Nutrient availability affects carbon turnover and microbial physiology differently in topsoil and subsoil under a temperate grassland

Increasing subsoil organic carbon inputs could potentially mitigate climate change by sequestering atmospheric CO2. Yet, microbial turnover and stabilization of labile carbon in subsoils are regulated by complex mechanisms including the availability of nitrogen (N), phosphorous (P), and sulfur (S). The present study mimicked labile organic carbon input using a versatile substrate (i.e. glucose) to address the interaction between carbon-induced mineralization, N-P-S availability, and microbial physiology in topsoil and subsoils from a temperate agricultural sandy loam soil. A factorial incubation study (42 days) showed that net losses of added carbon in topsoil were constant, whereas carbon losses in subsoils varied according to nutrient treatments. Glucose added to subsoil in combination with N was fully depleted, whereas glucose added alone or in combination with P and S was only partly depleted, and remarkably 59–92% of the added glucose was recovered after the incubation. This showed that N limitation largely controlled carbon turnover in the subsoil, which was also reflected by microbial processes where addition of glucose and N increased β-glucosidase activity, which was positively correlated to the maximum CO2 production rate during incubation. The importance of N limitation was substantiated by subsoil profiles of carbon source utilization, where microbial metabolic diversity was mainly related to the absence or presence of added N. Overall, the results documented that labile carbon turnover and microbial functions in a temperate agricultural subsoil was controlled to a large extent by N availability. Effects of glucoseinduced microbial activity on subsoil physical properties remained ambiguous due to apparent chemical effects of N (nitrate) on clay dispersibility

Reducing Global Warming and Adapting to Climate Change: The Potential of Organic Agriculture

Climate change mitigation is urgent and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. Agriculture, currently responsible for 20-30% of global greenhouse gas emissions counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO2 through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legumes leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning and the avoidance of synthetic fertilizers and the related production emissions from fossil fuels. Common organic practices also contribute to adaptation. Building soil organic matter increases water retention capacity, and creates more stabile, fertile soils, thus reducing vulnerability to drought, extreme precipitation events, floods and water logging. Adaptation is further supported by increased agro-ecosystem diversity of organic farms, due to reduced nitrogen inputs and the absence of chemical pesticides. The high diversity together with the lower input costs of organic agriculture is key in reducing production risks associated with extreme weather events. All these advantageous practices are not exclusive to organic agriculture. However, they are core parts of the organic production system, in contrast to most non-organic agriculture, where they play a minor role only. Mitigation in agriculture cannot be restricted to the agricultural sector alone, though. Consumer behaviour strongly influences agricultural production systems, and thus their mitigation potential. Significant factors are meat consumption and food wastage. Any discussion on mitigation climate change in agriculture needs to address the entire food chain and needs to be linked to general sustainable development strategies. The main challenges to climate change mitigation and adaptation in organic agriculture and agriculture in general concern a)the understanding of some of the basic processes, such as the interaction of N2O emissions and soil carbon sequestration, contributions of roots to soil carbon sequestration and the life-cycle emissions of organic fertilizers such as compost; b) approaches for emissions accounting that adequately represent agricultural production systems with multiple and diverse outputs and that also encompass ecosystem services; c) the identification and implementation of most adequate policy frameworks for supporting mitigation and adaptation in agriculture, i.e: not putting systemic approaches at a disadvantage due to difficulties in the quantification of emissions, and in their allocation to single products; d) how to assure that the current focus on mitigation does not lead to neglect of the other sustainability aspects of agriculture, such as pesticide loads, eutrophication, acidification or soil erosion and e) the question how to address consumer behaviour and how to utilize the mitigation potential of changes in consumption patterns

Global diversity and phylogeny of pelagic shrimps of the former genera <i>Sergestes </i>and <i>Sergia </i>(Crustacea, Dendrobranchiata, Sergestidae), with definition of eight new genera

We revise the global diversity of the former genera Sergia and Sergestes which include 71 valid species. The revision is based on examination of more than 37,000 specimens from collections in the Natural History Museum of Denmark and the Museum of Natural History, Paris. We used 72 morphological characters (61 binary, 11 multistate) and Sicyonella antennata as an outgroup for cladistic analysis. There is no support for the genera Sergia and Sergestes as they have been defined until now. We define and diagnose eight genera of the former genus Sergia (Sergia and new genera Gardinerosergia, Phorcosergia, Prehensilosergia, Robustosergia, Scintillosergia, Challengerosergia, and Lucensosergia) and seven genera of the former genus Sergestes (Sergestes, Deosergestes, Eusergestes, Allosergestes, Parasergestes, Neosergestes, and a new genus Cornutosergestes). An identification key is presented for all genera of the family Sergestidae. The phylogeny of Sergestidae is mainly based on three categories of characters related to: (1) general decapod morphology, (2) male copulatory organs, and (3) photophores. Only simultaneous use of all three character types resulted in a resolved tree with minimal Bootstrap support 75 for each clade. Most genera are interzonal mesopelagic migrants, some are benthopelagic (Scintillosergia, Lucensosergia), bathypelagic (Sergia), or epipelagic (Cornutosergestes). Within each of meso- and benthopelagic genera there is one species with panoceanic distribution, while most species ranges are restricted to a single ocean. The genera demonstrate two different strategies expressed both in morphology and behavior: protective (Eusergestes, Sergestes, Cornutosergestes, Prehensilosergia, Scintillosergia, Lucensosergia, Challengerosergia, Gardinerosergia, Robustosergia, Phorcosergia, Sergia) and offensive (Neosergestes, Parasergestes, Allosergestes, Deosergestes)

Registration in the Danish Regional Nonmelanoma Skin Cancer Dermatology Database: completeness of registration and accuracy of key variables

Anna L Lamberg1, Deirdre Cronin-Fenton2, Anne B Olesen11Department of Dermatology, 2Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, C, DenmarkObjective: To validate a clinical database for nonmelanoma skin cancer (NMSC) with the aim of monitoring and predicting the prognosis of NMSC treated by dermatologists in clinics in the central and north Denmark regions.Methods: We assessed the completeness of registration of patients and follow-up visits, and positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of registrations in the database. We used the Danish Pathology Registry (DPR) (n = 288) and a review of randomly selected medical records (n = 67) from two clinics as gold standards.Results: The completeness of registration of patients was 62% and 76% with DPR and medical record review as gold standards, respectively. The completeness of registration of 1st and 2nd follow up visits was 85% and 69%, respectively. The PPV and NPV ranged from 85% to 99%, and the sensitivity and specificity from 67% to 100%.Conclusion: Overall, the accuracy of variables registered in the NMSC database was satisfactory but completeness of patient registration and follow-up visits were modest. The NMSC database is a potentially valuable tool for monitoring and facilitating improvement of NMSC treatment in dermatology clinics. However, there is still room for improvement of registration of both patients and their follow-up visits.Keywords: nonmelanoma skin cancer, validation, database, positive predictive value, completenes