocean in a High-CO2 World in Hobart, 3–6 May 2016. Topics will include changing oceanic carbonate chemistry, biological responses and ecological impacts, and studies will represent advances in both observational and modeling approaches. All symposium participants are invited to submit original research presented in Hobart to this special issue.
Ecosystem processes and functioning across current and future dryness gradients in arid and semi-arid lands
02 Aug 2016–30 Jun 2017 | Guest editors: T. Zha, C. Bourque, Z. Xing, S. Luyssaert, and P. Stoy | Information
Ecosystems in arid and semi-arid regions of the world are frequently affected by periods of extended drought and resource over-exploitation. Dryland ecosystems are particularly sensitive to climate change in terms of plant species associations, plant distribution along environmental gradients, ecosystem functioning, and ecological and economic productivity. Environmental change in these areas may require that new management strategies and field approaches be developed to protect these vulnerable ecosystems. A devoted account of dryland ecosystems and their response to changing environmental conditions can help develop new management strategies and inform policy.
To facilitate the study of arid and semi-arid ecosystems and provide recent research findings in the area, we propose that the special issue address the following:
Progress in quantifying ocean biogeochemistry – in honour of Ernst Maier-Reimer
01 Jul 2016–30 Jun 2017 | Guest editors: C. Heinze, T. Ilyina, A. Winguth, J. Segschneider, and M. Hofmann | Information
Ernst Maier-Reimer was one of the pioneers in global modelling of ocean biogeochemical cycles and especially the carbon cycle. He published – together with Klaus Hasselmann – the first comprehensive paper on anthropogenic carbon uptake by the ocean. He provided extensive models on both the inorganic as well as the organic carbon cycle in the ocean. His models were elegant in their mathematical formulation, efficient, and computationally economic. He was very influential in this field through the sharing of his knowledge. A number of state-of-the-art biogeochemical ocean model components in Earth system models can be traced back to him and his modelling philosophy. His ability to separate important processes from unimportant provided a role model for geoscientific modellers. Ernst implemented numerous different tracers into his ocean models and took advantage of considering all in a synoptic view of constraining the overall biogeochemical action of the world ocean. This special issue is open for submissions from everyone who knew Ernst, learned from him, or collaborate with him. It should be a celebration of classical and new topics in quantitative biogeochemistry with key papers aimed at understanding the ocean as a chemical plant.
NETCARE (Network on Aerosols and Climate: Addressing Key Uncertainties in Remote Canadian Environments)
(ACP/AMT/BG inter-journal SI)
23 Feb 2016–28 Feb 2019 | Guest editors: L. Bopp, K. Carslaw, D. J. Cziczo, and L. M. Russell | Information
NETCARE (Network on Aerosols and Climate: Addressing Key Uncertainties in Remote Canadian Environments) is a large research network focusing on aerosol–cloud–climate interactions. While Canadian-based, it operates with many international collaborations. It is comprised of scientists working in both atmospheric science and marine biogeochemistry, with particular attention given to a suite of intensive field measurements (with both atmospheric and oceanic components) and model evaluation and development. There are three major research directions within the network: 1. Carbonaceous Aerosol, 2. Arctic Clouds, and 3. Ocean–Atmosphere Interactions. A large amount of the research has an Arctic focus, it being a region especially susceptible to anthropogenic input and experiencing a large degree of biogeochemical change. The website for the network is www.netcare-project.ca. On the website, there is more information on research activities, field campaign details, modeling activities, data products, and personnel.
Changing Permafrost in the Arctic and its Global Effects in the 21st Century (PAGE21) (BG/TC/GMD/ESSD inter-journal SI)
01 Jan 2016–31 Jul 2017 | Guest editors: K. Thonike, V. Brovkin, P. Stoy, S. Natali, I. Laurion, and B. Elberling | Information
Permafrost is defined as ground that remains continuously at or below 0°C for at least two consecutive years; some 24% of the land surface in the Northern Hemisphere is classified as permafrost. In the northern high latitudes, strong warming has been observed over the recent decades, and climate models project strong future warming. A projected decline in the extent of permafrost will have a major impact on the Earth system, affecting global climate through the mobilization of carbon and nitrogen stored in permafrost. This special issue invites results of the large-scale European project PAGE21 with the aim to quantify the vulnerability of permafrost environments to a changing global climate, and to investigate the feedback mechanisms associated with increasing greenhouse gas emissions from permafrost zones. The focus is on (i) the combination of field mapping and measurements of permafrost landforms, ground ice content, processes, pools, and fluxes, with remote sensing data and global climate models at local, regional, and pan-Arctic scales, as well as (ii) advancing our understanding of permafrost processes at multiple scales, resulting in improvements in global numerical permafrost modeling.
Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) (ACP/BG inter-journal SI)
26 Sep 2014–30 Sep 2017 | Guest editors: W. T. Sturges, L. M. Russell, C. Robinson, L. Bopp, H. Wernli, and M. Krämer
Data assimilation in carbon/biogeochemical cycles: consistent assimilation of multiple data streams
(BG/ACP/GMD inter-journal SI)
01 Jan 2015–30 Apr 2017 | Guest editors: M. Scholze, M. Heimann, V. Brovkin, C. Sierra, and C. Gerbig
Interactions between climate change and the Cryosphere: SVALI, DEFROST, CRAICC (2012–2016) (TC/ACP/BG inter-journal SI)
19 Jun 2012–30 Jun 2017 | Guest editors: J. Bäck, M. Bilde, M. Boy, T. R. Christensen, J. O. Hagen, M. Hansson, H. Järvinen, M. Kulmala, T. Laurila, A. Stohl, H. Skov, A. Massling, M. Glasius, and S. M. Noe