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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2006.08.014 Byline: Dorothee C.E. Bakker (a), Philip W. Boyd (b), Edward R. Abraham (c), Matthew A. Charette (d), Mark P. Gall (e), Julie A. Hall (f), Cliff S. Law (c)(g), Scott D. Nodder (c), Karl Safi (f), Dick J. Singleton (c), Kim Tanneberger (a), Thomas W. Trull (h), Anya M. Waite (i), Andrew J. Watson (a), John Zeldis (e) Keywords: Iron enrichment; SOIREE; Carbon budget; Lagrangian Abstract: The Lagrangian Southern Ocean Iron Release Experiment (SOIREE) allowed study of a gradually evolving iron-mediated phytoplankton bloom in water labelled with the inert tracer sulfur hexafluoride, SF.sub.6. This article describes a pelagic carbon budget for the mixed layer in SOIREE and assesses the extent to which closure of the budget is achieved. Net community production (NCP) converted 837mmolm.sup.-2 of inorganic carbon to organic carbon in 12.0d after the first iron addition. A large fraction (41%) of NCP remained as particulate organic carbon in the mixed layer of the iron-enriched patch, while 23% was lost by horizontal dispersion and 0-29% was exported. The closure of the carbon budget is hampered by the lack of measurements of dissolved organic carbon (DOC), by a major uncertainty in carbon export, and by use of empirical conversion factors in estimates of carbon biomass and metabolic rates. Lagrangian carbon-budget studies may be improved by direct measurement of all major carbon parameters and conversion factors. Carbon cycling in the SOIREE bloom resembled that in 'natural' algal blooms in the open Southern Ocean in some respects, but not in all. Daily NCP in the SOIREE bloom (70mmolm.sup.-2 d.sup.-1) was higher than in natural blooms, partly because other studies did not account for horizontal dispersion, were for longer periods or included less productive areas. The build-up of POC stock and carbon export as a fraction of NCP in SOIREE were in the lower range of observations elsewhere. Author Affiliation: (a) School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK (b) National Insitute of Water and Atmospheric Research (NIWA) Ltd., Centre for Chemical and Physical Oceanography, Department of Chemistry, University of Otago, Dunedin, New Zealand (c) NIWA., P.O. Box 14-901, Wellington, New Zealand (d) Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA (e) NIWA, P.O. Box 8602, Christchurch, New Zealand (f) NIWA, Box 11-115, Hamilton, New Zealand (g) Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, UK (h) Antarctic Co-operative Research Centre, CSIRO Marine and Atmospheric Research, University of Tasmania, GPO Box 252-80, Hobart 7001, Australia (i) Centre for Water Research, University of Western Australia, Nedlands 6907 WA, Australia Article History: Received 9 June 2005; Revised 24 August 2006; Accepted 28 August 2006

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Phosphorus (P) is an essential element for living organisms and a major limiting factor in many ecosystems. In recent years, global warming and nitrogen (N) deposition have become increasingly serious, with significant effects on the P cycle in terrestrial ecosystems. A series of studies were carried out on the soil P cycle, but how climate change affects this remains unclear. Field experiments with warming and N addition were implemented since April 2007. Infrared radiators manipulated temperature, and aqueous ammonium nitrate (10 g [m.sup.-2] [year.sup.-1]) was added to simulate N deposition. Compared with the control, N addition reduced soil total P; warming and N addition decreased soil available P; warming, N addition and warming plus N addition decreased microbial biomass P, but increased litter P; and warming and N addition increased phosphatase activity significantly. Correlation analysis showed that soil total P, available P, microbial biomass P and phosphatase activity were positively correlated with soil temperature and water content. Soil total P was positively correlated with microbial biomass P and phosphatase activity; and available P was positively correlated with microbial biomass P but negatively correlated with litter P. The results showed that warming and N deposition accelerated the soil P cycle by changing soil physical and chemical properties and soil biological activities (microbial and phosphatase activities). However, N addition reduced the capacity of microbes to fix P and reduced microbial biomass P, resulting in losses to the soil P pool, further aggravating P limitation in the Songnen Grassland ecosystem. Additional keywords: global warming, nitrogen addition, P cycle. Received 9 May 2019, accepted 7 September 2019, published online 28 October 2019, Introduction Over the last 60 years, terrestrial ecosystems have been influenced by significant human-induced environmental changes, including increases in nitrogen (N) deposition and average global temperatures (IPCC 2014). Global change [...]

Chromatin structure is important for the compaction of eukaryotic genomes, thus chromatin modifications play a fundamental role in regulating many cellular processes. The coordinated activities of various chromatin-remodelling and--modifying complexes are crucial in maintaining distinct chromatin neighbourhoods, which in turn ensure appropriate gene expression, as well as DNA replication, repair, and recombination. SWR1-C is an ATP-dependent histone deposition complex for the histone variant H2A.Z, whereas NuA4 is a histone acetyltransferase for histones H4, H2A, and H2A.Z. Together the NuA4 and SWR1-C chromatin-modifying complexes alter the chromatin structure through 3 distinct modifications in yeast: post-translational addition of chemical groups, ATP-dependent chromatin remodelling, and histone variant incorporation. These 2 multi-protein complexes share 4 subunits and function together to regulate the circuitry of H2A.Z biology. The components and functions of both multi-protein complexes are evolutionarily conserved and play important roles in multi-cellular development and cellular differentiation in higher eukaryotes. This review will summarize recent findings about NuA4 and SWR1-C and will focus on the connection between these complexes by investigating their physical and functional interactions through eukaryotic evolution. Key words: SWR1-C, NuA4, H2A.Z, chromatin-modifying complexes. La structure de la chromatine est importante pour la compaction du genome des eucaryotes. Ainsi, les modifications de la chromatine jouent un role fondamental dans la regulation de plusieurs processus cellulaires. Les activites coordonnees des differents complexes de remodelage et de modification sont cruciales pour maintenir les environnements de la chromatine distincts ce qui, en retour, garantit une integrite de l'expression genique et de la replication, de la reparation et de la recombinaison de l'ADN. SWR1-C est un complexe de depot d'histone dependant de l'ATP qui est specifique au variant d'histone H2A.Z, alors que NuA4 est une histone acetyltransferase qui agit sur les histones H4, H2A et H2A.Z. Ensemble, les complexes de modification de la chromatine NuA4 et SWR1-C changent la structure de la chromatine de trois facons distinctes chez la levure : par l'ajout de groupes chimiques apres la traduction, le remodelage de la chromatine de facon dependante de l'ATP et l'incorporation de variants d'histone. Ces deux complexes multi-proteiques ont quatre sousunites en commun et fonctionnent ensemble pour reguler les differentes activites biologiques de H2A.Z. Les composantes et les fonctions de ces deux complexes multi-proteiques sont conservees a travers l'evolution et jouent un role important dans le developpement multicellulaire et la differenciation cellulaire chez les eucaryotes superieurs. Cet article de synthese resumera les decouvertes recentes portant sur NuA4 et SWR1-C, et plus particulierement les liens existants entre ces deux complexes en examinant leurs interactions physiques et fonctionnelles au cours de l'evolution des eucaryotes. Mots-cles : SWR1-C, NuA4, H2A.Z, complexes de modification de la chromatine. [Traduit par la Redaction] Biochem. Cell Biol. 87: 799-815 (2009) doi: 10.1139/O09-062 Published by NRC Research Press, Introduction Regulation of chromatin structure plays an important role in basic cellular processes and its mis-regulation contributes to various diseases in humans (e.g., cancers and neurodegenerative diseases). The basic repeating [...]

External agricultural inputs such as mineral fertilisers, organic amendments, microbial inoculants, and pesticides are applied with the ultimate goal of maximising productivity and economic returns, while side effects on soil organisms are often neglected. We have summarised the current understanding of how agricultural inputs affect the amounts, activity, and diversity of soil organisms. Mineral fertilisers have limited direct effects, but their application can enhance soil biological activity via increases in system productivity, crop residue return, and soil organic matter. Another important indirect effect especially of N fertilisation is soil acidification, with considerable negative effects on soil organisms. Organic amendments such as manure, compost, biosolids, and humic substances provide a direct source of C for soil organisms as well as an indirect C source via increased plant growth and plant residue returns. Non-target effects of microbial inoculants appear to be small and transient. Among the pesticides, few significant effects of herbicides on soil organisms have been documented, whereas negative effects of insecticides and fungicides are more common. Copper fungicides are among the most toxic and most persistent fungicides, and their application warrants strict regulation. Quality control of organic waste products such as municipal composts and biosolids is likewise mandatory to avoid accumulation of elements that are toxic to soil organisms. Additional keywords: fertiliser, compost, manure, biosolids, pesticide, soil biology., Introduction Agricultural inputs External inputs to agricultural production systems include mineral fertilisers such as urea, ammonium nitrate, sulfates, and phosphates; organic fertilisers such as animal manures, composts, and biosolids; various [...]